The Morrison Formation is a distinctive sequence of Upper Jurassic sedimentary rock found in the western United States which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone, and limestone and is light gray, greenish gray, or red. Most of the fossils occur in the green siltstone beds and lower sandstones, relics of the rivers and floodplains of the Jurassic period.
Theiophytalia is a genus of herbivorous iguanodontian dinosaur from the lower Cretaceous period of Colorado, USA. It contains a single species, T. kerri.
The Dakota is a sedimentary geologic unit name of formation and group rank in Midwestern North America. The Dakota units are generally composed of sandstones, mudstones, clays, and shales deposited in the Mid-Cretaceous opening of the Western Interior Seaway. The usage of the name Dakota for this particular Albian-Cenomanian strata is exceptionally widespread; from British Columbia and Alberta to Montana and Wisconsin to Colorado and Kansas to Utah and Arizona. It is famous for producing massive colorful rock formations in the Rocky Mountains and the Great Plains of the United States, and for preserving both dinosaur footprints and early deciduous tree leaves.
The Naturita Formation is a classification used in western Colorado and eastern Utah for a Cretaceous Period sedimentary geologic formation. This name was "applied to the upper or carbonaceous part of Dakota Group" by R.G. Young in 1960, naming it for Naturita, Colorado. The name is not used by U.S. Geological Survey authors, but has found growing acceptance by the Utah Geological Survey
Dakotadon is a genus of iguanodont dinosaur from the Barremian-age Lower Cretaceous Lakota Formation of South Dakota, USA, known from a partial skull. It was first described in 1989 as Iguanodon lakotaensis, by David B. Weishampel and Philip R. Bjork. Its assignment has been controversial. Some researchers suggest that "I." lakotaensis was more basal than I. bernissartensis, and related to Theiophytalia, but David Norman has suggested that it was a synonym of I. bernissartensis. Gregory S. Paul, working on a revision of iguanodont species, gave "I." lakotaensis its own genus (Dakotadon) in 2008. He measured its length at 6 metres (20 ft) and body mass at 1 metric ton.
The Fox Hills Formation is a Cretaceous geologic formation in the northwestern Great Plains of North America. It is present from Alberta on the north to Colorado in the south.
The Mowry Shale is an Early Cretaceous geologic formation. The formation was named for Mowrie Creek, northwest of Buffalo in Johnson County, Wyoming.
The Plainview Formation is an Early Cretaceous (Albian) geologic formation of the Dakota Group in Colorado. Fossil ankylosaur tracks and tracks of Caririchnium sp. have been reported from the formation.
The Pajarito Formation is a geologic formation in eastern New Mexico and west Texas. It preserves fossils dating back to the Albian Age of the Cretaceous Period.
The Kiowa Formation or Kiowa Shale is a Cretaceous geologic formation in Kansas, diminishing to member status in Colorado and Oklahoma. In Colorado, the Kiowa Shale was classified as a member of the now abandoned Purgatoire Formation. In the vicinity of Longford, Kansas, the local Longford member comprises thinly bedded siltstone, clay, polished gravel, lignite, and sandstone suggests a river and estuary environment.
The Mancos Shale or Mancos Group is a Late Cretaceous geologic formation of the Western United States.
Paleontology in Colorado refers to paleontological research occurring within or conducted by people from the U.S. state of Colorado. The geologic column of Colorado spans about one third of Earth's history. Fossils can be found almost everywhere in the state but are not evenly distributed among all the ages of the state's rocks. During the early Paleozoic, Colorado was covered by a warm shallow sea that would come to be home to creatures like brachiopods, conodonts, ostracoderms, sharks and trilobites. This sea withdrew from the state between the Silurian and early Devonian leaving a gap in the local rock record. It returned during the Carboniferous. Areas of the state not submerged were richly vegetated and inhabited by amphibians that left behind footprints that would later fossilize. During the Permian, the sea withdrew and alluvial fans and sand dunes spread across the state. Many trace fossils are known from these deposits.
The Graneros Shale is a geologic formation in the United States identified in the Great Plains as well as New Mexico that dates to the Cenomanian Age of the Cretaceous Period. It is defined as the finely sandy argillaceous or clayey near-shore/marginal-marine shale that lies above the older, non-marine Dakota sand and mud, but below the younger, chalky open-marine shale of the Greenhorn. This definition was made in Colorado by G. K. Gilbert and has been adopted in other states that use Gilbert's division of the Benton's shales into Carlile, Greenhorn, and Graneros. These states include Kansas, Texas, Oklahoma, Nebraska, and New Mexico as well as corners of Minnesota and Iowa. North Dakota, South Dakota, Wyoming, and Montana have somewhat different usages — in particular, north and west of the Black Hills, the same rock and fossil layer is named Belle Fourche Shale.
The Greenhorn Limestone or Greenhorn Formation is a geologic formation in the Great Plains Region of the United States, dating to the Cenomanian and Turonian ages of the Late Cretaceous period. The formation gives its name to the Greenhorn cycle of the Western Interior Seaway.
The Inyan Kara Group is a geologic group classification applied in South Dakota and adopted in portions of Wyoming and Montana. It preserves fossils of the mid-Cretaceous period. Of late Albian age, this classification correlates with the lower Dakota Formation known in the southwest corner of the State.
The Mesa Rica Sandstone is a geologic formation in Oklahoma and New Mexico. It preserves fossils dating back to the Cretaceous period.
The Belle Fourche Formation or Belle Fourche Shale is a fossiliferous early Late-Cretaceous geologic formation classification in Wyoming. Named for outcrops in Belle Fourche River, Wyoming, this unit name is also used in Montana, North Dakota, and South Dakota.
The Tucumcari Formation is a geologic formation in New Mexico. It preserves fossils dating back to the Albian Age of the early Cretaceous period.
The Lytle Formation or Lytle Sandstone is a geologic formation found in Wyoming, Colorado, and New Mexico.
The Glencairn Formation is a geologic formation found in Colorado and New Mexico. It preserves fossils characteristic of the Albian Age of the Cretaceous Period.
Colorado 
United States 
