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IntroductionIn 1989, legislationwas passed that directed theNorthDakotaGeological Survey to establish a public repository for NorthDakota fossils. Shortly thereafter, theGeological Survey signedaMemorandumofAgreementwith theStateHistorical Societyof North Dakota which provided space in the North DakotaHeritage Center for development of this North Dakota StateFossilCollection,includingofficesforthecuratorofthecollection

and a laboratory specialist, a laboratory for preparation offossils, anda fossil storagearea. TheNDGSpaleontology staff,nowhousedat theHeritageCenter,consistsof JohnHoganson,State Paleontologist, and paleontologists Jeff Person and BeckyGould. ThisarrangementhasallowedtheGeologicalSurvey, incollaborationwith the StateHistorical SocietyofNorthDakota,tocreateprehistoriclifeofNorthDakotaexhibitsattheHeritageCenter and displays of North Dakota fossils at over 20 othermuseumsandinterpretivecentersaroundthestate.

The first of the Heritage Center prehistoric life exhibits wasthe restoration of the HighgateMastodon skeleton in the FirstPeople exhibit area (fig. 1). Mastodons were huge, elephant-likemammalsthatroamedNorthAmericaattheendofthelastIceAgeabout11,000yearsago. Thisexhibitwascompleted in1992andwasthefirstrestoredskeletonofaprehistoricanimaleverdisplayedinNorthDakota.Themastodonexhibitwas,andstill is,amajorattractionintheHeritageCenter. Becauseof itspopularity,itwasdecidedthatadditionalprehistoriclifedisplaysshouldbe included in theHeritageCenterexhibitplans. Theseexhibits would be called the Corridor of Time and be installedin theentranceareaof themaingallery. TheywouldtracethehistoryoflifeinNorthDakotathroughdisplayoffossilsfromtheNorthDakotaStateFossilCollection.Changesinthestatesclimateandenvironmentsthroughtimewouldalsobeaddressedintheseexhibits.TheCorridorofTimewouldprovideanintroductiontotherestofthemaingallerywhich interpretsthehumanhistoryoftheState.

Corridor of Time Prehistoric Life of North Dakota Exhibit at the North Dakota Heritage Center Completed

by John W. Hoganson

Figure 1.RestoredskeletonoftheHighgateMastodon,anelephant-likemammalthatlivedduringtheIceAgeabout11,000yearsago.

Figure 2.RestoredskeletonofPlioplatecarpus, a mosasaurthatwasthemainpredatorinthePierreSeathatcoveredNorthDakotaabout75millionyearsago.ThisspecimenwascollectednearCooperstown,NorthDakota.

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Phase I and Phase IITheCorridorofTimewouldbedividedintosixtimeperiods.Theinitialplanwastoconstructall of the Corridor of Time at once. Fundingconstraints did not allow this to happenso we have had to generate the exhibits inphases. Phase I is about life that existed intheoceans that coveredNorthDakotaduringtheLateCretaceous, fromabout80millionto68million years ago. It is also referred to asthemosasaur exhibit. Fossils of animals thatlivedintheshallow,warmoceansthatcoveredNorth Dakota during that time are displayed.The featured fossil is the spectacular 23-foot-long restored skeleton of the Cooperstownmosasaur,Plioplatecarpus (fig. 2). Mosasaurswere huge marine lizards and the largestpredators in these Late Cretaceous oceans.Also included in this exhibit are fossils ofanimals that co-existed with the mosasaursincludingsharksandotherfish,seabirds,giantsquids,cephalopods,gastropods,clams,crabs,lobsters,seaurchins,corals,andshrimp.

Phase II includes fossils of the animals andplants that lived in North Dakota during theLate Cretaceous about 65 million years agowhenwesternNorthDakotawasavastdeltaiccoastal plain. The climate at that time waswarm-temperate to subtropical. This coastalplain provided habitats for several kinds ofexoticplantsandanimals includingdinosaurs.Askullandpartialskeletonofthehugethree-horneddinosaurTriceratopsisfeaturedinthisexhibit. This partial skeleton is arranged asa death mount where the carcass is being

scavengedbysmalldromaeosaurs,theropoddinosaurs(fig.3).Fossilsofotheranimalsandplantsthat livedduringthistimeare also displayed including remains of duckbilled dinosaurs,pachycephalosaurs,Tyrannosaurus rex,turtles,fish,pterosaurs,freshwaterclamsandsnails,and leaves fromseveralkindsofplantsincludingpalmtrees.Awall-sizehabitatreconstructionmural, showing the appearance of western North Dakota atthistime,isabackdropforthediorama.Arecentadditiontothisexhibitisthedisplayofthearmandtailofthemummified

Figure 3. Dioramashowingtheskeletonofthesmallmeat-eatingdromaeosauriddinosaurthatlivedinNorthDakotaduringtheCretaceousPeriodabout65millionyearsago.

Figure 4.HabitatreconstructionwallpaintingshowinglifeinNorthDakotaabout60millionyearsagowhenwesternNorthDakotawasasubtropical,forestedswampland.

Figure 5. Ribbon-cuttingceremonyattheCorridorofTimePhaseIIIexhibitopening.

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duckbilled dinosaur called Dakota withpreserved, fossilized skin. About 65millionyearsagooneofEarthsgreatestbiologicalcatastrophesoccurred. Aboutthree-fourthsofalllifeonEarth,includingthelastofthedinosaursbecameextinctat thistime. One theory toexplain thisextinction suggests that the Earth wasstruckbyamassiveasteroid.Meteoritesfound in North Dakota are displayed tohelpinterpretthisevent.

The secondpart of thePhase II exhibit,thatwecallNorthDakotaEverglades, isaboutlifethatexistedinthesubtropical,forested swamps that covered muchof western North Dakota during thePaleocene about 60 million years ago,about5millionyearsaftertheextinctionof thedinosaurs. Fossilsof theanimalsthat lived in North Dakota at this time including crocodiles,champsosaurs(crocodile-likeanimals),turtles,fish,salamanders,mammals,birds, and freshwater snails and clamsaredisplayed(fig.4).Extensive,lushforestscontainingMagnolia,baldcypress,ginkgo, palm and many other plants grew in this Paleoceneswampland.Theirfossils,includingpetrifiedwood,leaves,seeds,andevenflowersofsomeplantsareonexhibit.ThebackdropforthisdioramaisahugehabitatreconstructionwallmuralrecreatingaforestedswamplandsceneshowingwhatwesternNorthDakotawaslike60millionyearsago.

Phase IIIThelastoftheCorridorofTimeexhibits,PhaseIII,werecompletedinJanuary2009.TheexhibitswereunveiledduringalegislativereceptiononJanuary8andthegrandopeningwasJanuary10(fig.5).PhaseIIIoftheCorridorofTimeisdividedintothreedisplays:PrimordialSeas,CannonballSea,andNorthDakotaScrublands.

Phase III: Primordial SeasForavastexpanseoftimeduringthePaleozoicEra,fromabout500 million to 250 million years ago, North Dakota was often

inundated by oceans. Rocks depositedduring the Paleozoic donot occur at theEarths surface in North Dakota and yet,surprisingly,weknowquiteabitaboutlifeinNorthDakotaduringthistime.Thisisaresultofexplorationforpetroleum.Sincethe 1950s petroleum companies havebeenactively exploring foroil and gas inNorthDakota.Attimesduringthedrillingprocess, cylinders of rocks called cores,are recovered from the subsurface andanalyzedbygeologistsandpaleontologiststo help determine if hydrocarbons arepresent. On occasion, fossils are foundin these cores. The oldest fossils that

Figure 6.DisplayshowingcoreandoilsamplesfromnumerousrockformationsinNorthDakotaandamodelofadrillingrig.Inset:OilwellcorefromtheOrdovicianStonyMountainFormationcollectedinRamseyCountyfromadepthof2,456feet.Thiscorecontainsbrachiopod(clam-likeanimals)fossils.CrudeoilfromtheOrdovicianRedRiverFormationinBowmanCountyisinthebottle.

Figure 7. FossilsfromthePaleoceneCannonballFormationandawallpaintingdepictinganimalsthatlivedintheCannonballSea.

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wehaveintheNorthDakotaStateFossilCollectionareshellsofbrachiopods(marineanimalssimilartoclams)fromanOrdovicianStonyMountainFormationcorerecoveredfromadepthof2,456feetinRamseyCounty.Thesefossilsareabout450millionyearsold andare featured in thisdisplay (fig. 6). Other cores in thedisplaycontainfishfossils(DevonianDuperowFormation,depth4,429feet,WellsCounty),sponge-likestromatoporoid(DevonianDuperowFormation,depth4,402feet,WellsCounty),gastropod(snail)(MississippianMadisonGroup,depth9,617feet,McKenzieCounty),corals(MississippianMissionCanyonFormation,depth9,209feet,BurkeCounty),brachiopods(Devonian/MississippianBakken Formation, depth 7,580 feet, Burke County), sea lilies(DevonianWinnipegosis Formation, depth5,283 feet,McHenryCounty), corals and brachiopods (Devonian WinnipegosisFormation,depth5,274feet,McHenryCounty)andinarticulatebrachiopods (Pennsylvanian Tyler Formation, depth 7,895 feet,Golden Valley County and depth 7,949 feet, Billings County).ThesefossilsindicatethatNorthDakotawascoveredbyshallow,warm,marinewatersonseveraloccasionsduringthePaleozoic. ExamplesofcrudeoilfromseveralformationsincludingtheRedRiver(Ordovician), Interlake(Silurian),Winnipegosis(Devonian),Duperow (Devonian), Bakken (Devonian/Mississippian),MissionCanyon (Mississippian), Lodgepole (Mississippian), and Tyler(Pennsylvanian)arealsodisplayedtoshowvisitorsthevariationincolorandviscosityofcrudeoilrecoveredinNorthDakota.

Wewereveryfortunatetohaveanincrediblydetailedmodelofanoperatingoilwelldrillingscenethatincludesaderrick,associated

buildings,vehicles,andequipmenttocomplimentthePaleozoicrock, fossil, andcrudeoil exhibit (fig.6). Mastermodelmaker,MitchGriese,donatedthis1/48-scalemodeltotheStateHistoricalSocietyofNorthDakota.AlargephotographofthewesternNorthDakotabadlandsprovidesanappropriatebackdropfortheoilwellscene.

Cannonball Sea: The Last North Dakota SeaThelastseatocoverNorthDakotaiscalledtheCannonballSea.It coveredmuchof the state, except forwesternNorthDakotawhich was a forested swampland, during the Paleocene about60 million years ago. Shortly after 60 million years ago, theCannonballSearecededandoceanicconditionshavenotreturnedtoNorthDakotasince. TheCannonballSeawasshallow,warm,and teemingwith life. The shoreline sand deposits of the seayieldbeautifullypreserved fossils of theanimals that inhabitedthis body ofwater. These fossils include teeth of sharks, stingrays,eaglerays,ratfish,andotherfish(fig.7). FossilsdisplayedintheCannonballSeaexhibitalsoincludeshellsofmarineclams,snails, crabs, shrimp,andcephalopods. Featured in theexhibitareseveralspecimensofNorthDakotasstatefossil,Teredo-boredpetrifiedwood.SixtymillionyearsagodriftwoodfloatedneartheshoreoftheCannonballSea.Smallclams(Nototeredo),sometimescalledshipworms,boredintothewoodformingelongate,tubularlivingchambers.Aftermillionsofyears,thiswoodandtheshellsofNototeredoand itselongatetubesbecamefossilizedformingTeredo-boredpetrifiedwood.

Figure 8. DioramashowingfossilsofmammalsandturtlesfromtheOligocene(about30millionyearsold)BruleFormationinNorthDakotaaccompaniedbyahabitatreconstructionwallpainting.Thelargeanimalintheforegroundisthegiantpig-likeanimalArchaeotherium.Inset:skullofthe30million-year-oldsabertoothedcat-likeanimalDinictisdisplayedintheOligoceneexhibit.

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North Dakota Scrubland BytheOligocene,about30millionyearsago,NorthDakotahadchangeddramaticallyfromthesubtropical, forestedswamplandconditions dominated by crocodiles during the Paleocene to atemperate,nearlytreelessscrublandhabitatsupportingvastherdsofexoticmammals.MammalfossilsfromtheBruleFormationaredisplayedintheNorthDakotascrublandexhibit(fig.8).Remainsofabout60speciesofmammalshavebeenrecoveredfromthisformationinNorthDakota. Oneofthemorespectacular isthegiantpig-likeanimalcalledArchaeotherium. Askullandcastoftheskeletonofthisanimalarefeaturedspecimensinthisdisplay.Fossils of several other herbivores including the ubiquitousoreodont, Merycoidodon,asheep-likeanimalare intheexhibit.Oneoftheearliesthorses,Mesohippus,livedinNorthDakotaatthistime.Thisthree-toedhorsewassimilartothemodernhorseinsomewaysbuttheadultswereonlyabouttwofeettall.AskullandlowerjawsofMesohippusaredisplayed.Remainsofsomeofthesmallmammals,insectivores,rabbits,squirrel-likeanimalsarealsointheexhibit.

Fossilsofcarnivoresarenotcommon in theBruleFormation inNorthDakota.SkullsofDinictis,asaber-toothednimravid(cat-likeanimal),aboutthesizeofasmallmountainlion,areaccompaniedbyaskeleton(cast)ofthatanimalperchedonacliff.Askullofoneoftheothercarnivores,Hyaenodon,isalsointheexhibit.Severalspecies of turtles lived in North Dakota at that time includingthe large tortoise, Stylemys.SomeofthesewerethesizeofthelivingGalapagostortoise.Fossilsoftheseanimalsarealsointheexhibit.

A wall-size mural that reconstructs this 30 million-year-oldscrublandhabitatinNorthDakotaisabackdropforthediorama.

Acknowledgements The following either provided funding, allowed access to theirproperty, or donated fossil specimens for the Corridor of TimePrehistoricLifeExhibit:AmeradaHess;AmocoFoundation;BasinElectric Cooperative and Dakota Gasification Company; GaryBates;PamBethke;SharonBogren;HaroldBrady;BureauofLandManagement;CentralDakotaGemandMineralSociety;LaVerneCoons;theCoteauPropertiesCompany;JimDaly;DepartmentofGeologyandGeophysics,UniversityofMinnesota;DepartmentofMineralSciences,NationalMuseumofNaturalHistory,SmithsonianInstitution;DickinsonChapteroftheAmericanPetroleumInstitute;J.MarkErickson;JacquelineEvenson;theFalkirkMiningCompany;BobFittererfamily;FortAbrahamLincoln Corral of Westerners International; Mitch Griese; VernHansen;MikeHanson;DennisandVerlaHalvorson;F.D.Holland,Jr.;LaVonneHunze;DavidJensen;ClarenceandClariceJohnsrudfamily; Pat Liska; Tyler Lyson; Manitoba Museum; MarmarthResearchFoundation;WilliamandElizabethMarshall;MilwaukeePublic Museum; Montana Dakota Utilities Foundation; MikeNewbrey;FredNagelfamily;NationalParkService;PennyNatwick;North Dakota Geological Society; North Dakota PaleontologicalSociety;NorthDakotaPetroleumCouncil;RonandBobObritschfamily;KentPelton;AlbertPrivratskyfamily;JacobandCatherineSchlosser;BevandJergenSoma;BebandTimSoma;KathySoma;SonsofNorway;theSonsallafamily;JohnStumpf;SuperValuRetailSupportCompany;GloriaThompson;ThreeAffiliatedTribes;Bev,Orville,andScottTranby;UnisysCorporation;USArmyCorpsofEngineers,OmahaDistrict,GarrisonProject;USWestFoundation;USDAForest Service-DakotaPrairieGrasslands; LindaandDougVannurden;SusanWilhelm,WillistonBasinChapterAmericanoftheAmericanPetroleumInstitute.

North Dakota History: Readings about the Northern Plains State receives national award

ArecentbookdetailingNorthDakotashistoryfromdinosaurstothe21stCentury(seeJune2008Newsletter)hasbeennamedanationalawardrecipientbytheAmericanAssociationofStateandLocalHistory(AASLH).NorthDakotaHistory:ReadingsabouttheNorthernPlainsState,hasbeenselectedasarecipientoftheAASLHsAwardofMerit.Thisawardispresentedtorecognizeexcellenceforprojects,individualachievement,andorganizationalgeneralexcellence. NorthDakotaHistoryisacollaborativepublicationoftheStateHistoricalSocietyofNorthDakota(SHSND)andtheNorthDakotaCenterforDistanceEducation.ThebookisacollectionofarticlesandimagesfrommorethanacenturyofSHSNDpublicationsandalsofeaturesnarrativesbyseveralNorthDakotascholarsincludingsurveypaleontologistJohnHoganson.

AlthoughintendedforuseasaNorthDakotahistorytextbookforhighschoolstudents,NorthDakotaHistorywillappeal

toanyonewithaninterestinthestateshistoricandprehistoricpast.