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GEOLOGY VOL. 33, NO. 2

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GEOLOGY

VOL. 33, NO. 2

CONTENTS

Looking under the grass .......................................................................... 1Reefs, ripples, and rocks—Home at last....................................................... 2Earth science teachers’ corner—Earthquake hazard in Pennsylvania ..... 8New releases ........................................................................................... 9

Moraine and McConnells Mill State Parks............................................ 9Geologic shaded-relief map of Pennsylvania ....................................... 10

In memoriam—Jesse L. Craft, 1930–2002............................................... 12

ON THE COVER

Two museum-quality rock specimens on display at the Middletown office ofthe Pennsylvania Geological Survey. The one in the front shows two setsof ripple marks (called interference ripples), and the one in the back is partof an ancient coral reef formed by the colonial coral Halysites (see articleon page 2). Photograph by Gary M. Fleeger.

PENNSYLVANIA GEOLOGY

PENNSYLVANIA GEOLOGY is published quarterly by the Bureau of Topographic andGeologic Survey, Pennsylvania Department of Conservation and Natural Resources,3240 Schoolhouse Road, Middletown, PA 17057–3534.Editors: Anne B. Lutz and Jay B. Parrish.Contributed articles are welcome. Guidelines for manuscript preparation may be obtainedat www.dcnr.state.pa.us/topogeo/pub/mag-ins.htm or by contacting the editors at theaddress listed above.Articles may be reprinted from this magazine if credit is given to the Bureau of Topographicand Geologic Survey.

VOL. 33, NO. 2 SUMMER 2003

DEPARTMENT OF CONSERVATION AND NATURAL RESOURCESBUREAU OF TOPOGRAPHIC AND GEOLOGIC SURVEY

IN COOPERATION WITH THE U.S. GEOLOGICAL SURVEYTOPOGRAPHIC MAPPING

GROUNDWATER-RESOURCE MAPPING

Main Headquarters3240 Schoolhouse RoadMiddletown, PA 17057–3534717–702–2017FAX: 717–702–2065

Pittsburgh Office500 Waterfront DrivePittsburgh, PA 15222–4745412–442–4235FAX: 412–442–4298

BUREAU STAFF AND TELEPHONE NUMBERSDirector and State GeologistJay B. Parrish, P.G. 717–702–2053

Assistant DirectorSamuel W. Berkheiser,

Jr., P.G. 717–702–2055

Administrative ServicesLynn M. Goodling 717–702–2054Elizabeth C. Lyon 717–702–2063

Library ServicesRichard C. Keen 717–702–2020Lewis L. Butts, Jr. 717–702–2018

Publication ServicesJody R. Zipperer

(General Inquiries) 717–702–2073Christine E. Miles, P.G. 717–702–2044Caron E. O’Neil, P.G. 717–702–2042Anne B. Lutz 717–702–2043

Local Government Outreach ServicesKristen L. Reinertsen

(East) 717–702–2047Jaime Kostelnik (West) 412–442–5828

Database ServicesCheryl L. Cozart 412–442–4234Janice Hayden 412–442–4287Joseph E. Kunz 412–442–4235Lynn J. Levino 412–442–4299Karen L. McCoy (Oil and

Gas GIS Services) 412–442–5826

GIS ServicesMichael E. Moore, P.G. 717–702–2024John H. Barnes, P.G. 717–702–2025Thomas G. Whitfield, P.G. 717–702–2023

GIS Services (continued)Stuart O. Reese, P.G. 717–702–2028John G. Kuchinski 717–702–2027

Water Well ServicesSharon E. Fesus 717–702–2074Jody R. Zipperer 717–702–2073

Groundwater ServicesGary M. Fleeger, P.G. 717–702–2045Thomas A. McElroy, P.G. 717–702–2046

Geologic Mapping ServicesJon D. Inners, P.G. 717–702–2034Gale C. Blackmer 717–702–2032Helen L. Delano, P.G. 717–702–2031Clifford H. Dodge, P.G. 717–702–2036William E. Kochanov, P.G. 717–702–2033James R. Shaulis, P.G. 717–702–2037Viktoras W. Skema, P.G. 717–702–2035

Laboratory and Geochemical ServicesRobert C. Smith, II, P.G. 717–702–2021Leslie T. Chubb 717–702–2022

Coal-Bed Methane ServicesAntonette K. Markowski,

P.G. 717–702–2038

Coal Quality and Availability ServicesRodger T. Faill, P.G. 717–702–2041Leonard J. Lentz, P.G. 717–702–2040John C. Neubaum 717–702–2039

Oil, Gas, and Subsurface GeologicalServicesJohn A. Harper, P.G. 412–442–4230Christopher D. Laughrey 412–442–4232Joseph R. Tedeski 412–442–4295Kristin M. Carter, P.G. 412–442–4233

COMMONWEALTH OF PENNSYLVANIAEdward G. Rendell, Governor

DEPARTMENT OF CONSERVATION AND NATURAL RESOURCESMichael DiBerardinis, Secretary

OFFICE OF CONSERVATION AND ENGINEERING SERVICESRichard G. Sprenkle, Deputy Secretary

BUREAU OF TOPOGRAPHIC AND GEOLOGIC SURVEYJay B. Parrish, Director

Bureau web site: www.dcnr.state.pa.us/topogeoDCNR web site: www.dcnr.state.pa.us

Pennsylvania home page: www.state.pa.us

STATE GEOLOGIST’S EDITORIAL

Looking Under the Grass

Our Assistant State Geologist, Sam Berkheiser, frequently saysthat our job is to get people to “look under the grass.” By that, hemeans that the surface of a nice subdivision may look normal, butunderneath the surface, the geology may determine if there will beenvironmental problems down the road. It is better to plan around thegeology than assume that the earth is an infinite homogeneous half-space. An infinite homogeneous half-space is a convenient construc-tion by geophysicists, who assume that the earth is the same in alldirections below the surface—kind of like dividing the universe intotwo halves, air and rock. It makes the mathematics of modeling theearth much easier, but doesn’t really capture just how diverse theworld really is.

The earth is much more complicated than an infinite homoge-neous half-space. But when all we see is suburban grass, we maymake the mistake that it is all the same underneath. As good stew-ards of natural resources, we need to plan which water, mineral, en-ergy, and rock resources should be considered before developingthe land surface. For instance, we don’t want to pave over our best

water supply or put subdivisions on top ofour only source of paving stone. Addition-ally, all those radon-bearing fractures andareas of potential sinkholes can exist underthe most uniform of man-made lawns.

If we “look under the grass,” we’ll seea much more complicated world. But we’llbe glad we looked.

Jay B. ParrishState Geologist

MOVING THE ROCKS. Anyone who ever visited the Harrisburg of-fice of the Pennsylvania Geological Survey in the Executive House,where we were quartered from 1975 to 1993, may remember two largeboulders on display in the garden near the rear parking lot. After 10years of separation, these display boulders have finally found theirway home to our new office near Middletown (see back cover), whichwe have occupied since January 2002.

When the Survey moved in 1993 from the Executive House tothe Evangelical Press Building in uptown Harrisburg, we were forcedto leave these large boulders behind because there was no placeoutside the Evangelical Press Building where they could be displayed.When we moved to our current home, we began the process of hav-ing our boulders moved from the Executive House so they could onceagain be displayed near our office. In late May 2003, workers fromthe Bureau of Forestry generously donated their time and equipmentto move the rocks for us. Robert “Pete” Peters and Frank Mertz ex-pertly loaded the rocks, transported them to our new office location,and placed them in the grass adjacent to our parking lot (Figure 1).

After they arrived and were placed, one of the authors, GaryFleeger, began to wonder about the display history of the two rocks.Both preceded his employment with the Survey, and, in fact, one pre-ceded the employment of almost everyone currently at the Survey.That one is an estimated 3-ton specimen. A plaque on it indicatesthat it is a 400 million-year-old fossil coral reef from Bloomsburg (Fig-ure 2). The other rock, a beautiful specimen of interference ripples,had no plaque and no explanation.THE RIPPLED ROCK. Thomas Berg, currently the State Geologistof Ohio and formerly the Chief of the Geologic Mapping Division atthe Pennsylvania Geological Survey, was recently in town for a con-ference that Gary also was attending. During a break, Gary corneredTom to interrogate him on his knowledge of the two rocks. Tom recalledthat he had found the rippled rock (Figure 3) in 1978 in the Catskill

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Reefs, Ripples, and Rocks—Home at Last

by Gary M. Fleeger and Donald M. Hoskins1

Bureau of Topographic and Geologic Survey

1State Geologist Emeritus.

Formation along U.S. Route 6 in Tioga County while doing reconnais-sance work for the 1980 Geologic Map of Pennsylvania (Berg andothers, 1980). He mentioned it to Donald Hoskins (one of the au-thors and, at that time, Assistant Director of the Survey), who wentto see it. Don inquired about the rock at the Pennsylvania Depart-ment of Transportation (PennDOT) and discovered that the decisionhad been made to destroy it. Because of the museum quality of thespecimen, Don asked PennDOT staff if they could preserve it andtransport it to Harrisburg to be put on display. He left his name andoffice location with the PennDOT staff and returned to Harrisburg.Some time later, a flatbed truck pulled into the Executive House park-ing lot. The driver asked Don where he wanted the rock to be placed,it was unloaded, and we had our rippled display rock.“TADPOLE NESTS.” The ripple-marked rock is a single layer ofsandstone. Its component quartz sand and associated dark miner-als (such as mica) were deposited quickly from marine currents inthe Late Devonian seas that covered what is now northern Pennsyl-vania. Most of these seas were relatively shallow, and their currentsand waves were similar to those in present-day shallow coastal seas.

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Figure 1. “Pete” Peters and Frank Mertz of the Bureau of Forestry stand nextto the fossil coral reef specimen that they had just moved from the ExecutiveHouse to our new office near Middletown.

Following deposition of the sand, current action in the shallow wa-ters above the sand produced “waves” in the deposit. These wavesare now the preserved ripple marks. The crests (uppermost part) of theripple marks are oriented perpendicular to the current flow. When ripple-marked rocks are found in outcrop it is thus possible to determine thedirection in which the current was flowing when the ripples were formed.

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Figure 2. Plaque on the coral reef specimen.

Figure 3. This specimen preserves two sets of ripple marks (interference rip-ples). The older set trends from lower left to upper right.

Because two sets of ripple marks are preserved, we can con-clude that the sand layer experienced flow from two very different di-rections. The set of ripples that is most prominent was the first oneformed. It has a longer wavelength and greater ripple height than thesecond set. Later, another current flowed over the sand layer from adifferent direction and produced the second set of ripples, which “in-terfere” with the original set. Thus, such dual sets of ripple marks arecalled interference ripple marks. Interference ripples are known col-loquially as “tadpole nests” because they were originally thought tohave been excavated by tadpoles (Hitchcock, 1858). In our specimen,the ripples in the younger set are largely confined to the troughs ofthe older set. The second current probably had a lower velocity and/oroccurred in shallower water than the first. However, its velocity wassufficient to move the as yet unhardened sand grains so that the newripple marks could be formed without destroying the first set. Thereare a number of possible explanations for why the current changeddirection, including interfering waves and tidal- or stream-current flow,or the influence of storms.

Soon thereafter, additional sediment was deposited over the twosets of ripple marks, preserving them to the present day.

THE CORAL REEF ROCK. The coral reef specimen (genus Halysites)is half of a larger specimen that came from limestone of the Silurian-Devonian Keyser Formation. Richard Conlin and Don Hoskins foundit in a quarry (the Grovania quarry of the Lycoming Silica Sand Com-pany, located between Bloomsburg and Danville in Columbia County)when they were doing the reconnaissance work for the 1960 Geo-logic Map of Pennsylvania (Gray and others, 1960). When they sawthe specimen, it had been discarded by the quarry operators be-cause it was too large and the silicified corals degraded the qualityof the limestone. At that time, Donald Hoff (the geologist curator forthe State Museum when it was completed in 1965) was looking forgood specimens to install in the new geology section of the museum.He came to the Survey for suggestions. Staff members thought thatthis rock would be an excellent showpiece for the new museum, andhe was taken to the quarry to see it. He agreed that it was a finespecimen but said that it was too large and too heavy for the mu-seum. The Survey went back to the quarry owners and asked if theywould break it into two specimens. When they learned that a portionof this rock would be in the museum, they agreed to drill it into twoparts. They also consented to bring both halves to Harrisburg.

Exactly where the Survey’s half of the rock was first displayed isnot certain. The Survey office was in the South Office Building until

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after the new State Museum opened in 1965. It then was moved tothe Old Museum (which is now the Ryan Office Building) adjacent tothe Capitol. However, no one has any recollection of the rock everbeing at the South Office. Apparently, the first display location of therock was outside the Old Museum.

The Survey made its infamous move to Cameron Street in 1972,just in time for the flood caused by tropical storm Agnes, but, luck-ily, the rock had not been moved to Cameron Street. The rock alsodid not follow the Survey during its several moves to temporary post-flood homes. It was moved when the Survey relocated to the Execu-tive House in 1975, where it remained until May 2003.

The specimen was most likely from the Jersey Shore Member ofthe Keyser Formation. More commonly, the Jersey Shore Membercontains stromatoporoids (extinct Paleozoic marine sponges), ratherthan coral reef beds (Jon Inners, personal communication, 2003). TheKeyser was deposited in a shallow marine, subtidal shelf environment.The corals and stromatoporoids occurred in shallower and more oxy-genated, nutrient-rich areas (Inners, 1981).

THE CORAL HALYSITES. The predominant coral in the specimen isthe genus Halysites, or chain coral. Halysites is a widespread fossilthat occurs in rocks of the Ordovician and Silurian Periods on nearlyall continents. It was known to Linnaeus, the famous scientist whodeveloped the style of naming groups of living and fossil plants andanimals by genus and species. Linnaeus called it Tubipora in 1767(Linnaeus, 1767). Later, the paleontologist Fischer renamed it Allysites(Fischer, 1813), and still later (Fischer, 1828), he changed its nameto Halysites, by which it has been known ever since. When seenfrom above (Figure 4), the fossil appears as anastomosing chains(networks of branching and rejoining chains) of small rings. Whenseen from the side, each ring is actually a small three-dimensionaltube that is connected to at least two more similar tubes. When theorganism was alive, a small, fleshy coral animal lived attached at thetop of the tube, its tentacles waving about in the sea water, collect-ing bits of food that were then ingested. As it lived, it grew by de-positing calcium carbonate vertically on the tube walls. Thousandsof tubes grew together and formed a network (called a colony) thateventually trapped calcium carbonate between the chains, which be-came the hard rock in which we now find the fossil. Later, silica se-lectively replaced the calcium carbonate deposited by the animal, butnot the sedimentary calcium carbonate trapped in the spaces be-tween the chains of tubes.

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When you stop by our Middletown office, be sure to examinethese two outdoor display rocks (see photograph on front cover), aswell as many smaller specimens on display in our lobby and through-out the building.

REFERENCESBerg, T. M., Edmunds, W. E., Geyer, A. R., and others, compilers, 1980, Geologic map

of Pennsylvania: Pennsylvania Geological Survey, 4th ser., Map 1, scale 1:250,000.Fischer von Waldheim, G. F., 1813, Zoognosia tabulis synopticus illustrata [editio

tertia]: Moscow, Nicolai S. Vsevolozsky, v. 1, 465 p.________ 1828, Notice sur les polypiers tubipores fossiles: Moscow, Imp. de l’Uni-

versité Impériale, p. 9–23.Gray, Carlyle, Shepps, V. C., Conlin, R. R., and others, compilers and eds., 1960,

Geologic map of Pennsylvania: Pennsylvania Geological Survey, 4th ser., Map 1,scale 1:250,000.

Hitchcock, Edward, 1858, Ichnology of New England; a report on the sandstone ofthe Connecticut Valley, especially its footmarks: Boston, William White, 220 p.

Inners, J. D., 1981, Geology and mineral resources of the Bloomsburg and Mifflin-ville quadrangles and part of the Catawissa quadrangle, Columbia County, Penn-sylvania: Pennsylvania Geological Survey, 4th ser., Atlas 164cd, 152 p.

Linnaeus, Carolus, 1767, Systema Naturae [12th ed.]: Laurentius Salvius (Holmiae),v. 1, pt. 2, p. 533–1327.

Figure 4. Detail of Halysites, showing the chains of individual tubes.

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The Pennsylvania GeologicalSurvey has recently published thesecond edition of EducationalSeries (ES) 10, Earthquake Haz-ard in Pennsylvania. The 14-page booklet was revised byCharles K. Scharnberger, a re-tired professor at Millersville Uni-versity who also wrote the origi-nal version.

Earthquakes occur when thereis a sudden release of stored en-ergy as rocks fracture along faultplanes within the earth. The en-ergy travels through the earth oralong its surface as seismicwaves. These waves can be de-tected and recorded by seismo-graphs. The magnitude of an earth-quake (on the Richter scale) is anumber that expresses its size

relative to other earthquakes.Magnitude is based on the am-plitude of the waves recorded bythe seismograph. The largestknown Pennsylvania earthquakeoccurred in 1998 in Mercer Countyand had a magnitude of 5.2.

In Pennsylvania, the earth-quake hazard is low. A map inES 10 shows the relatively smallnumber of earthquakes that hadepicenters in our state. Most of theepicenters are concentrated in thesoutheastern part of the state.More specific information aboutPennsylvania earthquakes is in-cluded in a table in the booklet.

The author analyzed three re-gions in the eastern part of thecountry that have had earthquakesin the past that have affected ourstate. He concluded that futureearthquakes there would proba-bly cause little or no damage here.

The author also included anearthquake-hazard map for thestate, which shows areas wherecertain levels of ground shakingcould be caused in the future byearthquakes both in and outsidethe state.

Copies of ES 10, as well asother booklets in the EducationalSeries, are free upon request fromthe Pennsylvania Geological Sur-

COMMONWEALTH OF PENNSYLVANIADEPARTMENT OF

CONSERVATION AND NATURAL RESOURCESBUREAU OF TOPOGRAPHIC AND GEOLOGIC SURVEY

Educational Series 10

Earthquake Hazard

in Pennsylvania

Earthquake Hazard

in Pennsylvaniaennsylvaniain P

e HazardEarthquakennsylvaniain P

e HazardEarthquak

EARTH SCIENCE TEACHERS’ CORNER

Earthquake Hazard in Pennsylvania

9

vey, 3240 Schoolhouse Road,Middletown, PA 17057–3534,telephone 717–702–2017. Thebooklets are also available as

PDF files on the Survey web siteat www.dcnr.state.pa.us/topogeo/pub/pub.htm.

NEW RELEASES

Moraine and McConnells Mill State Parks

The Bureau of Topographicand Geologic Survey, in cooper-ation with the Bureau of StateParks, recently published ParkGuide 4, Moraine and Mc-Connells Mill State Parks, But-ler and Lawrence Counties—Glacial Lakes and DrainageChanges. This new addition tothe “Trail of Geology” series com-bines former Park Guides 4 and9, which had addressed the twoparks separately. In this two-color,well-illustrated 13-page booklet,Survey geologist Gary M. Fleegerand Slippery Rock University Pro-fessors Emeriti Kent O. Bushnell

and Donald W. Watson explorethe geologic history of the parksand highlight places of geologicinterest. A centerfold map showsthe extent of geologic formationsand the southeast limit of glacia-tion with respect to the parks, aswell as the locations of featuresand sites described in the guide.

How two parks that look so dif-ferent can be geologically relatedis the story of this park guide. Thedissimilar topography of the twoparks resulted from the same gla-cial events. Lake Arthur, in Mor-aine State Park, exists at the siteof a former glacier-dammed lake,

called Lake Watts. SlipperyRock Gorge, in McConnellsMill State Park, containserosional features—narrowgorges and rapid streams,

A rock city along the exit road inMcConnells Mill State Park. Itwas formed by separation alongvertical cracks in the bedrock.

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numerous waterfalls, and rockcities—that resulted from thedrainage of Lake Watts and otherglacial lakes.

Park Guide 4 and an expand-ed interactive version of theguide are posted on the Surveyweb site at www.dcnr.state.pa.us/topogeo/parkguides/trail.htm.The published guide is availableto visitors at the park office,which is located at MoraineState Park, 225 Pleasant ValleyRoad, Portersville, PA 16051–

9650, or it can be obtained fromthe Pennsylvania Geological Sur-vey, 3240 Schoolhouse Road,Middletown, PA 17057–3534,telephone 717–702–2017.

Geologic Shaded-Relief Mapof Pennsylvania

The Bureau of Topographic andGeologic Survey announces therelease of Map 67, GeologicShaded-Relief Map of Pennsyl-vania, a beautifully colored, 46-by 35-inch map of the state show-ing the bedrock geologic units su-perimposed on a shaded-reliefimage. The map is the third in aseries of digitally generated full-color 1:500,000-scale maps (theother two are Map 65, DigitalShaded-Relief Map of Pennsylva-nia, and Map 66, Land-Cover Map

of Pennsylvania), which wereprinted in cooperation with theU.S. Geological Survey and aredistributed free of charge by theBureau of Topographic and Geo-logic Survey. All three maps haveproved to be popular educationaland outreach products.

The geologic shaded-reliefmap was compiled primarily fromtwo data sets. The first is the Na-tional Elevation Dataset (NED) forPennsylvania, a product of the U.S.Geological Survey that provides

Winter view of Alpha Falls in Mc-Connells Mill State Park. This streamformed as the glacier that dammedLake Watts began its retreat, allowingthe lake to partially drain past thissite. The stream flows into SlipperyRock Gorge, which was eroded bylater phases of glacial lake drainage.

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regional elevation data for pointsspaced about every 30 meters.The elevation data were used togenerate the shaded-relief image,which gives the map its three-dimensional appearance. The sec-ond data set contains geologic con-tacts and faults that were slightlymodified by Pennsylvania Geo-logical Survey staff from the 1980state geologic map (PennsylvaniaGeological Survey Map 1, com-piled by T. M. Berg and others,scale 1:250,000). The latter dataset was further modified and gen-eralized by Christine E. Miles, thecompiler of Map 67. The colors ofthe geologic units were made trans-parent by digital procedures sothat the shaded-relief image wouldbe visible. The effect of this pro-cess is the appearance of the geo-logic units “draped” over the relief.

The new map shows, in a verystriking way, the regional distribu-

tion of the geologic units and struc-tural patterns, and the relation-ship between the geologic unitsand the topography. No symbolswere placed on the map otherthan fault lines, county boundarylines, and major streams so thatthe view of the terrain would beas unobstructed as possible.

Two full-color inset maps areincluded showing (1) physiograph-ic provinces and sections of thestate and (2) general ages of thegeologic units. Small thumbnailmaps in the explanation show theareal distribution of the rock unitslisted for each geologic period andgeographic area.

Map 67 (as well as Maps 65and 66) may be ordered from thePennsylvania Geological Survey,3240 Schoolhouse Road, Middle-town, PA 17057–3534, telephone717–702–2017.

A detail of the geologicshaded-relief map inthe west-central partof the state, showingthe Allegheny Front,which separates theAppalachian Plateausphysiographic prov-ince (west) from theRidge and Valley prov-ince (center and east).The geologic units,which appear in fullcolor on the map,cannot be adequatelyshown in this gray-scale image.

Dr. Jesse L. Craft was the en-vironmental geologist in the Pitts-burgh office of the PennsylvaniaGeological Survey from 1972 until1979. He passed away on Decem-ber 17, 2002, and is survived by hiswife, Joan, and his brother, Floyd.

Jesse was born in Kansas,served in the Air Force during theKorean War, and received geologydegrees from Sul Ross State Uni-versity in Texas, Syracuse Univer-sity in New York, and the Univer-sity of Western Ontario. He joinedthe Survey in 1972 to investigategeologic hazards and conduct stud-ies of the glacial deposits of north-western Pennsylvania. During histenure with the Survey, Jesseworked on a variety of projects, buthis most important contribution wasinvestigating local geologic hazards.He had a reputation for assistinghomeowners with solutions for re-storing their property and rebuild-ing their lives. Twenty years afterhe left the Survey, the Pittsburghoffice still received calls from peo-ple who wanted to express theirgratitude for his help.

After Jesse left the Survey in1979, he taught for a year at KentState University in Ohio before join-ing the U.S. Bureau of Mines. In1982, the group he worked with wastransferred to the Department ofthe Interior’s Office of Surface Min-

ing, where heremained forthe rest of hiscareer. While there, he developeda reputation as one of the nation’sleading experts in mine subsidenceand reclamation. Perhaps his crown-ing achievement came in 1985 fol-lowing the devastating Mexico Cityearthquake that destroyed hun-dreds of buildings and killed or in-jured thousands of people. Manyof the victims were buried beneathcollapsed buildings. At that time,Jesse’s team had been working witha down-hole video camera for in-vestigating mine voids. After theearthquake, Jesse and the teamwent to Mexico City and used thecamera to locate victims trappedin voids within the rubble. This re-sulted in many people being res-cued who otherwise would havebeen left for dead. As a result, theMexican government gave Jesse anaward of National Gratitude in 1986.

Jesse was generous with histime and knowledge, and was al-ways willing to discuss the intrica-cies of geology and potential geo-logic hazards with students, pro-fessionals, the public, governmentofficials, and the press. With hispassing, the citizens of westernPennsylvania have lost one of theirbest and most influential advocates.

—John A. Harper

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IN MEMORIAM

Jesse L. Craft1930–20021972–1979 Pennsylvania Geological Survey

CONTENTS

Looking under the grass .......................................................................... 1Reefs, ripples, and rocks—Home at last....................................................... 2Earth science teachers’ corner—Earthquake hazard in Pennsylvania ..... 8New releases ........................................................................................... 9

Moraine and McConnells Mill State Parks............................................ 9Geologic shaded-relief map of Pennsylvania ....................................... 10

In memoriam—Jesse L. Craft, 1930–2002............................................... 12

ON THE COVER

Two museum-quality rock specimens on display at the Middletown office ofthe Pennsylvania Geological Survey. The one in the front shows two setsof ripple marks (called interference ripples), and the one in the back is partof an ancient coral reef formed by the colonial coral Halysites (see articleon page 2). Photograph by Gary M. Fleeger.

PENNSYLVANIA GEOLOGY

PENNSYLVANIA GEOLOGY is published quarterly by the Bureau of Topographic andGeologic Survey, Pennsylvania Department of Conservation and Natural Resources,3240 Schoolhouse Road, Middletown, PA 17057–3534.Editors: Anne B. Lutz and Jay B. Parrish.Contributed articles are welcome. Guidelines for manuscript preparation may be obtainedat www.dcnr.state.pa.us/topogeo/pub/mag-ins.htm or by contacting the editors at theaddress listed above.Articles may be reprinted from this magazine if credit is given to the Bureau of Topographicand Geologic Survey.

VOL. 33, NO. 2 SUMMER 2003

DEPARTMENT OF CONSERVATION AND NATURAL RESOURCESBUREAU OF TOPOGRAPHIC AND GEOLOGIC SURVEY

IN COOPERATION WITH THE U.S. GEOLOGICAL SURVEYTOPOGRAPHIC MAPPING

GROUNDWATER-RESOURCE MAPPING

Main Headquarters3240 Schoolhouse RoadMiddletown, PA 17057–3534717–702–2017FAX: 717–702–2065

Pittsburgh Office500 Waterfront DrivePittsburgh, PA 15222–4745412–442–4235FAX: 412–442–4298

BUREAU STAFF AND TELEPHONE NUMBERSDirector and State GeologistJay B. Parrish, P.G. 717–702–2053

Assistant DirectorSamuel W. Berkheiser,

Jr., P.G. 717–702–2055

Administrative ServicesLynn M. Goodling 717–702–2054Elizabeth C. Lyon 717–702–2063

Library ServicesRichard C. Keen 717–702–2020Lewis L. Butts, Jr. 717–702–2018

Publication ServicesJody R. Zipperer

(General Inquiries) 717–702–2073Christine E. Miles, P.G. 717–702–2044Caron E. O’Neil, P.G. 717–702–2042Anne B. Lutz 717–702–2043

Local Government Outreach ServicesKristen L. Reinertsen

(East) 717–702–2047Jaime Kostelnik (West) 412–442–5828

Database ServicesCheryl L. Cozart 412–442–4234Janice Hayden 412–442–4287Joseph E. Kunz 412–442–4235Lynn J. Levino 412–442–4299Karen L. McCoy (Oil and

Gas GIS Services) 412–442–5826

GIS ServicesMichael E. Moore, P.G. 717–702–2024John H. Barnes, P.G. 717–702–2025Thomas G. Whitfield, P.G. 717–702–2023

GIS Services (continued)Stuart O. Reese, P.G. 717–702–2028John G. Kuchinski 717–702–2027

Water Well ServicesSharon E. Fesus 717–702–2074Jody R. Zipperer 717–702–2073

Groundwater ServicesGary M. Fleeger, P.G. 717–702–2045Thomas A. McElroy, P.G. 717–702–2046

Geologic Mapping ServicesJon D. Inners, P.G. 717–702–2034Gale C. Blackmer 717–702–2032Helen L. Delano, P.G. 717–702–2031Clifford H. Dodge, P.G. 717–702–2036William E. Kochanov, P.G. 717–702–2033James R. Shaulis, P.G. 717–702–2037Viktoras W. Skema, P.G. 717–702–2035

Laboratory and Geochemical ServicesRobert C. Smith, II, P.G. 717–702–2021Leslie T. Chubb 717–702–2022

Coal-Bed Methane ServicesAntonette K. Markowski,

P.G. 717–702–2038

Coal Quality and Availability ServicesRodger T. Faill, P.G. 717–702–2041Leonard J. Lentz, P.G. 717–702–2040John C. Neubaum 717–702–2039

Oil, Gas, and Subsurface GeologicalServicesJohn A. Harper, P.G. 412–442–4230Christopher D. Laughrey 412–442–4232Joseph R. Tedeski 412–442–4295Kristin M. Carter, P.G. 412–442–4233

COMMONWEALTH OF PENNSYLVANIAEdward G. Rendell, Governor

DEPARTMENT OF CONSERVATION AND NATURAL RESOURCESMichael DiBerardinis, Secretary

OFFICE OF CONSERVATION AND ENGINEERING SERVICESRichard G. Sprenkle, Deputy Secretary

BUREAU OF TOPOGRAPHIC AND GEOLOGIC SURVEYJay B. Parrish, Director

Bureau web site: www.dcnr.state.pa.us/topogeoDCNR web site: www.dcnr.state.pa.us

Pennsylvania home page: www.state.pa.us

LOCATION MAP FOR BUREAU’S HEADQUARTERS

Bureau of Topographic and Geologic SurveyDepartment of Conservation and Natural Resources3240 Schoolhouse RoadMiddletown, PA 17057–3534

Address Service Requested

PRSRT STDU.S. Postage

PAIDHarrisburg, PAPermit No. 747

/22

/11

/15

/322/322

/322

,76

,283

,76

,81

,81

,83

,83

,83

322221

15111

283

283

581

581

Middletown

HarrisburgInternational

Airport

Harrisburg

Vin

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tree

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SchoolhouseRoad

Swatara

Creek

Conodoguinet

Creek

Su

squ

ehanna

River

DogwoodLane

PennsylvaniaGeological

Survey

N

0 2 MI

0 3 KM

SCALE

236

242 247

DirectionsFrom Harrisburg—Follow I-83 North to I-283 South. Takethe Lancaster exit onto Route 283 East.From the PA Turnpike—Take exit 247, Harrisburg East,and then take the first exit onto Route 283 East.From Route 283 East—Take the Hummelstown-Middle-town exit. At the end of the ramp, turn left onto VineStreet. Stay in the left-hand lane and turn left at the firstintersection onto Schoolhouse Road. Make the next leftonto Dogwood Lane. At the top of the hill, take the firstright into the parking lot.

If you would like to receive up-to-date Bureau announcements,please send your e-mail address to [email protected].

An Equal Opportunity Employer 2200-BK-DCNR0103Recycled Paper