ARCHAEAN AND ALOONKIAN. 71 



places where the kaolinite is to be found. Below, a 

 certain depth from the surface the feldspar of these 

 granitic veins hsrs escaped t'he action of the atmos- 

 phere, and is in its original form, while nearer the 

 surface it has generally been converted into kaolinite. 

 It is evident that in all these primary or original de- 

 posits the kaoliuites mixed with the other and less 

 destructible constituents of ithe granite, viz., the 

 quartz and the mica, and by consequence all the 

 kaolinite from such original deposits must be washed 

 to free it from these substances. When ifhe granite 

 or granitic rock contains comparatively little of iron- 

 bearing minerals the resulting kaolinite will be cor- 

 respondingly free from iron stain and of pure white 

 color, and thus suitable for the manufacture of the 

 finer grades of stone w r are or china. 



All the important deposits of this kind are, at the 

 present time, at a distance from any railroad, and 

 none of them have been developed in a commercial 

 way. We have at hand very few analyses and itests 

 made of these kaolinites. A material of tlrs kind 

 from near Louina in Randolph county was analyzed 

 many years ago by Dr. Mallett for Prof. Tuomey, 

 with t'he following result: 



Analysis of Kaolinite from Louina, Randolph Co. 



Silica 37.29 



Alumina 31.92 



Ferric Oxide trace 



Potash, Lime and Magnesia 0.72 



Water 15.09 



Undecomposed Mineral 14.28 



Prof. Tuomey remarks upon the absence of iron in 

 this kaolinite as most favorable to its use in making 

 fine porcelain ware, and he predicts that when Ran- 

 dolph county has communication by railroad with the 



