IN GLEN TILT. 315 



■—We were prevented from examining the higher parts of Ben 

 y Gloe, by an unusually inclement season, which brought 

 showers of snow, for several days together, before the middle 

 of September. 



On the northern side of Glen Tilt, there is not much of 

 the fixed rock to be seen upon the lower parts of the declivi- 

 ties. At the foot of the lowest fall of the Crochie, and on the 

 west side of it, there is grey sienite, approaching to sienitic 

 greenstone. In the bed of the first torrent to the east of the 

 bridge above Forest Lodge, there is, on the lower part of the 

 mountain, granular quartz, stratified, and dipping at a large 

 angle to the south-west, but irregular. Higher up the same 

 stream, there is sienitic greenstone. 



30. I he rock was examined in the bed of another torrent, 

 which joins the I ilt between the bridge and a fall a few hun- 

 dred yards below it. On ascending the course of this stream, 

 the first fall in it discovers hornblende-slate, obscurely strati- 

 fied, but, as far as could be judged, conforming to the ordina- 

 ry stretch of the strata on the south side of the valley. A 

 little higher, there is sienitic greenstone, and this continues, 

 as you proceed, to a considerable distance. The hornblende- 

 slate seemed to lie over the sienitic greenstone. In a spot not 

 far below the Lodge, and at the height of perhaps three or four 

 hundred feet above the river, the rock is partly sienitic green- 

 stone, and partly granular quartz- 

 Si. We examined the fixed rock of the crags on the brow 

 of the mountain in one or two places only, nearly opposite to 

 the point M, and it was there a small-grained sienitic green- 

 stone. But very satisfactory information, with respect to the 

 nature of these crags, was afforded by the angular blocks, and 

 loose fragments, strewed over the steep declivity below. We 

 examined numbers of them through almost the whole length 

 of the valley, and found them to consist chiefly of gradations 



between: 



