=Sinclairella dakotensis= Jepsen, 1934
The type of the species, Princeton no. 13585, was discovered in
Chadronian strata of the upper part of the Chadron Formation cropping
out in Big Corral Draw, approximately 13 miles south-southwest of
Scenic, in southwestern South Dakota (Jepsen, 1934, p. 291). Detailed
descriptions of the type specimen are given in papers by Jepsen (1934)
and Scott and Jepsen (1936). Isolated teeth of Chadronian age referable
to _Sinclairella dakotensis_ have been discovered subsequently at a
locality in Nebraska and fossils of Orellan age, also referable to _S.
dakotensis_, have been collected at two localities in Colorado. The
sample from each locality is described separately.