- GeoRef, Copyright 2004, American Geological Institute.
Foraminifera and marine mollusks were found in the upper 1.5 m of the Satanka Shale, a Permian unit, at Laramie, Wyoming. This fossiliferous interval was divided into three distinct units based on lithology and fauna. The lower unit is a porous sandstone bed characterized by pelecypods, gastropods, and scaphopods. The middle limestone unit contains abundant foraminifera and small pelecypods. The upper unit is mudstone containing foraminifera and scattered small pelecypods. The fossiliferous interval probably represents the early stage of the Wordian transgression that resulted in the overlying stromatolitic Forelle Limestone. The fossils decrease in diversity upward in the fossiliferous interval, suggesting that salinity changed as deposition proceeded. The irregularly coiled foraminifera belong to a single species whose tests accumulated at times in sufficient abundance to form individual laminae.