96 CEOLOGY OF THE EUBEKA DISTRICT. 



a bed of conglomerate about 25 feet in thickness made up mainly of rounded 

 quartz pebbles followed by another l)elt of shale quite like the one below, 

 40 feet in thickness. In both series of shale occur beds of carbonaceous 

 material and thin seams of impure coal, but nowhere on the surface are the 

 exposm-es more than three inches in width. Still higher up is anotlier belt 

 of conglomerate can-ying more or less lime and followed by buff colored 

 massive limestone changing to brownish gray limestone followed by a cherty 

 limestone, the latter extending to the top of the mountain. This series of 

 limestones has an estimated thickness of nearly 1,000 feet. Fossils cliarac- 

 teristic of the Coal-measures are common throughout the limestone, but are 

 more abundant in the lower beds, more especially in those immediately 

 above the coal, although no horizon presents any special faunal peculiarities. 

 Scattered throughout the limestone occur the following species: 



Zaphreiitis centralis, 1 Productus costatus 



Diphyphyllum, sp. ?. Productus semiicticulatus. 



Chaetetes, u. sp. Spirifera caiiieiata. 



Discina, sp. 1 Spirifera rockymoiitana. 



Orthis pecosi. Spiriferina keutuckiensis. 



Orthis resupinata. Eetzia mormoui. 



Streptorhynchus crenistria. Athyris roissyi. 



Chonetes grauulifera. AthjTis siibtilita. 



Productus cora. Terebratula bovideus. 



This grouping maj* be said to present some distinctive features con- 

 taining forms regarded as belonging to the Lower Carboniferous, mingled 

 with others typical of the Coal-measures. Zaplirmtls centralis, Diphifphyllum 

 and Athyris roissyi give to the horizon a Lower Carboniferous aspect, 

 while the relatively large number of Coal-measure species would ordinarily 

 determine the position t)f the beds. Not only do the Coal-measure species 

 outnumber the others, but several of them happen to be those forms like 

 Orthis pecosi and Betzia mormoni, which have as yet been recognized only 

 in the Upper Coal-measm-es. Nevertheless, the evidence of the fauna is 

 strongly in favor of the lower horizon for these coal beds, as certain species 

 are elsewhere unknown higher up in the Carboniferous, wliereas it is a 

 feature of the Coal-measure fauna of the Great Basin that it })resents a wide 

 vertical range. 



Lithologically the evidence is not specially decisive. The series of 



