CLAYS OF KEW YOEK 625 



at several points in Hocking co., and tlie Carboniferous conglom- 

 erate also contains several beds of fire clay. Other beds occur 

 over the Sharon coal in the Massillon sandstone, and are used for 

 making sewer pipe and pottery. Another important bed under- 

 lies the lower Mercer limestone. Several important clay deposits 

 occur in the lower Coal Measures, the beds varying in thickness 

 f]om 6 to 30 feet. The Kittanning clay and shale is the most 

 important in the state, and is the horizon which yields the well 

 known Mineral point fire clay. Other beds are found in the 

 middle Kittanning and the lower and upper Ereeport members of 



the Coal Measures. 



« 



In northern and western Ohio, the drift clays form an abundant 

 supply of material for the making of common brick. 



Pennsylvania 



The most prominent clay deposits of Pennsylvania are the re- 

 fractory shales and clays which occur in the C'oal Measures, spe- 

 cially in the western portion of the state. The beds are often 

 extensive, and occupy well marked stratigraphic positions. Among 

 the more important of these may be mentioned the Bolivar fire 

 clay, which occurs just under the Freeport upper Coal Measures. 

 Another important bed of clay lies immediately under the Kit- 

 tanning coal, throughout Beaver co. Another valuable bed is 

 found near the top of conglomerate 12, and is mined in Cambria, 

 Indiana and Beaver co. 



Large quantities of true kaolin are mined in Chester and Dela- 

 ware CO., and the mines at Brandy wine summit have been in opera- 

 tion for a number of years. 



The brick clays are abundant and important in and around 

 Philadelphia, where they belong to the Columbian formation; 

 while the river terraces in the valleys of the Ohio and Beaver 

 rivers are underlain by cLay suitable for the Jiianufacture of brick, 

 terra cotta and stoneware. 



