1112 General Notes. 
Penfield and Sperry, ! and found to have the composition :— 
SiO, Al,O, Fe,O, CaO Na,O BaO K,O _ Ign. 
62.95 19.82 Ayi 25 4.01 3.95 8.57 11 
tinge, byt 
microlites, like the glass that often solidifies in the peny = re ere 
pots. It has the usual perfect cleavage of oligoclase, uri dia 
striated. According to Messrs. Penfield and Sperry, a pi 
properties of the mineral are abnormal. Sections pi le A 
show a positive extinction of 39°-40°. Those parallel to æ £% 
. pseudomorphs of 
pseudomorphs after spodumene from Peru, Me. ; pseu : 
tron oxides after aragonite from Puma Co., Ariz., nese 
transparent cyanite from Bakersville, N. C.—Crosby an 
1 Amer. Jour. Sci., xxxvi., p. 317. 
* Miner. u. Petrog. Mitth., x., p. 161. 
* Amer. Naturalist, 1888, p. . 
* Amer. Jour. Sci., xxxvi., p. 321. 
* iD. p. 222. 
€ Amer. Jour. Sci., Xxxvi., p. 324. 
~ ` Technology Quarterly, May, 1888, p. 407. 
