no ANNALS NEW YORK ACADEMY OF SCIENCES 



Section in Green Canyon 



Feet 



D. Gray non-magnesian limestone, partly covered 900± 



C. Dark gray to black magnesian limestone, generally with saccha- 



roidal texture 1,100± 



B. Thin-bedded limestone, buft' or brownish near the top, with peculiar 

 concretionary development with thin-bedded bluish-gray lime- 

 stone in lower part 100 



A. White to light gray magnesian limestone, with chert or siliceous 



beds locally developed 150 



Total 2,250 



Kindle correlates the dark magnesian limestone (C) with the Jeffer- 

 son limestone of Montana. The following is a list of the species ob- 

 tained from Green Canyon : 



Productella spiniilicosta 

 Camarotwclila sp. 

 Spirifer argentarius 

 Leiorhynchus ntaliensis sp. nov. 

 Spirifer cltsjunctus var. animasensis 

 Pterinopecten sp. 

 Actinopteria sp. 

 Cytherella sp. 



In discussing the evidence of the fauna of the Jefferson limestone, 

 Kindle has chosen three forms, Spirifer utahensis, S. engelmanni and 

 Martinia maia, as the most abundant species represented, all of which 

 are not reported from the northern Wasatch section. All of these, how- 

 ever, and seven other types common to the Jefferson are characteristic 

 fossils of the Nevada limestone of Eureka, Xevada, with which it is 

 correlated. 



The Jefferson limestone has a known north-south extent of 425 miles, 

 and from the thickness given for it in the northern Wasatch, it should 

 be expected to continue southward a considerable distance. Aside from 

 strata of close lithologic resemblance with the Jefferson reported by 

 Blackwelder from the region northeast of Ogden, nothing is known of 

 these beds south of Cache Valley. Eastward, they are not known beyond 

 a line through central Montana and western Wyoming. From northern 

 Colorado south to the southern part of New Mexico, the Ouray type of 

 Devonian prevails, characterized by Camarotmcliia endlichi and other 

 Upper Devonian types. The east-west line which separates these two 

 faunas appears to be the borderline between Colorado and Wyoming, 

 latitude 41° N. Extended westward, this line intersects the Wasatch 



