662 T. W. STANTON 



Comanche fauna, although some of them belong to unnamed species 

 and others are not well enough preserved to justify positive specific 

 determination. Among those collected at this locality are: 



Inoceramus comancheanus Cragin 

 Trigonia emoryi Conrad ? 

 Cardium kansasense Meek 

 Cyprimeria sp. 

 Pholadomya sancti-sabae Roemer? 



Farther up the Purgatoire, in the neighborhood of Chaquaqua 

 Creek, where the underlying formations are better exposed, this 

 fossiliferous horizon was easily recognized and fossils were collected 

 from it in Browns Canyon, on the ridge east of Chaquaqua Creek, 

 and in Iron Canyon. These localities added to the list of species 

 Protocardia texana Conrad, Leptosolen conradi Meek and an unnamed 

 species of Tapes ( ?) which also occurs in the Kiowa shales of Kansas. 

 No specimens of Gryphaea corrugata were found on the Purgatoire, 

 but the forms listed are elsewhere associates of that species and there 

 is no doubt that the horizon is the equivalent of some part of the 

 Washita group, and should be directly correlated with the Kiowa 

 shales of southern Kansas. It must certainly be removed from the 

 Dakota. The underlying sandstone, which has been called Lower 

 Dakota, probably goes with the shales in the Comanche series, 

 though the evidence on this point is net conclusive. Its variation 

 in thickness and its absence from some sections would suggest a 

 possible erosion interval after its deposition. 



The variegated shales and the sandstones and limestones, of the 

 Morrison with an average thickness of about 200 feet are partly 

 exposed in the neighborhood of Higbee, but they may be better seen 

 farther up the river especially near Chaquaqua Creek, about fifteen 

 miles southwest of Higbee. 



Here Mr. Lee had previously announced the occurrence of large 

 dinosaurs, and Mr. Gilmore was able to recognize Brontosaurus 

 and other dinosaur genera of the Morrison fauna. At the locality 

 where the bones were seen in the greatest abundance, near the south- 

 east corner of the Timpas quadrangle, the dinosaur horizon is about 

 200 feet below the marine Comanche fossils. 



Beneath the Morrison formation, or possibly forming a member 



