NOTES ON THE OHIO SHALES AND THEIR FAUNAS 



E. B. BRANSON 

 Professor of Geology 



Three Plates 

 STRATIGRAPHY 



The Ohio shales in the vicinity of Oberlin, Ohio, are about 

 610 feet thick and are quite uniform in color and texture from 

 top to bottom. Within the area discussed in this paper, which 

 extends from east of Elyria to west of Norwalk, the shales are 

 brown to black, with occassional greenish layers, and in a few 

 places one or two layers of fine grained sandstone one to six 

 inches in thickness are present. In well records the designations 

 "blue shale," "black shale" and "brown shale" are frequently 

 used but without consistency and in the field it is impossible to 

 distinguish different formations by colors. The thickness of 

 the shales is determined rom well records. More than fifty 

 wells that pass through them to the Delaware limestone have 

 been drilled in the vicinity of Oberlin. Unfortunately the data 

 for most of the wells were not kept and the depth, which gives 

 roughly the thickness, is the only thing known. Detailed data 

 for only five wells are known to the writer. 



The argillaceous and arenaceous shales and calcareous 

 layers that distinguish the Chagrin formation farther east are 

 absent here excepting as mentioned above. They cannot be 

 considered as marking a formation at any place. Near Birming- 

 ham where Newberry mentions the presence of the Erie the 

 only distinguishing feature is a thin bed of greenish shale. 



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