The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes in three basins along the present-day Green River in Colorado, Wyoming, and Utah. The sediments are deposited in very fine layers, a dark layer during the growing season and a light-hue inorganic layer in the dry season. Each pair of layers is called a varve and represents one year. The sediments of the Green River Formation present a continuous record of six million years. The mean thickness of a varve here is 0.18 mm, with a minimum thickness of 0.014 mm and maximum of 9.8 mm.
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.
The Laramie Formation is a geologic formation of Late Cretaceous (Maastrichtian) age, named by Clarence King in 1876 for exposures in northeastern Colorado, in the United States. It was deposited on a coastal plain and in coastal swamps that flanked the Western Interior Seaway. It contains coal, clay and uranium deposits, as well as plant and animal fossils, including dinosaur remains.
The Uinta Basin is a physiographic section of the larger Colorado Plateaus province, which in turn is part of the larger Intermontane Plateaus physiographic division. It is also a geologic structural basin in eastern Utah, east of the Wasatch Mountains and south of the Uinta Mountains. The Uinta Basin is fed by creeks and rivers flowing south from the Uinta Mountains. Many of the principal rivers flow into the Duchesne River which feeds the Green River—a tributary of the Colorado River. The Uinta Mountains forms the northern border of the Uinta Basin. They contain the highest point in Utah, Kings Peak, with a summit 13,528 feet above sea level. The climate of the Uinta Basin is semi-arid, with occasionally severe winter cold.
The Cedar Mountain Formation is the name given to a distinctive sedimentary geologic formation in eastern Utah, spanning most of the early and mid-Cretaceous. The formation was named for Cedar Mountain in northern Emery County, Utah, where William Lee Stokes first studied the exposures in 1944.
The North Horn Formation is a widespread non-marine sedimentary unit with extensive outcrops exposed in central and eastern Utah. The formation locally exceeds 3,600 feet (1,100 m) in thickness and is characterized by fluvial, lacustrine, and floodplain dominated systems, representing a terrestrial, high energy, depositional environment. The sediments date from Late Cretaceous (Maastrichtian) to early Paleocene in age and include the K-Pg extinction event boundary; however, this boundary is extremely difficult to locate and there is no strong stratigraphic evidence available that indicates a specific marker bed such as an iridium rich clay layer. Thus far, the only visible evidence is represented in the form of faunal turnover from dinosaur to mammal-dominated fossil assemblages. Taxa from the Cretaceous part of the formation include squamates, testudines, choristoderes, crocodyliforms, sharks, bony fishes, amphibians, mammals, dinosaurs, eggshell fragments, trace fossils, mollusks, plant macrofossils, such as wood fragments, and palynomorphs.
The Mancos Shale or Mancos Group is a Late Cretaceous geologic formation of the Western United States.
The Wasatch Formation (Tw) is an extensive highly fossiliferous geologic formation stretching across several basins in Idaho, Montana Wyoming, Utah and western Colorado. It preserves fossils dating back to the Early Eocene period. The formation defines the Wasatchian or Lostcabinian, a period of time used within the NALMA classification, but the formation ranges in age from the Clarkforkian to Bridgerian.
The Burro Canyon Formation is an Early Cretaceous Period sedimentary geologic formation, found in western Colorado, the Chama Basin and eastern San Juan Basin of northern New Mexico, and in eastern Utah, US.
The Price River Formation is a geologic formation in Utah. It preserves fossils dating back to the Cretaceous period. The Price River Formation is approximately 200 metres (660 ft) thick at its type locality and consists of cliff-forming sandstone and siltstone visible in the Book Cliffs.
The Curtis Formation is a geologic formation in Utah. It preserves fossils dating back to the Callovian age of the Jurassic period.
The Duchesne River Formation is a geologic formation in the Uintah Basin of northeastern Utah. It was originally named the Duchesne Formation by Carnegie Museum paleontologist OA Peterson, and modified to the Duchesne River Formation by Carnegie Museum paleontologist JL Kay because Duschesne Formation was previously used for a Jurassic limestone. In naming the formation, no type section was given, only that it is named for the Duchesne River, which flows roughly southeast and east to join the Green River.
The Uinta Formation is a geologic formation in northeastern Utah. The name appears on a geologic map accompanying the Clarence King Fortieth Parallel report for 1876 but not defined until 1878 as the Uinta Group. As defined, it consisted of all Tertiary strata overlying the Green River Formation and was composed of coarse, conglomeratic sandstones, passing up into finer-grained sandstones and calcareous mudstones. Numerous vertebrate fossils were collected and described by Othniel C. Marsh of Yale University. The formation was subsequently subdivided into three informal horizons based on mammalian fossils. Horace Wood proposed the name Wagonhound Member for Uinta A+B and Myton Member for Uinta C. However, these names are not based on lithology, but on mammalian vertebrate faunas. For that reason, they have not been accepted as proper lithostratigraphic names.
The Rock Point Formation is a geologic formation in New Mexico, Arizona, and Utah. It preserves fossils dating back to the late Triassic.
The Mesaverde Group is a Late Cretaceous stratigraphic group found in areas of Colorado, New Mexico, Utah, and Wyoming, in the Western United States.
The Blairmore Group, originally named the Blairmore Formation, is a geologic unit of Early Cretaceous age in the Western Canada Sedimentary Basin that is present in southwestern Alberta and southeastern British Columbia. It is subdivided into a series of formations, most of which contain plant fossils. In some areas it contains significant reservoirs of natural gas.
The Monteith Formation is a geologic formation of Early Cretaceous (Valanginian) age in the Western Canada Sedimentary Basin that consists primarily of sandstone. It is present in the northern foothills of the Canadian Rockies and the adjacent plains in northeastern British Columbia and west-central Alberta.
The Boulder Creek Formation is a geologic formation in northeastern British Columbia. It was named for a tributary to Commotion Creek in the Pine Pass area by E.M. Spieker in 1921. At one time considered to be a member of the Commotion Formation, it was elevated to formation status by D.F. Stott in 1982.
The Bickford Formation is a geologic formation of Early Cretaceous (Valanginian) age in the Western Canada Sedimentary Basin that consists primarily of nonmarine sediments. It is present in the northern foothills of the Canadian Rockies in northeastern British Columbia.
The geology of Utah includes rocks formed at the edge of the proto-North American continent during the Precambrian. A shallow marine sedimentary environment covered the region for much of the Paleozoic and Mesozoic, followed by dryland conditions, volcanism and the formation of the basin and range terrain in the Cenozoic. Utah is a state in the western United States.
