PLATE XL. 



FIG. 1. 



FELSPAR-PYROXENE BOCK. 



KYLE SKU, SUTHERLAND. 

 Magnified 30 diameters. Ordinary light. 



The minerals represented are felspar (10), pyroxene (7), brown mica (9) and 

 iron-ores. 



The felspar occurs in grains of tolerably equal dimensions in the different 

 directions. Fine lamellar twinning is sometimes present, sometimes absent. 

 The monoclinic pyroxene is green in thin section (the tint is slightly exaggerated 

 in the figure). It shows good prismatic cleavages and not unfrequently contains 

 numerous inclusions arranged in one or more sets of parallel planes. In another 

 portion of the same slide hyper sthene occurs. 



This rock forms a portion of the banded gneissic series of Sutherland and 

 often shows foliation in hand specimens. 



FIG 2. 

 ZOISITE-AMPHIBOLITE. 



NEAR BEINN HUTIG, SUTHERLAND. 



Magnified 50 diameters. Ordinary light. 



The minerals represented are hornblende (8), zoisite (21), and felspar (10). 



The zoisite-prisms lie in a colourless matrix, the larger grains of which often 

 show the lamination of plagioclase. Some of the colourless material may be 

 quartz. The rock occurs in an area of regional metamorphism. It is probably a 

 metamorphosed basic igneous rock. 



