194 DETAILED REPORT ON ALABAMA CLAYS. 



(No.- 128, Stevens.) 

 BRICK CLAY. 



ARGO, JEFFERSON CO. 



This was a very plastic smooth clay, which took 22.20 

 per cent, of water to work it up. The tensile strength 

 varied from 120 to 136 pounds per square inch. The air 

 shrinkage was 7 j er cent. The behavior of the clay at 

 other temperatures was as follows : 



At 2250 F. the shrinkage was 12 per cent., color yel- 

 lowish gray. 



At 2300 F. the shrinkage and the color the same, but 

 incipient fusion had begun. 



At 2500 F. the clay was vitrified, and the total shrink- 

 age was 14 per cent. In the Deville furnace, at cone 27, 

 the clay became thoroughly viscous. 



It could not therefore be called a very refractory clay, 

 bat would work no doubt very well for pressed brick or 

 for other purposes. 



The composition of the clay is as follows : 



Analysis of Brick Clay, Argo, Jefferson Go. (No. 128 Stevens.) 



Silica 72.87 



Alumina 18.03 



Ferric oxide 2.00 



Lime .61 



Magnesia 42 



Alkalies .53 



Ignition 6 62 



Total fluxes 



MISCELLANEOUS -CLAYS. 



These are all derived from the Tuscaloosa formation of 

 the lower Cretaceous. 



