PLATE XLV. 

 Fig. a. 



(Sp. No. 23356. Without analyzer, x 35.) 



Bronzite-norite-porpliyry. The plienoorysts of loronzite lie in a groundmass of bronzite, mouo- 

 clinic pyroxene, hornblende, and feldspar. In the drawing the bronzite and monocliuic pyroxene of 

 the groundmass can not be distinguished. (Described, p. 247.) 



Pig. B. 



(Sp. No. 23353. Without analyzer, x 18.) 



Feldspathic wehrlite. One can readily distinguish the constituents — augite, hornblende, olivine 

 and feldspar — in the illustration. The augite is automorphic where it is near the feldspar. It is 

 surrounded by a brown hornblende zone. Between the olivine and the feldspar there are always two 

 zones. One, the inner one, best seen between crossed nicols, is orthorhombic pyroxene; the other, 

 the outer one, is compact green hornblende. This green hornblende is in optical continuity with the 

 brown hornblende which surrounds the augite. (Described, p. 255.) 



320 



