Paleontology in Montana
Much of Montana remained covered by seawater into the Late Jurassic, but exposed areas were greened by a flora of conifers, cycads, ferns, and ginkgoes.
This coastal plain was home to dinosaurs including the ornithopod Camptosaurus, the sauropods Apatosaurus and Diplodocus, and the theropod Allosaurus.
Other important discoveries include the plant and insect fossils of Ruby Valley and Deinonychus, which triggered the Dinosaur Renaissance.
[2] Further into the Paleozoic, Mississippian brachiopods, bryozoans, and corals left behind fossils in the Bridger Range and at Shell Mountain south of Big Timber.
[9] South of Montana's sea was a coastal plain split by streams flowing west from areas of higher elevation to the east.
This coastal plain was home to dinosaurs including the ornithopod Camptosaurus, the sauropods Apatosaurus and Diplodocus, and the theropod Allosaurus.
[13] During the Campanian Stage of the Late Cretaceous the coastal plain bordering the Western Interior Seaway was lined with rivers and dotted with a few lakes.
[15] Late Cretaceous fossil dinosaur footprints are surprisingly rare in Montana compared to other western states with contemporary deposits.
[18] Later in the Maastrichtian stage, volcanic activity was still ongoing in the Elkhorn region and the Western Interior Seaway began to withdraw.
By the late Maastrichtian stage large rivers flowed across the eastern part of the state, depositing the sediments that would one day become the Hell Creek Formation.
[20] Among the Oligocene flora of Montana were ailanthus, ash, beech, cattails, cedar, cinquefoil, dogwood, elm, ferns, milfoil fernbush, gooseberry, climbing grapes, grasses, greenbriers, horsetails, ironwood, katsura tree, liverwort, mountain mahogany, maple, false mermaid, mosses, oak, pennycress, pondweed, dawn redwood, roses, sedges, smoke tree, snowberry, spiraea, false strawberry, and vetches.
[22] Montana's Miocene plants and mollusks left behind remains at Bear Butte, northwest of Melville in Sweet Grass County's Fort Union Beds.
[23] The Miocene mammals preserved in the Fort Union beds included arctocyonids, insectivores, multituberculates, pantodonts, primates, taeniodonts.
Archaeological sites on the Crow Reservation between Pryor and St. Xavier include fire pits lined with sizable dinosaur bones.
[25] The Crow people prospected for minerals to use in making pigments in Unit VII of the Cloverly Formation, which is exposed in Montana.
[26] The Crow Indians sought red mineral pigments in the same Cloverly Formation strata that have produced dinosaur remains including Deinonychus, Sauropelta, and Tenontosaurus.
These were called Bulukse'e or Buruksam Wurukce, names meaning "large meat-eater" but commonly translated as "giant lizard or alligator".
This may be derived from observations of the isolated remains of the two-fingered forelimbs left by tyrannosaurids such as Tyrannosaurus rex, which could be mistaken for the limb of a large unknown kind of bird.
[31] The Triceratops and Tyrannosaurus fossils of Montana's Hell Creek Formation may have influenced Cheyenne beliefs in monsters called ahk.
[34] When the Sioux lived around the Great Lakes, they imagined their mythical Water Monster Unktehi as a large aquatic buffalo-like mammal.
This image was likely derived from early observations of large Pleistocene mammal fossils such as mammoths and mastodons eroding out of the banks of local lakes and rivers.
[35] As some groups of Sioux began moving west into the regions that includes Montana their depictions of Unktehi tended to converge on the characteristics of local fossils.
[36] In 1855, United States Geological Survey geologist Ferdinand Vandeveer Hayden was exploring a region of what was then called Nebraska Territory, but which is located what is now central Montana.
Leidy could tell that these teeth were different than those of any known animal, yet were recognizably dinosaurian based on their similarities to previously discovered dinosaur fossils in England.
As the remains were distinct from any previously described dinosaur taxa, Leidy erected three new genera and species for them; Deinodon horridus, Trachodon mirabilis, and Troodon formosus.
[37] In 1901, Dr. Earl Douglass discovered fossil plants, mollusks, and vertebrae at Bear Butte, northwest of Melville in Sweet Grass County's Fort Union Beds.
[3] Montanan Tertiary deposits in the Ruby Valley basin were first studied in 1947 by Dr. Herman F. Becker on behalf of the New York Botanical Garden.
[39] It exhibited important anatomical similarities to birds that helped scientists shed antiquated ideas interpreting dinosaurs as "overgrown lizards".
[40] In 1978, paleontologist Bill Clemens alerted Jack Horner and Bob Makela to the presence of unidentified dinosaur fossils in Bynum.
Their effort paid off with the discovery of the first scientifically documented dinosaur eggs of the Western Hemisphere and a new kind of duck-bill, Maiasaura peeblesorum.
