The Trempealeauan is the upper or latest stage of the Upper or Late Cambrian in North America, spanning about 4 million years from about 492.5 to 488.3 m.y.a., equivalent to the Fengshanian of China. The name comes from the Trempealeau Formation, named for the town of Trempealeau in western Wisconsin, located on the Mississippi River.
The Munising Group or Formation is a 1,700 feet (520 m) thick, white to light grey Cambrian sedimentary unit that crops out in Michigan and Ontario. At one end of its extent, it comprises a basal conglomerate overlain by the Chapel Rock Member and the Miners Castle Member; elsewhere, it comprises the Eau Claire, Galesville (=Dresbach), and Franconia Members. Anhydritic evaporite deposits are present in places. The conglomerate was deposited by rivers in flood, with the Chapel Rock member, which contains deltaic deposits, representing transgression as the conglomerate cones became submerged; the Miners Castle member was deposited further from the shoreline, representing shelf deposits. Its uppermost strata may be Early Ordovician in age, and contain conodonts, trilobites and phosphatic moulds of brachiopods, ostrocoderm fish and gastropods.
Dells of the Eau Claire County Park is in the north-central Wisconsin Town of Plover, east of the city of Wausau. It is divided in two by the Eau Claire River. The river flows through a rocky gorge to form cascades and waterfalls as it passes over and around weathered boulders, outcrops, and other formations. The depth of the river can vary depending on the time of the year. The park also has areas designated for camping, swimming, hiking, and picnicking.
The Whitewater Formation is a geologic formation in Ohio and Indiana. It preserves fossils dating back to the Ordovician period.
The Salem Formation is a geologic formation in Illinois, Indiana, Kentucky, and Missouri. It preserves fossils dating back to the Mississippian subperiod. This formation is quarried and used as a building material, known as "Indiana limestone", also called Bedford limestone.
The Davis Formation is a geologic formation in Indiana and Missouri. It preserves fossils dating back to the Cambrian period.
The Big Clifty Formation is a geologic formation in Indiana. It preserves fossils dating back to the Carboniferous period.
The Kinzers Formation is a geologic formation in Pennsylvania. It preserves fossils dating back to the Cambrian Period.
The Chamberlain's Brook Formation is a thin but distinctive geologic formation of dark red calcareous mudstones that crops out from Rhode Island to Massachusetts and, Nova Scotia, New Brunswick and Newfoundland. It preserves fossils, including trilobites, dating back to the lower mid-Cambrian period. Its lowermost member is the Braintree Member and the uppermost member is the Fossil Brook Member.
The Dresbach Formation is a geologic formation in Wisconsin. It preserves fossils dating back to the Cambrian period.
The Franconia Formation is a geologic formation in the upper mid-western United States, with outcroppings found in Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio, and Wisconsin. It preserves fossils dating back to the Cambrian period. It was named the Franconia Formation due to the first published documentation of exposures in vicinity of Franconia, Minnesota in the 1897 Ph.D. dissertation by Charles P. Berkley at the University of Minnesota titled Geology of the St. Croix Dalles. The Franconian stratigraphic stage was named after this formation.
The Jordan Sandstone is a geologic formation in Wisconsin. It preserves fossils dating back to the Cambrian period.
The Potosi Formation is a geologic formation in Missouri, Illinois and Indiana. It preserves fossils dating back to the Cambrian period.
The Deadwood Formation is a geologic formation of the Williston Basin and Western Canada Sedimentary Basin. It is present in parts of North and South Dakota and Montana in the United States, and in parts of Alberta, Saskatchewan, and southwestern corner of Manitoba in Canada. It is of Late Cambrian to Early Ordovician age and was named for exposures in Whitewood Creek near Deadwood, South Dakota. It is a significant aquifer in some areas, and its conglomerates yielded significant quantities of gold in the Black Hills of South Dakota.
The Dunderberg Shale is a geologic formation in Nevada and Utah.
The Windfall Formation is a geologic formation in northeastern and southern Nevada.
The Brigus Formation is a fossiliferous upper lower Cambrian geologic formation in Newfoundland and Labrador.
The Skoki Formation is a stratigraphic unit of Early to Middle Ordovician age that is present on the western edge of the Western Canada Sedimentary Basin in the Canadian Rockies of Alberta and British Columbia. It was named for Skoki Mountain near Lake Louise in Banff National Park by Charles Doolittle Walcott in 1928. The Skoki Formation is fossiliferous and includes remains of brachiopods and other marine invertebrates, as well as conodonts and oncolites.
The Mount Whyte Formation is a stratigraphic unit that is present on the western edge of the Western Canada Sedimentary Basin in the southern Canadian Rockies and the adjacent southwestern Alberta plains. It was deposited during Middle Cambrian time and consists of shale interbedded with other siliciclastic rock types and limestones. It was named for Mount Whyte in Banff National Park by Charles Doolittle Walcott, the discoverer of the Burgess shale fossils, and it includes several genera of fossil trilobites.
The Mount Simon Sandstone is an Upper Cambrian sandstone and is found in many states in the Midwest such as Wisconsin, Minnesota, Iowa, Illinois, Iowa, and Missouri.
