198 DETAILED REPORT ON ALABAMA OLATB. 



Analysis of Mottled Clay^ Bexar, Marion Co. {No. 41 8.) 



Silica (total) 72.40 



Alumina 14.86 



Water 5.05 



Ferric oslde 7.64 



Lime 20 



Magnesia -40 



Moisture .05 



101.20 



Free silica (sand) 55.20 



Fluxes 8.24 



Specific gravity 2.445 



(No. 18 S.) 

 BLUE CLAY. 



THIKD CUT NEAR GLEN ALLEN, MARION CO. 



A very fine-grained soft clay with little grit, which 

 slakes very readily on being thrown into water. 

 [.It required 28 per cent, of water to make a workable 

 mass which was slightly plastic. The shrinkage of this 

 paste in drying was 8.3 per cent., and in burning 7 per 

 cent., giving a total shrinkage of 15.3 per cent. The 

 tensile strength of the air dried briquettes was 56 lbs. 

 per square inch on the average, with a maximum of 65 

 lbs. per square inch. 



Incipient fusion occurs at 1950° F., vitrification at 

 2150° F., and viscosity at 2350° F. 



The clay burns to a light blufi"- 



The composition on analysis was found to be as follows: 



Analysis of Blue Clay, R. B. Cut, near Olen Allen, Morion Co. (No. 18 S.) 



Silica (total) 68.10 



Alumina 21.89 



Water 5.05 



Ferric oxide 2.01 



Lime .80 



Magnesia .28 



Alkalies 40 



Moisture .70 



99.230 



Free silica (sand) 41.60 



Total 4.19 



Specific gravity 2.44 



