﻿1848. SILURIAN STRATA. 283 



intervals. The quartz rock beds acquire occa- 

 sionally a pistachio-green colour, as if from the 

 presence of epidote. A similar stone occurs at 

 Pigeon River on the north shore of Lake Superior ; 

 and the limestones and sandstones of the latter 

 district, with their associated trap rocks, as at 

 Thunder Mountain, correspond in most respects 

 with those between Cape Parry and the Copper- 

 mine River ; and consequently, if we can rely on 

 lithological characters, they may be considered as 

 the oldest members of the silurian series, or as the 

 rocks on which that series is deposited, to which 

 epoch the Lake Superior formation has been as- 

 signed. If we had been able to trace up the lime- 

 stone spurs of the Rocky Mountains which traverse 

 the Mackenzie, they would most probably have been 

 found running up to and connected with the lime- 

 stone of this coast. 



At six in the afternoon the wind veerino^ round 

 to the south-west, we embarked again, and con- 

 tinued under sail till three in the morning of the 

 1 8th, when the wind failing us we dropped anchor 

 in the mouth of Roscoe River. We resumed our 

 voyage at 8 a.m., after preparing an early break- 

 fast. 



A little to the westward of Point de Witt 

 Clinton, a range of basalt and limestone cliffs 

 extends for a mile along the beach, under which 



