216 GEOLOGY OF OHIO. 



There is probably some inaccuracy in the statement quoted above, as 

 two wells were bored for oil by Mr. D. M. Fisher, near the mouth of 

 Black River, and in these 700 feet of shale were passed through before the 

 limestone was reached.* These wells were begun nearly 100 feet lower, 

 geologically, than that at Elyria ; so that the interval between the Berea 

 grit and the Corniferous limestone, under the central portion of Lorain 

 county, cannot be less than 800 feet. 



All these borings indicate that the Erie shale, and probably the Huron, 

 have thinned very much in the interval of thirty miles between the 

 valleys of the Cuyahoga and Black River. Going west, this thinning still 

 continues ; in the valley of the Vermilion the Erie shale having pretty 

 much disappeared, the Cleveland shale apparently resting directly upon 

 the Huron. A well bored at the mouth of the Vermilion shows the 

 thickness of the shales which separate the Berea grit from the Sandusky 

 limestone to be less than 400 feet, and gives a thickness to the Huron 

 shale of about 300 feet. The borings made in the eastern counties indi- 

 cate that it has in some places a thickness nearly twice as great. 



ECONOMIC GEOLOGY. 



As has been stated, much the most important element in the mineral 

 resources of Lorain county is the Berea grit, which already makes a 

 gross annual contribution of more than a half million dollars to the 

 wealth of the county; and there is every reason to believe that this treas- 

 ury is not only inexhaustible, but that it is destined to be far more 

 largely drawn upon in future years than it has yet been. The variety 

 of stone furnished by this formation greatly enhances its value, as it 

 serves many useful purposes. It supplies, perhaps, the most highly es- 

 teemed and popular building stone known in the State, which is now 

 not only extensively used throughout northern Ohio, but is exported to 

 St. Louis and Chicago on the west, Canada on the north, and Boston and 

 New York in the east. It is every where highly appreciated for its 

 beauty, durability, and the ease and certainty with which it is worked. 

 In its different varieties the Berea grit is applicable to all kinds of grind- 

 ing, and grindstones made from it are not only sold in all the principal 

 markets of our own country, but are exported to nearly all parts of the 

 civilized world. Although passing through a large number of the coun- 



* About 130 feet below the bottom of the shale, or 830 feet from the surface, in 

 both wells, fissures, oil, gas, and salt water were reached. The oil was heavy — 30° 

 Beaume — and the quantity was small. It was probably derived from the Niagara 

 below. 



