RECONNAISSANCE IN COLORADO AND UTAH 651 
Carboniferous section and they are rarely associated with pebbles 
of other rocks. 
In this limestone conglomerate occur almost everywhere small 
fragments of bone and occasional teeth, vertebrae or other small 
bones, which have been identified by Lucas as belonging to belodont 
crocodiles, or to dinosaurs of megalosauroid types. Unios, gastero- 
pods, and plant remains are sparingly associated with the vertebrates. 
In the Red Beds paper (8) the wide distribution of this fossil- 
bearing conglomerate was pointed out and the even greater extent 
| 
Fic. 4.—The La Plata sandstone. In Canyon of Grand River a few miles above 
ferry at Moab, Utah. The massive beddings are specially marked in this vicinity. 
Through irregular jointing rude alcoves have been initiated, suggesting one of the 
processes involved in their formation. 
of the fauna it carries. It is necessary here merely to repeat that the 
peculiar conglomerate with its upper Triassic fauna, marks a horizon 
of great importance in the stratigraphic column of the Plateau country 
and the adjacent mountain slopes. The importance of this horizon 
is further emphasized by the fact that at Ouray, on the north flank 
of the San Juan Mountains, the ‘“‘saurian conglomerate” is found 
to rest unconformably on the Permian (?) red beds and on the fos- 
siliferous Pennsylvanian section below them, testifying to an important 
stratigraphic break. 
