PLATE XXXII. 



Fig. 1. 



Ophitic Dolerite, No. X. — The felspar is the lightest in colour, the 

 iron ores are the darkest. The fresh Augite, in which the felspars are 

 imbedded, is intermediate in shade. A couple of crystals of altered 

 Olivine appear in the lower right-band quadrant. Magnification, 

 28 diam. 



Fig. 2. 



Ophitic Dolerite, No. XIII. — In this the Augite is so much 

 darkened by decomposition-products as to be hardly distinguish- 

 able in many places from the opaque iron ores. Magnification, 

 28 diam. 



