ORDOVIOIAN TRILOBITES FROM THE VALONGO AREA, PORTUGAL.

OHEIRURIDAE, PLIOMERIDAE AND DIONIDIDAE

B1"

M. L. K. CURTIS

The Valongo area, east of Oporto, has long been famous for the trilobites found there in the Ordovician rocks. Of par­ticular note are tbose occurring in the Uralichas ribeiroi Sla­tes which are of approximately upper Llanvirn or Llandeilo age. The trilobites ofthis horizon are remarkable both for lheir abun­dance and for the large size atlained by several of lhe species.

Tbe specimens described in the following pages form part of the fine colleclion made by Mr. J. T. Wattison, and recently presented by bim to the British Museum (Natural Hislory), London. Mr. Wattison resided in Oporto between 1910 and 1936, and during tbat pel'iod spent much time collecting from the Ordovician roeks where lhey crop out in tbe hilly country to the soutb of Valongo. As a result of this work he amassed a rich collection from the UralÍ(:has ribeiroi Slates, consisting of more lhan 2500 specimens, of which about 2000 are tri­lobites.

HORIZON AND LOCALLTIES

The specimens described here are from the narrow outcrop of the Uralichas ribeiroi Slates (Division S!) which extends in a south-south-easterly direction from Valongo (see map by DEL-

GADO, 1908, pi. 3). 1'he outcrop is situated on lhe western flank of a range of wooded hills wbich attain an elevation of 376 metres at lhe Serra de Santa Justa, but gradually dimi­nish in height southwards towards the Rio Douro. The spe­cimens were collected by Mr. Waltison from various localities along this outcrop, particularly on lhe western side of ~he Serra de Santa Justa and to the south of lhe Rio Souza near Covelo, and excavations were made by bim in order to obtain material of good qualily.

FAUNA OF THE URALICHAS RIBEIROI RLATES

'rhe Uraliohas ribeiroi Slàtes contain a varied sbelly fauna which includes brachiopods, lamellibranchs, gastropods, cepha­lopods and pteropods. !tis lhe trilobites, howaver, which form the predominant and most characteristie element of the fauna; these are represented by the families Asaphidae, JUae­nidae, Liehidae, Odontopleuridae, Calymenidae, Dalmanitidae, Cbeiruridae, Pliomeridae, Dionididae and Harpidae, and lbey inelude sue h \vell-known species as Pseudobasilious nobilis (Barrande), lllaenus giganteus (Burmeister), Uraliohas ribeiroi Delgado, Pharostoma pulohrum (Beyrieh), Nesuretus trislani (Brongniart), Colpoooryphe arago (Rouault), Dalmanitina maorophthalma (Brongníart), Plaooparia tournemini (Rouault) and Dionide formosa (Barrande). 1'he number of trilobite speeies is not great, but it includes several forms wbich have a wide dislribution in Europe and Norlh Africa.

Except in the case of Uraliohas ribeiroi itself (DELGADO, 1892 and 1897), lhe fauna of lhe llraliohas ribeiroi Slátes has not been deseribed in detail. A faunal list has been gi ven by DELGADO (1908, pp. 106-9), and brief deseriplions or figures of trilobites from the Valongo area ha ve been published by SHARPE (18M3), SALTER (1853), TÔRRES (1936), COSTA (1942) and 1'HADEU (1949). ln addition, THADEU (1955) has given an aecount of the fauna ofthe Arouca area, south ofthe Rio Douro, and compa­rablcl faunas from olher regions ha ve been deseribed, notably the Nesuretus tristani fauna of Almaden in Spain (BORN, 1918).

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ln the present paper the following species are described: Eccoplochile mariana (VerneuiL and Barrande), Âctinopeltis 1vattisoni sp. nov., Placopa1'ia lournemini (Rouault) and Dio­nide formosa (Barrande). Of these, Placoparia lournemini is fairly common at Valongo; the others are rarer.

The horizon of this fauna, in terms of the British Ordo­vician succession, is difficult to assess, chief]y because of the few species common to tbe Portuguese and British strata, the two regions apparently having been. situated in different fau­nal provinces. The Uralichas t'ibeiroi Slates conlain a fauna which shows close affinities with the Llanvirn, and many of the species occurring in these beds are known to range up from Lhe Didymograptus Slates (DELGADO, 1908, pp. 1069). Generally, however, it has been customary to regard the Vra­lichas ribeiroi Slates as belonging to Lhe Llandeilo (COSTA, 1931, p. 39; TEfXEIRA, 1955, p. 25; THADEU, 1955, p. 28). A more detailed study of the fauna as a whole is necessary before the age of these beds can be determined satisfactorily.

Ackno1Vledgmenls. l am grateful to Mr. J. T. Wattison for kindly allowing me to describe this part of his collection and for supplying me with information about the specimens and Lheir occurrence. I wish to tbank Prof. W . .fi'. Wbittard for giving me facilities to carry out the research in tbe Geology Department of the University of Bristol, and for considerable help in preparing the description of Placoparia lournemini. My tbanks are due also to Mr. D. Waddams, who translated much foreign literature for me, and to Mr. E. W. Seavill, who pbotographed the specimens, and I gratefully acknowledge' Lhe award of a grant by the Royal Society of London. Wbile in Portugal and Spain l received much kind help from geolo· gists tbere, and would like to thank particularly Prof. Décio Thadeu of tbe J nstituto Superior Técnico, Lisboa, Prof. Car­los Teixeira of lhe Universidade de Lisboa, Prof. D. Rosas da Silva of the Universidade do Porto, and Prof. Bermudo Melen­dez and Snr. Jacinto Talens of the Museo de Ciencias Natu­rales, Madrid.

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SYSTEMATIC DESCRIPTIONS

FamiJy CHEIRURIDAE Salter

Eccoptochile mariana (Verneuil and Barrande)·

(PI. I, figs. 1.2; PI. II, figs. 1-2; Pi. lIl, fig. 1}

1855 Cheirurus Marianus Verneuil & Barrande, p. 972, pI. ~8, fig. 4. 1896 Vhei'l'urus (Eccoptocheile) marianus Reed, p, 164. 1908 Cheirurus claviger Delgado, pp. 57,80,106. 1918 ÇJhei'l'urus clavige'l' var, marianus Born, p. 351, pi. 27, fig, 1. 1947 Chei'l'urus claviger Thadeu, p. 2~8, pI. 3, figs. 2·3.

Well preserved cranidia, measuring up to 40 mm. in Jenglh, are included among lhe nine specimens examined.

Cephalon is convex and approximately semicircular in outline with a nearly straight posterior margino Glabella is oval, but is truncated posteriorJy and expands slightly towards the fron t; the specimens described here are dislorted and do not show lhe extreme convexily of lhe glabella mentioned both by Verneuil and Barrande and by Born as being one of lhe chief cbaracteristics of the species. F'rontal lobe is short. rrhe three pairs of glabelIar furrows curve inwards and ba("kwards~ lbe anterior pair is lhe most feebly developed, whlle the posterior pair, which reaches batk nearly to lbe occipital turrow, is lhe stl'ongest. A hyposlomal pit is pre-

. senl where the first glabellar furrow meets lhe deep axial furrow, and within lhe pit, on its anlerior side, is a minute granule. Occipital ring is well developed. The median third of the occipital furrow is shallow, but la terally it becomes deeper and narro\ver, swinging back\ovards slightly and then forwards again near lhe axial furrow. An anterior border, wbich surroundslhefrontal lobe of lhe glabella, is somewhat angular in outline and its exterior margin is raised to form a rim. ln some individuais lhe. anterior bordel' is broad, and in olhers is narrow, but lhis apparent difference is probably

5

to be attributed to distortion, and in all other' respects the broad-bordered and narrow-bordered specimens are alike. Fixed cheek is wide and its con vex surface is ornamented with small pits. An eye-ridge starts close to the hypostomal pit and extends postero-Iaterally as far as the palpebral lobe; it appears to be cut into by twú small horizontal grooves, of 'Ivhich lhe anterior one is scarcely more than a pit. Palpe­bral Jobe is genlly curved and is separaled from the rest of the fixed cbeek by a wall-defined groove. Pleuroccipital furrow, which leaves the axial furrow a little behind its junco lion wilh lhe occipital furrow, extends about three-"'Iuarters of the distance to the lateral margino Post.erior border is narrow near the occipital ring but expands laterally. -At its postero-Iateral corner the cheek extends back\vards as a short, tlat, fixigenal spine. Eye is crescentic in shape, and is situa­ted approximately opposite the second glabellar lobe. 'l'be proparian facial suture crosses the anterior border a little in front of the first glabellar furrow and runs in a posterior direction as far as lhe eye-ridge; after following lhe eye-ridge and palpebrallobe the suture swings abruptly outwards, and then curves backwards slightly at the lateral border. }i'ree cbeek is small.

Thorax, which is as wi<;le as the cephalon, is incomplete, but in one specimen ten segments are preserved_ Axis is broad and slightly tapering. Rings extend nearly straight across and have a somewhat rectangular appearance. Pleu­ral furrows are a little in front of the ring turrows, andnot continuous wilh tbem. The inner half of eacb pleul'a is parallel-sided, has a thin, horizon~1 pleural groove, and a small swelling against lhe axial furrow at its anterior comer; the outer half of lhe pleura is represented by a grarlually taper­ing spine which curves gently bacbvards and has an angular dorsal surface.

Pygidium is poorly preserved, but shows an almost trian­gular axis consisting of four rings, and three pairs of blunt spinose pleurae which curve backwards and inwards. ln one specimen (Pl.m, fig. i) the preservation is such that tbe pleurae of the tborax and pygidium appear to bave rounded terminations.

6

Remarks. A closely related form is Eccoptochile clavigera (BEYR CH, 184,5, p. 13, pI., figs. ~·3; BARRANDE, 1852, pi. 40, figs. 1-12; pI. 4~, fig. 1) from the Ddl"{ beds of Bohemia.That species differs from E mariana in the following respects: (1) the frontal lobe is longer; (2) lhe eye.ridge starls a litlle in froot of the first glabellal' furrow, Ínstead of leveI wilh il; (3) the eye is situated furlher forward, being opposite the first glabellar lobe or the second glabellar furrow, a,nd consequently the fixed cheek is slightly larger and more triangular, aod the free cheek is slightly smaller; (4) according to VERKEUIL and BARRANDE (1855, p. 970) the glabella is less convex than in E. mariana.

BORN (1918, p. 35t) considered E.mariana to be a variety of E clavigera, distinguishing it merely by its more convex olabella and narrower formo The differences mentioned above, gowever, are more significant, and are certainJy sufticient reason for retaining E. mariana as a separate species.

Actinopeltis wattisoni sp. novo

(Pi. III, fig. ~; Pi. I V, fig. 1 )

A new _species of ActinopeUis is represented by the inter­nal and external moulds of a single specimen in which the cephalon is incomplete and whicb bas been elongated by com­pressiono The cephalon (excluding tbe projecting portion of tbe glabella) is 16 mm long, the thorax 33 mm, and the pygi· dium 11 mm.

Cephalon is approximately semicircular in ouUine. Tbe large and strongly convex glabella is oval, expanding ante­riorly; in a complete and undistorted specimen the glabella would extend well beyond the fronl of the rest of tbe cepba­lon, and its outline would probably be more rounded. Exter­nal surface of glabella is ornamented by several minute, widely separaled punctae, eacb "vi'ith a depression at its centre. A small bul pronounced pair of basal glabellar lobes is defi-

7

ned by strong glabellar furrows which curve inwards and backwards. Olher glabellar furrows are not visible, but a small depression suggestive of one occurs levei with the ante· rior part of the eye. Occipital furrow is shallow. Occipital ring appears to curve forwards at the centre and to be deve­loped laterally inlo strong forwardly-projecting lobes. Axial furrows are deep and diverge anteriorly, the angle of diver­gence increasing in front of the basal glabellar lobes. Chel"k is moderately convex, and its surface, apart from the lateral and posterior borders, is ornamented with small pits. Late­ral border extends oulwards approximately at right angles to the side of the glabella and then curves backwards. Lateral border furrow is deep, and at tbe fixigenal angle cmves round to join the pleuroccipital furro\\' wbich bas a wavy anterior edge towards the axial furrow. A moderately long, bluntly pointed and strongiy convex fixigenal spine extends backwards and slightly oulwards. Posterior border is bent about midway beLween the axial furrow and the fixigenal spine, and is slightly swollen at tbe point of bending. Tbe crescentic eye is strongly raised and is situated well forward. Anterior branch of thefdcial suture appears to cross the lal,eral border cIose to the poinl where the latter is oveftapped by the gla­beIla, and then runs backwards and ouLwards a little to lhe eye. Close behind lhe eye the facial suture swings round sharply and runs oulwards as far as the lateral border where it curves into a postero-lateral direction. Doublure is nearly as wide as the lateral border and is ventrally convex, but towards lhe fixigenal spine becomes ven\-ally concave.

Thorax consists of twel ve segments. Axis. is narrow but markedly convexo Axial rings curve forwards at lhe centre and are swollen laterally as strong forwardly-projecting lobes; the posterior edge of the ring is sharply defined, but in tront lhe ring is separaled from its articulating half-ring by a shallow ring furrow. Axial furrows are deep. Pleura comprises an outer half which is spinose, and an inner half which consisls of a large flat raised area bounded by thin anterior and pos­terior bands; the raised area carries a faint horizontal rib furrow, and its outline is somewhat square against the axial

8

furrow, witb a small swelling at the anterior corner. At the fulcrum the anterior and posterior bands of the pleura curve forwards a little and end as rounded corners; the raised area at this point becomes bigher and at thesame time thinner (this feature is more pronounced in tbe internal mould tban in the external). '1'he spinose portion of the pleura expands slightly at first, but then gradually tapers, curving backwards and downwards; the dorsal surface of the spine is slightly convex, and the ventral surface is concave.

Pygidium is small and consists of a tapering axis and four pairs of spinose pleurae. Axis comprises four rings and an elongated raised structure wbich may I'epresent a fifth ring; the anterior ring is well developed and is swollen laterally to form small forwardly-projecting lobes, but posteriorly the rings become feeble. Axial furrows decrease in depth rapidly towards the posterior. PleUl ai furrows are shallow. Pleurae curve backwards; in the first three pairs there is a flat inner part whicb is squared in outline against the axial furrow, and is slightly swollen at the fulcrum. The spinose portion of the pleura is long and carries a well defined rib furrow which is strongest in the second and, more particularJy, tbe third pleurae; on the ventral surface of the spine is a groove wbich coinciCles in position with the rib furrow.

Remarks. PRANTL and PRIBYL (1947, p. ~9) bave stated tbat Actinopeltis is known only from the U pper Ordovician of Central Bohemia. THADEU (1947, p. 18, pI. 3, figs. 6-7), however, bas described specimens from Loredo in Portugal as having affinities with A. completus (Barrande), and TERMIER and TERMIER (1950, p. 45, pI. ~O~, 6gs. 1~2) bave referred a cra­nidium from Ikbf n Ouzreg in Morocco to A gryphus (Barrande).

A comparison of the only available specimen of Actino­peltis 1vattisoni is made difficult by its distorted condilion. It differs from all other described members of the genus in possessing twelve thoracic segments instead of eleven. 1'he closest species is A. gryphus (BARRANDE, 1872, p. 88, pI. 3, 6gs 10-17) from the Dd 5 beds of Bobemia, a form with sbort­er 6xigenal spines. A. globosus (BARRANDE, 185~, p. 776, pI. 35,

9

figs. 1-7; pI. 40, figs. 926-27; pI. 43, fig. 27) and A. insoüialis (BARRANDE, 1852, p. 778, pI. 40, figs. 28-31; 1872, p. 89, pI. 7, figs. 15-18) are shown as having smaller fixed cheeks; the latter species, moreover, has no fixigenal spines and its pygi­dial pleurae are less spinose. A. üampletus (BARRAKDE, 1872, p. 86, pI. 2, fig. 41; pI. 5, figs. 38-40) is distinguished by its smaller, non-projecting glabella.

Family PLIOMERIDAI!} Raymond

Placoparia tournemini (Rouault)

(PJ. v, figs. 1-4; PI. VI, figs. 1-2)

1847 Calymene Tout'nemini Rouault, p. 320, pI. 3, fig. 4. 1852 Placoparia Tout'neminei Barrande, pp. 801-3. 1853 Placopat'ia 'Zippei Salter, pp. 159, 160, pI. 7, figs. 2a-e. 1855 Placoparia Poul'nelninei Verneuil & Barrande, p. 963, pI. 23, fig. 6,

6a-c. 1908 Placoparia Zippei Delgado, p. 57. 1908 Placoparia Tourneminei Delgado, pp. 100, 101, 106, 1 LO, 134, 135,

137, 138, 140, 142, Vi3. 1918 Placopat'ia Tout'neminei Born, p. 347, pI. 27, fig. 7a-b. 1942 Placopada tourneminei Sampelayo, p. 703, 1950 Placoparia Tout'neminei Termier & Termier, p. 44, pI. 202, figs. 3,20.

With few exceptions among a collection ofmore than lwo hundred specimens the preservation is in ytie form of internal moulds. 1'here h; a considerable range in size, lhe largest individual measuring approximately 46 mm. in length, of which lhe cephalon accounts for 12 mm., the thorax for 26 mm., and the pygidium for 8 mm.

Cephalon is convex and nearly semicircular in outline. Glabella widens anleriorly, attaining its maximum at the levei of lhe first glabellar lobes where it is half as w.ide again as al the frontal 10be. Axial furrows are straight and deep. Ofthe lhree pairs of glabellar lobes, the first is subangular and the others are rounded. First glabellar furrows curve backwards

10

at aboul 45°, while Lhe second and Lhird are almost horizon­tal. Anterior border furrow is moderately strong medially, but becomes weak laterally where it .curves back to join the firsl glabellar furrows. Anterior border is narrow and tumid and in a few favourably preserved specimens is cros~ed by seven ridges separated by grooves. Occipital furrow is mode­rately deep. The convex occipital l'ing curves forwards slightIy at the centre wlth a tendency for lobes lo be deve­loped laterally, and, in external moulds, carries a minute gra­nule at its summit. Fixed cheek is large and rises sharply from the surroundilJg furrows. Pleuroccipital furrow is strong. P03terior border is wedge-shaped; its lateral edge is indented, apparently for Lhe reception of the posterior extremity of the free cheek, and lhis gives it the appearance of having a smaU fixigenal spine. Opposite lhe first glabellar furrow, and appearing as a continuation of that furrow, is a groove which extends outwards and curves round on the cheek to form the lateral border furrow. At tbe point where this groove meets the axiàl furrow there is a minute bypostomal pito A second groove extends outwards approximately opposite lhe first glabellar lobe, then curves postero-Iaterally, but rapidly weakens and soon dies out. These lwo grooves define a ridge which may be the remnant of an eye-ridgf'.

Facial suturevery nearly cuLs the postero·laLeral angle of lhe cephalon, but whelher it is proparian or opislhoparian Ís not clear.~:-Traced fOfVvards the suture curves oulwards and thf'n inwards at the levei of Lhe pleuroccipital furrow, migra­tes across tbe lateral border furrow on to the free cheek, again crosses lbis furrow opposite toe end of the eye-ridge, and moves on to the anterior bordel' where it is separated in the mid-line from the facial sutureof the opposite side by a nearly triangular rostral pIa te. Rostral sulure is in almost direct con· tinuation with tbe facial sutures, and lbe connective sutures converge downwards. Tbere are no eyes. Free cbeek con­sists of little more Lhan the lateral border, and its anterior edge is crossed by six 01' seven transverse ridges with alter­nating grooves, fOl'ming a lateral sequence with similar ridges which cross Lhe anterior border.

1\

Externally, lhe cephalon is ornamented by granules; those on tbe anterior border and free cheeks are exceedingly fine and dense, white lhose on lhe glabella ano fixed cheeks are slightly coarser and more widely separaled. ln addition, lhe fixed cheeks carry pits which are noliceably larger than lhe granules.

Hypostome, which is preserved only in a distorted condi- . tion, appears to consist of a single convex lobate area, sur· rounded by a groove and a pronounced lateral and posterior border. Lobate area is tongue-shaped with a straight anterior edge, and is ornamented with fine granules. Antero-lateral corners of lhe hypostotI!e are produced into wings. l'raced posteriorly the hypostome seems to be nearly parallel-sided, but at about two·thirds its lenglh lhe sides converge to form a blunt\y pointed terminatíon. Neither posterior wings nor maculae have been detected.

Thorax consists of eleven segments. Axis is broad, strong­ly arched and slightly tapering. Axial rings curve forwards centrally and are swollen laterally lo form smalL forwardly­projecting lobes. Each pleura consists of flat anterior and posterior bands separated by a strongly raised median portion which is slightly swollen near lhe axial furrow and at the fulcrum, and extends beyond the outer edge of lhe rest of lhe pleura as a bicon vex bluotly-pointed spine; the latter is directed steeply downwards anel slightly ba('kwards, and thus makes a sharp bend at lhe fulcrum.

Pygidium is small. Conical axis carries four distinct rings and a minute hemispherical terminalpiece. Rings extend nearly straight across lhe axis '.\·ilh little t,éndency to curve forwards, and are separated by broad, deep rihg furrows. Thel'e are four pairs of pleurae, each having a strongly convex median portion, similar to lhat of the thoracic pleurae but more pro­nounced; lhe con vex surface extends oUlwards, increases in size, and theo turns abruptly downwards to end in a blunt spine. The effect is like a series of four claws on eilher side of the pygidium.

Remarks. Placoparia tournemini is structurally close to P. zippei(Boeck)from lhe Ddn beds of Bohemia (BARRANDE,1872,

1~

p. 106, pI. 8, figs. 28.42; PRANTL and SNAJDH, 1957, pp. 505, 518, pI. 32, figs. 8-15) and from lbe Didymograptus bi{-idus Zone of Britain (WHlTTARD, 1958, p. 104, pI. 14, figs. 6·10), but differs in having eleven lhoracic segments instead of twelve, and in possessing transverse ridges and grooves on the anterior and lateral borders of lbe cephalon.

Family DlONIDIDAE Gürich

Dionide formosa (Barrande)

(Pl. VII, figs. 1.~; PI. VIII, fig. 1)

1E46 Dione formosa Barrande, p. 33. 1847 Dionide fOt'mosa Barrande, p. 391. 184-7 Polytomu,'us formosus Hawle & Corda, p. 37, pI. 3, fig. 16. 185~ Dionide fOt'mosa Barrande, p. Oi!, pI. 4~, figos. ~4, ~. nan figs. ~5·~7. 1908 Dionide formosa Delgado, pp. 10~, 106, 134, 135. 19~5 Dionide formosa Raymond, p. ~~; 195~ Dionide fOt'mosa Whittington, p. 6, pI. 1, figs_ 1, ~,5, text-fig. 1.

Tbe tbirly-six specimens studied are preserved as inter­nal and external rrioulds. _ Tbe largest individuaIs are appro­ximately 25 mm. -itl lengtb, and tbe genal spines may be more than twice the lengtb of tbe tborax and pygidium together.

A detai-ted description of material from the Dds beds of Bobemia bas been given by BARRANDE (1852, pp. 641 2) and supplemented by remarks, chief]y on tbe fringe and doublure, by WHlTTINGTON (1952, pp. 6-7, text-fig. 1). Tbe Portuguese specimens show some addilional points of interest. Tbe gIa­bella carries a single spine which in internal and some exter­nal moulds appears as a tUbercle, but in oLber external moulds is seen as a distinct spine which apparentIy curves backwards and in one specimen (ln 49169) is at least 5 mm. longo Tbe exterior margin of lhe cepbalon is raised as asmall rim which forms lhe dorsal surface of the girder; on its outer and ventral surfaces the lalter is striaLed longiLudinally. Fragmenls of lbe doublure (ar lower lamella of lbe fringe of WHlTTINGTON,

13

1952, p. 6, text-fig. 1) are preserved in a single specimen (Pt. VII,

fig. 1) as a thin perforated layer. ln the pygidium about 16 axial rings and 14 pairs of pleurae are visible.

Remarks. The presence of a glabeIlar spine in Dionide formosa was indicated by HAWLE and CORDA (184:7, pI. 3, fig. 16), but has not been confirmed by subsequent workers, probably because their sLudies were based chief]y on internal moulds in which the base of lhe spine generally appears as a tubercle.

REFERgNCES

BARRANDE, J. (1846). Notice préliminaire sur le Systeme silurien et les trilobites de Bohême. Leipzig.

-- (1847). Über das Hypostoma und Epistoma, zwei analoge, aber verschiedene Organe der Trilobiten. Neues Jahf'b, f. Min. 6eog.6eol, u. Petf'efakten·Kunde, 385·99. Stuttgart.

-- (185~). Systeme silurien du centre de la Bohême. l ére partie. Recherehes paléontologiques. 1. Prague & Paris.

-- (1872). Systeme silurien du centre de la Bobême. lere partie. Recherches paléontologiques. 1. Supplément. Prague & Paris.

BEYRICH, E. (1845), Ueber einige bõhmische Trilobiten. BerJin. BORN, A. (1918). Die Calymene Tt'istuni·Stufe (mitlleres UntersiJur) bei

Almaden, ihre l"auna, Gliederung und Verbreitung . .Abhandl. Sen­ekenberg. Naturf. 6esell., 36, (3),309·53. Frankfurt am Main. Trans­lated into Spanish by B. MELENDEZ (1953), Puby. exl1'anj. sob1'e geol. Espaiia,7, (3), 175-259. Madrid. I

COSTA, J. C. da (1931). O Paleozóico português (Síntese e crítica), Porto. -- (194~). Notas sôbre a família CaJymenidae. Bol. Soe. 6eo1. Portu­

gal, 1, (~), 91-100. Porto. DELGADO, J. F. N. (1892). Fauna silurica de Portugal. Descripção de uma

fórma nova de lrilobite: Liehas (U1'aliehas) 1·ibeÍf'oi. Nem. Gomln. T1'ab. 6eol. Portugal. Lisboa.

-- (1897). Fauna siluricade Portugal. Novas observações ácerca de Lichas (Uf'alichas) f·ibeiroi. Meln. Comln. T1·ab. 6eo1. rm'tugal. Lisboa.

-- (1908). Systeme siJurique du Portugal. Étude de stratigraphie paléontologique. 1I1em. Comm. Servo 6eol. Pm·tugal. Lisboa.

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HAWLE, I. and CORDA, A. J. C. (1847). Prodrom einer Monographie der bõhmischen Trilobiten. Prague.

PRANTL, F. and PRIBYL, A. (UH7). Classíficalion of some Bohemian Chei­ruridae (Trilobitap). Sbm'n, Národ. Mus, Pt·az6. Acta Mus. Nat. Pmg., 3 B, (1), 1-44. Prague.

PRANTL, F. and SNAJDR, M. (1957). Studie o rodu Placoput'ia Hawle a Corda (Trilobílae). Sborn. úst. Úst. g601., 23 PaI., 497-521. Prague.

RAYMOND, P. E. (1925). ~ome .trilobites of the Lower l\Hddle Ordovician of eastern North America. Btdl. Mus. Comp. Zool. (Harvard), 67, (1), 1-180. Cambridge, Mass.

REED, F. R. C. (1896). Notes on the evolution of lhe genus Ch6irurns. G601. Mag, (4),3, 117 -23,161-7. London.

ROUAULT, M. (1847). Exlrait du mémoire SUl' les trilobites du département d'Ille-et-Vilaine. Bull. Soe. géol. Ft'ance, (~), 4, 309-28. Paris.

SALTER, J. W. (1853). Notes on the trilobites. (Appendix C to "On lhe Carboniferous and Silurian formations of the neighbourhood of Bus­saco in Portugal" by C. RIBEIRO). Quat·t. Journ. G60l. Soe. 9, 15860. London.

SAlIlPELAYO, P. H. (1942). Explicación de! nuevo mapa geológico de Espafía. 2, E! Sistema Siluriano. M6m. Inst. G60l. Min. Espaí"ía. Madrid.

SHARPE, D. (1848). On lhe geo!ogy or the neighbourhood of Oporto, in­cluding the Silurian coa! and s!ates or Vallongo. Quart. Jouf'n. Geol. Soe.; 5, 142-53. London.

TEIXEIRA, C. (1955). Notas sobre geologia de Portugal. O Sistema Silú­rico. Lisboa.

TERMrER, G. and H. (1950). Paléonlologie marocaine. 2, ~nvertébrés de l'Ere Primaire. Fase. 4, Annélides. A rthropodes, Echinodermes, Conularides et Graptolithes.'"' Paris.

'rHADEü; D. (194i). Trilobites do Silúrico de Loredo (Buçaco). Bol. Soe. G60l, POf'tugal, 6, (3), 2L7-36. Porlo.

-- (L949). "Galimenídeos portugueses. Bol. Soe. Geol. Pm'tt~gal, 8, (L-2), 129-34. Porto.

-- (1955). Note SUl' le Silurien beiro-durien. Bol. Soe. G601. Pm'tugal, 12, (L-2), 1-38. Porto.

TÔRRES, A. S. (1936). Uma raridade paleontológica. Nahwalia, 1, (2), 113-6. Lisboa.

VERNEurL, E. DE and BARRANDE, J. (1855). Description des fossiles trouvés dans les terrains silurien et dévonien d' Almaden, d'une partie de la Sierra Morena et des montagnes.de Tolêde. Bull. Soe. géol. Franc6, (~), 12, 964-1025. Paris.

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WHfTTINGTON, H. B. (L952), The trilobite family Dionididae. Jouf~n.

Paleont., 26, 1-11. Tulsa.

15

EXPLANATIDN DF THE PLATES

The specimens illustrated are in the Department of Palaeontololl'Y, British Museum (Natural History), London. Photographs areby Mr. E. W. Seavil!.

PLATE I Eccoptochile ma1'iana (Verneuil and Barrande)

Fig. 1 - Internal mould of cranidium showing hypostomal pits, eye­-ridge, aud ornamentation of fixed cheek (!n 49177). Covelo. x~.

Fig. ~ -Internal mould of crauidium aud part of thorax ([n 49178). Covelo. X 2.5.

PLATE II Eccoptochile ma1'iana (Verneuil and Barraude)

Fig. 1 - Internal mould of cranidium and pygidium (ln 49179). Covelo. x~.

Fig. ~ - Distorted internal mould of cephalon showing eye and free cheek (ln 49180), Covelo. x~.

PLATE 1Il Eccoptockile ma1'iana (Verneuil and 8arrallde)

Fig. 1 - Latex cast of external mould of part of thorax and pygidium (ln 49181), Santa Justa. X~.

Actinopeltis 1vattisoni sp. novo

Fig. ~ - Latex cast of external mould of part of cephalun and lhorax of holotype (ln 49184). Covelo. x 2.5. /

PLATEIV Actinopeltis 1vattisoni sp. novo

Fig, 1 - Internal mould of hololype (lu 4918i). Covelo. X 2 5.

PLATE V Placopa1'ia tournemini (Rouaull)

Fig. 1 - Internal mould ([n 49159). Covelo. x 2. Fig. ~ - Internal mould with free cheeks slightly displaced (ln 49160),

Valongo area. X~,

I •

16

Fig. 3 - InLernal mould of pygidium seen obliqueJ y from Lhe poste­rior (lo 49164). Santa Justa. X 3.

Fig. 4 - Latex cast of exte'rnal mould of cephalon with displaced free cheek; showiog ornameotatioo and transverse ridges on a nterior border and on lateral border of free cheek (lo 491 61). Covelo. X5.

PL ATE VI Placopal'ia tournemini (Ronaul t)

Fig. 1 - Slab wilb ex ternal mould of cephaloo and thorax and severai internal moulds (In 49 16:l). Covelo. x ~.5.

Fig. ~ - E xtE)rnal mould of cephalon showing facial suture (ln 491611). Co velo. x 6.

PLATE VII Dionide fonnosa (Ban'ande)

Fig . 1 - Internal mould with fragments of Lhe perforated doublure of the cephaloo (lo 49170). Saota Justa. x 3.

Fig. ~ - Internal mould showing genal spines (ln 49 I(8). Santa J usta. X '!.5.

PLATI!; VlII Dionide fOl'mosa (Barrand e)

Fig. l .- Latex cast or external mou ld showiog ornamentation of cephalon, genal spine and base of g labellar sp ine (ln 49167) . Sanla Justa. X 4.

M. L. K. CURTIS - Trilobites trom lhe Va longo area PL. I

2 Bol. Soe. Ceol. de po,·I u.gdl - Vol . X IV - 1961

M. L . K. CURT[S - Trilobites from lhe Valongo arex PL. II

2

M. L. K. CU RTtS - Trilobites from lhe Valongo area PL. III

2 B oi . Soco Clol. de Portuga l - Vc l. XIV - 1961

lVI. L. K. CURTIS -- Trilobites froln lhe Valongo area PL. IV

M. L. K . CURTIS - Trilobites from lhe Valongo area PL. V

2

3

4 BoI. Soe. Geol. de P01't"gal - Vol . XIV - 1961

M. L K . C URTIS - Trilobites {rom fhe Valongo area PL. VI

2

M. L. K C URTIS - Trilobites Irom the Valongo area PL. VII

2 Boi. S oe. Geol. de Podugal . Vol. X IV -196i

M. L. K. CURTIS - Trilobites trom the Valongo area PL. VIII