630 GEOLOaY OP OHIO. 



well upon it. Much of it can be made to take a very good polish. An 

 establishment for rubbing the stone has lately been set up in Columbus 

 and is doing good work. 



As to durability, which after all is the main element in determining 

 its value as a building stone, it can be said that the Corniferous lime- 

 stone furnishes much material decidedly above the average of limestones. 

 The chief drawback lies in its highly fossiliferous character. Some- 

 times the fossil is so firmly cemented in the body of the rock that there 

 is no more tendency to the weathering of the stone about it than else- 

 where, but oftener, there is a slight difference in composition between the 

 fossil and the rock, the fossil being the firmer. 



Along the line of union, atmospheric agencies take easy hold, and a 

 few years are sufficient to give to the dressed block a rough and un- 

 promising appearance. Examples enough can be found of this agency 

 in the best building for which the limestone has yet been used, viz., the 

 State Capitol. Thinner courses, those measuring six or eight inches, 

 are generally the ones that show worse in this respect, and smoothly 

 dressed surfaces are disfigured more than others. It is within the 

 architect's province to so use the stone as to escape the appearance of 

 weakness and decay, for the evil chiefly lies in the unsightly face which 

 the slight weathering produces. The strength of the block when well 

 laid is good for centuries. 



The thickness of the several courses of cutting stone may have been 

 already noted. Almost any required thickness can be furnished within 

 the limits of four and sixty inches. To make an enumeration, we find — 



A 4-inch course ; a 6-inch course ; a 7-inch course ; an 8-inch course ; a 

 10-inch course ; an 11-inch course ; a 12-inch course ; a 14-inch course ; a 

 16-inch course ; a 19-inch course ; a 24-inch course ; a 27-inch course ; a 

 30 inch course ; a 34-inch course ; a 60 inch course. 



One other important use to which this limestone is put, is in the 

 making of road-beds. Like other limestones, this one proves unsatis- 

 factory for the surface of a much-used roadway. It grinds quite easily 

 into fine dust, the lightness of which allows it to be lifted into the air 

 very easily. But when used as a foundation for concrete or other surface, 

 it serves a very useful purpose. 



The principal quarries now worked, are the two of which sections 

 have been given, viz., the State quarries, and Smith and Price's quar- 

 ries. The former are taken to include the many openings that are made 

 in the immediate vicinity of the quarries owned by the State, as well as 

 these extensive excavations. Numerous parties are now engaged in 

 quarrying, in a small way, on both sides of the river, for four miles 

 above the city. 



