2 PEOCEEDIN'GS OF THE NATIONAL MUSEUM vol. 69 



marls and argillaceous and limy shales containing fossil parasu- 

 chians and labyrinthodonts ; above it, 30 meters of sandstone, 7 

 meters of well bedded limestones, 25 meters of so-called "Motar 

 Beds," limy shales with flint, and, finally, 60 meters of calcareous 

 marls. This series of beds has been restudied by Gregory ^ and is 

 now divided into the Chinle formation (upper 450 meters) and Shin- 

 arump conglomerate (basal 30 meters). The "Fossil Zone" of 

 Ward is 120 to 240 meters below the top of the Chinle, about the third 

 quarter of the formation. Fragments of bones are recorded also in 

 the Shinarump conglomerate and in the lower part of the Chinle 

 formation as defined by Gregory. The detailed petrologic char- 

 acters are varied but the larger features are the same for long 

 distances. 



In southwestern Colorado above the Permian Cutler formation 

 the unconformable Triassic Dolores formation may be dis- 

 tinguished.^ The relations of the Dolores formation to the Chinle, 

 the Shinarump, and the Moenkopi formations are still somewhat 

 uncertain, though it probably includes the Chinle and the Shin- 

 arump. The lower part of the Dolores contains abundant frag- 

 mentary remains of vertebrates. 



Vertebrates occur low in the Chinle formation, as Mehl* 

 demonstrates in published sections frota the region of the Petrified 

 Forest, Arizona, and as noted above in the work of Gregory. 

 Hills ^ found very well preserved fish remains {Catopterus of. 

 gi'aeilis) associated with parasuchian teeth in southwestern Colo- 

 rade 15 meters below the " Shinarump conglomerate " (in lower 

 Dolores). Ward*' found them also, as noted above, in a second 

 and higher horizon near Tanners Crossing in the Little Colorado 

 Valley, Ariz. 



The author's experience in New Mexico^ (west and southwest of 

 Abiquiu) is that Parasuchians and Labyrinthodonts occur only in 

 and below a conglomerate like Cross's Shinarump, the " Poleo sand- 

 stone," now accepted as the equivalent of the Shinarump. From 

 what I have seen in the southern Chama River region in New 

 Mexico, the larger part of the Triassic deposits lie above the Poleo 

 sandstone. In these upper beds the fauna is quite different^ — Typo- 

 thorax^ E piscoposauTus^ and two other Parasuchian genera, Belodon 

 scolopttx and Coelophysis. It is evident, then,, that the lower 

 fauna — Madumroprosopus^ Heterodontosuchus, Palaeo^'hinus, An- 



^ U. S. Geological Survey, Professional Paper 93, pp. 30-50, 1917. 



3 Cross, Whitman, Bull. Geol. Sec. America, vol. 16, 1905, p. 468. 



* Mehl, M. G., Quart. Bull. Univ. Olilahoma, March, 1916, pp. 1-44. 



6 Hills. R. C, Note on the occurrence of fossils in the Triassic and Jurassic beds near 

 San Miguel, Colo. Amer. Journ. Sci., ser. 3, vol. 19, 1880, p. 490. 



^ Amer. Journ. Sci., ser. 4, vol. 12, 1901, p. 413. 



^ Huene, F. v., Kurze Mitteilung iiber Perm, Trias u. Jura in New Mexico, Neues Jahrb. 

 fur Min., etc., Beilage Band 32, 1911, pp. 730-738, pi. 32. 



