316 GEOLOGICAL APPEARANCES 



between grey sienite and sienitic greenstone, all bearing a strong 

 resemblance to one another in their general character, as well 

 as to those which have been already mentioned, as occurring in 

 the fixed rocks on different parts of the mountain. In these 

 aggregates, the felspar is commonly whitish, but has various 

 shades of colour, and is sometimes tinged with red. The pro- 

 portion of the hornblende to the felspar is generally large. 

 The grains are in some instances large and distinct, and in 

 others extremely minute. Quartz is seldom an ingredient, and 

 mica still more rarely. I conceive the most appropriate name 

 for all the varieties to be Sienitic Greenstone, as the majori- 

 ty of them approach more nearly to that substance, than to sie- 

 nite. 



32. Among the angular blocks of sienitic greenstone, there 

 occur also a few of gneiss and granular quartz ; and a little 

 below the point marked B in the plan of the river, I saw, on 

 the side of the mountain, some fragments of hornblende- 

 slate and greenstone-porphyry. 



33. Along the declivity, from a point over against M, to 

 another a little above Forest Lodge, there are occasionally 

 fragments of a sienite, similar to that which appears so often 

 in the bed, and on the banks, of the river. This differs, in se- 

 veral respects, from that which approaches to sienitic greenstone. 

 Its chief ingredient is felspar, sometimes grey, but most com- 

 monly red. It also contains less hornblende, and quartz in va- 

 rious proportions. Nearly opposite to the point B, I found a 

 few fragments of it a little below the crags, and about seven 

 hundred feet above the Tilt. 



34. To these remarks on the northern bank of the valley, it 

 may be added, that the Griurnon, a point several hundred feet 

 above the crags of sienitic greenstone, consists of granular quartz, 



containing 



