616 REPORT UNITED STATES GEOLOGICAL SURVEY. 



Agnostus josepha, Hall. 



Gonocoryplie (several species). 



Bathyurellus (Asaphiscus) hradleyi Meek. 



Bathyurus saffordi Billings. 



Bathyurus or JDilcelocephalus. 



Bathyurellus (Bilcelocephalus) (1) truncatus Meek. 



Asaphus {Megalaspis) (!) goniocercus Meek. 



The fossils collected by us during the season of 1877 have not been 

 carefully studied as yet, so that the list following is not complete. It 

 is probable that many of them are identical with some collected by Pro- 

 fessor Bradley. 



List of Silurian fossils. 



Bathyurus and other ob- ) Head of the middle canon of Bear Eiver at the 

 obscure Silurian forms. ) South end of Gentile Valley. 



Biscina sp.l Caiion east of Smithfield. 



Orthis like 0. plicatella 1 



Orthis li^e O.testudinata. '.Forks of Logan Eiver, in canon near Sta- 

 Several species of trilo- ( tion 125. 

 bites. 3 



ConocorypJie sp. ? ") 



miwUcepUm sp. ? I g^^jj^^ ^33 ^.^tween Marsh and Cottonwood 



otlXTpT" '^- ^^^^-' "«rth of Co^he VaUey. 



Biscina sjj. ? j 



Bathyurus sp. 1 ") Mouth of Weston Creek Caiion on west side 



Hyolithes sp. f I ®^ *^® Cache Yalley, at the south end of the 



Acrotreta. sp. f [ northern portion of Malade Range, near sta- 



Biscina sp. % j tion 130. 



^ ,. . » ) Head of Station Creek, west of Bear Eiver 



Orthis ^V^. J ;g^^g^_ 



CARBONIPEEOUS. 



In the eastern and middle portions of the district the Carboniferous 

 formation occupies a prominent and important position, the outcrops 

 representing the important ranges, into whose structure they largely 

 enter, sometimes making up whole ranges. They are the lowest rocks 

 exposed in the Wyoming and Salt Eiver Eanges. In the Bear Eiver 

 Eange the Carboniferous limestones overhe conformably the Silurian, 

 and we do not have the entire upward extension of the beds shown. 

 I shall now briefly recapitulate the most important exposures of the 

 Carboniferous. 



Labarge Mountain. — At this locality we have two isolated masses of 

 Carboniferous rocks. The most prominent was named after the stream 

 just south of it and is a monoclinal ridge surrounded by Tertiary strata. 

 There are between 400 and 500 feet of limestones exposed on the eastern 

 face of the mountain, and a few indistinct fossils of Carboniferous aspect 

 were seen in the beds on the summit. Whether this mountain and the 

 northern smaller mass are the remnants of an anticlinal, or .whether they 



