PLATE IX. 



A. "Amphibolite." Diorite dike. Hoosac mountain, south of Cheshire. Micrephotograph, x 33. 



Crystalloids <>r grains of plagioclase feldspar («) and of brown hornblende (fc) are seen around 

 the edge of the figure. In the center we have an aggregate of irregular patches of secondary feld- 

 spar, green hornblende, epidote, etc., forming a confused aggregate, little veins of which are seen to 

 penetrate the feldspars or pass between them. 



B. Amphibolite. Mount Holly, Vermont. Microphotograph; polarized light x 33. 



The large black anas are a deep greenish-brown hornblende, surrounded by a friuge of light 

 green hornblende. This shows best in the crystal in the center («) with the fringe (h). The portion 

 between the black crystals is an aggregate of epidote prisms, masses of green hornblende, and 

 feldspar 



114 



