﻿i4 Bulletin 20 92 



Schuchertella inflata 

 Spirifer centronatus 

 Martinia rostrata 

 Spiriferina solidirostris 

 Composita humilis 

 Camarotcechia metallic a 

 Camarotcechia aff. sappho. 

 Composita immatura 

 Cleiothyridina aff. hirsuta 

 Eumetria verneuiliana 



Devonian Rocks in Idaho. — The only data we have relating to 

 the Devonian in Idaho are based on a small collection of fossils 

 made by Mr. F. B. Weeks during the summer of 1907. This col- 

 lection was procured from a dark limestone "in southeastern 

 Idaho, east of Manson station, Oregon Short Line Railroad." 

 The three species represented in the collection are Atrypa reticu- 

 laris, Productella cf . subaculeata, and Spirifer disjunctus cf . var. 

 animasensis. The first species is the most abundant in the fauna. 

 The presence of Sp. disjunctus seems to indicate an Upper De- 

 vonian horizon. The fauna is not sufficient to show whether or 

 not the Jefferson limestone is represented by it. Probably, how- 

 ever, it is from this formation. The appearance of the rock, 

 which is a dark, somewhat magnesian limestone, is highly sug- 

 gestive of the Jefferson limestone. The evidence of the small 

 fauna, though inconclusive, points to the Jefferson limestone 

 rather than to the Threeforks shale as its source. 



About 60 miles southeast of this locality in northeastern Utah, 

 the Jefferson limestone is well developed. 



Sections in Utah. — Field studies in Utah were limited to the 

 northern part of the Wasatch Mountains. Numerous excellent 

 sections of the Paleozoic are exposed by the deep canyons east of 

 Cache Valley. The canyons cut at right angles the general trend 

 of the structure, which is of the moderately folded type, few of the 

 heavier dips exceeding 30 . Nearly vertical cliffs 2000 feet or 

 more in height alternate with slopes of every degree of inclination 

 along the sides of the canyons. 



