308 HQRNBLGNDE SCHIST. 



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SYNOPSIS OF HORNBLENDE SCHIST. 



FIRST DIVISION. 



Simple : of hornblende alone. 



A. Very compact, with a smooth and dull frac- 

 ture ; the particles being almost invisibly minute. 



B. Granular, from small irregular aggregated 

 crystals : varies in the degree of fineness. 



C. Scaly, from an aggregation of flat crystals. 



D. Flat continuously laminar. 



a. Large laminar. 



b. Minutely laminar. 



E. Fibrous. 



a. Simply fibrous and with short fibres. 



b. Fibrous, radiated. 



c. Very fine fibrous and silky. 



F. The texture so fine that it loses its character 

 and passes into argillaceous schist. 



These varieties are sometimes imperfectly, or 

 not at all fissile, and thus form what is called 

 hornblende rock. Occasionally many different 

 textures are intermixed in the same mass, or 

 specimen ; thus producing additional diversities 

 of aspect. Sometimes large distinct crystals of 



