640 WHITMAN CROSS 
Newberry. Cope states that Newberry excavated the bones of 
Dystropheus ‘‘from the red and green rocks usually referred to the 
Trias, hence from the same formation which yielded the Ty pothorax 
already described.” The Typothorax in question was found in 
New Mexico with belodont crocodile and other forms almost demon- 
strating that its horizon is the fossiliferous zone of the Dolores Triassic 
formation, the place of which in the Grand River section is nearly, 
or quite, 1,000 feet below the McElmo beds, as will be shown 
in a later section. Cope adds emphasis to his error as follows: 
“More than usual interest attaches to this fossil. It is the first 
one found in the Triassic beds of the Rocky Mountain region. ... . 
“The rock is described by Professor Newberry as the same as that 
which I have identified in New Mexico as the Trias and is of the 
usual red color” (2, p. 36a). In harmony with the occurrence of 
Distro pheus vienale in the McElmo beds it has recently been pointed 
out by F. von Huene that its affinities are Jurassic rather than Triassic 
(20). 
That the McElmo beds contain the vertebrate fauna of the 
‘‘Atlanta-saurus beds” of Marsh has been demonstrated by Riggs who 
discovered many dinosaurian remains in that formation near the 
junction of the Grand and Gunnison Rivers at the northeastern base 
of the Uncompahgre Plateau (34, p. 651). While this vertebrate 
fauna has not as yet been described, it is referred to by Riggs as clearly 
the same which characterizes the Jurassic beds of Wyoming and the 
eastern base of the Front Range in Colorado. It is said that “ Repre- 
sentatives of a single genus (Morosaurus) have been observed to range 
through the entire series,” meaning a section some 500 or 600 feet 
in thickness below the Dakota. 
It is to be regretted that Riggs did not make the importance of 
his discovery in the correlation of the Colorado Jurassic more evident 
to the general reader by a reference to the literature concerning 
occurrences of supposed Jurassic in western Colorado. There is no 
mention of the beds for which Eldridge proposed the term Gunnison 
in the Anthracite-Crested Butte folio (1894), nor to my division of 
the Gunnison into McElmo and La Plata formations in the Telluride 
folio (1899). Riggs applies the term ‘‘Como beds” to the “‘ Dinosaur 
beds” of Wyoming and Colorado, although Morrison (Eldridge, 1894) 
