516 



GEOLOfiT OF OHIO. 



erous formation. They point to the deposition of a Sub-carboniferous 

 limestone, which has been cut out and removed by the agencies which 

 brought in and deposited the materials of the Conglomerate. Small frag- 

 ments of precisely similar cherty material I have found at the base of 

 the Conglomerate at Nelson Ledges, in Portage county, and in the same 

 position, mingled with other large, angular, and flat rock fragments, in 

 Boston, Summit county. The form of these fragments, and their occur- 

 rence in thin patches of the Conglomerate and at the base of the thick 

 sheet of the north, are quite significant. This Conglomerate seems to be 

 a deposit like the modern Drift, brought in by a force which abraded and 

 pulverized all except the harder materials, and left these in the form of 

 water-worn pebbles. At the base are angular and unworn fragments of 

 the local rocks. It is thickest where the modern Drift is thickest, and at 

 the close of the epoch of its deposition there were eroding torrents which, 

 at the north, removed the mass of the material, leaving only thin 

 patches in protected places. In the larger part of the county it is 

 entirely wanting, being represented in places by a thin layer of coarse 

 sandstone, without pebbles, and often by a hard, compact, fine-grained, 

 white, silicious rock, a few inches thick. This latter is filled with stig- 

 marise, precisely like that which is often found as the bed-rock of Coal 

 No. 1 in Summit county, while at other places the Coal Measures are 

 to be seen resting directly on the Waverly. 



The following sections illustrate the transition from the Coal Measures 

 to the Waverly. The first is a section of the ravine at Motes's bank, 

 Monroe township : 



Vertical Scale, 1 inch to 72 feet. 



Covered. 



Spring — probable^^horiison of Ooal. 



Covered. 



Blue limestone and Coal. 



Sandstone. 

 Iron ore. 



Black shale. 



Coal and shale. 



Coal, sandy shale and sandstone. 



Coal No. 1, Motes's Bank. 



Fire-clay. 



Waverly. 



