156 DETAILED REPORT ON ALABAMA CLAYS. 



No. 2. 



Silica 55.61 



Alumina 27.36 



Ferric oxide 2.73 



Lime ■^'^ 



Magnesia ■'^'^ 



Alkalies •'^1 



Titanic oxide 1-38 



Sulphuric acid* -51 



Moisture 2.26 



Ignition r 11.13 



•Sulphur 25 



No 1 is from Layton Stat'on, Pa. (18)7 Rtport Pennsylvania S'ati College, p. 90, 

 T. C Hopkins). 



No. 2, St. liouis, Mo., Washed pot clay (Missmri Geological Survey Report, Vo'. 

 XI, p. 568.) 



(No. 1). 

 FIRE CLAY, 



PEAEOES MILLS, MARION COUNTY. 



This clay forms a bed from four to six feet thick in 

 the ravine to the east of the mill. It is a hard rock- 

 like material, and wten mined has more the appear- 

 ance of a white argillaceous sandstone than a clay. 

 It is very hard, and when thrown into water practi- 

 cally does not slake at ail, but it isi very porous. 

 When ground to 30 mesh and mixed with water it is 

 very lean, but grinding it to 80 mesh increases tlie 

 plasticity. In this latter condition it required 37 per 

 cent, of water to work it up. The air shrinkage was 

 4 per cent., whereas when burned to 2100° F. it was 5 

 per cent., and at 2200° F. the total shrinkage was 7^ 

 per cent., the color of the bricklet being still white 

 like the original clay, but the porosity great. At 

 about 2300° F. the bricklet developed a slightly gray- 

 ish tint, and at 2400° the color was the same, but tlie 



