82 (lEOLOGY OF THE EUKEKA DISTKK'T. 



structurally well sIk^wu with a typical fauna in l)oth horizons is found at 

 Newark Mountain. The mountain presents a bold impressive mass of 

 bluish gray limestone with the physical features of the Upper Devonian 

 strata. The section here is as follows: 



Feet. 



1. Black argillaceous shale more or less arenaceous and similar to the lower black shale 1,000 



2. Compact fine grained sandstone with minute dark siliceous pebbles scattered through 



the beds 100 



3. Black argillaceous shale with fine intercalated beds of arenaceous shale. These shales 



crumble ou exposure to atmospheric influence 500 



4. Reddish gray shal.v calcareous beds 100 



5. Dark gray heavily bedded siliceou.s limestone passing into bluish gray limestone in places 



finely banded 3,500 



Several hundred feet below the top of the Nevada limestone and cal- 

 careous shale the limestone yielded a small group of fossils, some of them 

 common to both the upper and lower horizons, but none of them character- 

 istic of the Lower Devonian. 



Stromatopora. Spirifera pinoiiensis. 



Strophodouta perplana. Atiypa reticularis. 



Productus shumardianus. Pteriuea uewarkeusis. 



Spirifera disjuncta. Platyschisma maccoyi. 



Immediately below the black shales, near the eastern end of Newark 

 Mountain, the following species occur: 



Ortliis tulliensis. Atrj-pa reticularis. 



Spirifera disjuucta. Nyassa parva. 



Spirifera engelmanni. Straparollus newarkeusis. 



Athyris angelica. Beyrichia occidentalis. 



Reddish gray calcareous shales pass rapidly into the argillaceous 

 beds. Invertebrate remains wherever found in the black shale are imper- 

 fectly preserved so that specific determinations are in most instances out of 

 the question. From the lower beds were obtained Avkidopedcn and a 

 species of Goniatites, while the upper and rather more sandy beds have 

 furnished a more varied material in which, according to Mr. G. D. Walcott, 

 the facies is Devonian with a foreshadowing of the Carboniferous period. 

 Among the genera found here are Fenestella, Chonetes, Modiomorpha, sp. !, 

 Ctjpricardinia, sp.?, Palaeoneilo, sp.'?, Cardiomorpha, sp.?, Conocardluw, sp.?, 

 and Goniatites. In only two cases were specific determinations possible: 



