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Virgelle Sandstone
The Virgelle Sandstone is a geologic formation overlain by the Two Medicine Formation The Two Medicine Formation is a geological formation, or rock body, in northwestern Montana and southern Alberta that was deposited between 82.4 Ma and 74.4 Ma, during Campanian (Late Cretaceous) time. It crops out to the east of the Rocky Mountai ...."Geological Setting," Trexler (2001); pages 300-301. It formed from the beach sands exposed on northern and western shores of the receding Colorado Sea. Footnotes References * Trexler, D., 2001, Two Medicine Formation, Montana: geology and fauna: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, pp. 298–309. {{Clear Sandstone formations of the United States Cretaceous Montana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Montana
Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, and the Provinces and territories of Canada, Canadian provinces of Alberta, British Columbia, and Saskatchewan to the north. It is the List of U.S. states and territories by area, fourth-largest state by area, but the List of U.S. states and territories by population, eighth-least populous state and the List of U.S. states and territories by population density, third-least densely populated state. Its List of capitals in the United States, capital is Helena, Montana, Helena, while the List of municipalities in Montana, most populous city is Billings, Montana, Billings. The western half of the state contains numerous mountain ranges, while the eastern half is characterized by western prairie terrain and badlands, with smaller mountain ranges f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the semi-exclave of Alaska in the northwest and the archipelago of Hawaii in the Pacific Ocean. The United States asserts sovereignty over five Territories of the United States, major island territories and United States Minor Outlying Islands, various uninhabited islands in Oceania and the Caribbean. It is a megadiverse country, with the world's List of countries and dependencies by area, third-largest land area and List of countries and dependencies by population, third-largest population, exceeding 340 million. Its three Metropolitan statistical areas by population, largest metropolitan areas are New York metropolitan area, New York, Greater Los Angeles, Los Angel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two Medicine Formation
The Two Medicine Formation is a geological formation, or rock body, in northwestern Montana and southern Alberta that was deposited between 82.4 Ma and 74.4 Ma, during Campanian (Late Cretaceous) time. It crops out to the east of the Rocky Mountain Overthrust Belt, and the western portion (about thick) of this formation is folded and faulted while the eastern part, which thins out into the Sweetgrass Arch, is mostly undeformed plains. Below the formation are the nearshore (beach and tidal zone) deposits of the Virgelle Sandstone, and above it is the marine Bearpaw Shale. Throughout the Campanian, the Two Medicine Formation was deposited between the western shoreline of the Late Cretaceous Interior Seaway and the eastward advancing margin of the Cordilleran Overthrust Belt. The Two Medicine Formation is mostly sandstone, deposited by rivers and deltas. History of research In 1913 in paleontology, 1913, a US Geological Survey crew headed by Eugene Stebinger and a US National Museu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorado Sea
Colorado is a state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas to the east, and Oklahoma to the southeast. Colorado is noted for its landscape of mountains, forests, high plains, mesas, canyons, plateaus, rivers, and desert lands. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. Colorado is the eighth-largest U.S. state by area and the 21st by population. The United States Census Bureau estimated the population of Colorado to be 5,957,493 as of July 1, 2024, a 3.2% increase from the 2020 United States census. The region has been inhabited by Native Americans and their ancestors for at least 13,500 years and possibly much longer. The eastern edge of the Rocky Mountains was a major migration route for earl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
