EPI CONTLNEN PAL SHA OP fURA SSiEVAGE 251 
densus, Trigonia Quadrangularis, and Pleuromya weberensis ? This 
stratum of 125 feet is all of the section that can, with certainty, 
be assigned to the Jura, as the other layers are unfossiliferous. 
The third and fourth layers correspond in character to the 
Como beds in other areas in Wyoming. 
THE NORTHERN UINTA AREA 
Flaming Gorge..—I\n the Flaming Gorge the total thickness 
of the Jurassic is placed at 700 feet. Three hundred feet near 
the middle of the outcrop contains: Camptonectes bellistriatus ; 
Gryphea calceola; Pentacrinus astericus; Rynchonella gnathophora ; 
Trigonia americana, Trigonia conradi,; Ostrea strigulecula ; and Belem- 
nites densus. In the absence of fossil evidence the portion of the 
outcrop lying above and below this horizon cannot with cer- 
tainty be assigned to the Jura. Therefore it is possible that the 
three hundred feet represents the whole thickness of the Jura 
for this area. 
South of Dead Man’s Springs calcareous beds which are 
thought to represent the middle part of the Jura for that area 
contain: Camptonectes bellistriatus ; Myophoria lineata; Gryphea cal- 
ceola; and Pentacrinus astericus. 
Vermillion Cliffs?—From Vermillion Cliffs in Northwestern 
Colorado White determined the following Jurassic species: 
Belemnites densus; Cardtoceras cordiforme,; Pentacrinus astericus ; 
Rhynchonella gnathophora; Rhynchonella myrina,; Ostrea strigile- 
cula; Ostrea procumbens; and Modiola subtmbricata. 
The limits of the Jurassic sea in a southeasterly direction do 
not appear to have been far from this point. Northwestern 
Colorado has up to this time been the only part of the state to 
which unquestionable Jura could be assigned. 
On Sheep Creek a basal limestone yielded Camptonectes bel- 
listriatus; Myophoria lineata; Gryphea calceola; Pentacrinus astert- 
cus; Belemnites densus; and specimens of Ostrea, Trigonia, and 
Volsella. 
*KinG: Geology of the goth parallel, Vol. I, p. 290. 
2 WHITE: Geology of Northwest Colorado, U.S. Geol. Surv., Vol. XII, 1878. 
