580 THE UPPER SILURIAN. 



into Northumberland Strait and Chiegnecto Bay from those flowing into 

 Cobequid Bay and Mines Basin and Channel. In like manner, the 

 complicated group of hills extending westward from Cape Porcupine 

 and Cape St George, though less elevated than the Cobequid hills, 

 contains the sources of all the principal rivers of the counties through 

 which it extends. The largest of these is the St Mary's river. Its 

 western branch, originating in the same elevated ground that gives 

 rise to the Musquodoboit, the Stewiacke, and the Middle River of 

 Pictou, flows for about thirty miles nearly due east along the valley 

 which here separates the Lower and Upper Silurian districts. Its 

 east branch flowing from the hills in the rear of Merigomish, and 

 passing near the lakes from which the principal branch of the East 

 River of Pictou flows, receives tributary streams from the meta- 

 morphic promontory stretching towards Cape Porcupine, and unites 

 with the west branch at the northern margin of the LoAver Silurian 

 metamorphic band. The united stream then flows through a narrow 

 valley, cutting the Lower Silurian belt transversely, to the Atlantic. 



Judging from the direction of the principal streams, as for instance 

 the Liverpool River, it would appear that in the western counties, as 

 well as in the eastern, this group of metamorphic rocks, with its 

 associated igneous masses, forms the most elevated ridges. In the 

 southern part of New Brunswick also, and in Cape Breton, we every- 

 where find these rocks forming rocky ridges separating the river 

 valleys. 



The character of the surface over these rocks is very similar to 

 that which prevails in those parts of Lower Canada (Quebec) and 

 New England, in which similarly altered Upper Silurian rocks occur. 

 The soil, where not too rocky for cultivation, is fertile ; and in their 

 natural state the hills are clothed with a rich growth of hard- wood 

 trees. 



M. Jules Marcou, in the summary of American geology which 

 accompanies his geological map, endeavours to apply to these ele- 

 vations De Beaumont's theory of the parallelism of mountain ranges 

 of like age. According to this view, the Cobequid Mountains, and 

 the hills on the east side of the Bras d'Or Lake, belong to a system 

 of elevations older than the Lower Silurian rocks ; and the Meri- 

 gomish and Antigonish Mountains, with the hills of Western Cape 

 Breton, to a later dislocation, dating at the close of the Silurian 

 period. It appears to me that both these dates are by much too ! 

 ancient. I have already stated that the rocks of the Cobequid 

 Mountains have been altered and elevated before the Carboniferous 

 period ; but, on the other hand, these altered rocks themselves are in 



