ARGILLACEOUS SCHIST. 357 



SECOND DIVISION. 



Compound : indurated schistose clay, with 

 some other ingredient conspicuously intermixed. 



A. Simple argillaceous schist, and mica. 



a. The mica extremely thin and broad : passes 



into micaceous scbist. The lustre is 

 sometimes silky, or plumbaginous. 



b. With minute scales of mica, either irregu- 



larly intermixed or disposed in laminae. 

 Micaceo-argillaceous schist : the fine 

 graywacke schist of some mineralo- 



B. Simple argillaceous schist and talc: of a 

 greasy feel, and silky lustre : passes into talcose 

 schist. 



C. Simple argillaceous schist intermixed with 

 chlorite. 



a. The chlorite invisibly minute, as if pow- 



dery, the fracture dull and earthy. 



b. The chlorite foliated, or scaly, and the 



fracture glossy. 



These varieties pass into chlorite schist. 



D. Simple argillaceous schist intermixed with 

 hornblende. 



a. The hornblende in minute scaly crystals, 



or irregular grains, or flat plates. 



b. The hornblende fibrous : fascicular ; or else 



straight, or curved, and radiated. 



