Stratigraphic chart of the lower Permian (partial)
Content updated October 16, 2005
RICHARDS SPUR UNIDENTIFIED
SPHENACODONTID
Synapsida-Eupelycosauria-Sphenacodontidae
Above: pictures of a cervical vertebra that could belong to a Sphenacodontid on the basis of narrow excavated neural arch, and sharp keeled centra: in lateral and anterior views. From Richards Spur (Dolese Quarry) - Comanche Co. Oklahoma. Lower Permian.