No. 17 OHIOGeoFacts DEPARTMENT OF NATURAL RESOURCES • DIVISION OF GEOLOGICAL SURVEY

FOSSIL COLLECTING IN OHIO

Hobbyists have long known about Ohio’s great abundance and WHERE FOSSILS ARE FOUND IN OHIO diversity of fossils. Many world-famous paleontologists—geologists who study fossils—began their careers as youngsters collecting fossils Ordovician rocks in Ohio are world famous for in their native Ohio. Fossils from Ohio are important constituents the abundance, variety, and excellent preserva- of museum collections throughout the United States and Europe. tion of the fossils they contain. The limestones and shales exposed in almost every road cut or WHY OHIO HAS FOSSILS stream bed in southwestern Ohio, southeastern Indiana, and north-central Kentucky provide The area that is now Ohio was not always dry land as it is today. the opportunity to collect a bonanza of fossils. Approximately 510 million years ago (m.y.a.), Ohio was south of the Among the more abundant types of fossils col- Equator. As the North American Plate moved to its current position ORDOVICIAN lected from Ordovician rocks are brachiopods, 508–438 m.y.a. through the process of plate tectonics, tropical to subtropical seas bryozoans, gastropods, and trilobites. repeatedly transgressed over the plate. It is because of those warm Silurian rocks of western Ohio are not known seas that Ohio has the abundant fossils that people collect today. for their fossils. When the limestones and shales The seas that covered Ohio during the Ordovician, Silurian, and were fi rst deposited they were quite fossilifer- most of the Devonian Periods of the Paleozoic Era were the site of ous. Unfortunately, most of the fossils were abundant limestone deposition. Sediments that form limestone are destroyed when the limestones containing the generally only deposited under shallow, open-marine conditions, fossils were altered to dolostones. One Silurian much like the seas around Caribbean islands today. rock unit that still retains well-preserved fos- Near the end of the Devonian Period, conditions in the seas sils is the Brassfi eld Formation. The Brassfi eld covering Ohio changed, so that the sediments deposited were pri- SILURIAN is composed almost entirely of fragments of 438–408 m.y.a. marily muds and sands that would become shale and sandstone. crinoids. Even the dolomitized formations The oldest exposed major shale unit is the Ohio Shale; outcrops of contain molds and casts of fossils, in particular this shale are present from Ashtabula westward along Lake Erie to brachiopods and trilobites. Quarry operations Milan and southward to Portsmouth. These same conditions con- in western Ohio have exposed several reefs tinued into the early Mississippian Period, when the Bedford and preserved in Silurian rocks. Reefs are indicative Sunbury Shales were deposited. After deposition of the Sunbury that warm, open-marine conditions existed in Shale ceased, long intervals of extensive open-marine conditions Ohio at this time. Colonial corals are the most infrequently returned to Ohio. prominent fossil type composing reefs. Silurian During most of Mississippian time and the rest of the Paleozoic Era, rocks are well exposed in an arc from west of what is now Ohio may have been dry land in the west (Cincinnati Dayton to near Portsmouth. to Toledo), and the Appalachian Mountains were continuing to rise Devonian rocks in Ohio are as famous for to the east of Ohio; between these two areas was the Appalachian their fossil abundance and diversity as are Basin. The eastern coastline of the basin was dominated by numer- Ohio’s Ordovician rocks. There are two main ous deltas deposited by rivers carrying sediments eroded from the areas of exposure of Devonian rocks in Ohio: a ancestral Appalachian Mountains. These deltas were sites of vast north–south belt through the center of the state swamps and marshes, particularly during the Pennsylvanian Pe- then east along Lake Erie and in the northwest riod. In fact, Ohio’s Pennsylvanian rocks probably are better known corner. The shales of the Silica Formation near for their coal deposits, formed from the plant material deposited Sylvania, in northwestern Ohio, contain abun- in these wetlands, rather than for their fossils. However, because DEVONIAN dant trilobites and brachiopods. The Columbus 408–360 m.y.a. coal is composed of compressed plant material, it is a type of fossil, and Delaware Limestones, exposed from central hence the term “fossil fuel.” The marine units in the Pennsylvanian Ohio to the Lake Erie islands, are quite fossilif- rocks of Ohio are fossiliferous, containing pelecypods, gastropods, erous. Fossils in the Columbus Limestone are trilobites, echinoderms, and others. Nonmarine units of Pennsylva- notable for their large size. Perhaps the most nian and Permian age contain plant and insect fossils and remains spectacular fossils from Ohio’s Devonian rocks of fi sh, amphibians, and reptiles. come from the Ohio Shale near Cleveland. Con- Dinosaurs roamed Earth during the Mesozoic Era (245–65 m.y.a.). struction projects in and around Cleveland have Undoubtedly, dinosaurs lived in Ohio, so why haven’t dinosaur uncovered the bony armored plates and jaws skeletons been found here? The answer is that Ohio does not have of fossil fi shes known as arthrodires. any rocks dating to that time. Therefore, no dinosaur remains can be Mississippian rocks in Ohio were deposited collected in Ohio. Why doesn’t Ohio have any Mesozoic-age rocks? as deltas by rivers that fl owed westward from Two possibilities may explain this quandary: Ohio may have been the ancestral Appalachian Mountains into the above sea level and no sediments were deposited, or any sediments Appalachian Basin. A similar process is taking that were deposited during this time were eroded away. place today where the Mississippi River fl ows During the Pleistocene Epoch (2 m.y.a–10,000 y.a.), about two- into the Gulf of Mexico. Some of Ohio’s Missis- thirds of Ohio was covered periodically by ice that fl owed south sippian rocks are quite fossiliferous, containing from Canada. Remains of animals and plants that lived during abundant limonite-stained molds and casts Pleistocene time have been collected in Ohio from deposits repre- MISSISSIPPIAN of brachiopods, pelecypods, and echinoderm senting lakes and ponds, caves, and streams. Some of these remains 360–320 m.y.a. fragments. Mississippian rocks are exposed include the elephantlike mastodons and mammoths, giant beaver, from near Portsmouth northward to Lorain elk, and muskoxen. and eastward to Ashtabula.

continued ➮ Geological Surveyorthegeology departmentofanearbyuniversity. well-preserved fossil,letanexpert examineit.ContacttheDivisionof fossil, leaveitaloneratherthan riskdamagingthefossil. as anair-abrasive machine.When indoubtabouthowtocleana with water. Othersmayrequire advancedcleaningequipment, such rock unitsshouldbekeptseparate. collected from thesamelocalitybutfrom di areas mayprove bene access tofossil-collectingareas. Contactingtheoperatorsofthese and countyparks,aswellprivatecampingareas, mayhave Nelson-Kennedy Ledges)butdonotallowcollecting.Local,city, logic features (e.g.,HockingHills,CliftonGorge, GlacialGrooves, state parks,nature preserves, andmemorialshaveprominent geo- fossils canbecollectedatFossilPark(Sylvania).ManyofOhio’s Park (Fairborn)alsoallowscollecting.InnorthwesternOhio, the U.S. Army CorpsofEngineersVisitor Center).OakesQuarry Creek StateParkrequires acollectingpermit(availablefree from check attherangerstationsfordesignatedcollectingareas. Caesar Stonelick (ClermontCounty)StateParksallowfossilcollecting; County), HuestonWoods (Preble andButlerCounties), Counties), CowanLake(ClintonCounty),EastFork(Clermont located insouthwesternOhio:CaesarCreek (Warren andClinton cessible collectinglocalitiesare actuallyscarce. Mostsitesare interesting rock, withlittlescienti and dateofcollection.Lackingthisinformation,afossilis just an locality shouldhavealabelthatprovides thelocality, collector, would wantsomeonetotreat asiteonyourland. practice the“GoldenRule”andtreat acollectionsitetheway you rocks ontoroadways, sidewalks,driveways,orinto streams. Inshort, the wayyoufoundthemorwere askedtoleavethem;donot throw permit fossilcollecting,exceptindesignatedareas. before collecting.Mostpubliclands(local,state,orfederal)donot PENNSYLVANIAN If youhavecollectedwhat thinkisauniqueorexceptionally There are manywaystocleanfossils.Somefossilscanbecleaned Even thoughOhioiswellknownforitsfossils,publiclyac- Keep fossilsfrom di Each fossilorgroup ofsimilarfossilsfrom agivenrock unitor Always exercise caution.Nofossilisworthriskinglifeorlimb. Leave theproperty thewayyoufoundit:nolittering;leavegates Most landinOhioisprivateproperty. 320–286 m.y.a. 286–245 m.y.a. PERMIAN WHERE TOCOLLECTFOSSILSINOHIO RULES FORCOLLECTINGFOSSILS The Divisionof GeologicalSurveyGeoFacts Seriesisavailableonlineat easy toseebecausetheycovermostofOhio. been unearthed.Depositsfrom thisperiodare forests buriedbytheadvancingglaciershave been collectedfrom depositsofthistime.Even particularly mastodonsandmammoths,have western Ohio.BonesofPleistocenemammals, consolidated materialacross northernand are exposedinsoutheasternOhionearMarietta. collected from rocks ofthisage.Permianrocks reptiles andplantinsectfossilshavebeen iferous. However, bonesofamphibiansand periodically limestone andshaledepositedwhenthesea and brachiopodsare abundantinthinbedsof Marine fossilssuchaspelecypods,gastropods, and rare fossilsofinsectsandamphibians. rocks are notedforwell-preserved fossilplants along the Appalachian Basincoastline.These in swampyconditionsassociatedwithdeltas eastern Ohioandwere depositedprimarily Pleistocene Permian Pennsylvanian ff fi erent collectingsitesseparate.Evenfossils cial. rocks ofOhioare notveryfossil- • ThisGeoFacts compiledbyDouglasL.Shrake •UpdatedJune2014 fl glaciersleftamantleofun- ooded thecoastalcoalswamps. fi c value. rocks are wellexposedin Always obtainpermission ff erent spotsordi ff erent

Sturgeon, M.T., Windle, D.L.,Mapes,R.H.,andHoare, R.D., 1997,Pennsyl- Sturgeon, M.T., andHoare, R.D.,1968,Pennsylvanian brachiopodsofOhio: Stewart, G.A.,1927,FaunaoftheSilicashaleLucasCounty:Geological Shrake, D.L.,1995, Shrake, D.L.,1994,Ohiotrilobites:DepartmentofNaturalResources, Shrake, D.L.,1992,ExcursiontoCaesarCreek StateParkinWarren County, Ohio StateParks,1967,FossilsofHuestonWoods: OhioDepartmentof Morningstar, Helen, 1922,PottsvillefaunaofOhio:GeologicalSurvey Merrill, G.K.,1974,PennsylvanianconodontlocalitiesinnortheasternOhio: La Rocque, Aurèle, andMarple,M.F., 1955,Ohiofossils:Department La Rocque, Aurèle, 1966,PleistoceneMolluscaofOhio,Introduction, geo- Hoare, R.D.,Sturgeon, M.T., andKindt,E.A.,1979,Pennsylvanianmarine Feldmann, R.M.,andHackathorn,Merrianne,eds.,1996,FossilsofOhio: Eriksson, Mats,2002,Tiny hiddentreasures—The microfossils ofOhio:OhioDe- Davis, R.A.,ed.,1985,Cincinnatifossils—Anelementaryguidetothe Brezinski, D.K.,Sturgeon, M.T., andHoare, R.D.,1989,Pennsylvanian drawings willspeedfossilidenti how toidentifythem.Itsnumerous photographicplatesandline fossils, where to (Feldmann andHackathorn,1996),whichexplainshowtocollect many Ohiolibraries. A bookworthspecialmentionis few are listedbelow. Out-of-printpublicationscanbeconsultedat speci an extensivereference list,glossary, andindexesofgeneric Identi There are manypublicationsrelated toOhiopaleontology. A Identi Collector: ______Date collected: Formation: ______Location: ______Species: ______Genus: Phylum: ______NOTES: Division ofGeologicalSurveyBulletin 71,95p. vanian cephalopodsofOhio:Ohio DepartmentofNaturalResources, Bulletin 63,95p. Ohio DepartmentofNaturalResources, DivisionofGeologicalSurvey Survey ofOhio,FourthSeries,Bulletin 32,76p. Resources, DivisionofGeologicalSurveyGeoFacts5. Division ofGeologicalSurveyGeoFacts4. 12, 18p. ment ofNaturalResources, DivisionofGeologicalSurveyGuidebook Ohio—A classicUpperOrdovician fossil-collectinglocality:OhioDepart- Natural Resources, DivisionofParksandRecreation, 16p. Ohio, FourthSeries,Bulletin25,312p. Guidebook 3,25p. Ohio DepartmentofNaturalResources, DivisionofGeologicalSurvey of NaturalResources, DivisionofGeologicalSurveyBulletin54,152p. Division ofGeologicalSurveyBulletin62,parts1–4,796p. logic setting,andpaleoecology:OhioDepartmentofNaturalResources, sources, DivisionofGeologicalSurveyBulletin67,79p. Bivalvia andRostroconchia ofOhio:OhioDepartmentNaturalRe- Bulletin 70,577p.[Reprintedwithminorrevision 2005.] Ohio DepartmentofNaturalResources, DivisionofGeologicalSurvey partment ofNaturalResources, DivisionofGeologicalSurveyGeoFacts24. Museum ofNaturalHistory, 61p. Ordovician rocks andfossilsoftheCincinnati,Ohio,region: Cincinnati Geological SurveyReportofInvestigations142,18p. trilobites ofOhio:OhioDepartmentNaturalResources, Division of fi c namesoffossils. fi fi A labelcardsuchasthisoneshouldaccompanyfossilspecimens. cation number: ______er: ______Isotelus— fi nd them,howtoprepare andcare forthem,and www.OhioGeology.com FURTHER READING Ohio’s StateFossil:OhioDepartmentofNatural fi cation. Thebookalsocontains Fossils ofOhio

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