58 GEGLOGY OP OHIO. 



in the drilling of deep wells to the east and south of its present outcrops. 



It is at present used at but one point in the state in the large wav. 

 The Akron Vitrified Brick Company employes the red shale in the manu- 

 facture of a pressed brick that is certainly not surpassed by any like 

 product of the state. The shale is mined and worked at or near Inde- 

 pendence. The great possibilities of this stratum for such applications 

 have been recognized and indeed demonstrated for many years. It is 

 surprising that but one practical attempt has been thus far made to ren- 

 der it available for economic uses. 



The Cuyahoga shale, (No, lid) a great stratum one hundred and 

 fifty to four hundred and fifty feet in thickness, consists of light colored 

 grey or blue shales that has unlimited possibilities of service in the prac- 

 tical -way, but which has been almost completely ignored thus far. Its 

 day is, however, sure to come. Its adaptation to paving block manufac- 

 ture in particular will be recognized, and it will be at once demonstrated 

 as, soon as it is used, that no better material for this purpose is found in 

 our entire series than the Cuyahoga shale can supply. It has a broad 

 outcrop and is available for use in every county in which it is due from 

 the Lake shore to the Ohio Valley. Without doubt different sub-divisions 

 will be established in the formation when it comes to be generally used. 

 Particular beds will be discovered adapted to particular kinds of clay 

 manufacture. 



The Subcarboniferous limestone horizon (No. 12) holds a far more 

 valuable argillaceous deposit than any that has yet been described in our 

 series. The limestone itself is an uncertain deposit, but its place in the 

 series is well marked. In a few instances in southern Ohio, and in a 

 much larger number of instances in Kentucky, a hard fire clay, known 

 as flint clay, comes into the section. This clay is one of the two or three 

 strictly first-class clays of the state. It has been worked largely at Scioto- 

 ville and Portsmouth, and is accordingly commonly designated in Ohio as 

 the Sciotoville clay. Other outcrops of it occur near Logan, Hocking 

 county, and here it is called the Logan clay. It has been used in manufac- 

 tures, here also, to quite an extent. Wherever found, its great value is at 

 once recognized. It becomes a basis of manufacture of fire clay products in 

 the strictest use of this word. Furnace linings and other similar uses 

 demanding refractory quality of high grade absorb' the entire product 

 of this seam. A single analysis exhibits the general characteristics of 

 the Sciotoville clay. (Lord). 



Silica 50.95 



Alumina '. 39.49 



Alkalies 30 



Magnesia 28 



Water 9-18 



