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Paleontology in South Dakota refers to paleontological research occurring within or conducted by people from the U.S. state of South Dakota. South Dakota is an excellent source of fossils as finds have been widespread throughout the state. During the early Paleozoic era South Dakota was submerged by a shallow sea that would come to be home to creatures like brachiopods,
cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
s, corals, and ostracoderms. Local sea levels rose and fall during the
Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...
and the sea left completely during the Permian. During the Triassic, the state became a coastal plain, but by the Jurassic it was under a sea where ammonites lived. Cretaceous South Dakota was also covered by a sea that was home to mosasaurs. The sea remained in place after the start of the
Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...
before giving way to a terrestrial
mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
fauna including the
camel A camel (from: la, camelus and grc-gre, κάμηλος (''kamēlos'') from Hebrew or Phoenician: גָמָל ''gāmāl''.) is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. C ...
'' Poebrotherium'', three-toed
horses The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...
, rhinoceroses, saber-toothed cat, and titanotheres. During the Ice Age
glaciers A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...
entered the state, which was home to mammoths and mastodons. Local Native Americans interpreted fossils as the remains of the water monster Unktehi and used bits of '' Baculites'' shells in magic rituals to summon buffalo herds. Local fossils came to the attention of formally trained scientists with the Lewis and Clark Expedition. The Cretaceous horned dinosaur ''
Triceratops horridus ''Triceratops'' ( ; ) is a genus of herbivorous chasmosaurine ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the Late Cretaceous period, about 68 million years ago in what is now North America. It is one ...
'' is the South Dakota
state fossil Most American states have made a state fossil designation, in many cases during the 1980s. It is common to designate one species in which fossilization has occurred, rather than a single specimen, or a category of fossils not limited to a single ...
.


Prehistory

No
Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the ...
fossils are known from South Dakota, so the state's fossil record does not begin until the Paleozoic. At the start of the Paleozoic South Dakota was submerged by a sea. The state's
Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...
life left behind a rich trace fossil record. Paleozoic marine life of South Dakota included brachiopods,
cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
s, and corals. The sea temporarily withdrew from South Dakota during the Ordovician period. But, in the
middle Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (disambiguation) * Middle Brook (disambiguation) * Middle Creek (d ...
or late Ordovician, ostracoderms swam over South Dakota. Similar ostracoderms were preserved near Canon City, Colorado. Later, during the
Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...
period, sea levels again began to rise and fall. Marine life from this time included brachiopods and corals, but the rock record preserves evidence for local brackish and freshwater environments as well. The sea withdrew from the state altogether during the Permian and local sediments began being eroded rather than deposited. During the Triassic period sedimentation resumed. The geologic record reveals that South Dakota was moist coastal plain at that time. Seawater once more covered South Dakota during the Jurassic. This sea was home to creatures like ammonites, clams, crinoids, and
starfish Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish ...
. As the sea retreated South Dakota became a terrestrial environment dotted with lakes,
stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream ...
s, and
swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
s. The state was covered again by the sea during the Cretaceous period. This sea was called the Western Interior Seaway. This sea was home to many invertebrates, aquatic birds, and
marine reptile Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. The earliest marine reptile mesosaurus (not to be confused with mosasaurus), arose in the Permian period during the ...
s. The Cretaceous life of South Dakota was similar to that of Wisconsin. Some of South Dakota's ammonites were very unusual for the group. During the Late Cretaceous the region now occupied by the Black Hills of South Dakota may have attracted long necked plesiosaurs from hundreds of miles away as a source of
gastroliths A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract. Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. In othe ...
. Short-necked plesiosaurs like '' Dolichorhynchops'' also lived in the Western Interior Seaway of South Dakota during the Campanian. They were fast swimmers who fed on contemporary small fish and cephalopods. Most short-necked plesiosaurs were relatively small, with body lengths of less than ten feet. However, one South Dakotan individual was long. More shark species are known from the Cretaceous Western Interior Seaway deposits of South Dakota than other states with rocks from the same environment like those of Kansas. Otherwise these two states had similar shark communities. During the Late Campanian, South Dakota was home to the colossal sea turtle '' Archelon ischyros''. The first specimen was long. ''Archelon'' is the largest known turtle in history. Its size is comparable to that of a small car. Also during the Cretaceous, geologic uplift was forming the Black Hills in the western part of the state. Local
dinosaurs Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
included the armored '' Edmontonia'', duck-billed ''
Edmontosaurus ''Edmontosaurus'' ( ) (meaning "lizard from Edmonton") is a genus of hadrosaurid (duck-billed) dinosaur. It contains two known species: ''Edmontosaurus regalis'' and ''Edmontosaurus annectens''. Fossils of ''E. regalis'' have been found in rocks ...
'', the
ostrich dinosaur Ornithomimosauria ("bird-mimic lizards") are theropod dinosaurs which bore a superficial resemblance to the modern-day ostrich. They were fast, omnivorous or herbivorous dinosaurs from the Cretaceous Period of Laurasia (now Asia, Europe and North ...
'' Ornithomimus'', ''
Pachycephalosaurus ''Pachycephalosaurus'' (; meaning "thick-headed lizard", from Greek ''pachys-/'' "thick", ''kephale/'' "head" and ''sauros/'' "lizard") is a genus of pachycephalosaurid dinosaurs. The type species, ''P. wyomingensis'', is the only known species, ...
'', '' Triceratops'', and '' Tyrannosaurus''. During the early part of the
Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...
, central and eastern South Dakota was still covered by the sea. The uplift responsible for the Black Hills continued to elevate their topography. As the Cenozoic continued the sea shrank away from the state. In its place, grasslands formed and were roamed by herds of grazing mammals. Later, during the
Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...
, at least part of South Dakota was covered in seawater. The
White River Formation The White River Formation is a geologic formation of the Paleogene Period, in the northern Great Plains and central Rocky Mountains, within the United States. It has been found in northeastern Colorado, Dawes County in western Nebraska, Badlands ...
was being deposited in the White River badlands as the sea gradually receded. The Oligocene flora left behind few fossils, but among them were hackberry seeds and petrified wood. Although plant fossils are scarce, these deposits preserve one of the best Tertiary
mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
faunas in the world. More than 175 different kinds of animals were preserved from this time. The local mammals included the three-toed
horses The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...
, pig-like animals, the camel '' Poebrotherium'', ''
Protoceras ''Protoceras'' ('first horns') is an extinct genus of Artiodactyla, of the family Protoceratidae, endemic to North America. It lived from the Oligocene to the Early Miocene 33.3—16.0 Ma, existing for approximately . Morphology ''Protoceras ...
'', rhinoceroses, rodents, saber teeth, tapirs, and
titanothere Brontotheriidae is a family (biology), family of extinct mammals belonging to the order Perissodactyla, the order that includes horses, rhinoceroses, and tapirs. Superficially, they looked rather like Rhinoceros, rhinos, although they were actua ...
s. Contemporary birds also left behind bones and even an egg. These are significant because bird fossils are very rare. Many
streams A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream ...
carried even more sediment into the region from the young Rocky Mountains and Black Hills. At the time South Dakota consisted of plains dotted with marshes and shallow lakes and split by wide streams. Some of the local Oligocene wildlife left behind footprints that would later fossilize. The Brule Formation preserves one of only seven Oligocene fossil tracksites in the western United States. Volcanic activity sporadically showered the state with ash. During the Ice Age, glaciers scoured the state. As they melted, they deposited sediments that would preserve the fossil remains of creatures like
bison Bison are large bovines in the genus ''Bison'' (Greek: "wild ox" (bison)) within the tribe Bovini. Two extant and numerous extinct species are recognised. Of the two surviving species, the American bison, ''B. bison'', found only in North Ame ...
, horses, mammoths, and mastodons.


History


Indigenous interpretations

Fossils feature in some of the legends of local people. The
Sioux The Sioux or Oceti Sakowin (; Dakota language, Dakota: Help:IPA, /otʃʰeːtʰi ʃakoːwĩ/) are groups of Native Americans in the United States, Native American tribes and First Nations in Canada, First Nations peoples in North America. The ...
believed that in the first creatures in
creation Creation may refer to: Religion *'' Creatio ex nihilo'', the concept that matter was created by God out of nothing *Creation myth, a religious story of the origin of the world and how people first came to inhabit it *Creationism, the belief that ...
were the insects and
reptiles Reptiles, as most commonly defined are the animals in the Class (biology), class Reptilia ( ), a paraphyletic grouping comprising all sauropsid, sauropsids except birds. Living reptiles comprise turtles, crocodilians, Squamata, squamates (lizar ...
, who were ruled by the Water Monster Unktehi. Reptiles were very diverse and came in all shapes and sizes, but they became violent and bloodthirsty until they were petrified by lightning sent by the Thunder Birds. The physical bodies of the Thunder Beings killed by the lightning, including Unktehi, also ended up being buried. The Sioux believe that earth has a history of four distinct ages. These events occurred during the Age of Rock. This portrayal of the Thunder Birds may have been influenced by associations of fossils of the Cretaceous pterosaur Pteranodon with marine reptiles of the same age in the western US. Local people also employed fossils in ritual.
Plains Indians Plains Indians or Indigenous peoples of the Great Plains and Canadian Prairies are the Native American tribes and First Nation band governments who have historically lived on the Interior Plains (the Great Plains and Canadian Prairies) of N ...
like the Blackfeet and Cheyenne have a tradition of using '' Baculites'' fossils to summon buffalo herds. When used this way the fossils are called "buffalo-calling stones" or Iniskim. This practice derives from the complex shapes of the fossil's internal structure, which can sometimes bear shapes resembling buffalo. Iniskim have been discovered in South Dakota
archeological Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscape ...
sites. Archeological evidence exists for the buffalo-calling stone tradition that is at least 1,000 years old. One interesting South Dakota fossil was actually found not far from the Gobernador ruins in New Mexico during the 1980s. It was the jawbone of an
Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...
mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
endemic to South Dakota. This means someone would have had to transport the bone for 800 miles from the place it was discovered. The Blackfeet engaged in regular trade with the
Cliff Dweller In archaeology, cliff dwellings are dwellings formed by using niches or caves in high cliffs, and sometimes with excavation or additions in the way of masonry. Two special types of cliff dwelling are distinguished by archaeologists: the cliff ...
and
Navajo The Navajo (; British English: Navaho; nv, Diné or ') are a Native American people of the Southwestern United States. With more than 399,494 enrolled tribal members , the Navajo Nation is the largest federally recognized tribe in the United ...
peoples of the southwest, which may explain how the fossil ended up so far from its place of origin.


Scientific research

On September 10, 1804, four members of the Lewis and Clark Expedition recorded in their journals a fossil discovery along the banks of the Missouri River in what is now Gregory County of south-central South Dakota. The find was a 45-foot-long articulated vertebral column with some ribs and teeth associated that was located at the top of a high ridge. The men interpreted the remains as originating from a giant fish, but today scientists think the specimen was probably a mosasaur, or maybe a
plesiosaur The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared ...
. The expedition sent back some of the fossils, but these were later lost. Later, in 1847, Dr. Hiram A. Prout published a description of a fragmentary
titanothere Brontotheriidae is a family (biology), family of extinct mammals belonging to the order Perissodactyla, the order that includes horses, rhinoceroses, and tapirs. Superficially, they looked rather like Rhinoceros, rhinos, although they were actua ...
jaw discovered in the White River Badlands in the
American Journal of Science The ''American Journal of Science'' (''AJS'') is the United States of America's longest-running scientific journal, having been published continuously since its conception in 1818 by Professor Benjamin Silliman, who edited and financed it himself ...
. Not long afterward, Joseph Leidy described the
Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...
camel A camel (from: la, camelus and grc-gre, κάμηλος (''kamēlos'') from Hebrew or Phoenician: גָמָל ''gāmāl''.) is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. C ...
'' Poebrotherium'', which was discovered in the same general region as Prout's titanothere jaw. The government responded to these discoveries by dispatching an expedition into the area. In 1850 the Smithsonian sent its own collectors into the area. The Tertiary deposits of the White River Badlands was active for decades and still ongoing in 1920 when the South Dakota School of Mines published its Bulletin No. 13. This publication summarized the results of all the paleontological fieldwork done in the White River Badlands. In 1877, the United States Geological Survey published a report on the ancient plants and invertebrates of South Dakota. In 1895,
George Wieland George may refer to: People * George (given name) * George (surname) * George (singer), American-Canadian singer George Nozuka, known by the mononym George * George Washington, First President of the United States * George W. Bush, 43rd President ...
discovered YPM 3000, the nearly complete and articulated type specimen of the giant sea turtle now known as '' Archelon ischyros'', which had been preserved in the Pierre Shale. The discovery was the likely instigator for Wieland's subsequent research into Late Cretaceous
sea turtles Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leatherback, loggerhead, ...
that began the next year. After more work reconstructing the specimen, Wieland noticed that its plastron was very similar to that of ''
Protostega gigas ''Protostega'' ('first roof') is an extinct genus of sea turtle containing a single species, ''Protostega gigas''. Its fossil remains have been found in the Smoky Hill Chalk formation of western Kansas (''Hesperornis'' zone, dated to 83.5 million ...
'' and he began to doubt that ''Archelon'' was truly distinct. Therefore, in 1898, he reclassified it as a species of ''Protostega'', ''P. ischyros''. After examining the pelvis and skull of "Protostega" ischyros, however, Wieland recovered his confidence in his original view that YPM 3000 belonged to a genus distinct from ''Protostega'' and reclassified "''P.''" ''ischyros'' as ''Archelon ischyros'' again. Later, in 1940, the South Dakota School of Mines and Technology collaborated with
National Geographic ''National Geographic'' (formerly the ''National Geographic Magazine'', sometimes branded as NAT GEO) is a popular American monthly magazine published by National Geographic Partners. Known for its photojournalism, it is one of the most widely ...
on an expedition into the badlands. They uncovered tons of fossils from at least 175 different species of Oligocene life. The fossils were taken to the South Dakota School of Mines in Rapid City. Among the mammal discoveries were the remains of rhinoceroses, tapirs, three-toed
horses The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...
, pig-like animals, and
rodents Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are nat ...
. The team also uncovered some bird fossils, which are very rare. One of these was a
fossil egg Egg fossils are the fossilized remains of eggs laid by ancient animals. As evidence of the physiological processes of an animal, egg fossils are considered a type of trace fossil. Under rare circumstances a fossil egg may preserve the remains of t ...
, which author Marian Murray has called " e best find" of the entire expedition. Only a few plant specimens were discovered, but these included fossil hackberry seeds and petrified wood. Some of the fossils were so precariously located that the excavators had to use block and tackle to lower the fossils down from the tops of "slender pinnacles". The fossils were preserved in channel sandstones that had received little scientific attention prior to the expedition. In June 1947 the South Dakota School of mines sent another expedition into the Badlands. They uncovered a wide variety of fossils preserved in the Oligocene White River Formation. Among the creatures discovered were rhinoceroses, saber teeth, giant pig-like animals, '' Protoceros'', tapirs, horses and more. In 1990, Sue Hendrickson discovered a new specimen of Tyrannosaurus rex that would later be nicknamed in her honor. The specimen made headlines when a dispute over ownership rights raged for more than five years. "Sue" was determined to rightfully belong to the owner of the property it was found on. The rancher put the specimen up for auction and was purchased by the Chicago Field Museum for 8.36 million dollars. In 1996 Bell and others reported the discovery of a mosasaur of the genus '' Plioplatecarpus'' in South Dakota's Pierre Shale. The specimen was important because it preserved several juvenile skeletons inside its pelvic region. Similar fossils have been put forward as evidence of live birth in other types of marine reptiles.


Protected areas

*
Fossil Cycad National Monument Fossil Cycad National Monument was a national monument in the U.S. state of South Dakota beginning in 1922. The site contained hundreds of fossil cycads, one of the world's greatest concentrations. Because vandals stole or destroyed all of the vi ...
(no longer exists) * The Mammoth Site


National Register sites by region/county

NIt is intended that all National Register-listed archeological sites (places that have Smithsonian trinomials) in the state be listed here. This includes sites in counties of Fall River, Custer, Pennington, Meade, and Harding in the west of the state, and Corson, Stanley, and Jackson in next north-to-south swathe of states, and Campbell, Walworth, Potter, Sully, Hughes, Hyde, Hand, Buffalo, and Lyman in the next, and from Roberts, Spinks, Beadle, Jerauld, Sanborn, Davison, Hanson, McCook, Minnehaha, Hutchinson, Turner, and Lincoln in the last. This may not be complete; other sites might be included in large historic districts or listed under non-obvious names. Numerous archeological sites in
Fall River County Fall River County is a county in the U.S. state of South Dakota. As of the 2020 United States Census, the population was 6,973. Its county seat is Hot Springs. The county was founded in 1883. It is named for Fall River which runs through it. ...
were listed on the National Register of Historic Places in batches in 1982, 1993, 2005 and 2016. These were deemed significant for their information potential. The specific locations of these sites are not disclosed, but their general regions are. hese should be re-arranged into regions: southern Black Hills, north Cave Hills, Sandstone Buttes, etc. They are:


Natural history museums

*The Journey Museum, Rapid City *The Mammoth Site Museum of Hot Springs, SD,
Hot Springs A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by circ ...
*Museum of Geology, South Dakota School of Mines & Technology, Rapid City


See also

* Paleontology in Colorado *
Paleontology in Iowa Paleontology in Iowa refers to paleontological research occurring within or conducted by people from the United States, U.S. state of Iowa. The paleozoic fossil record of Iowa spans from the Cambrian to Mississippian age, Mississippian. During the ...
*
Paleontology in Minnesota Paleontology in Minnesota refers to paleontological research occurring within or conducted by people from the U.S. state of Minnesota. The geologic record of Minnesota spans from Precambrian to recent with the exceptions of major gaps including the ...
* Paleontology in Montana *
Paleontology in North Dakota Paleontology in North Dakota refers to paleontological research occurring within or conducted by people from the U.S. state of North Dakota. During the early Paleozoic era most of North Dakota was covered by a sea home to brachiopods, corals, and ...


Footnotes


References

* Everhart, M. J. 2005. ''Oceans of Kansas - A Natural History of the Western Interior Sea''. Indiana University Press, 320 pp. * Lockley, Martin and Hunt, Adrian. '' Dinosaur Tracks of Western North America''. Columbia University Press. 1999. * Mayor, Adrienne. ''Fossil Legends of the First Americans''. Princeton University Press. 2005. . * McCarville, Kata, Gale Bishop, Dale Springer, and Judy Scotchmoor. July 1, 2005. "South Dakota, US.
The Paleontology Portal
Accessed September 21, 2012. * * "SUE's Journey: From Field to Field Museum.
Sue at the Field Museum
Accessed 11/06/12. * Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. .


External links


Geologic units in South Dakota

Paleoportal: South Dakota
{{National Register of Historic Places in South Dakota South Dakota Natural history of South Dakota Science and technology in South Dakota