310 HORNBLENDE SCHIST. 



grains of both substances, and from their relative 

 proportions : the felspar being sometimes in 

 equal proportion, at others scarcely discernible. 

 These modifications also vary in colour ; the fel- 

 spar being white, greenish, or red. The horn- 

 blende also may be black or dark green. The 

 laminar mixtures are also sometimes straight, at 

 others large or minutely undulated. It is to these 

 varieties that the term primitive greenstone seems 

 to be applied, 



D. The felspar in excess, and the mixture 

 granular. 



This rock is placed here on account of its 

 geological connexions, occurring with common 

 hornblende schist and chlorite schist, in the 

 chlorite series of Argyllshire. Its aspect is how- 

 ever entirely different from that of any, other 

 hornblende schist. The felspar being of q, 

 greenish colour, that of the rock is a greenish 

 grey. 



E. A minute admixture of hornblende with dark 

 compact felspar ; the two minerals not distinguishable 

 without much attention. The felspar is dark green or 

 lead blue. 



