526 GEOLOGY OF OHIO. 



from its great hardness, that its fragments wauld long withstand abra- 

 sion, and be found in greater or less abundance in the sandy or gravelly 

 debiis. 



A quarry, one-half mile north-east of Ashland, exposes rock precisely 

 like the stratum below the Fossiliferous limestone indicated in the sec- 

 tion above. 



Three-fourths of a mile n> rth-east of Mifflin, on a small branch of 

 Black Fork, a quarry shows the following section : 



BT. 



Coarse, shaly ferruginous sandstone 4 



Coarse, yellow, massive stone 8 



Shaly sandstone, with alternate layers of argillaceous shale 25 



On the opposite side of the stream, the section is as follows : 



FT. 



Coarse, yellow, ferruginous sandstone, thin layers 10 



Coarse, yellow layers 4 



Thin layers, at bottom, blue, alternating with argillaceous shale 20 



Two miles north of Mifflin, the reck is imperfectly stratified, massive 

 in places, and colored red, somewhat like the Mansfield stone. It forms 

 a steep ridge on the east side of Black Fork, the slope being covered with 

 the debris of the ledge, which resembles the debris of the Sub-carbonifer- 

 ous Conglomerate. At the height of forty feet, is a bench, showing the 

 presence of argillaceous shales ; and another ridge beyond, rising ninety- 

 five feet above the top of this coarse sandstone, has its slopes covered 

 with the debris of Cuyahoga shales. 



Southward from this point, this coarse rock rises to the height of two 

 hundred and fifty feet above Perrysville Station, showing a thickness of 

 one hundred and seventy-five feet, and indicating either a great uplift of 

 the Waverly Conglomerate, or that the ordinary olive shales take, at this 

 place, the form of the Conglomerate. Much of this rock contains a great 

 number of partially formed concretions of white quartz, the blocks which 

 have been weathered, presenting to the eye the appearance of being 

 filled with quartz pebbles. These concretions are all small, have a par- 

 tially radiated structure, and shade off imperceptibly into the uncrystal- 

 ized rock. The rock is sometimes broken through them, leaving a mam- 

 milary surface on the face of fracture. Their appearance recalls the old 

 controversy in regard to the origin of the quartz pebbles of the Carbonif- 

 erous Conglomerate, and, at first, seems to favor the hypothesis that they 

 may be formed by the aggregation and crystallization of the quartz during 

 the consolidation of the rock. But these concretions all lack the homo- 

 geneous structure, the regular cleanage, and polished and smooth outline 

 which characterizes the transported and water- worn pebbles. This ledge, 



