624 NEW YORK STATE MUSEUM 



Residual clays. These occur in the western half of the state 

 west of the line passing through Welclon, Kaleigh and Eocking- 

 ham. They form an almost universal mantle and vary in thick- 

 ness from 3 to 20 feet. These impure residual clays are gen- 

 erally sandy and very porous, but with proper machinery and 

 treatment they yield a good grade of brick. 



The residual fire clays found at Pomona and Grover are coarse- 

 grained clays with much intermixed quartz and mica. 



The kaolins are of special importance and of excellent quality, 

 the most important being at Webster, and west of Sylva. 



Sedimentary clays. The coastal plain deposits of IsTorth Caro- 

 lina furnish the most extensive beds of clay to be found within 

 the state. They have been classed as belonging to Cretaceous, 

 Eocene and Pleistocene formations. The Potomac clays of the 

 Cretaceous are exposed at Prospect Hall on the Cape Fear river, 

 and the Eocene beds are well shown in railroad cuts at Spoutsprings 

 Eayetteville. 



Many clays suitable for the manufacture of brick and of pot- 

 tery are found underlying the river terraces farther inland, as 

 along the Catawba, Yadkin, and the Clark rivers. Other sedi- 

 mentary clays are well developed around Wilson, GoldsborO', and 

 Eayetteville. 



North Dalcota 



The clays of ISTorth Dakota are of Cretaceous, Tertiary, and Post- 

 tertiary age, and abound in many sections of the state. While they 

 are suitable for a variety of purposes, they have thus far been but 

 little worked. (Report of commissioner of labor and agriculture. 

 1891-92) 



OJiio^ 



The principal centers of development of clays are in most in- 

 stances the same as those which furnish the coal. The Subcar- 

 boniferous contains valuable deposits of flint clay, which is mined 



1 Ohio geol. sur. v. 7, pt 1. E. Orion jr. Clays and clay-icorking industries' 

 of Ohio. 



