Ccognost/ of Si. Pdiil's Bat/. 99 



primary and secondary (iiichuliiig the transition liujcstonc 

 umier the latter term) rocks. This had been before 

 observcfl near the second mill, on the western side of the 

 bay. The specimens of primary rocks we collected, were, 

 first — an aggregate composed of blackish brown mica, red 

 felspar, and grey quartz ; secondly, of felspar and quartz 

 alone, both of a pale cohiur ; thirdly, a trapp containing 

 much hornblend ; fourthly, micaccotis schist. The lime- 

 stone was the same as has been described. 



Descending again into the road, we pursued our journey 

 over alluvium, until reaching a bluflT, or |)recii)ice by the 

 road side, we stopped to dine. This bluft', which is caused 

 by a spur from the primary chain here meeting the road, 

 is of granite. 



Some distance beyond this bluflT, we crossed a plentiful 

 stream of water, strongly impregnated with iron, and 

 which had its source in some hills on our left hand. 



The next thing that |)articularly attracted our notice was 

 a species of cboulcment, by which a part of the road had 

 been broken away and thrown into the river, an event 

 evidently of common occurrence, as many portions of the 

 weiJtern bank attest. 



It appears that the river U rapidly gaining on this bank, 

 and receding from the eastern, a fact which is owing to the 

 deep alluvial section that the former presents in many 

 places, while the latter foiins in general a gradual slope to 

 the foot of the mountains, which on the eastern side is 

 much nearer the river than on the western. 



Against this section, already weakened by the geiuM-al 

 thaw, the spring torrents rush with such imi)eluoHiiy un to 

 tear away u portion of the feeble liarrier opposed to them, 

 particularly at the *iid<len bi'iids (jf the river, where ilu-ir 



