expansa' (Dunbar & Condra) preferred argillaceous (clayey) environments, were commonly found in thin layers immediately above or unfossiliferous beds, and rarely carried any epifauna. Mudge and Yochelson (1962) stated that the related species 'C. Rudwick (1965) has suggested that brachiopods with deeply plano-convex shells may have lived with convex shell pressed into the soft substrate. planoconvexa' is commonly found in the offshore, dysaerobic environments where a diverse bivalve fauna is found, and it is usually the only species of brachiopod observed there. planoconvexa' is one species of brachiopod that is commonly found associated with bivalves. You are referred to any standard text book on invertebrate paleontology to see how these features relate to the body of the living or fossil animal.ĭescription: Two views of 'Crurithyris planoconvexa' (Shumard) showing brachial valve (left) and two pedicle valves. Many morpholgic terms are used in describing the fossils below. Geinitz who worked in Nebraska in the 1850's and 1860's first described many of the fossils that are illustrated below. Holterhoff and Pabian (1990), Pabian and Boardman (1995), and Pabian and Diffendal (1989, 1991, in press) recorded several outcrops of the Foraker Formation in Richardson and Pawnee counties. Subsequent workers (Moore and Condra, 1932 Condra, 1935, Moore, 1936, and Burchett) revised the Hughes Creek Shale and beds now called the Oaks Shale, the Houchens Creek Limestone, and Stine Shale were removed from the lower part of the Hughes Creek.Ĭondra (1927) named the Long Creek Limestone for the beds that immediately overlie the Hughes Creek Shale for cavernous (vuggy?), irregular beds that are exposed on Longs Creek at the foot of the bluff west of the cemetery at Auburn, Nemaha County, Nebraska. Condra, 1927, originally applied the name Hughes Creek Shale to up to 50 feet (16 m) of blue, clayes shale, dark shale and thin limestone beds for Hughes Creek, south of Auburn, in Nemaha County, Nebraska. The Americus Limestone heralds the return in the midcontinent of sedimentation patterns that were more similar to those observed in the older (late Pennsylvanian) Missouri and early Virgil series. The Americus Limestone may have three to five beds that are separated by thin shale seams in the southeastern Nebraska outcrop area. It is usually dense, finely crystalline, fossiliferous, and may be the transgressive limestone of a cyclothem. In southeastern Nebraska, the Americus Limestone is usually only about 2 feet (0.7 m) thick. Kirk (1896) named the Americus Limestone for the village of Americus, Lyon County, Kansas, where it is about 7 feet (2.6 m) thick. The Foraker Formation has three members, in ascending order: The Americus Limeston, the Hughes Creek Shale, and the Long Creek Limestone.

In its type locality, the Foraker Formation is about 75 feet (23 m) thick but the Foraker is only about 40 feet (12 m) thick in southeastern Nebraska. Heald (1916) applied the name Foraker Formation to rocks that are exposed in the vicinity of Foraker, Osage County, Oklahoma.

Archimedes fossil