Geology of Archeological Site 48SH312, Wyoming

Abstract

Archeological Site 48SH312 occurs upon slightly weathered shale in the uppermost portion ot the Fort Union Formation (Paleocene) of eastern Sheridan County, Wyoming. Only a trace of a paleosol is developed on the shale. Colluvium overlies the shale. The site is a small remnant of a ravine floor which existed during Kaycee time. Physiography of the present ravine and local distribution of resistant lenticular strata in the Fort Union Formation, suggest that the paleo-ravine was a box ravine with near vertical walls of 5-10 meters. Paleosol development, weathering features, and homogeneity of colluvium are interpreted as indicating a surface that represents late Kaycee time and provides a geological age for the site of 3500 to 4000 years before present.