612 NEW YORK STATE MUSEUM 



The red and purple clays of tlie Tuscaloosa formation would 

 probably also make a good vitrified brick. 



China clays and stoneware clays. These occur in the counties of 

 Randolph, Clay, Cleburne and others, and are sedimentary. 



Among the residual deposits of the Cambrian and Silurian for- 

 mations are large beds of white clay, which are sometimes associated 

 with limonite beds, as at Rockrun. 



The subcarboniferous formation contains some good deposits of 

 white burning clay, near Fort Payne, Valleyhead, etc. 



In the Cretaceous formation are important beds of clays of vari- 

 ous qualities, which outcrop in a belt extending from Columbus, 

 Ga., into the northwest corner of the state. 



Fire clays occur and are mined at Woodstock, Bibbville, Oxford, 



etc. 



Arhansas 



In the Mesozoic regions of Arkansas are found a great variety 

 of clays. Those occurring within the Tertiary region have been 

 used for the manufacture of pottery, but the Cretaceous clays have 

 not yet been employed for this purpose. Kaolin is said to occur 

 in Pike, Pulaski, Saline, and Ouachita co., but the beds are seldom 

 over 2 feet in thickness. (ArJc. geol. sur. 1888. 5: 11) 



The deposits of Pulaski co. are the only ones of those above men- 

 tioned that are true kaolins, the others being white burning sedi- 

 mentary clays. Good brick clays are found in all second bottom 

 streams, and bricks are made at Little Pock, Texarkana, Arkadel- 

 phia, etc. Paving bricks are made at Fort Smith. 



Colorado^ 



The clay-bearing formation of Colorado may be roughly divided 

 into the following three groups: 



1 Loess, and alluvial deposits 



2 Jura-Trias, and Cretaceous 



3 Tertiary clays 



1 H. Ries. T. A. I. M. E. 1897, p. 336. 



