RECONNAISSANCE IN COLORADO AND UTAH 653 
cerning which Mr. J. M. Gidley of the U. S. National Museum reports 
that “though somewhat crushed and weathered, it is recognizable 
as belonging, probably, to a Triassic form of carnivorous Dinosaur, 
although it may possibly be referable to a genus of Belodont. It is 
certainly reptilian and of a more advanced type than any I know 
from the Permian.” 
On West Side Creek, a branch of West Creek, where the Trias is 
represented only by its lower beds, resting on the Archean (see p. 648), 
Fic. 5.—This cross-bedded lower La Plata sandstone. View in a ravine tribu- 
tary to Cafion Colorado. This cross-bedding stands out prominently in most ‘cliff 
exposures. 
a fragment of bone was found in the limestone conglomerate, which 
Mr. Gidley considers with reasonable certainty to be ‘“‘a portion of 
a fibula (lacking the distal end) of a carnivorous Dinosaur probably 
of Triassic age.” 
Ill-preserved Unio shells were found in association with the vertebra 
mentioned. Much better material was obtained in t901 by Mr. L. 
M. Prindle, now of the U. S. Geological Survey, in certain of the 
reddish sandstones between the Vermilion Cliff and limestone con- 
