176 DETAILED REPORT ON ALABAMA CLAYS. 



(No. 70S.) 

 POTTEEY CLAY. 



W. DOTY, FAYETTE CO. 



A fine grained, rather gritty, reddish clay. In water 

 it'slakes quickly to small irregular grains. The addition 

 of 25 per cent of water gave a plastic mass, which shrunk 

 6.2 per cent, in drying and an additional 5.8 per cent, in 

 burning, giving a total shrinkage of 1 2 per cent. 



Briquettes of the air dried clay had an average tensile 

 strength of 95 pounds per square inch, and a maximum 

 of 151 pounds. 



Incipient fusion occurred at 2000° F., and viscosity at 

 2400° F. The clay burns to a yellowish color at 2000°, 

 but to a red at 2200°. The body of the burned clay is 

 smooth and dense. 



The clay analyzed as follows: 



Analj/sis of Pottery Clay, W. Doty, Faette Co. (No. 70 S.) 



Silica (total) 67.10 



Alumina 19.37 ' 



Water 6.08 



Ferric oxide 2.88 



Lime tr. 



MagneBia .725 



Alkalies .672 



Moisture 1.71 



98.537 



Free silica (sand) 43.93 



Total fluxes 4.27 



Specified gravity 2.416 



In fompositon this clay resembles some-what a clay 

 used for pottery and sewer pipe, and obtained at Gilker- 

 son Ford, Henry Co., Mo.* 



•Mo. Geol. Survey XI, p. 828. 



