1873. 



397 



[Genth. 



Thos. M. Chatard. The alcalies iu the second analysis were determined 

 by myself. 



100.69 



101.77 



The oxygen ratio of an average of the two analyses for RO : R 2 O s : 

 Si0 2 : HX> is = 1.52 : 3 : 3.98 : 2.3 = 3:6:8:5 nearly, 

 giving the formula : 3 RO, 2 Si0 2 + 2 (RA Si0 2 ) + 5 H 2 0. 



About one-sixth of RO are alcalies R.,0. 



24. Willcoxite (a new species). 



There is still another mineral which appears to be new. It consists of 

 white and greenish-white or grayish-white scales of a pearly lustre, and 

 much resembles talc. B. B. in thin splinters, it fuses with difficulty into a 

 white enamel ; colors the outer flame yellow. With chlorhydric acid 

 decomposed with difficulty with separation of silicic acid in pearly scales. 

 It occurs sparingly, and I have seen it only in connection with corundum 

 as a result of its alteration. One specimen from Shooting Creek, Clay 

 County, North Carolina, is a fragment of a semiglobular mass, which 

 probably once consisted entirely of corundum and which now has a 

 nucleus of white lamellar corundum, invested with the scaly mineral. The 

 largest diameter of the specimen is two and a-half inches, and that of 

 the core of corundum three-fourths of an inch. 



It is named in honor of Col. Joseph Willcox, who presented me with 

 the specimen from Shooting Creek, and who possesses a still larger, but 

 otherwise very similar one. 



It is found more or less intermixed with white corundum at the Cul- 

 lakenee Mine, in Clay County, and probably at the Culsagee Mine, in 

 Macon County, if a specimen of a grayish and greenish-white scaly 

 mineral with a nucleus of white corundum which I received from there, 

 really comes from this locality. 



Dr. Geo. A. Koenig furnished me with two analyses of this mineral (1) 

 from material from the Shooting Creek specimen surrounding the nucleus 



