298 Canadian Record of Science. 



mineral occurs in the anorthosites of this as well as in 

 those of other areas. 



The outer zone, that is to say, the one bordering on the 

 plagioclase, consists of a bright green actinolite in very 

 thin needle-shaped crystals, which form a rim around the 

 pyroxene, from which they project in a radiating manner 

 into the feldspar. This zone is considerably wider than 

 the pyroxene zone, and the actinolite individuals always 

 stand perpendicular to the surface of the latter. The 

 mineral is frequently more massive near the pyroxene 

 than it is farther away from it. 



In a hand specimen from the north shore of Lake 

 Kenogami the hornblende of the outer zone is full of 

 small inclusions of spinel. These have a dark green colour, 

 are isotropic, have a high index of refraction and no cleav- 

 age. They occur mostly in portions of the horneblende 

 zone nearest the pyroxene. We find them at times in the 

 form of grains, but generally in peculiarly bent sheaf-like 

 forms, resembling the quartz in fine-grained pegmatites 

 or granophyres. These are arranged within the horne- 

 blende crystals or between them in a direction perpen- 

 dicular to the surface of the inner pyroxene zone. This 

 spinel often occurs in the horneblende in lines parallel to 

 the surfaces of the prisms, while some small individuals 

 fork in such a manner that they run parallel to the two 

 prismatic cleavages. A quite similar case was described 

 by Lacroix as occurring in the olivine-norite of the Heias 

 mine near Tredestrande, in Norway. 1 In this rock the 

 olivine is surrounded by a double zone, the inner one 

 consisting of hypersthene and the outer one of amphibole, 

 in which occur scattered grains of green spinel, which 

 frequently give rise to a kind of pegrnatitic (granophyric) 

 structure. According to Becke 2 the kelyphite which 



i Lacroix, Contributions a l'etude des Gneiss a Pyroxene et des Roches a Wernerite. 

 Bull. soc. min. Fr., Avril, 1880, p. 149. 



2 F. Becke, Min. u. Pet. Mitth., VII., p. 250. 



