Tensleep Formation

Tensleep Formation Stratigraphic range: Late Pennsylvanian to very Early Permian PreЄ Є O S D C P T J K Pg N
Type	Geological formation
Underlies	Phosphoria Formation or Chugwater Formation
Overlies	Sacajewea Formation or Amsden Formation
Thickness	up to 535 feet (160 m)
Lithology
Primary	Sandstone
Other	Limestone
Location
Region	Wyoming
Country	USA
Type section
Named for	Ten Sleep, Wyoming
Named by	N.H. Darton, 1904

The Tensleep Sandstone is a geological formation of Pennsylvanian to very early Permian age in Wyoming.

In 1932 Edward Branson and Maurice Mehl reported the discovery of a fossil trackway in the formation. A new ichnospecies, Steganoposaurus belli, was erected for these footprints. The tracks were probably made by a web-footed animal slightly less than three feet long. This creature was originally presumed to be an amphibian, but the toe prints it left behind were pointed like a reptile's rather than round like an amphibians. The actual trackmaker may have been similar to the genus Hylonomus. The ichnogenus Tridentichnus are similar footprints preserved in the Supai Formation of Arizona.