.326 QUARTZ KOK. 



. , Arenaceous, or finely granular. 



a. Condensed saccharine^ passing into var. 0. 



b. Loose, arenaceous, resembling the secon- 

 dary sandstones. 



These varieties are occasionally hlueish grey, 

 or ochre yellow, or brown or dark red 5 or deeply 

 stained on the surface with a reddish yellow from 

 the decomposition of pyrites. They are some- 

 times yellow internally, and bleached on the 

 surface to a pure white. They also pass into the 

 red primary sandstone. 



SECOND DIVISION. 



Compound ; of two ingredients. 



SUBDIVISION. Of quartz and felspar. 



A. The quartz compact, opake or hyaline, with 

 imbedded particles of felspar irregularly disposed. 



B. Similar varieties of quartz with interspersed 

 felspar, but with a laminar tendency ; the felspar also 

 predominating in one lamina rather than in another. 



This variety often presents a resemblance to 

 gneiss, which it frequently accompanies. 



