Journal of the Association of Teachers of Geology

Volume 7 Number 1 March 1982

NEWS 2 ARTICLES

Treasurer's Report, New Members, "Earth boundedness" in geological observation 16

Council 1982-83, Emergency Meeting of A.T.G., 16+ G.C.S.E. Geology Report 23

A.T.G. Annual Conference, Council Report, 16+ G.C.S.E., B.P. Studentship, Ecology and FIELDWORK 27

Evolution Conference, Remote Sensing Society Conference, Palaeontographical Society Annual REVIEWS

Volume. Open University T.V. Programmes 28

Clades!? 30

SHOPFLOOR 10 Books Received 33

Experiments in Structural Geology for 'A' Level 11 CPMMENT 35

TREASURERS REPORT 1980-81

May I first present apologies for the late appearance of this report. This is entirely due to the increased pressure of work in my new post and the simple fact that I have had less than two weeks of free time since March 1981. It was with some regret that I tendered my resignation from this post. I have enjoyed my contacts with both members and officers of this Asso­ciation, but I welcomed the generous offer by Stephen Alcock to stand for this office.

I am most grateful to Derek Ellis who has audited these accounts and, in his own meticulous way, has checked the financial record books and files at a time when his own school has been settling down after a recent re-organisation.

Subscriptions Journals Advertisements Slides Miscellaneous Balance from 1979/80

Postages Council Expenses

INCOME

EXPENDITURE

Journal Production etc. (Vol. 5) Refunds Telephones Photocopying etc. Miscellaneous

(including Promotions Group items)

Balance for 1981-82: £4,305.26

£ P 5,911.30

629.94 1,264.00

464.20 25.12

3,783.13

£12,077.69

£ P 708.74 621.07

5,369.61 69.05 56.33 99.39

848.24

£ 7,772.43

The Association is in better health financially than when took over in 1977 but, if this condition is to continue, it is necessary to review the level of subscriptions. The membership has almost doubled in that period, which has had important consequences, at least with regard to my own efficiency.

I would like to thank my former colleagues for their assistance and forebearance. I would also like to thank my long-suffering

2

family for their patience and their not inconsiderable generosity in terms of help and assistance. Finally, I wish all members of the Association the very best of good fortune and may they continue to enjoy the benefits of membership.

W.B. Whitfield

NEW MEMBERS MARCH 1982

Will existing Members in neighbouring establishments please make new members welcome by making contact with them and offering advice where appropriate.

Full Membership Mr K. BLAND, Saithborough School, Hook Road, Surbiton,

Surrey. Mr M.R. DE POMERAI, Hinchinbrooke School, Huntingdon,

Cambs. Ms J.M. HONE, Croesyceiliog Comp. School, Woodland Road,

Cwmbran, Gwent. Mr A. THOMAS, Dyson Perrins C of E High School, Yates Hay

Road, Malvern.

Student Membership Mr S.R. BLAKE, Department of Education, University of

Keele, Staffs. Mrs J.E. JONES, City of Liverpool College of Higher

Education, The Hazells, Prescott, Merseyside.

Foreign Membership Mr S FRID~IKSDOTTIR, Hjallabraut 11, 220 Hafnarfjordur,

Iceland.

D.B.T.

COUNCIL 1982-83

Nominations are invited for election to Council. Three vacancies arise by normal rotation, and expiry of term of service of Ordinary Members of Council. One vacancy exists for one year: it arose last year as a result of the change of function of members of Council, and has remained without nomination. Nominations, duly proposed and with the candi­dates written agreement (see Rule 12), should be sent to reach the Secretary as soon as possible (not later than the A.G.M.).

M.J.C.

EMERGENCY MEETING OF ATG

There will be an emergency General Meeting of the Associ­ation, to be held in the Conference Room, Park Site, St Paul and St Mary College, Cheltenham at 11.00 am, 8th May 1982 when a motion will be put to the membership of the Association to raise membership subscriptions from October 1982. As foreshadowed in the discussion at Liverpool at the AGM in September it will be moved that the new subscription rates would be:

Ordinary membership Student membership Retired persons' membership Institutional membership

£6.00 £3.00 £3.00

£12.00

This motion needs to be passed before the Annual General Meeting at the September Conference in order to print and ·distribute the new banker's order forms before 1 st October 1982.

Steve Alcock

l 3

A.T.G.

ANNUAL CONFERENCE

At a Council Meeting held at the University of Keele on Saturday 23rd January 1982 it was confirmed that arrange­ments had been made to hold the Annual Course and Con­ference at the Park Site of the College of St Paul and St Mary, Cheltenham, on Friday, Saturday and Sunday 10-12th September 1982. For the first time, the Conference was to run alongside two programmes planned in order to offer in-service help in teaching geological topics to local primary school teachers and local secondary science teachers.

D.B.T.

CLUES DOWN 1 His linked tabulate

(9,5,5) 2 Change steals shape 3 Trial well frame (4,3) 4 Devonian scouring - rush 5 Is close I 6 22 down's No 1 powder 7 Graded bedding? (4,6,9)

11 Possible origin of 10 across 13 Hollow with watery 21 down 1 5 Servile crustacean 16 Bflck-bending,lip-smacking

rock 18 Clays ... into silts 21 Levelled rock-waste 22 OHM; mixed resistance 23 Footsoiled 26 Aragonite variety (4,5) 27 Rugose septum 30 Get steamed-up with this

male 31 Ashy cinders 33 Colloquial seismic site 34 Molluscan muscle movement

CLUES ACROSS 1 Faulting rule of thumb

(5,2,3,9) 8 Typical clay scenery 9 Keel slat

10 Maxwell's hammer 12 Lava-remnants (perfect

specimens?) 14 Quick mile~tone 17 Dicky corundum 19 Small cone 20 Permian footprints helped

locate the marbles 24 Pre Cambrian forest 25 Frighten ing detail preserved 27 Jurassic scampi 28 Bones hidden in Kirkdale

(N. Yorks) 29 eg Harmotome (Hercynite) 32 Parts seldom preserved 35 Trilobite eye cover 36 Obsolete geology examiner's

occupation? 37 Stone idol 38 Ruin sail 39 Frodingham's important

deposit (5,4, 10)

Johnathan R.A. Le Vine, Head of Geology Dept., Hornsea School and Institute of Higher Education, Eastgate, Hornsea, North Humberside HU18 1DW.

)

COUNCIL REPORT

Report of Council Meeting, 7th November 1981 For some time Council has felt that members of the Asso­ciation should be kept better informed of the items and issues being discussed at its quarterly meetings. The following report will not attempt to provide a substitute for the minutes of the meeting, but rather report a variety of points that might be of interest to members. Many of the items will receive much more comprehensive treatment in the Journal at later dates, but for others this may be their only contact with a wide range of issues.

The meeting opened with the very sad news that Mrs Owen, the wife of the President-elect, had been killed in a motor accident in the early autumn, and that Professor Owen had been very seriously injured in the same incident. Professor Kelling had been in contact with Professor Owen shortly before the meeting and, on behalf of the Association, had expressed both our deepest sympathy and wishes for his own speedy and full recovery.

Council discussed the informal talks that had been taking place between the officers of the Association and those of the Geological Society concerning the possible benefits of some form of affiliation by the ATG. It was agreed to continue exploring the possibilities with a view of having a full proposal to put to the members at the AGM in September 1982.

David Thompson reported that Chris Wilson had been writing a joint paper concerned with the role of curriculum develop· ments in relation to the Earth Science, within the general framework of the Schools Council Science Curriculum Study Review. The document was to be circulated for discussion via the constituent bodies of RSSESEC, before any action was to be taken to implement its proposals.

, A further development in which the Association has become involved is the proposal of a syllabus for a DES Regional Course in the summer of 1983. This course is to be aimed at LEA inspectors and Heads of Science and will pay particular reference to Earth Science for the 11 to 14 years age group. Initial ideas are being collated by the Chairman of the Cur­riculum Working Group with a brief to make a submission to DES by mid-January 1982.

Mr Gordon Margretts has kindly agreed to act as Director for the 1982 A TG Annual Course and Conference to be held at the College of St. Paul and St. Mary, Cheltenham. In addition to the normal full programme of workshops, lectures and field excursions, it is hoped to arrange a series of meetings con~ centrating on the geological content of Science courses in the Lower Secondary and Upper Primary age groups. Besides being open to ATG members these meetings would be avail­able to ASE members and other interested teachers in the local area.

A further working party is preparing comments on behalf of the Association concerning a document entitled 'Advanced Level Core Corriculum in Geology'. This is in response to a request by the London Examinations Board for our views on this matter as a subject association.

4

-As a result of rising postal charges and a steady increase in production costs of the Journal, the Treasurer is likely to have to recommend a modest increase in subscriptions in the next year. The Editor also warned of problems being experienced in the editing and preparation of the journal for printing. Council agreed to give this problem its urgent attention, and Dr Standley offered to investigate the possibility of a team at the City Polytechnic carrying out at least part of the preparation of the journal on a regular basis.

News from many of the Local Groups' was rather depressing, with many having to cancel meetings. Indeed Chairman of ATG's own Working Groups were reporting very low atten­dance at Conference meetings. Some council members questioned the 'image' of some Working Groups, and ex· pressed the view that far too many members at Conference were apparently unaware that they would be very welcome at any or all of the meetings of the Groups. Possible changes of the name of some groups was discussed in order to reduce their possibly 'exclusive' image, as was a change in the timing of their meetings at Conference. The activities of the Pro­motions Group provided one of the few bright spots, with a steady increase in the range of items offered to members, and the hope of further items being produced by the 1982 Conference.

The next meeting of Council was arranged for 23rd January 1982, (and then one after that for early May. Ed) so, if you have any views or items that you want to being to our atten­tion, send them to the Secretary well before that date.

John Aram

• mnemonics ••••••••

Geological Periods and Epochs China Owls Seldom Deceive Clay Pigeons. They Just Chase Past Each Other Making Preposterous Puns.

Mohs' Scale of Hardness Tall Gyroscopes Can Fly Apart Orbiting Quickly To Complete Disintegration.

Can any members supply further useful examples of geological mnemonics?

(after South Australia Earth Science/Geology Newsletter No 9 1981 and the Geology Newsletter, New South Wales Museum).

• D.B.T .••••••••••••••

FIFTH MEETING OF THE GEOLOGICAL SOCIETIES OF THE BRITISH . ISLES This meeting will take place at the University of Glasgow on 23-26 September 1982.

The Provisional Programme is as follows (symposia last for the whole day unless stated otherwise):

Thursday 23rd 1. Palaeontological Association and Liverpool Geological

Society (2 days): Fossils and climate.

2. Petroleum Geochemistry Group (2 days): Petroleum geochemistry and exploration of Europe.

3. Yorksh ire Geological Society (morning): The geology of the Northumbrian trough.

4. Institution of Mining and Metallurgy: Geophysical methods in the search for metalliferous mineral deposits.

5. Marine Studies Group: Current offshore research.

6. Metamorphic Studies Group (sponsored by the Geo­logical Society and Mineralogical Society): Fluids in metamorphism.

Evening: Reception by Glasgow Corporation

Friday 24th 1. Palaeontological Association and Liverpool Geological

Society - continuing from Thursday.

2. Petroleum Geochemistry Group - continuing from Thursday.

7. Geologist's Association: The geology of Southeast England.

8. Joint Association for Geophysics (sponsored by the Geological Society and the Royal Astronomical Society): The deep geology of Scotland.

9. Mineral Deposits Studies Group: Sediment-hosted stratiform metalliferous ores.

Evening: Reception by the University of Glasgow

Saturday 25th 10. Quaternary Research Association: The glaciation of

Scotland.

11. British Micropalaeontological Society (morning): The micropalaeontology of Southeast England.

12. Earth Science Education Methods Group (morning): Innovations in Earth Science teaching.

13. Geological Information Group (morning): Geological information on hydrocarbon exploration on the UK continental shelf.

14. Mineralogical Society (morning): Scottish Mineralogy.

15. Clay Minerals Group of the Mineralogical Society, and British Sedimentological Research Group (afternoon): Clay minerals in recent sediments.

16. Geological Society of Glasgow (afternoon): The Ordovician of the Midland Valley of Scotland.

17. Institution of Geologists: (afternoon): Geology and Conservation.

Sunday 26th Excursions - details to be given later.

5

The meeting is organised by the Geological Society of London and the Department of Geology, University of Glasgow. Enquiries about a particular symposium should be addressed to the secretary of the society involved. Enquiries of a more general nature should be sent to: Dr W.E. Tremlett, Depart­ment of Geology, The University, Glasgow G12 800. Accommodation will be available in single rooms in University Halls of Residence, a short walk from the lecture rooms at the following costs: Bed and Breakfast - £8.50 per night, D'inner - £3.00 per night. Transport to Glasgow by British Rail will be at concessioriary fares. Registration forms will be dis­tributed in March 1982, mostly through geological societies of the British Isles. The cost of registration will be £4.00 per day (Thursday to Saturday) or £10.00 for the full three days. These costs will be halved for persons producing evidence that they are full-time students (undergraduate or postgraduate).

TELEPHONE Management (0305) 786911

23 Kirtleton Avenue WEYMOUTH

Dorset DT4 7PS

At Hotel Sunnywey we specialise in accommodating field study groups and educational parties. We will arrange meal times, menus and provide facilities to suit your own requirements.

HOTEL AMENITIES INCLUDE * Full Central Heating * Choice of Varied Menus * Study or Lecture Room * Generous Portions * Bar - Licensed or Soft * Fresh Meat & Vegetables * Lounge with Colour TV * Comfy Beds - Bedside * Parking for Cars/Coaches Lamps

* Razor sockets & Radios

WEYMOUTH is central for visits to Portland - Chesil Beach - Lyme Bay - Swanage Kimmeridge Oil Wells -Purbeck Hills.

Write or telephone for brochure and terms to:

Mr & Mrs G. T. DALLEY

16 + G.C.S.E.

Southern Examining Group A.T.G. member Mr G.J. Sparks of Park Barn School, South· way, Guildford, Surrey is the Reviewer for the Southern Regional Examinations Board's Mode 1 examination in Geology. We are pleased to report that he has been accepted to serve on the Southern Examining Group's Science Umbrella Panel to represent the interests of geologists as well as interests common to all science teachers. He will keep council informed of developments.

Midland Examining Group The Working Party set up to produce an interim report on the 16+ in Geology has completed its work as far as possible in the short time it was allowed. The report, which appears elsewhere in the journal, has been circulated to all schools in the Group's area and comments on all aspects of the document have been invited.

N.W.D.

THE DIRECTOR WAS A BRICK

Ramsay, while a Director of the Survey, held also a Professor's Chair. At the end of a lecture, it was his practice to speak a few rapid, colloquial words about the specimens on the table. One morning, before he came in, a student to take a rise out of the Professor substituted for one of them a bit of an old brick. Ramsay lectured, and then turned to the specimens. "This, Gentlemen, is a piece of granite, this is a piece of Vesuvian lava, this" (with a moment's pause at the brick) "this, Gentle­man, is a piece of impudence".

Told by E. Greenley 1938 "A land through time" Vol. 11. p. 481. London, Murby.

BSc Honours Degree in EARTH SCIENCES

with options in: GEOLOGY & ENVI RONMENT

GEOLOGY APPLIED GEOLOGY

The degree in Earth Science is part of the Modular Course at Oxford Polytechnic. Students specialise in one of the above options, each of which contains a wide choice of modules. The Modular Course gives the individual student considerable freedom to choose his own programme of study and to change it as his knowledge increases and interests develop. Currently over 500 modules are offered by the Polytechnic, and students are encouraged, as part of their degree pro­gramme, to select a number of modules from outside their immediate study area.

GEOLOGY in the BA, BSc, BEd Degree and Honours Degree and DipHE Modular Course

The Modular Course also offers the single field of GEOLOGY which is studied in combination with anyone of the following fields:

Accounting & Finance. Anthropology. Biology. Studies. French Language & Literature. Cartography. Catering. Computer Studies. Geography. German Language & Contemporary Economics. BEd: Nursery & First School. BEd: Studies. German Language & Literature. History. Junior & Middle School. Education. English History of Art. Law. Mathematical Studies. Literature. Environmental Biology. Food Science & Music. Physical Sciences. Politics. Psychology. Nutrition. French Language & Contemporary Sociology. Visual Studies

The Department of Geology & Physical Sciences has well-equipped geology laboratories located in the modern Science block on the main Headington site overlooking the City of Oxford. Earth Sciences and Geology students attend a number of field courses during the vacations and also undertake a period of independent geological mapping during the long vacation between the second the third years of the course. In addition, Earth Sciences students are required to undertake a project directly related to their chosen option.

Prospectus, course booklet and application form from: The Registry, Room 364, Oxford Polytechnic Headington, Oxford OX3 OBP.

6

S.P. STUDENTS HIP

BP TO FUND CENTENARY STUDENTSHIP

A new three-year studentship is being offered by the Natural History Museum to enable advanced specialist study of lichens and their rock hosts. The studentship is being funded by British Petroleum to mark the centenary of the Museum at South Kensington. The study will be important in refining ways in which lichens can be used to discover more about rock chemistry and its interaction with the botanical environment. Lichens are already recognised as important indicators of air pollution, and it is hoped that this study will establish further uses. The full title of the project is "The dependence of saxicolous lichen floras on host rock chemistry". Botanists are invited to apply before 15th March. (When are geologist­biologists invited to apply! Ed.)

A NEED FOR GEOLOGICAL

EDUCATION

**** "Last year Cardowan (the colliery at Stepps near Glasgow, Ed.) was scheduled for closure, but then reprieved as part of a national compromise package between the union and the Coal Coal Board in the face of a strike threat.

Its future has been in question since because of the difficulty in producing coal from thin limestone seams, and the high level of methane - the highly-inflammable gas which results from the bacterial decay in the cellulose elements in vegetable matter'~ ..

"There is so much methane in the pit that it is pumped to a large distillery nearby, where the gas is used as a valuable souce of energy. ,,*

Before commenting on the newspaper account quoted above, I am sure that all members of ATG would wish to join me in recording sincere condolences to the injured and to the relatives of those killed in this disaster.

After reading the account, ATG members and their students are invited to discuss and enlarge upon the geological context of the disaster and to reflect on the typically unknowing journalistic licence, if not to say inaccuracy, displayed in the report.

* From the Guardian, 28th January 1982, p. 8. cols. 4 and 5.

D.B.T.

7

ECOLOGY AND EVOLUTION

The Institute of Biology (EDUCATION DIVISION and NORTH WESTERN BRANCH) with The Association of Teachers of Geology present a one-day conference:

ECOLOGY AND EVOLUTION

Biologists and Geologists examine topics of common interest. Talks on marine ecology and evolution will introduce the discussion.

Saturday 24th April 1982,10.00 - 16.30 at Manchester Polytechnic, All Saints Lane, Manchester.

Non-members are welcome to attend and teachers are asked to invite enthusiastic sixth form students, as all the talks should be of value to those on A-level courses in Biology and Geology. Please apply to Education Division, Institute of Biology, 41 Queen's Gate, London SW7 5HU.

PROGRAMME 10.00 Introduction - Biology and Geology in Education

P.R. Booth H.M.I.

10.20

11.05

11.35

12.20

12.45

2.00

2.45

The present as a key to the past John Hawthorn Purbeck Marine Reserve (A consideration of the ecology of this unique coastal and underwater reserve)

Coffee and fi Im: Living sediments, prelude to palaeoecology

The ecology of fossil bivalves in shallow water Dr J.E. Pollard Department of Geology, University of Manchester

Discussion

Lunch

A biologist looks at the palaeontological evidence for evolution Dr P.H. Greenwood British Musuem (Natural History) London

The interpretation of human fossils Miss T.I. MOllesan British Museum (Natural History) London

3.30 Discussion and tea

4.30 Conference closes

Chairmen: Professor G. Kelling (A.T.G.) Dr G. Beedham (1.0.B. Education Division)

Registration. There will be a conference fee of £ 1.50 to be paid in advance. This is to cover coffee and tea and adminis­trative costs. However students may attend at the reduced fee of 50p.

Lunch. A range of lunches from simple snacks will be available at the Polytechnic. Please indicate on the form if lunch is required.

REMOTE SENSING

The Education Committee of the Remote Sensing Society is organising a one day conference on Wednesday 19th May 1982 with the title: "Low Budget, Cost-Effective Research and Teaching Methods in Remote Sensing". The venue is the Department of Geography, University of Nottingham.

The object of this conference is to discuss a variety of low cost field, analytical and interpretational techniques applicable to the remote sensing of environmental data. A full programme of papers, demonstrations and exhibits has already been assembled. Further details from: D.J. Carter, Senior Lecturer in Geography, Portsmouth Polytechnic, Remote Sensing Society, clo Department of Geography, University of Reading, Earley Gate, Reading RG6 2AU, Berkshire.

PALAEONTOGRAPHICAL SOCIETY ANNUAL VOLUME 134

The Palaeontographical Society's 134th Annual Volume for the year 1980 was published in October 1981. It contains two parts. They are:

No. 559. British Wenlock trilobites, Part 2, by A.T. Thomas. The second Part of this monograph deals with 24 named species and subspecies (4 new) and 24 forms under open nomenclature. They are assigned to 22 genera referable to the Cheiruridae, Encrinuridae, Staurocephalidae, Lichidae and Odontopleuridae.

No. 560. The Ammonoidea of the Plenus Marts and the Middle Chalk, by C.W. Wright and W.J. Kennedy. This monograph, describes the ammonite fauna of the Plenus Marls and the Middle Chalk (Upper Cenomanian and Turonian) which consists of 49 species and subspecies (8 new) referable to 27 genera. This description provides a basis for the revision of the ammonite zonation of the Upper Cenomanian and Turonian of Great Britain and for the correlation with the sequences in the Paris Basin and the stratotype areas in Sarthe and Touraine.

The price of Volume 134 is £36. Separate parts may be purchased singly. For membership details (the 1982 sub­scription rate for individuals is (13) write to F .G. Dimes, Palaeontographical Society, clo Institute of Geological Sciences, Exhibition Road, South Kensington, London SW7 2DE.

8

Bude - Cornwall

GEOLOGY FIELD STUDY COURSES SEPTEMBER AND OCTOBER

* A.A. Listed Accommodation * Full Course Programme Prepared * Ideal for '0' and 'A' Level Students * Mini-Bus, Lecture Facilities * Video Films * Protective Helmets * Full Central Heating * Drying Facilities And Study Room * Just Minutes From Shore-Line Exposures

11

** Complete Course and Full Board £50 plus V.A.T.

20 Schools And Colleges Stay With Us Each Year, Great Home Cooking, Hospitality And Comfort.

Excellent Sedimentary And Structural Geology. Plus, Granite, Volcanics, Hanging Valleys, Sub-Glacial Channels And Till; Raised Beaches, Permo-Trias Breccia - All Within 18 Miles And Amidst Magnificent Scenery.

So Why Not Come To North Cornwall For Your Next Field Study Trip - It's Our Business To Look After You.

Details From: Nick Cole, Shoreline Holidays, Downs View, Bude, Cornwall. EX23 SRG. Tel. (0288. 3134.

New Geology Books from Alien & Unwin

Metamorphic geology An introduction to tectonic and metamorphic processes Con Gillen, University of Aberdeen

In this concise introduction to metamorphism - the 'haunted wing' of geology- the author aims to demonstrate that the subject isn't so difficult to understand after all The emphasis is on processes, with due attention to products, in the context of tectonics and mountain building, and the links between orogeny and metamorphism are made clear. Minerals and rock textures are carefully introduced to illuetrate how they can be used to deduce the history of formation and evolution of a metamorphic rock in the Earth's crust Each chapterpQncludes with a summary and a few exercises. The treatment is fully illustrated with maps, diagrams and photographs. Examples are taken from many countries. ~ May 1982 160 pages 51 line & 18 tone illustrations 0045510571 Hardback£10.00 004551058 X Paperback£4.95 Special topics in geology: I

Sedimentary structures J.D. Collinson, BNOC and D. B. Thompson, University of Keele

This book provides a comprehensive field-and laboratory-orientated account of sedimentary structures, thereby filling a conspicuous gap in the sedimentologicalliterature. Contents Introduction to the study of sedimentary structures; Bedding; Basic properties of fluids, flows and sediment; Erosional structures; Depositional structures in muds, mudstones and shales; Depositional structures of sands and sandstones; Depositional structures in gravels, conglomerates and breccias; Depositional structures of chemical and biological origin; Structures due to deformation and disturbance; The study of assemblages of structures. July 1982 240 pages 109 line & 89 tone illustrations 0045510178 Hardback£18.00 0045510186 Paperback£8.95

The Lake District The Cumberland Geological Society

Visited by hundreds of thousands each year, the Lake District is an area of natural beauty which also has much to fascinate those with an active interest in rocks and fossils, and this book provides a reliable field guide to many of the important localities. Written by members of the Cumberland Geological Society, it covers a wide area and takes in rocks ranging in age from Ordovician to Pleistocene. There are 13 self­contained itineraries which are fully illustrated with maps, diagrams and photographs. A general introduction presents the geological history of the area and a glossary of specialised terms will help those with little knowledge of the subject April1982 144 pages 30 line & 25 tone illustrations o 04 554007 1 Unwin Paperback £3.95 Rocks and Fossils: No. 4

Introduction to small-scale geological structures Gilbert Wilson, formerly, Imperial College, London (in collaboration with John Cosgrove)

Small-scale structures have been relatively neglected in general texts on structural geology. This book deals with them in full and thereby provides a concise and authoritative treatment of a subject important to all students of structural geology. Contents Introduction; Stress and strain; Structural symmetry; StruCture and stratigraphical succession; Structures in brittle rocks: tension fractures and shear zones; Rock cleavage and schistosity: generalities; Fracture cleavage and strain-slip cleavage; Flow cleavage, schistosity and lineation; Boudinage; Drag-folds and parasitic folds; Mullion and rodding structures; Superposed minor structures; Minor structures and large-scale tectonics; Conclusions. May 1982 160 pages 49 line & 6 tone illustrations 0045519512 Hardback£10.00 0045519520 Paperback£4.95

Sedimentology: process and product M.R Leeder, University of Leeds

This major new text provides a unified treatmept of the whole of sedimentology. The artificial division between carbonate and clastic studies has been eschewed in favour of a general approach rooted firmly in the basic sciences. The whole book is organised around the logical progression from the birth of grains to their cementation in sedimentary rock and it integrates qualitative and quantitative approaches at every opportunity. It is profusely

. illustrated with almost 400 line drawings and photographs, and each chapter is accompanied by a helpful summary of its content and a guide to further reading. Apr.il1982 384 pages 349 line & 44 tone illustrations 0045510539 Hardback£25.00 0045510547 Paperback£11.95

The Peak District LM. Simpson, University of Manchester

This third book in the Rock & Fossils series covers the geology of a popular national park close to several large conurbations. Like its companion volumes, it will provide the student, amateur geologist and enquiring general reader with an authoritative, concise and portable field companion to their enjoyment of part of Britain's countryside. The book includes 15 itineraries in localities where geological features are particularly well displayed April 1982 128 pages 17 line and 61 tone illustrations o 04 554006 3 Unwin Paperback £3;95 Rocks and Fossils: No. 3

These books are available from all good bookshops. In case of difficulty they can be obtained direct from Alien & Unwin Please apply to the address below, enclosing your remittance. Please add £0.75 per order for delivery charge. Geo~ George Alien & Unwin, PO Box 18, Park Lane, Hemel Hempstead, Herts HP2 4 TE.

Alle win E

9

r 1 ti ." !It 'f •• f]l :r j - 1 i AlIi n

EXPERIMENTS IN STRUCTURAL GEOLOGY FOR 'A' LEVEL 11

Peter Hendry, in his second contribution on the teaching of structural geology, discusses the development, shape and characteristics of folds and associated structures in bedded rocks as illustrated by the use of plasticine, putty and card-pack models.

Introduction The use of plasticine and putty as well as card decks to il­lustrate concepts of structural geology in the laboratory is not new. Both Ramsay in "Folding and Fracturing Rocks" (1967) and the Open University (1972) in the second level textbook "Internal Processes" have made use of such materials. In this article, concepts and models are introduced in order to demon­strate how structural relationships can be illustrated in the classroom.

Equipment and materials The following materials are required:

Sheet of glass approximately 50 x 50 cm (or any flat polished surface) 1 Kg linseed oil putty 1 Kg plasticine Two pieces of wood approximately 30 x 6 x 2 cm

glass sheet

putty

"bedding plane"

/1'l:i(:!I,': [(l~.'

r'~------'\---~-----lll{"~ Il----------\" ~r

--r-------'~_II~;:;l~l ---jL----~.-----l['Jiih. --+------\---1!~lI';; I -+------+-..f.·li~li' --t-------I---l{'lll:

-~-_____7'_'--__j~\~[j;: ---""-,--~--~[·:il" ----1-----4, .. ,\ ---+-------l:'!(;;j!

·i; ~!i'I~! circular imprint from base of can

1:1"1 :

(a) Undeformed model

wood

plan view

!IT § 12

Pack of playing cards Knife Tin can (pepsi-cola or equivalent) Biro end with plastic insert removed Water

Model One This model introduces the concept that rocks of uniform composition and mechanical properties can be compressed and strained without faults or folds developing. A calculation for strain is also discussed.

Method: Place the sheet of glass on a level surface and lubricate the upper surface with a few drops of water. Mould some putty into a block about 10 cm square and 1 cm thick and place it onto the glass (the water will prevent the putty sticking to the glass). On the putty surface impress a circle using the base of the tin can and with the knife cut some parallel lines into the putty, ensuring that these cuts merely scratch the surface. The lines represent bedding planes, while the circle is used as a strain marker (Fig. 1 a). The circle indicates that the putty is unstrained, whereas it changes into an ellipse on being strained (Fig. 1b). In nature, the circle may represent a spherical pebble, an oolith or an undeformed fossil.

Using the two pieces of wood, compress the sides of the putty so that the block is shortered by about 20% in width Le: from 10 cm to about 8 cm. After compression, the circle has

glass sheet

strain elli"pse

(b) Deformed model

6 min

6 min

undisturbed "bedding plane"

long axis

Figure 1. Model One before and after deformation (not to scale)

10

deformed to an ellipse, the long axis of which is perpendicular to the maximum compressive stress direction (8 maxI (Fig. 1 b).

The length of the long axis compared to its original length is directly related to the amount of resulting strain. This ellipse is therefore known as a strain ellipse, and the amount of strain can be measured.

The percentage of strain on a line (e%) can be calculated as follows:

e% = present length (L1) - original length (La) x 100%

original length (La)

., ........ (I)

Pupils can therefore measure the length of the putty sheet before and after deformation and therefore calculate the strain (e%). This value can then be compared with the strain measured on the ellipse axes.

E.g. Strain of ellipse long axis

length of long axis - diameter of original circle _________________________________ x 100%

diameter of original circle .......... (iil

Eg. Strain on ellipse short axis

length of short axis - diameter of original circle __________________________________ x100%

diameter of original circle

6cm

I 1 cm

I 6cm

1 14 cm

(a) UNDEFORMED MODEL (plan view)

... ,' ..

.......... (iii)

Putty

Plustl< ine

Putty

Notice that for (ii) the strain has a positive value because of extension, and for (iii) the strain has a negative value because of shortening. However for both (ii) and (iii) the percentage strain obtained should be similar.

Fig. 1 b also demonstrates that the bedding itself is shortened and thickened while the bedding planes remain undisturbed Le: no faulting or folding has occurred. The putty has behaved like a homogenous rock, for example a thick mudstone unit in which there are no layers of varied composition nor any bedding plane weaknesses. (If the lines cut into the putty are too deep, then the putty does not remain homogenous and the lines or 'bedding planes' may fold, thus simulating what can happen to a laminated shale, for example).

Although no folds are produced, a common structure that can develop under these conditions is cleavage. As the circle is converted into an allipse with its long axis orientated normal to the maximum compressive stress, so original particles in a rock (e.g. qtlartz grains) can be flattened into lenses where the long axes are all parallel. (Mica flakes would rotate from their original position to become perpendicular to the maximum compressive stress). Thus the rock will split preferentially along, rather than across the grains, giving the familiar cleavage of slate. The relationship between cleavage and the strain ellipse is very well illustrated by many roofing slates in North Wales. These commonly contain green "reduction spots" which were originally spherical but which were subsequently distorted during the conversion of the mud stone into slate, so that their long axes lie parallel to the cleavage.

Model Two This model introduces the concepts of competence contrast and folding due to compression.

Method: Arrange the putty and a strip of plasticine as indicated in Fig. 2a. The putty - plasticine multilayer should be at least 2 cm thick in order to avoid complications. Using the wood, sqeeze the sides of the multi layer so that it is shortened to

develupment uf (uncentric folds in plasticine layer

---dpprox 9 cm ---I

(b) DEFORMED MODEL: Showing concentric fold in competent plasticine layer

Figure 2. Model Two before and after deformation (not to scale)

11

1[1Id LIi

37 cm

0000000000 0 0 00000 00 0 0000 00

~" 0 0 ~ 0 Si 0 _0 0 0 C! 0 0 0 Q 0 R 0 0 0 0 0 0 Q 0 0 q,

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Competent - plasticine layer

(with bedding plane cut)

o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ° 0 o. 0 ° 0 0 0 0 0 D 0 0 0 0 0 0 0 0 0

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00000000000000000000000000000000

the multllayer should be about 2 cm thick and placed on the lubricated glass surface.

Figure 3a. Model Three: un deformed model; preparation for use

about 9 cm. Carefully observe what happens to the plasticine layer (Fig. 2b).

In the first model, the homogenous putty layer deformed only by a change of shape. However, when a layer of different mechanical properties is introduced, compression along the layering will induce folds Two key points are illustrated. Firstly, the plasticine is more resistent to compression and be referred to in this context as a competent material (Iow ductility, high viscosity, high rigidity) whereas the putty deforms easily and is said to be incompetent (high ductility, low viscosity, low rigidity). It is the competent layer which folds, the incompetent material flowing passively in response. Secondly, the (orthogonal) plasticine layer deforms into folds in which the bedding thickness remains constant from hinge to limb. These are concentric, parallel or buckle folds which have very different characteristics and modes of origin to similar folds as produced in Model Four.

Model Three This model illustrates many features associated with the compression of a sequence of competent and incompetent layers.

Method: Arrange the putty and plasticine on the glass sheet as indicated in Fig. 3a. Lightly cut 'bedding planes' at regular intervals into each material and using the biro end lightly mark on cicles, ensuring that some circles are marked across the boundaries between the competent and incompetent layers. Using the pieces of wood, compress the sides of the multilayer so there is about a 15% shortening. ie. from 37 cm to about 32 cm. The results of this compression are illustrated in Fig. 3b.

In examining this deformation the following features can be observed and explained:

1. Because the multilayer comprises alternating competent and incompetent layers the folding which takes places is controlled by the competent layers which buckle whilst the incompetent material moves passively into spaces between the competent layers.

12

2. There is no change in the orthogonal thickness of the folded competent layers i.e. parallel or concentric folds have developed (see Model Two). However, in the incompetent layers, the orthogonal thickness does vary; it is thicker in the hinge area and thinner on the limbs of the folds. Although these resemble similar folds (see Model Four) the bedding thickness parallel to the axial plane is not truly constant. Such folds are merely produced by the flattening of concentric folds.

3. The fold axial traces (lines joining points of maximum curvature in consecutive layers) are approximately normal to the maximum compressive stress which was applied to the multilayer.

4. The competent layers have responded differently to the same amount of compression. In the thicker layer a single fold has developed with a large wavelength whilst in the thin layer, there are three folds with small wavelengths. These differences can· be explained in a simplified way in terms of a formula which states that the wavelength (Wd) of a bucklefold is theoretically a function of:

(a) the thickness (t) of the competent layer and:

(b) the ratio of the viscosity of the competent layer (P1) to the viscosity of the incompetent layer (P2)'

Wd

.. ........ (iv)

In the experiment, the viscosity ration~ for each layer is P2

constant as plasticine and putty are used in both cases. There­fore, the wavelength of the competent layer is a function of the thickness of the layer i.e. the thinner the competent layer, the smaller the wavelength of the folds which will develop. From this it is seen that thin layers with many folds

o

dlsplactd strain ellipse showing flexural slip

10 cm

long axis of strain ellipse parallel to layering

long axis of strain ellipse normal to layering

-:s:~~~"",,~*-_'ong axis of strain ellipse at on acute angle to the axial plane trace.

'saddle reef'

(drawn from photogroph of actual model)

Figure 3b. Model Three: the result of deformation of the multi layer

are NOT necessarily more strongly deformed that a broadly warped thick layer.

5. Because the number and wavelengths of folds in the two competent layers are different, the folding can be described as disharmonic. However, it is seen from the sketch that to some extent the layers have responded together and have been deformed into a broad open fold. This occurs because the zones of strain surrounding each layer slightly overlap and composite folding results. If the two layers are more widely separated by putty so that there is no overlap of their zones of contact strain, they will fold completely independently of each other according to the formula (jv) above.

If they are more closely spaced, there is considerable overlap of the zones of contact strain and the layers fold exactly together to form harmonic folds; the wavelengths of these folds will then no longer be controlled by the formula in any simple way.

6. A study of the long axes of the strain ellipses in the thicker competent layer reveals a distinct orientation pattern. In the outer arcs of folds the long axes are parallel (tangential) to the layering indicating that extensional strain has occurred. In nature, tension cracks may occur which are normal to the layering and strike parallel to the intermediate principal stress (Fig.3c).

In the inner arcs, the long axes of the strain ellipses are normal (longitudinal) to the layering, indicating that the maximum compressive stress was parallel to the layering. In nature, this can lead to the development of thrusts (see Hendry 1980). A good example of this can be seen at Broadhaven, Pembroke­shire, where competent sandstones of Carboniferous age have

13

been folded and subsequent continued stress has caused a thrust to occur. Above this thrust, minor conjugate thrusts have developed on the inner arc of the competent sandstones (Fig. 3d).

o minimum o in termed iate

IrJ i / I

tension joints

o minimum o intermediate

Figure 3c. Development of tension joints in the outer arc of a fold, with principle stress axes shown.

Therefore, during the deformation of the competent layer, as illustrated in Model Three, contemporaneous compressional and tensional forces were in operation. This mechanism, which produces a buckle fold, is called tangential longitudinal strain.

.'

. ~. . ",

r::::::::::::1 Sandstone -ne •••••

0 Srn.

I I

Figure 3d. Conjugate thrusts resulting from longitudinal strain on the inner arc of Carboniferous sandstones, Broadhaven, Pembrokeshire. (Grid reference 860413 Sheet 157; vie"w looking east)

7. In the competent layer, the long axes of the ellipses of compressional strain converge towards the inner arc from the outer arc of each fold. If slaty cleavage had developed parallel to the long axes of the ellipses (Model One) then a convergent cleavage fan would have formed.

8. In part of the incompetent material, the deformation tends to be more homogenous (Model One). This can be observed by noting that the strain ellipses have similar shapes and are uniformly orientated. However, the strain is markedly inhomogenous near to the competent layers in the area where curvature of the competent layers is greatest. Here the long axes of the ellipses are not normal to the maximum com­pressive stress but have been rotated to be at acute angles to the axial plane trace. This is the result of the combination of flexural flow (simple shear on a microscopic scale) in the incompetent layer and flexural slip (simple shear on bedding planes: see point 9 below) between the competent and in­competent layers.

14

The sense of rotation of the ellipses is different on either side of the fold axial trace because of the opposite sense of simple shear in the two halves of the fold. Therefore, a divergent cleavage fan would form if slaty cleavage developed parallel to the long axis of the strain ellipse and consequently, in a sequence of competent and incompetent beds, cleavage refraction will occur.

9. Flexural slip (bedding plane slip) occurs along the bedding surfaces between the competent and incompetent beds. This is recognised on Model Three (Fig. 3b) by the way in which strain ellipses are displaced across the layer boundaries of the thicker competent layer. The sense of displacement is opposite on different sides of a fold and the amount reaches a maximum near the mid-points of limbs and is zero in the hinges.

Bedding plane slip can produce slickensides on the bedding surfaces in the fold limbs (Fig. 3f),

SlIckensldes on flexural slip surfaces dyIng out In fold hInges

Figure 3f. The development of slickensides on flexural slip surfaces

10. In the hinge area of the folds of the multilayer, the bedding planes have opened up to give arcuate fissures be· tween the competent and incompetent material. This may also occur within the incompetent layer if the bedding plane cuts are deep. In nature, the features are termed saddle reefs and are usually infilled with secondary minerals.

Model Four This model introduces the concept that beds can undergo folding by shear processes whilst homogenous flattening is taking place independently. The folds produced in this way are termed similar folds and are fundamentally different to concentric folds produced by lateral compression (Model Two and Model Three).

Method: Take the pack of cards and mark some parallel lines across one of the sides to represent bedding planes (Fig. 4a). Holding the cards, push the bottom of the pack with a finger so the 'beds' become folded (Fig. 4b).

The bedding planes have folded without lateral compression, a process referred to as shear folding. Here folds have formed by minute shearing movement along planes. It was thought that these shear planes are the visible cleavage planes that develop but in fact there is no simple relationship between them; this aspect is beyond the scope of an "A" level course.

Figure 4. Model Four: formation of shear folds using a pack of cards

15

thickenIng of bed in /'~ hinge area of fold

constant thIckness of bed --- - parallel to the axial plane

thInnIng of bed -- in fold 11mb

axial plane

Figure 4c. Characteristics of a similar fold

The fold type produced is a similar fold, characterised by bedding maintaining a constant thickness when measured parallel to the axial plane, but when measured normal to the layering, bedding is thickened in the hinge area and thinned on the limbs. (Fig. 4c) True similar folds are in fact rare in nature occuring in glaciers and salt domes, but folds approaching a ' similar type (strictly "flattened concentric folds") are common in shales folded between sandstones or limestones (Model Three, point 2).

Conclusions and Discussion It should be noted that the models demonstrated can be modified. For instance, in Model Three, the thicknesses of the competent and incompetent layers can be varied and resulting effects noted. Another possibility is to adapt Model Two to produce a boudinage structure. This can be achieved by cutting the plasticine layer into blocks each block about 2 cm wide and applying pressure normal to the layering. (The 'crack' between each block would represent a joint). The competent blocks will separate and the incompetent material will flow into the spaces between the segments. These seg­ments are called boudins and are indicative of large tensile stresses which are built up parallel to the competent and incompetent layers.

References Hendry, P.J. 1981. Simple apparatus for teaching structural geology. Geology teaching 6 (3), 101-4. Open Un iversity 1972. Geology: Internal Processes. (Science: a second level textbook) pp. 78-84. inc. p. 93. PP. 96-101 inc. Milton Keynes, Open University Press. Ramsay, J.G. 1967. Folding and Fracturing of Rocks. New York, McGraw-Hill. Standley, R.C. and Hossack, J.R. 1981. An updating in Structural Geology. Geology Teaching 6 (1) 49-57.

For further reference: Hobbs, B.E., Means, W.D. and Williams P.F. 1976.An Outline of Structural Geology. New York. Wiley International. (Chap. 4 Pp. 161-211 includes a discussion on the problems associ­ated with fold development in multilayer models).

Acknowledgements I am grateful to Or W.R. Fitches of the Department of Geology, U.C.W., Aberystwyth for his advice during the preparation of the article.

Peter J. Henry, Department of Geology, Penglais Compre­hensive School, Aberystwyth, Dyfed SY23 3AW.

" -

Earth-boundedness" in geological observation

There are advtanges and disadvantages of having evolved on the earth's surface, and geologists may have to become increas­ingly aware of these as man reaches out beyond his own planet. In this article Peter Chadwick reports and critically assesses experimental data on the influence of various biases in the brain on the perception of the nature of folds, cleavages, faults and joints. In some cases our biases create fictions, but in others they help us to see what is really there. Simple practical techniques for eliminating certain distortional psy­chological influences on observation are presented.

16

INTRODUCTION That our evolutionary history and the manner of our adapta­tions to our environment can critically influence the way we perceive, and hinder our effectiveness in carrying out specialist geological tasks, is no surprise in itself. The usual solution to this age-old problem is to automate and standardise obser· vation as much as possible, but this does not avoid the problem that computer outputs still require human inter­pretation; standardised reliable reports of observations can still be questionable in terms of validity if all people make the same omissions. An additional problem is that much geological work is still carried out on site through scrutiny of outcrops, and the more complex is such an area, the more appropriate is this approach, since the best pattern recogniser is not a visual automaton but the human brain itself.

The case for recognising perceptual problems in geology can however be overstated; doing so risks equating the subjective with the inaccurate or the irrelevant. It breeds lack of con­fidence and underestimates the strivings for accuracy and precision characteristics of professional geologists. Even at the perceptual level, to say nothing of the subjectivity implied in the construction of hypotheses and theories, what is subjective can often correspond with what really is the case in the external world (see Fig. 1).

Since humans have evolved within the biosphere and not beneath it, it is inevitable that there will be a range of brain biases, either built-in oreasily learnt, which are useful in such an environment but which transfer experience negatively to the task of understanding and describing the geosphere. Many of the mistakes that beginners make in map interpretation and in the spatial visualisations appropriate for geology may well be due to negative transfer effects of this kind (see Fig. 2).

The purpose of this article, then, is to look at further examples of this "biosphere-geosphere conflict", and to try to work out why the conflicts occur and how they can most easily be avoided.

CURVATURE ILLUSIONS The visual system is optimally designed to process the shapes and patterns of the biosphere. Some recent Russian researchers suggest that we are especially well suited for analysing fibrous textures, since we meet these frequently in the form of grasses, leaves and the texture of bark and fur. These usually charac­terise objects or organisms either on, or growing out from, an undulating surface which we segment into antiformal "chunks". The relatively unusual patterns that present them­selves in rocks and metals can therefore occasionally cause problems. In Figure 3 are examples of curvature illusions in similar folds. In (i) and (iv) arcs of identical curvature (Class 2 in the terms of Ramsay 1967) appear to become more gently rounded downwards and upwards respectively (that is they appear to deviate from the similar class and become class 1 A/3). In (ii), the apparent changes in curvature almost completely disappear when the top cover is "removed", while in the natural example in (iii) (from Ramsay 1967) the curva· ture appears to become more gentle downwards despite in fact being invariant. These curvature illusions can be easily avoided; just compare arcs always of the same chord length when classifying folds.

On a cautionary note it shOUld be stated nevertheless that virtually all multilayer buckles, if sufficiently followed along their axial surface traces, change fold class and/or die out, such that perceived changes from class 2 to class 1 or 3 transversally may well often be real and not illusory.

A . I

. . 11

. . . III

B

. . 11

... III c .

I

D r"V"

~"."

FIG 1. Accurate subjectivity In A, a bias for finding right angular junctions would lead to a false "reading in" of their presence in (i). but not in (ii) and (iii). In B, a subjective contour, ie. a diagonal edge in (i) for which there are no physical cues in the location itself, is also present in (ii). but a real geological fault is physically present anyway. In (iii). there are faults with perceivable cues to their existence along their own length. Hence subjective contours can correspond exactly with real contours.

In C, the convergence of the linear elements is illusory in (i) and overestimated in (ii). Similarly, in 0, the divergence of the zones of thinning is illusory in (i) and over most of (ii). However, the traces in the third examples in C and 0 satisfy the (subjective) criterion of converging (C) and diverging (D) on one another as they are traced from outer to inner arcs. Hence the convergence and divergence is real, not illustory. (C(i) and D(i) from Chadwick 1976, 1977a, b).

17

1 I

AFFECTS ON ATTENTION AND RECOGNITION Why should undulating surfaces be perceptually segmented into antiformal "chunks" (Fig. 4A)? It may be that this is because the bias is functional in helping Lis interact with objects and organisms in everyday life. Patterns protruding upwards from the ground surface would usually signal to an organism the presence of other organisms as well as the presence of that which could be bumped into, picked up, hidden behind, or sat down on etc. The antiform is, in this sense, the most basic generalised object from within a commonly explorable medium. Since rock is not, however, a medium freely explorable by humans (except in science fiction), this otherwise usful bias can transfer negatively to geological work making people miss conceptually important details in synforms and inducing them to misremember what they have seen there.

In a recognition test (Fig. 4b) designed to examine people's perceptions over time, it was also found that all but one of eight geologists perseveratively matched the original to alter­natives similar in the antiform but very rarely to those similar in other locations including synforms.

Synforms, therefore, are neglected; (a) in the context of the observation of harmonic waves; (b) in the context of observing the undulations of a single interface such as ground level, and (c) when as half waves they are of low amplitude or located at the end of an observer's scan path.

EFFECTS ON EYE-MOVEMENTS AND RECALL Eye-movement recorders make it possible to study visual observation more directly than by using measures of attention and recognition. In the present study, it was considered that it would be valuable to check the inferences of scanning strategy derived from the previous studies on the folds through the use of such apparatus. .

The instrument used in this study recorded eye-movements only in the horizontal direction. Although it does not allow us to decide whether the observer is scanning the inner or outer arcs of a fold, it does enable us to see where along the arc­length he or she is fixating and scanning.

The patterns shown in Fig. 4C were used in the experiment. Observers were seated at a distance of 2 metres from the objective and each line or train of structures was revealed separately for observation through a rectangular slit. The pattern trains were 25 cms to 30 cms long; for three observer lines 1-5 were presented first followed by lines 6-11, for two observers lines 6-11 were presented first.

The 'page of folds' (Fig. 4C) was constructed to depict four types of shape: rounded (near circular), sine wave, chevron and box, and five curvature classes: 1A, 1 B, 1C, 2 and 3. Ninety-nine folds were therefore presented. Construcing a 5 x 4 matrix and assigning each fold ego Chevron 1 A, Chevron 1 B, Chevron 1 C, etc.) a range of five numbers, it was possible to draw up the overall pattern of structures from random number tables. Since the random number tables provided no rounded 1 B folds, this shape and class was assigned to eleven synforms post hoc. In this way the most common shape by far was of synformal attitude.

18

..

The following data were recorded from the five observers (all structural geologists):

1. Location of eye fixations.

2. Length of time of eye fixations.

3. Length of time each observer voluntarily looked at each fold train (no time limit having been suggested).

4. The observer's subjective impression, after the test, of the rank of frequency of occurrence of the four shapes - this being a judgement which is necessary also in geological tasks in the real world. (In this case, of course, the right answer was known; in field work it is not).

Fig. 5 shows a sample record of eye fixations and slow scans (inspections) derived from this experiment.

Results The most common length of time of eye fixation on one spot was between 0.2 and 0.4 secs. This was consistent from person to person. Observers rarely either fixated on, or inspected, a part of the structure voluntarily for more than three seconds and usually only "homed-in" QJ1 a particular structure after a very fast initial scan of the whole line.

Hinges were fixated on more than limbs; antiforms were fixated on first, synforms later. With the limited amount of visual data before each geologist, the total time spend looking at synforms was less than that spent looking at antiforms, both for each fold train and for each subject.

Most of the observers, although they thought they had in­spected all the folds presented, had actually ignored at least ten, and sometimes twenty or thirty, even in a 99-fold ob­jective. Observers increasingly tended to inspect folds in detail (rather than flit from one spot to another) in later lines.

With the exception of one observer who adopted an unusual strategy, all were satisfied that they had "absorbed" and covered each train satisfactorily in between 25 and 40 seconds.

The actual rank of frequency of the shape was:

1 st: Rounded (most common fold - whether antiformal or synformal)

2nd: Chevron 3rd: Sine 4th: Box (least common fold)

The predicted rank for an observer with antiform preference was:

1 st: Chevron (most common antiformal fold) 2nd: Box 3rd: Sine 4th: Rounded (least common antiformal fold)

Three out of five observers judged frequency to be as pre­dicted on the basis of antiform preference. One almost reacted as predicted, except that he ranked rounded folds as third and sine as fourth, and one observer (who had looked at each fold train almost twice as long as anybody else) judged the rank correctly.

The inferences made from the previous experiments were therefore confirmed here, as expected, most observers did not report the most common fold but the most common antifom fold - something hitherto predicted, but not actually tested by experimental observations.

A

B

c

. I ii • • •

III

FIG.2 Differences in the rules for interpreting patterns above ground level and in the geosphere. A. Density and brightness gradients in (i) and (ii) are not monocular cues to depth in the biosphere, but in rock (iii)

gradients in texture and/or brightness occur in a flat plane parallel surface in natural graded layers - the texture variation is penetrative through the material ("volume texture") rather than a surface property. (Leven Schists, Ballachulish).

B. Displacements (arrowed) in a pattern in a two dimensional image (i) need not be real, but when seen in a two dimensional section (ii) they are real, since the displacement is penetrative through the material. Knowledge of the latter, however, can itself lead to false inferences of deflection in flat layers of rock (iii). (From the Aberystwyth Grits).

C. Wave-like deflections in (i) usually represent sections through tumescences of limited extent in three dimensions (in (ii)) in the biosphere but not so in rock, where in plan view(iii) they are usually cylindroidal, (Leven Schists, north shore of Loch Leven). This learnt tendency to visuo-spatially "project" deflections orthogonally into a medium can however itself lead to inappropriate 3D constructions of garnets; stromatolites; repeatedly deformed material etc. (Chadwick 1977b, Powell and Treagus, 1970, Tipper, 1976).

19

o

o

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o 0

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~~~~t~~e illusions in folds of different shape. In (i) and (iv) arcs which are in fact of. identical c~~vature app.e~ to become more gently rounded downwards and upwards respectively. This misperception may Induce additional false.I~,erences, ~g. in (i). the inference of a fault. In (ii) the apparent changes almost ~ompletely disappear when the topcover IS removed . ((ii) based on natural example from a tributary at South Ballachuhsh, Laroch Valley, Argyll).

INTERIM SUGGESTIONS FOR THE ALLEVIATION OF BIAS What however can we do to alleviate such in-built biasses? The obvious strategy - reminding oneself not to ignore synforms -may not be the most effective. Another possibility, which would simultaneously solve the biases to miss right way-up grading and low amplitude, upside-down, current bedding traces (Chadwick and Hughes, 1980), - would be occasionally to use in the field scene-inverting prisms of the kind devised by Stratton (1896,1897). Would these eliminate all biases caused by the shape, orientation and position of the elements in the visual field? They would minimise a lot, but as the next section shows, not all.

A REVISED EXPERIMENT Although the results set down above were more or less consistent with those expected from using the previous tech­niques, they have the limitation that observers were restricted for the sake of the eye-movement recording, to scanning each fold train one at a time; What happens when they make a frequency judgement based on a global impression of the whole multi-layered pattern?

20

Different grounps of geology undergraduates and post­graduates, were asked to make such a global judgement on four versions of Fig. 4C, in which the order of the presentation of the fold trains was varied (lines 1-5, 6-11 being reversed in two cases as previously) and the scene was also shown rotated through 1800

•

The geological experience of four groups of observers (N = 76) varied from a few weeks to eleven years, with a mean at three and a half years. They had forty seconds to decide on the rank order of the shape frequencies. For the orientation shown in Fig. 4C, the actual rank order discovered by experiment on these observers (Chevron-Sine-Rounded-Box) lay between that predicted by antiform preference and the actual rank known to exist.

In order to make data amenable to a 2 x 2 independent group analysis, with each group providing judgement on one of each of the fold shapes, data from the box-fold shapes were jettisoned (nearly 70 per cent of subjects realised that these were in fact the least common) and the frequencies were collapsed and averaged across the chevron and sine conditions (referred as a "angular") and across the first two and last two rank orders.

11 B A

~ STAGE ,

lo~ STAGE 2 SELlCTlON

L ____________ J STAGE. 3

c STAGE (, INTEGRATION

o ALTERNATIVES

FIG.4 A. The two more central layers of the five-layer multilayer in (i) are usually "chunked" into peak-shaped rather than

trough-shaped segments in (ii). The numbers I to IV in (iil represent the most common sequence of "segmentation" of the scene (I first, IV last) during observation (as verbally reported by ten geologists). Visual analysis therefore is global ~ local ~ global over time.

B. The stages of perceptual segmentation and integration of the scene.

C. Eleven fold trains comprised of rounded ( n ), chevron ( 1\ ), sine ( n ) and box ( n ) shapes. Fold class is randomised across shapes. Observers scanned the pattern either one "line" at a time or freely, and then were requested to rank order the frequency of occurrence of the different shapes. Near circular arcs ("rounded") are the most common but are rarely judged as such, since they all occur as synforms (true circular arc shapes are not mechanically realistic) .

D. One of the ten stimuli (with the alternatives) used to test cleavage-fan recognition. The pattern at the left was shown for 4 secs., and observers had to select the alternative at the right most similar to the original. Alternative six (also shown enlarged) is the correct response. Others are similar in the antiform, limb or synform, but not in other parts.

21

LINE

LINE 2

LINE 3

LINE 6

FIG.5. A record of one observer's fixations during an inspection of four of the fold trains shown in figure 4C. This particular researcher was doing theoretical work on the subtleties of the geometry of fold limbs as an indicator of the mechanics and history of development of folds. This interest is reflected in the eye movement record. Arrows denote the zones over which slow scans or "inspections" occurred, whilst dots represent fixations. Note the greater coverage and the greater tendency to inspect in the later lines.

When the fold shapes were shown as in Fig. 4C, the difference from the cell frequencies expected on a 2:1 synform pre· ference is considerable (X~ = 11.81, 0.0005>p, one tailed). Varying the expected cell frequencies on the basis of a varying ratio of preference for antiforms over synforms, the x~ value goes through a minimum at an antiform p'reference of 1.5 to 1. That there is no monotonic decrease in X2 values shows that factors other than antiform preference are operative to bias the rank order frequencies. Data for frequencies on the 1800

rotated version of Fig. 4C show rank orders of angular and rounded folds to be little different from a no-difference hypo­thesis (p = 0.2) although the rounded folds are now more frequently judged as first in rank. These results show that the angularity of the folds also biases for their selection or for their retrieval from memory, and that it diminishes, although it does not override, antiform preference. When the antiforms are also angular, antiform preference is intensified. The bias for selecting-out angular shapes seems also to be a functional one: the more angular a pattern, the more likely it is to be capable of causing physical harm, so the source of this bias may also lie in our evolutionary history.

IMPLICATIONS So far reserach in this parodigm has concentrated on simple scientific tasks involving less-abstract brain processes. This obviously restricts its practical importance but the purchase conferred by the approach still seems considerable. Most important in the long term is the generalisation of the research into the analysis of specific thinking tasks. The aim is to analyse how biases in the abstract structures which mediate thought itself cause misinterpretations of features found in particular geological contexts.

22

H.

Philosophers of science have made the distinction between process and product in scientific research sacrosanct. But it is necessary to know both what to look for and how to find it. As discussed both above and previously, (Chadwick 1976, 1977al, the nature of the perceptual and investigatory pro­cesses in science can determine the nature of the instance!, out of all the possible alternatives, which will actually be found, ie. inappropriately 'read in' or most likely, missed. This means that processes and product in science are "mixable". Psychological investigations, if carried out in context, can reveal prenotions of phenomena which have the character of both process and product, and study their interdependence without blurring their identities. This can be done to the mutual benefit of the students of psychology and the other sciences.

REFERENCES Chadwick, P.K. 1976. Visual illusions in geology. Nature 260, 397-401. Chadwick, P.K. 1977a. Scientists can have illusions too. New Scientist 73, 768-771. Chadwick, P.K. 1977b. Geological Perception and the Core Curriculum. Geology Teaching 2, No. 2, 95-103. Chadwick, P.K. and Hughes, E. 1980. Which Way-up is Upside­Down? Geology Teaching 5 (3),87-89. Powell, D. and Treagus, J.E. 1970. Rotational fabrics in metamorphic minerals. Min Mag. 37, No 291, 801-814. Ramsay, J.G. 1967. Folding and fracturing of rocks. New York, McGraw Hill. Strattan, G.H. 1896. Some preliminary experiments on vision without inversion of the retinal image. Psych. Rev. 3, No 6, 611-617. Stratton, G.H. 1897 a, b. Vision without inversion of the retinal image. Psych. Rev. 4, No 4,341-360 (concluded in volume 4, No. 5,463-481). Tipper, J.C. 1976. The study of geological objects in three dimensions by the computerised reconstruction of serial sections. Journ. of Geol. 34,476-485.

Dr. P.K. Chadwick, Psychology Department, Bedford College, University of London, Regents Park, London NW1 4NS.

16 + G.e.S.E. Geology Report

Norman Dutton, Chairman of the Syllabus and Examinations Working Group of ATG, draws the attention of the member­ship to the report of the Working Party on GCSE geology in the area of the new Midland Examining Group. Herewith the complete report is presented. Whether or not members reside in the Midland area, they are invited to write to Norman with their comments.

23

MIDLAND EXAMINING GROUP EXAMINATIONS DEVELOPMENT COMMITTEE: INTERIM REPORT OF THE. 16+ SUBJECT WORKING PARTY IN GEOLOGY

MEMBERSHIP COSSEC

EMREB

TWMEB

L EA I nspectors/ Advisers EMREB area

Or O.J. Gobbett* Mr P. Knights-Branch Mr A.E. Land* Or A.B. Hawkins Mr P.E. Richard Mr R.P. Ramsdale* Mr N.W. Outton* Mr M. Robson

TWMEB area Mr K.P. Boon Cambridgeshire Representatives Mr M.G. Oonnelly

Mr K. Harker Secretary Or B.G. Fraser

(0 and C Board)

Or Hawkins (SUBJ representative) had been prevented by illness from attending four meetings of the Working Party. One nomination of a representative of LEA Inspectors/Advisers in TWMEB area was received rather late for the nominee to play a role in the activities of the Working Party.

* ATG member

INTRODUCTION 1. The Working Party met on 5 occasions prior to the

submission of this interim report. 2. The report sets out a statement on educational aims of a

Geology 16+ syllabus and assessment objectives together with an indication of syllabus content. One examination model is proposed.

3. The Working Party considered that there was sufficient agreement generally that one Board-based 16+ syllabus in Geology would be sufficient to meet the needs of all schools in the Midland Group.

4. The Working Party took note of several documents which refered to aims and objectives of examinations including those produced by the Association of Teachers of Geology. The Working Party did not have the benefit of reference to agreed 'National Criteria' in Geology as the Joint Council (GCE/CSE) had not made arrangements for a Working Party in this subject.

5. The Working Party noted that both a National and a Midland Working Party had been set up for Integrated/ Combined/General Science and it was considered that representation of Geology interests would be relevant to the deliberations of each of these bodies.

The Working Party would welcome comment from all Schools and Colleges on all aspects of this interim report.

DEFINITIONS The definitions below have been extracted from the Glossary of terms for a Single System of Examining at 16+ June 1981, published by 16+ GCE and CSE Boards' Joint Council for 16+ National Criteria.

The term aims refers to a statement of the educational purposes of a subject and of the particular examination syllabus provided on it for pupils within the context of the single system of examining at 16+. A statement of aims is likely to be broader than the associated statement of~­ment objectives (which is concerned with examinable.skills/ abilities) and may well include qualities and attributes which cannot or should not be assessed for examination purposes e.g. the pupil's motivation and attitude to the subject.

For the purposes of 16+ National Criteria, aims "should consist of clear statements setting out the educational purposes of following a course in the particular subject for all the potential candidates'~

ASSESSMENT OBJECTIVES The term assessment Objectives is used to describe the qualities and abilities which are measured for assessment purposes within a particular subject examination. Such assessment objectives should be expressed in terms of the observable and measurable behaviour which the achievement of the edu­cational aims of a course in the subject is intended to bring about. In the syllabuses for most subjects the statement of assessment objectives will list the knowledge and abilities which are to be tested in conjunction with the subject content listed in the syllabus.

AIMS Geology is seen by the Working Party as a science subject with aims much in common with those of other science subjects to be examined at 16+. Individual teachers may put different values on each of the aims and so position on the following list is not intended to indicate order of importance.

1. To utilise geology as a means of stimulating the imagin­ation of students.

2. To promote geology as a lasting, enjoyable pursuit. 3. To develop an appreciation of geology as an integrative

science. 4. To provide the essential background for study in subjects

to which geology is relevant. 5. To show that geology is a coherent framework of know­

ledge based on theory, observation and experiment. 6. To provide an appropriate body of knowledge and skills

for those not studying the subject beyond the 16+ stage, but which will also serve as a foundation for more advanced studies in geology.

7. To develop the skills of observation, experimentation, recording, processing and interpretation of data, including the selection and evaluation of evidence.

8. To encourage students to apply, qualitatively and quan­titatively, their knowledge and understanding of the principles of geology to familiar and novel situations.

9. To provide a basic knowledge, understanding and appreci­ation of the principles of geology.

10. To encourage the development of critical awareness of the importance of geology to man with regard to the utilisa­tion and conservation of natural resources.

11. To develop an appreciation of the scale of geological time. 12. To foster a knowledge and understanding of Earth's

history. 13. To provide, as part of the course, appropriate geological

work in the field and in the laboratory.

24

14. To ensure that students can tollow instructions and do comply with safety procedures.

15. To foster relevant communication skills, and the ability to work with others.

16. To promote a critical appreciation of the uniformity of geological processes in time and place.

ASSESSMENT OBJECTIVES A 16+ examination in geology within the Midland group will be set to test the following objectives both in theory and in practice. This will include examination of the Practical skills (1-9) listed below.

The order in which assessment objectives are listed is not intended to be hierarchical. a. Candidates will be expected to demonstrate knowledge of

facts, principles, terminology and definitions ii the methods used by geologists for the collection and

the recording of information iii the procedures used in geological investigations iv man's use of the geological environment v requirements for safety.

b. Cal)didates will be expected to show understanding of the various ways of presenting information (written, cartographical, tabulated, graphical or illustrated form)

ii of the equivalence of information presented in different forms

iii by translating from one form into another iv by giving appropriate explanations of familiar

phenomena in terms of relevant principles and models v of the nature of geological environments and processes.

c. Candidates will be expected to exercise judgement by critical appreciation of the uniformity of geological processes in time and place

ii recognition of and allowances for misconceptions, unreliable data and assumptions

iii drawing conclusions from given data and making pre­dictions from given data

iv making generalisations from given data.

It would be expected that a smaller proportion of the total marks for the examination would be allocated to part (c) objectives than to those in parts (a) and (b). In the whole examination (theory and practical skills) the suggested in­tended weighting for the assessment objectives is as follows:

a. demonstration of knowledge 35% b. showing of understanding 50% c. exercise of judgement 15%.

PRACTICAL SKILLS The basis of geology is practical work and it is important that the development of the appropriate skills for work in the field and in the laboratory forms an integral part of any geology course.

Candidates will be expected to do the following: 1. observe and measure with accuracy and to record appro-

priately in the field and in the laboratory 2. use and interpret geological maps and diagrams 3. recognise and identify items of geological importance 4. formulate hypotheses 5. select and perform basic tests 6. apply confirmatory tests and obtain such supporting/

confirmatory evidence for rejecting or accepting a hypo­thesis

7. show a logical approach to the solution of practical problems

8. recognise and allow for misconceptions and unreliable data

9. conform to appropriate standards of safety.

Expression The ability to express ideas and communicate information on geological topics in a clear and logical form will not be specified as skills to be tested but if candidates fail to express themselves clearly they will inevitably penalise themselves.

TECHNIQUES OF ASSESSMENT As the Working Party spent time in consideration of assess­ment techniques appropriate to a 16+ examination it would seem useful to include some discussion in this interim report. At this stage, however, no suggestions are put forward about the inclusion and weighting of particular techniques. Comment from schools would be welcome.

Short Answer Questions Defined as questions in which the examiner is not setting out to give the candidate an 'open brief' across the whole range of educational objectives, from knowledge to exercise of judgment. The examiner builds in the structure and this may be either skill structure or content structure. Such questions are not just knowledge items but can be designed to test the higher skills including critical judge­ment. Where these questions are employed all questions should be compulsory. They allow wide range sampling of the syllabus.

These questions do not demand all of the skills looked for in awarding the highest grades so it is not recommended that the whole examination for grades 1-3 be composed of this kind of question only.

Multiple Choice Questions Defined as items where the candi­date only records his choice of one answer from the four or five possible options offered in answer to the question. Research has shown that short answer and multiple choice questions can produce very similar marks i.e. there is high correlation between a short answer and multiple choice paper on the same topics. The advantage of multiple choice tests in speed and objectivity of marking were factors that should be kept in mind. Simple five choice items were seen as the most useful type of objective test items.

There were also a number of candidates for whom a multiple choice test was less daunting than an examination where written answers were demanded. In a multiple choice test even very weak candidates feel that they are able to do some­thing, even if decisions take a considerable length of time and some are arrived at by guess work. There was a need to bear in mind that reserach has suggested that girls found multiple choice tests more daunting that other tests where extended prose answers were expected.

None of the GCE or CSE Boards in the Midland Group has built up a bank of multiple choice questions though such questions had been used by the CSE Boards. If it is decided to use multiple choice items, then pre-testing in a 16+ situation was recommended before use in an operational examination.

A place was seen for multiple choice questions in a 16+ examination but it was considered that a multiple choice test should not completely replace short answer questions.

Free Response Open-ended Questions/Essay-type Questions or 'Whole Questions' This type of question is defined as setting out to tackle all assessment objectives from demonstration of knowledge to exercise of judgement by asking the candidate to decide for

25

himself what goes into the answer. Such a question required a high level of communication skills and demanded an ability to hold material in mind in readiness for other parts of the question. This type of question was seen as essential to differentiate grades 1 and 2. From experience it had been found that grade 3 candidates 'short change' on the sections of this type of question when an incline of difficulty was built in. It was thought essential that the examination model be one in which candidates awarded grades 1 and 2 answered questions of this type.

Aural, Oral It was not thought to be practicable to include such tech­niques in a 16+ geology examination.

Inclusion of a Teacher Assessed Component A compulsory teacher-assessed component involving an appreciable percentage of the total mark for the examination presented difficulties of organisation and resources including teaching time. It was appreciated that there were major problems of validity and expense associated with moderation of teacher assessment, but the assessment of Field Work/ Practical course work from the candidates own record was considered a vital aspect of the overall assessment.

Practical Examination A practical examination involving map work, rocks, minerals and fossils was considered vital in the 16+ examination.

EXAMINATION MODEL The Working Party considered that the needs of all 16+ candidates could best be met by one examination model.

CSE Boards were accustomed to set papers which discriminated across the range CSE grades 2-5 but left the high ability candidates all grouped in CSE grade 1. It was thought, with the introduction of some Free Response questions and some incline of difficulty built into Short Answer questions, that one theory paper could be made to differentiate across the whole 16+ entry. A Practical Examination was considered to be essential as was assessment of the Field Work/Practical course work.

The suggested intended weighting for the parts of the examination were: a. Theory Paper 50% b. Practical Examination 30% c. Field Work/Practical/Course Work (internally assessed by

the Teacher and moderated by the Board) 20%. Comment on this part of the interim report would be particularly useful to the Working Party.

INTRODUCTION TO SYLLABUS OUTLINE As geology is a coherent discipline the final syllabus should be based on a unifying theme to avoid the possibility of the subject being fragmented into different branches with little apparent connection between them. Such unifying themes could, for example, be "Rocks"; 'The Evolving Earth'; "Plate Tectonics"; "The Rock Cycle"; "Applied Geology".

Using the theme 'Rocks' the Working Party produced an outline syllabus.

Notes a. This is an outline of one possible examination syllabus. In

the final version much detail will be given so that the teacher is not in doubt as to what will be examined

b. This is not intended to be a teaching syllabus, so that the

order of the sections and their apparent length in this outline are of no significance.

c. It is intended that where possible teaching should be based on practical work. At least three full working days in the field is regarded as essential. The final syllabus will give appropriate practical work in each section of the suggested syllabus.

In the detailed syllabus cross reference will be given between sections of the syllabus.

The Working Party does not intend that the examination syllabus should be too long for study in accordance with the stated aims.

71

OUTLINE SYLLABUS BASED ON 'ROCKS' ~======== AS THE UNI FYING THEME I-

A. Investigating What Rocks Are Made Of 1. Texture, structure, voids, chemical composition, mineral

content, biological content. 2. Characteristics of common minerals including chemical

composition, the use of physical and chemical tests.

B. Investigating How Rocks Are Formed 1. Rock Formation By Internal Processes a. Igneous processes and the rocks which result. b. Metamorphic processes and the rocks which result.

2. Rock Formation By Surface Processes a. How rocks are broken down by weathering.

How erosion and transport processes affect the fragments. How different conditions of modern deposition help us

understand ancient sediments. How these deposits became clastic sedimentary rocks.

b. How the use of minerals by plants and animals can lead to the formation of other sedimentary rocks.

c. How inorganic precipitation can lead to the formation of other rocks.

The Working Party saw this section as offering good oppor· tunities for practical work in both the field and in the labora· tory.

C. Discovering And Using Rocks a. Rocks as energy resouces. b. Raw materials for industry. c. Use of rocks for water supply and waste disposal.

The Working Party welcomes useful comments from schools on the use of a unifying theme as the basis for construction of the syllabus Additionally, comment on the various themes listed and other such themes would be useful.

26

d. Rocks in Engineering construction. e. Consequences to the environment of using rocks.

D. Investigating The Stories In The Rocks 1. Geological History a. Theoretical and practical understanding of the principles

of historical geology. b. The geological time scale. c. Application of the principles of historical geology to a

geographical area.

2. Life of the Past a. How living things become fossils. b. How fossils are classified. c. Paleoecology and assemblages of fossils. d. Changes in the fossil record throughout geological time.

The Working Party saw this section as offering good oppor· tunities for practical work in both the field and the laboratory.

3. Earth Movement and Structure a. Evidence which suggests that continents move. b. Evidence for the internal composition of the Earth. c. Description of and formation of geological structures pro·

duced by deformation.

The Working Party saw part (c) of this Section as offering good opportunities~ for practical work in both the field and the the laboratory.

Comments of ATG members to N. Dutton, 11 Wesley Road, Shortheath, WiUen ha", West Midlands WC12 SOT.

"WHY CAN'T WE GO ON THE FIELD TRIP THIS YEAR, SIR?"

I wonder how many colleages have heard this cry recently?

In the past grammar schools with large local authority grants (and often their own endowment resources) were, able to foster out-of-school activities without too much difficulty. The arrival of comprehensive education, the need to spread allowances more evenly, the disappearance or decline of endowments and, of course, spending cuts, have changed all this.

For many years I have been able to organise week-long field trips for each of the upper and lower sixth forms. In Summer term we usually visit Cumbria and at Easter, Dorset. About forty pupils have been involved on each occasion and they have undertaken joint Geography, Geology and Biology activities. With such large numbers, mini-buses are unsuitable, so in addition to the cost of accommodation, for which the pupils are mainly responsible, the cost of a coach for a week has become an increasingly large drain on the School's Travel Fund. At £500 a time it becomes more and more difficult to justify such expenditure on a relatively small number of pupils.

So what is the answer? The simple one is to reduce activity but then of course the pupils suffer. More local field work is an alternative but in my experience the week away from home and school produces a much more sustained effort with improved results.

The answer at my school has been provided by my upper sixth pupils. After spending an enjoyable week in Cumbria during July 1981 there was considerable disappointment when I announced that we would not be able to offer the Easter 1982 trip. However the disappointment didn't last for long. I was approached by two enterprising young ladies who simply told me that they would raise the money. That is just what they did.

With the agreement of an understanding headmaster we have covered the cost of the coach hire by running discos for the sixth form in a local dance hall which has a separate and easily-policed suite of rooms for hire. I must admit that it was with some trepidation that several colleagues and I turned up to keep an eye on the first event but we were impressed with the behaviour of the pupils and their adherence to the "smart dress" requirement printed on the tickets. Earlier attempts to run social events in school had proved disappointing, mainly because of the difficulty in controlling 300 or 400 pupils in a rambling building at night. Attendances were excellent, mainly because of the advance publicity provided by posters pro­minently displayed throughout the school and because we were able to offer 'live' entertainment. Indeed, I discovered that I taught a member of a pop group!

27

In addition to the discos, one parent has held a fund-raising coffee morning, a sponsored darts-throwing event has been suggested, and even the sale of fruit to other pupils has been proposed.

Some colleagues may argue that it is not up to pupils or their teachers to be involved in raising money that should be pro­vided by the local authority. Even pupils in the sixth form have argued the principles with me. A few have disliked supporting the activities of a comparatively restricted group although they seem to have thoroughly enjoyed themselves at the discos. Unfortunately whilst the politics of the financing of education are discussed pupils pass through our hands. Should some of them suffer whilst we sit back and wait for improvements? Will the 'good old days' ever return again? It is quite apparent that the money can be raised if effort is made.

B.O. Podmore, King Edward VI High School, Stafford.

**WHITBY ** The proprietors of ESKLET GUEST HOUSE wish to offer accommodation to Geology students at reduced party terms.

ESKLET is a comfortable Georgian House with accommodation for approximately 18 guests.

For further information please apply to:

Miss P Hudson Esklet Guest House 22 Crescent Avenue West Cliff WHITBY N. Yorkshire Y021 3ED

Telephone: (0947) 605663

_________________________________________________ 1,;--

OPEN UNIVERSITY TV PROGRAMMES -

The following paragraphs provide synopses of 25 minute television programmes associated with Open University Course S237 The Earth: structure, composition and evolution (first presented: 1981).

TV1 The origin of the Earth. A series of film animations and planetary models is used to explain the origin of the chemical elements that occur in the planets and the Sun (using solar spectra). The seismic evidence for the Earth's internal structure, comprising the three main zones, mantle, outer core and inner core is summarised and is combined with the evidence from meteorites to suggest that these zones are made of, respectively, magnesium-rich silicate, a fluid iron-sulphur mixture and a solid iron-nickel alloy. Finally, the basis of the chondritic Earth model is discussed leading to a simple model for the origin of the different ' planets from the primitive solar nebula.

TV2 After the Earthquake This programme uses studio demonstrations and some exper­iments with explosives in a quarry (simulating ground motions associated with earthquakes) to study:

the destructive effects of earthquakes which are described using an intensity scale;

ii the relationship between the energy of an earthquake, its magnitude and intensity;

iii the design and use of seismometers to detect earthquake waves;

iv the causes of earthquakes and the location of their sources using records of P-wave and S-wave arrivals at different recording stations and arrays around the Earth.

TV3 Crust and mantle The programme starts with a generalised look at the compo­sition of the crust and upper mantle by considering the petrology and geochemistry of granite (upper continental crust), granulite (lower continental crust). gabbro (oceanic crust) and peridotite (upper mantle).

The second part begins an investigation of the crust and upper mantle beneath Scotland, emphasising that the mineralogical and chemical layering of the lithosphere is mirrored in con­trasting physical properties of the different rocks. The results of the Lithospheric seismic profile beneath Britain (LlSPB) survey are summarised.

28

TV4 Beneath Scotland Building on programme 3, several on-location visits are made to examine possible constituents of the seismic layers beneath Scotland: post-Caledonian sediments, meta-sediments and granites of the 'Caledonian layer', Lewisian granulites and, using nodules from the Midland Valley vents, garnet granulite and peridotite. The programme uses radiometric and gravity modelling to amplify various features of these layers, and it concludes with a tentative geological cross-section beneath the LlSPB line.

TV5 Ocean crust Four aspects of ocean lithosphere (crust and uppermost mantle) are illustrated:

the origin of ocean lithosphere by sea-floor spreading at ocean ridges, including film inserts of relevant volcanic processes;

ii the structure of ocean lithosphere from seismic refraction and reflection data, and the composition of the upper layers as deduced from dredge hauls and drilling;

iii the composition of the ocean lithosphere deduced from studies of ophiolite sequences on land, including a summary of how the ocean lithosphere forms by melting and crystallisation proceses beneath ridges;

iv the evolution of ocean basins and the destruction of ocean lithosphere at subduction zones.

TV6 Melts to minerals Various aspects of phase diagrams are illustrated, including:

the construction of a phase diagram for a simple binary eutectic system using, as an analogy melt crystallisation, observations of organic substances that melt at lower temperatures;

ii the characteristics of three-component phase diagrams with crystallisation at constant pressure and with special reference to the diopside-albite-anorthite system;

iii using thin sections of basalts, the relationship between phenocryst phases and their liquidus temperatures in mUlti-component silicate systems.

TV7 Lavas of Etna The first part of this programme uses on-location filming to illustrate some features of the structure and volcanic history of Mount Etna, including the petrological characteristics of lavas that may be related by fractional crystallisation processes. The second part, filmed at the O.U. laboratories, shows how the rocks are analysed and uses trace element and strontium isotope geochemistry to confirm and amplify the relationships demonstrated in the field. Two groups of lavas are dis­tinguished, each is related internally by fractionation, but the two groups are thought to have originated from different parts of the mantle.

TV8 The terrestrial planets With the exception of the Earth, the inner-planets - Mercury, Venus, Earth and Mars - appear to show no surface tectonic activity. On the Earth, the contrast between geologically young oceans and old continents indicates the occurrence of some form of internal convection. The surface expression of this convection is plate tectonics, and the measurement of instantaneous relative plate motion can be made by satellite. The surface, and possible internal features of the inner planets are summarised in the programme and are used to comment on past and present internal processes during the geological evolution of these bodies.

TV9 Geothermal Energy This programme, co-produced with the EEC geothermal division, provides a broadly-based review of the sources and utilisation of geothermal energy in Europe. After a short introduction to the concepts of heat transport and the global distribution of heat flow values, it uses three location visits to illustrate contrasting aspects of the geothermal story:

the tapping of high enthalpy steam, to drive turbines, from reservoirs beneath a volcanically-active region in Italy;

ii the use of low enthalpy hot water, for space heating and horticultural purposes, from aquifers in a deep sedi­mentary basin in the Paris region;

iii experimental work in S.W. England where the potential for creating artificial heat exchange surfaces in hot dry rocks (5Km depth in granite) is being evaluated.

TV10 Where has all the granite gone? This essentially geochemical programme examines the weath­ering of the Dartmoor granite and the fate of the weathering products during transportation via rivers to the sea. There are five main components:

a microscope study of weathering reactions and associated equations;

ii a field sequence showing the evidence for soil formation and weathering processes on Dartmoor;

iii field evidence of the fate of weathering products in rivers and the Tamar estuary;

iv a studio sequence illustrating the theory of geochemical processes in estuaries;

v a field visit to a claypit where the reconversion of solid weathering products into sedimentary rock is described.

TV11 Oil: from small beginnings This programme starts in the field by considering the form in which carbon occurs in different sedimentary rocks in a borehole, beneath N. Nottinghamshire, which encountered both coal and oil-bearing strata. The different biological, chemical and physical processes leading to the fixation of carbon in hydrocarbon and carbonate-rich sediments are discussed. A studio investigation of the different chemical components in crude oil leads into an extensive film animation illustrating the different stages in hydrocarbon diagenesis, starting with anoxic conditions in sea-floor sediments associated with high biological productivity in ocean waters and ending up with crude oil.

TV12 The search for oil Building on TV 11, this programme considers the historical development of oil prospecting from the recognition that oil is often associated with anticlinal structures to the modern geophysical prospecting methods that were used in the discovery and exploitation of the Forties oil field in the North Sea. Gravity and seismic reflection studies were particularly important in the preliminary stages but, since the first drilling

29

in 1969, extensive use has been made of down-hole gamma and sonic logs which, in this programme, are used to produce vertical geological profiles through various parts of the forties field.

TV13 When the lands divide This programme examines the question of how and why continental masses split apart in particular areas to form new ocean basins. The main example used is the embryonic ocean basin of the Red Sea; the geological history and geophysical characteristics of the area are examined to explain just why the Red Sea basin developed where it did in terms of what is known about plate movements of the time. The reasons for the formation of zones of anomalous IOW-density mantle Ibading to continental thinning and rupture to form a new ocean basin are reviewed.

TV14 Voyager's travels This compilation of Voyager 'film' sequences, film animations and interviews with members of the imaging team is used to consider the following points:

the relationship between density, structure and compo­sition for solid bodies within the Solar System;

ii the accretion of minature 'solar systems' around giant planets; the relationship of the satellites to the size and gravity of their parent planets and the way in which this aids an understanding of the evolution of the Solar System at large;

iii the use of surface features, such as the density of waters to indicate the bombardment history of bodies within the Solar System, and, in the case of internally-active bodies, to indicate the age of their surfaces and the nature of the last re-surfacing period;

iv from crater sizes, to illustrate the range of particle and planetesimal sizes available for bombardment and to consider this in relation to catastrophic fragmentation of small satellites.

--_._._._-_._._--

UNIVERSITY OF ABERDEEN

1982 GEOLOGY SUMMER SCHOOLS

Faroe Islands (Torshavn) Northwest Highlands (Ullapool) Grampian Region (Aberdeen)

5th-12th July. 24th-30th July.

31stJuly -7th Aug.

Brochure, descriptive leaflets and booking forms are available from Or C. Gillen, Department of Adult Education, The University, Aberdeen AB9 2UB. Tel. 0224 - 40241, extension 6389.

_.-._._._._._.---

TV15 Early earth evolution A series of field locations in the Lewisian area of N.W. Scotland is visited to illustrate how a part of the ancient continental crust formed at the surface, what sort of tectonics were involved in its formation and how it has evolved sub­sequently in jumps as external forces acted upon it. The second part of the programme is studio-based and is used to describe strontium isotopic evolution models for the Earth. Two aspects receive particular attention: first, the way in which the evolution of the continental crust is reflected in changes that have occurred in the strontium isotopes of the oceanic crust, and second, the way in which strontium iso­topes in seawater, reflected in ancient limestones, relate to continuous and multi-stage processes for continental growth since about 3700 Ma ago.

TV16 Colliding continents A brief introductory film sequence from a site within an ancient continental collision zone on the north Cornish coast is followed by a description of the most spectacular and youngest of such collision zones: the Alpine-Himalayan mountain chain. The geophysical evidence for the existence of a supercontinent, Pangaea, 200 Ma ago is summarised and is accompanied by an animation of the pattern of world-wide continental movements since Pangaea broke up to form the present continents. One of these movements has been the closure of Tethys to form the Alps and Himalayas: apart from obvious effects, such as the formation of mountains, con­tinental collision is associated with the uplift and deformation of sedimentary rocks, the intrustion of granite magmas and the emplacement of ophiolites. The origin and structural inter­pretation of the Oman ophiolite receive detailed consideration. Next the programme returns to Cornwall to show how Alpine­Himalayan features may be used to interpret an older con· tinental collision zone. Finally, there is a summary of present knowledge about the evolution of continental crust.

Or Geoffrey Brown, Department of Earth Sciences, Open University, Milton Keynes MK7 6AA.

CLADES !?

OLD DOGS AND NEW TRICKS

Six members of the London Group of the ATG, inspired by Beverly Halstead's talk to the annual conference in September 1980 at Keele, visited the Natural History Museum to make an appraisal of the new exhibition on the Dinosaurs. Some of us, the old dogs, were ready to damn it and some were wondering what the S.M. could have done to stir up so much debate.

The talk of those in the know as we walked through the hall­owed portals was of clades, cladograms and homologies* but none of us realised the circus of tricks that were to confront us. We had been brought up to digest and teach our charges about trees of evolution with their branches yielding the fruits of different species, families and orders, but the exhibition presented a new diagram; the cladogram. This usurper, what is more, replaced those trees without more than a muted refer­ence to evolution. Because of the similarity in appearance we tried to read the cladograms as evolutionary trees and this led to intense confusion. This was our greatest mistake.

30

I •••

Let me explain what the exhibition attempted to teach us (see Fig.1). It started rather alarmingly with our being fobbed off with some assumptions that to the wary were dubious, to the traditionalists were unacceptable, and to the objective amongst us were unexplained and not argued. The assumptions were to form the basis for all that was to follow and were, that the' generation (dare I say evolution) of new species comes about by an ancestor producing two new species, never one or more than two! This generated a great argument while we attempted to piece together our own explanation i.e. that three species can be produced by the division of an ancestor followed by the division of one of the offspring. But countless questions remained. is the ancestor an ancestral species or an individual, or even a mating pair?

Entrance

"1 __ Fig.1. Plan to show the position

of the DillQsaur Exhibit at the Natural History Museum.

The production of new species was plotted as a simple two pronged branch lying horizontally with the new species on the right of the cladogram (see Fig.2), but where did the ancestral species plot? It was never in the body of the diagram! Is it always doomed to die out? Is it deemed to have changed to a new species by producing its "offspring"? If we think of the ancestor as concept, we can puzzle over it later.

We hoped in vain for clarification as we continued our tour. At least we met a familiar word next. An homology is an inherited similarity, and it must not be confused with a purely functional similarity. Since homologies form the basis for constructing cladograms the difference is crucial. We were exercised in the identification of true homologies by analysing wings and fins of different animals: A whale's fin is homologous to the wing of a fly, but the wing of a fly and the wing of a flying fish have only a functional similarity. To reinforce the point we were shown a dolphin, a salmon and a squirrel and told, 'The dolphin is a similar shape to the salmon, and they both have 'fins', but the dolphin shares more homologies with the squirrel than the salmon. It is simpler to assume that the stream-lined shape evolved twice than that all the character­istics shared by the dolphin and the squirrel evolved twice."

Now that we knew that homologies link species on the clado­gram and were practised in the identification of clades from a prepared cladogram of a number of species from a sheep to a hippo and from a pig to a trout (see Fig.3), we realised that a clade comprises all the species to the right of any branching. A clade therefore can consist of only two species or can be as large as you like. But some have a greater status: there are clades within clades. We coined the terms 'sub-clades' and 'super-clades' and tried to relate them to families, genera and orders in our simple minds, only to be instructed to forget those old terms. Clades can transgress these old groupings since the birds are in the same clade as the kangaroos!

From this befuddling and all important section we passed on to dinosaurs at last. Using cladographics (my jargon) we were informed of some useful homologies of the dinosaurs and related animals. The amnion links the dinosaurs with the birds. Fossil birds, crocodiles, the pterosaurs and thecodonts together form a clade called the archosaurs because they all have a hole in their skulls in front of their eyes. Within this clade the hip structures of two groupings of dinosaurs, the ornithischians and the saurischians were described and differ­entiated. The crocodiles have the same hip bone structure as the saurischians (therefore they form a clade??) and the hip structure of the birds is like that of the ornithischians (there­fore they are in the same clade???).

species

(a) ,----.A

~---'B

"------.. c

Fig.2(a) Cladogram to show the links between the species, A, Band C. (A + B = a clade, A + B + C = a clade but B + C 'i a clade).

Fig.3 Cladogram of some present day species

r-

'---

r--

'" r--

-

31

Our understanding was checked by a press button game. We got it right second time around, and learned that to recognise and define the lower level clades within the ornithischians we must study carefully the shape of the bones of their hips and that the shape can be used as a linking homology.

More confusion was to come. We found out that the birds do not have a true homology in their hip bone structure with the ornithischians, but they are homologous with some of the saurischians and the saurischians do not form a clade!!!

We whizzed around the rest of the dinosaur exhibit remember­ing the time when, many years ago, as youngsters, we first saw their skeletons; we were three foot nothing high, socks limp

(b)

?? /

??? . . .

+ I I I TIME I I I I I

(b) Evolutionary tree showing the evolutionary links (? missing links?) between A, B and ,C.

r{ Kangaroo

Pig

Duckbilled Platypus

rl Magpie

Ostrich r-

r-- Crocodile

- Sand Lizard

- Tortoise

Frog

Lungfish

Coelacanth

.. Brown Trout

Blue Trout

I Fig.4. Cladogram showing the linking homologies of Archae· opteryx and individual saurischian dinosaurs

r Tyrannosaurus

~,.. mouth structure .., I r A rchaeopteryx

~,.. .., I hip bone structure I

---1 ,..

~I hip bone structure

around our ankles and sucking our thumbs in awe.

Sitting over coffee we tried to come to terms with homologies (easy), clades and cladograms (not so easy). What was wrong with those evolutionary trees? They showed everything, ex· plained nothing, but they did give us an idea of geological time and the ancestral links. Gradually we pieced together an understanding of cladograms:-

1. Species are always changing gradually and can be thought of as splitting into two species at a specific time, when one side cannot breed with the other. Therefore the ancestor is not an individual but a concept. If it survived without modi· fication it would be plotted on a cladogram on the right hand side at the end of a long branch. 2. Species never plot in the diagram, only on the right hand side. 3. The cladogram does not attempt to indicate time, but only the links in the order in which they occurred. (I trust that cladographers remember their stratigraphy, otherwise we might end up with an ancester that evolved from its off­spring twice removed). 4. They show evolutionary links that are unfettered by Linnean constraints, but they could be of greater use if the linking homologies could somehow be indicated on the cladograms (Fig.4.).

Certainly the exhibit was thought-provoking for the old trick­sters, but unfortunately even with its accompanying text it was not soundly enough explained. Despite the excellent visual displays that used a variety of response mechanisms for ques­tioning and answering, it left too many questions unanswered. Perhaps for today's thumbsucker it could be a sound educa­tional experience; even to the old dogs though, the new tricks were obviously of use. But we would need a lot of practice and reading around the subject before we could possibly introduce homologies, clades and cladograms to our students with con­fidence.

32

, .,.. wrist structure ""11

I

l Deinonychus

Gallimimus

--" Diplodocus

REFERENCES Anon, 1979. Dinosaurs and their living relatives, London,

. British Museum of Natural History. Anon,1980, Man's Place in Evolution, London, British Museum of Natural History, £3.95. (This book gives a much better explanation of cladograms.)

Or R. C. Standley, Department of Geology, City of London Polytechnic, Walburgh House, Bigland Street, London E1 2NG.

*Definitions i. according to "Dinosaurs and their living relatives"

CLADE - all the animals that share a common ancestor CLADOGRAM - a branching diagram showing all the animals that share a common ancester HOMOLOGY - a characteristic inherited from a common ancester

ii. according to "The Shorter Oxford Dictionary" CLADE - a disaster ... or? ... CLAD(O) --:- a prefix alluding to a young shoot or branch HOMOLOGY (bio!.) - correspondence in type or structure

ATG: BOOKS RECEIVED

In notifying the existences of the following books and materials the ATG does not wish to imply that it regards these books as appropriate to school, college or university geology or recommended for purchase. Where possible some details are given on the source of the books or material, their price and their likely market according to the following scheme: S = secondary (SL = Lower: SU = Upper); C = College of Edu­cation, Polytechnic and University students; F = Polytechnic, University and research; T = teachers' reference; G = general adult reference.

ATHERTON, M. and ROBINSON, R. 1981. Rocks and Earth History. (The third in the series "Study the Earth"). London, Hodder & Stoughton. 80 pp. £2.45. (A book upon which a good many CSE or Combined Science Courses could be passed, at least in part. Every page replete with diagrams and colour photos. Seventeen activities in­volving simple, practical or experimental work. The experience of the authors as teachers and science educationalists shines through. A good buy). SLSUT.

BIRe, J.B. 1980. The Natural Landscapes of Canada. A study in original earth science. 2nd edition. New York, Wiley, 260 pp. Paperback £5.40. SUCFT

BROWN, G.C. and MUSSETT, A.E. 1981. The Inaccessible Earth. London, Alien & Unwin 235 pp. Hardback £18.00. Paperback £9.95. CFTG.

The book is about the formation, evolution and internal state and composition of the Earth. The authors are particularly good at introducing and balancing the recent contributions of geochemistry and geophysics with respect to the problems cited, but they are equally adept when bringing astronomical and meteoritic evidence to bear. It would be nice to think that many university curricula in geology have been revised enough recently to have undergraduates turn to a book like this.

Teachers of Advanced Level courses will find that this book provides them with a relatively painless introduction to the basic physics and chemistry needed to teach such topics as the internal structure of the earth, the origin of the chemical layering of the planets, the core, mantle and crust of the earth. The final chapter on the evolution of the earliest continental crust from the Archaen to the present (22 pp) provides a very pithy summary of earth history from a very different view­point to the blow by blow stratigraphic history of save money A level syllabus.

CHALONER, W.G. and MACDONALD. P. 1981. Plants invade the land. Edinburgh H.M.S.O. for The Royal Scottish Museum. 18pp. £1.20. SUCFT. (A smaller booklet than those from IGS, but a well-written well-illustrated account of the material from the Rhynic Chert. For Advanced and Higher Level Students and beyond).

COHEN, S.1981. Fossil Catalogue. 11 pp. From: 75 South Street, Bridport, Dorset. Telephone Bridport 24239. CFT. (In a covering letter Mr Cohen writes "I'm, aware that the fossil dealer has a controversial image these days when so many classical sites seem to be 'falling under the hammer' the justification for my work has always been that I am preserving material that would otherwise be lost or destroyed and applying professional standards of collecting and preparation which few people have the time and resources to develop".)

33

In response to requests from ATG members, the Promotions Group have acquired a range of new items for sale, in addition to the slide sets already available.

• TARR'S WORLD SEISMICITY MAP* £1.50 (plus 50p for p & p) Depicts magnitude, depth and date of the world's major earthquakes. (Size approximately 90 x 120 cm).

• OPEN UNIVERSITY EVOLUTION CHART* £1.50 (plus 50p for p & p) Illustrates evolution of major faunal and floral groups through geological.time. (Size approximately 75 x 110 cm).

• USA STATE GEOLOGICAL MAPS** £1.00 (plus 20p for p & p) A set of 10 coloured geological maps of individual states, some with cross-sections and stratigraphic columns. (Size approxi­mately 30 x 40 to 50 x 55 cm).

• GRAIN SIZE SCALE 20p each (plus 20p for p & p) 15p each for 20 copies or more (plus 20p for p & p) 100 copies or more (post free) Specially printed for ATG in red and black on white plastic card. (Size 6 x 9 cm).

• ATG TIE £3.40 (plus 30p for p & p) Blue cloth tie with ATG motif

• SLIDE SETS Detailed descriptions given in GEOLOG Y teaching Vol. 6 (2) p.42.

Folds £2.50 (plus 25p for p & p) 10 slides with notes.

Intrusive Igneous Field Relationships £2.50 (plus 25p for p & p) 10 slides with notes.

* map and chart send folded flat - if you would like them rolled please send cardboard tube.

** Members who have purchased the set of 8 can obtain the other 2 maps FREE. Please send a large s.a.e.

Orders to Mrs R. Grum, 271 Stapleford Lane, Toton, Notting­hamshire (with cheques or postal orders made payable to the Association of Teachers of Geology), or collect from Mr P. Williams at Warrington Museum, Bold Street, Warrington.

CRAIG, R.G. and LABOVITZ, M.L. 1981. Future trends in Geomathematics. London, Methuen. 318 pp. Hardback £12.00 CFT.

GEOLOGICAL MUSEUM. 1978. Britain before Man. London, H.M.S.O. for IGS; 36 pp. £0.70. (Another in the splendid series of inexpensive booklets suit· able for younger and older students). SLSUCFTG.

GRIFFITHS, D.H. and KING, R.F. 1981. Applied Geophysics for Geologists and Engineers (second edition). Oxford, Pergamon. 230 pp. Paperback £5.95. CFT.

GUION, P.D., SCURRY, D.G.A. and ROBINSON, CA 1978. British Phanerozoic Palaeogeographies. Oxford, Oxford Polytechnic. 19 pp. SLSUCFTG. (4 colour generalised palaeogeographies at least one for each geological system at A4 size. Price 1-9 copies @ £1.10 each; 10-99 @ £1.00 each; above 100 copies @ £0.90 each (including carriage in each case). Copies from: Senior Technician, Department of Physical Sciences, Oxford Polytechnic, Oxford OX3 OBP.

HOWE, S.R., SHARPE, T. and TORRENS, H.S. 1981. Icthyosaurs: a history of fossil 'sea-dragons'. Cardiff, National Museum of Wales. 32 pp. (A fascinating, well-written account of a topic which relates to the theme of current exhibits in the National Museum. Though scholarly, the booklet is likely to motivate even the least imaginative students. The spirit of Sir Henry Thomas De La Beche lives on!). SUCFTG.

HOWELLS, M.F. etal. 1981. Dalgarrog. Description of 1 :25000 sheet SH 76. London, H.M.S.O. for IGS. 90 pp. £4.00 (Another in the excellent series of field guides to areas recently mapped by IGS). SUCFTG.

MOSELEY, F. 1981. Metods in Field Geology. Oxford, Freeman. £6.50. 211 pp. (A series of ten chapers on fieldwork survey methods is followed by ten on a variety of case histories relating to investigations made largely by the author and his students during a long and distinguished career). SUCFTG.

NEALE, J and FLENLEY, J. (Eds) 1981. The Quaternary in Britain. Oxford. Pergamon Press. 267 Pp. £14.50. CFT. (Essays by 22 authors in honour of Dr Lewis Penny. The topics range from the historical consideration of the connection of William Buckland to the growth of ideas on glaciation, through regional up-dating reviews to a new classification of glacial sediments).

PATERSON, W.S.B. 1981. The Physics of Glaciers (2nd Edition). Oxford, Pergamon. 380 pp. £7.20 Paperback, £20.00 Hardback. CFT. (A complete rewrite of a 12 year old Tour de force).

PRITCHARD, J.M. 1979. Landform and landscape in Africa. London, Arnold, 160 pp. £6.95. SUCFTG.

34

WAY, D.S. 1978. Terrain analysis. 2nd Edition. New York, McGraw Hill. 438 pp. SUCFT.

WHITTAKER, E.J.w. 1981. Cystallography. An introduction for Earth Science (and Other Solid State) Students. Oxford, Pergamon pp. 254 paper £8.35. Hardback £13.50. CFT.

D.B.T.

Kirtleton House 21 KirtIeton Avenue, Weymouth Dorset DT4 7PS Tel. (0305) 785296

FOR YOUR FIELD STUDY TRIP IN DORSET

All rooms hot and cold and shaver points * Excellent food * Large Car Park * Heating all rooms * Lounge with colour TV * Residents Bar * Fire Certificate * Drying Facilities * Open all year * Prices from £6 day for bed, breakfast and evening meal and packed lunch.

Brochure available from resident proprietors Mr and Mrs G Cole.

THE TEACHING OF EVOLUTION

Occasionally in the last ten years teachers of geology and biology in the UK have been aware of attacks being mounted on evolutionary theory. Here it is argued that such public and semi-public contretemps provide valuable opportunities for teachers to discuss quite far-reaching issues with older pupils of many ages.

As those members who were at the 1980 A TG Conference at Keele will remember, the first of the assaults on Evolution has concerned the nature of its pattern, and the alternative ways of organising present-day and fossil data relating to the history of life. In some cases spurred on by the early views of philo­sopher Popper that Darwinian evolution is more a meta­physical (i.e. untestable) theory than a scientific one, some writers have sought to present patterns in the data by means of cladograms (see Charig 1981, Patterson 1980, and the review of the exhibit at the British Musuem of Natural History by Bob Standley in this issue). Even here, however, some pro­tagonists believe that the declared motive of some of these writers, namely to carry out a better scientific analysis of the data, is not the only one, for Halstead (1980) believes that such interpretations can also be used surreptitiously to support a Marxist interpretation of history; hence the furor over the new evolution of man exhibit at the BMNH - reds under the showcases in one of our most stately victorian edifices! These challenges have led Popper to clarify his interpretation of what counts as a scientific theory (see Halstead 1980). and Darwin's evolutionary synthesis, upon which whole research pro­grammes have been based, is now said to pass the test of a true scientific theory.

, The second assault has been mounted because some believe that the teaching of only one theory on the history of life -the Neo-Darwinian one - smacks of indoctrination, and most educators, if they can recognise a doctrine, will avoid brain­washing students with it. Certainly some styles of teaching of biology and paleontology do assume that the Darwinian version of evolution has taken place.

Alas! in this case, also, the motives of those who have raised the indoctrination issue are not always clear and open. Some, like Harper (1977, 1979). can be credited with trying to promote the scientific discussion of alternatives to evolution, although it must be confessed that he has shown a lamentable grasp of the geological dimensions of the problem and has ended up by providing arguments which are feeble (see the ripostes by Ager 1980 and Moorbath 1980). Other have fundamental religious motives of the kind that pupils will readily recognise from encounters at their own doorsteps. This second assault has its clearest expression in the United States where in the last ten years politicians in most states have been under tremendous pressure from representatives of 30 million fundamentalists to enact laws to make the teaching of creationist theory an alternative to Darwinian evolution in science classes. Textbooks in biology have been produced claiming to present the scientific case for creation­alism (e.g. Moore and Slusher, 1970). In six states in the USA such laws have been enacted and the traditional separation in

35

schools of the affairs of the states and churches (which does not exist in the UK) has been broken. "Defence of Darwin" committees have been set up in 36 states (Anon 1981). The National Science Teachers Association has been under pressure from its members to make a policy statement on these matters. Such a statement has been produced and is set down below (from Brush 1981).

The i~troduction of these issues into the geology laboratory provides both dangers and opportunities. The dangers largely relate to the insensitive handling of discussions and the im­position of adult political and religious views on those too young to appreciate the context and the implications. The

NST A Position Statement

"Inclusion of Nonscience Theories in Science Instruction"

In light of increased requests from members and others regarding NSTA's position on the creationism/evolution controversy, the NSTA Board of Directors has requested that the Association position statement be reprinted in the NST A journals.

Throughout his recorded history man has been vitally concerned in finding out all that he can about his universe. He has explored it in many ways, raised questions about it, designed methods by which he could increase and organize his knowledge, and developed systems to aid him in under­standing and explaining his origin, and nature, and his place in the universe. Among these systems are philosophy, religion, folklore, the arts, and science.

Science is the system of knowing about the universe through data collection by observation and controlled experimentation. As data are collected, theories are ad­vanced to explain and account for what has been observed. The true test of a theory in science is threefold: (1) its ability to explain what has been observed; (2) its ability to predict what has not yet been observed; and (3) its ability to be tested by further experimentation and to be modified as required by the acquisition of new data.

The National Science Teachers Association upholds the right and recognizes the obligation of each individual to become informed about man's many endeavours, to under­stand and explain what each endeavour has contributed to mankind, and to draw his own conclusions in each area.

The National Science Teachers Association also recognizes its great obligation to that area of education dealing with science. Science education cannot treat, as science, those things not in the domain of science. It cannot deal with, as science, concepts that have been developed in other than scientific ways. Moreover, the National Science Teachers Association vigourously opposes all actions that would legislate, mandate, or coerce the inclusion in the corpus of science, including textbooks, of any theories that do not meet the threefold criteria give above.

opportunities relate to the fulfilment of a whole range of educational aims many of which may be of lifelong value:

• the satisfaction of students' curiosity about their place in the history of life and the universe;

• the study of the history of controversies that shocked Victorian England and brought geology to the forefront of public attention;

• the diminution of problems of identity and perspective that affect students when they are growing up;

• the chance for students to articulate their ideas and ex­perience of grappling with such issues, so that in discussion they come to see which of their views are supportable by evidence and experiment, which require an act of faith, and which are founded in sheer prejudice;

• the sharpening of understanding of what constitutes a scientific theory, and how, in contrast to metaphysical theories which require acts of faith, the best scientific theories withstand a great many tests designed specifically to destroy them;

• the blurring of subject boundaries, in this case those lying between history, politics, religion, biology and geology.

Here are the opportunities, given the teachers' ability to handle the material and the issues sensitively, to stimulate, provoke and draw out the best in pupils; a chance to breathe life into the dead bones of some of our CSE, 0 and A level palaeontology syllabuses - if one can find the time and rise to the challenge!

EDITORIAL SUBCOMMITTEE

David Thompson (Editor) Geoffrey Brown (Assistant Editor) Bob Standley (Deputy Editor) Stephen Hannath (Primary School Geology) Dick Mayhew (Reviews) Robin Stevenson (Fieldwork) Frank Spode (Primary School Geology, Teacher Training) David Thompson (News, Shopfloor) Ray Harris (Advertising)

Opinions and comments in this issue are the personal views of the authors and do not necessarily represent the views of the Association.

Advertising enquiries to: Ray Harris, 17 Caroline Buildings, Widcombe, Bath BA2 4JH.

Contributions for the next issue of GEOLOGY teaching will be welcome, and should be sent to the Editor, from whom notes for contributions are available.

Volume 7 Number 1 March 1982

AGER, D.V. 1980. Correspondence on Alternatives to Evol­utionsim. School Science Review 62 (218), 167-170.

ANON 1981. Defending Darwinism. Science Teacher 48 (8), pp. 28 and 30.

BRUSH, S.G. 1981. Creationism/Evolution: the case against "Equal time". The Science Teacher 48 (4),29-33.

CHARIG, A. 1981. Cladistics: a different point of view. Biologist 28 (1 I. 19-20.

GREENWOOD, J.D. 1979. Alternatives to Evolution by natural selection. School Science Review 61 (214),161-3.

HARPER, G.H. 1977. Darwinism and indoctrination. School Science Review 59 (207), 258-68.

HALSTEAD, L.B. 1980. Museum of Errors. Nature 288, p. 208 only.

HALSTEAD, L.B. 1980. Popper: good philosophy, bad science? New Scientist 87 (12101. 215-217.

HARPER, G.H. 1979. Alternatives to evolutionism. School Science Review 61 (214) 15-27.

MOORBATH, S. 1980. Correspondence - alternatives to Evolutionism. School Science Review 62 (2181. 172-3.

MOORE, J.N. & SLUSHER, H.S. 1970. Biology: a search for order in complexity. San Diego, Creation Reserach Society.

PATTERSON, C. 1980. Cladistics. Biologist 27 (5), 234-40.

SEVERAL AUTHORS, 1980. Correspondence - alternatives to evolutionism. School Science Review 61 (216),565-570; 61 (217), 791-792.

COUNCIL OFFICERS

President: Prof G. Kelling, Department of Geology, University, Keele, Staffs. ST5 5BG.

Secretary: M J Collins, 20 Pebworth Close, Alkrington, Middleton, Manchester M24 1QH.

Assistant Secretary: P.F. Cotterell, 207 Hurdsfield Road, Macclesfield, Cheshire, SK10 2PX.

Treasurer: S.M.P. Alcock, 43 Yoxall Avenue, Hartshill, Stoke­on-Trent, Staffs. ST4 7JJ.

Assistant Treasurer: P.W. Williams, 2 Kingsway, Northwich, Cheshire.

Editor: D.B. Thompson, Education Department, University of Keele, Staffs. ST5 5BG.

• Membership enquiries to the Assistant Secretary.

• Annual subscriptions enquiries to the Assistant Treasurer.

• Bankers' Orders enquiries to the Treasurer.

• Changes of address to the Secretary.

Published quarterly by the Association of Teachers of Geology.