262 GNEISS. 



B. Compact felspar with quartz ; in various pro- 

 portions* 



C. Compact felspar and chlorite : with gneiss, in 

 North Uist. Occurs also as a member of the chlorite 

 series of Argyllshire. 



D. Compact felspar, with quartz, and mica. 



E. Compact felspar, with quartz and hornblende, 

 or with mica superadded. 



F. Compact felspar superadded, in various ways, 

 to any of the preceding- varieties of gneiss which con- 

 tain common felspar also. 



The substances ranked in this division are 

 frequently traversed by veins of compact felspar, 

 often reticulating in an intricate manner, and so 

 numerous as to form a large proportion of the 

 rock. The predominant colours in the compact 

 felspar are various shades of grey, but green is 

 also very common. They occur abundantly, 

 sometimes in connexion with the varieties of the 

 first subdivision, in Sutherland and Rossshire ; 

 and are also found in North Uist and West Rona, 

 where they are connected with and pass into 

 argillaceous schist ; forming a compound included 

 in the next division. 



