166 GEOLOGY OF OHIO. 



The diminished thickness of the coal in the Bridgeport and German 

 Company's mines may be due to another cause than tuat I have sug- 

 gested, viz., a swell in the bottom of the marsh, where the coal accumu- 

 lated as peat, and on which, being relatively high, the peat was thin. 

 It is well known that the "swamps," or lowest portions of the coal mines, 

 have the thickest coal in them, and this is simply because the peat was 

 deepest there. On the ridges or swells of the bottom the coal is thin and 

 high, because the top only of the peat bed reached over them. The bar- 

 ren ridges which so often separate the coal "swamps" were islands in, or 

 the shores of, the coal marshes. These rose above the water-level, and 

 on their slopes the peat diminished in thickness upward till it came to 

 an edge. When covered with clay and sand, and compressed to solid 

 coal, that was thickest where the peat was thickest iu the bottoms of the 

 basins, and thinned out to nothing on tha slopes which bounded these 

 basins. 



The Massillon coal is usually overlain by a few feet of shale, and above 

 this is found a massive sandstone, which I have called the Massillon 

 sandstone. This is a marked feature in the geology of many of the 

 counties which lie in the northern half of the Ohio coal field. It is well 

 shown at the quarries of John Paul, at Fulton ; at the Bridgeport quarry 

 (.John Vogt's); and that of Warthorst it Co., at Massillon, where it at- 

 tains a thickness of from sixty-five to seventy -five feet. The stone of this 

 stratum varies considerably in texture in different localities and differ- 

 ent layers, but much of it affords very excellent building material, as well 

 as good grindstones. In these a large and active industry has been cre- 

 ated about Massillon, Warthorst & Co. giving employment to one hundred 

 men, and shipping three hundred to four hundred car loads of block stones 

 and fifteen hundred to two thousand tons of grindstones per annum. The 

 product of their quarry is mainly sold in Pittsburgh, J'hiladelphia, and 

 Baltimore. The stones for dry grinding — plows, springs, etc. — are espe- 

 cially esteemed. In Paul's quarries, near Fulton, a light variety of this 

 stone is ground up, and the sand is shipped to Pittsburgh for the manu- 

 facture of glass. 



In Mahoning, Portage, and Summit counties this rock affords a con- 

 venient guide in the explorations for coal, as it lies above the lower and 

 under the next two workable seams. It has also in many instances been 

 instrumental in the destruction of much valuable coal territory, inas- 

 much as the currents of water by which it was transported carried away 

 the underlying coal, and now sandstone occupies its place. In the deep 

 channels of these old currents this rock sometimes attains a thickness of 

 nearly one hundred feet. 



In many parts of Stark county borings have indicated the existence 



