218 Geology, *^c, ofMalbay^ L. C. 



This mica slate is often tolerably compact. It is full of 

 quartz veins, and of the beds of white feldspar, as on the 

 outside of the west arm of Malbaj. Its layers are, as is 

 usual, very tortuous, but like the gneiss, they affect on the 

 whole the north north-west dip. 



Half a*mile from the conglomerate precipice the gneiss 



is resumed, and continues for a great distance to dip into 

 the water in impassable mounds. I observed it at the Ri- 

 viere des Trois Saumons, nine miles below : where it has a 

 transverse vein of calcspar, mottled white, green, and red, 

 eighteen inches thick, and intersected obliquely by a vein 

 of white quartz six inches thick. 



The details which have Wow been entered upon at some 

 length, suggest the following observations : 



The rock formations of the north shore of the St. Law- 



r 



rence from Cape Torment, a precipitous headland 1,800 

 feet high, to the River des Trois Saumons, are of a charac- 

 ter similar to that of the district of Malbav. Thev rise in- 

 to mountains of magnificent features, which bound the river 

 in lofty capes and escarpments, and at distant intervals 

 break into rich but narrow valleys of alluvion, the outlets 

 of streams tributary to the St, Lawrence. 



Almost all the primary rocks are found in this distance 

 alternating in rapid succession, and thus contrasting in the 

 most forcible manner with the vast and monotonous tracts 

 of gneiss, limestone, and marbie of Upper Canada. 



The rocks of Malbay are, with one exception, of the or- 

 dinary kinds, but they are remarkable in their transitions 

 and position. 



These transitions are effected in different ways, as grad- 

 ually and longitudinally (that is, in the direction of the stra- 

 tum) in the primary rocks, one ingredient mica for instance, 

 slowly predominating to the exclusion of another. Thus 

 the laminated gneiss of the West Hill becomes well char- 

 acterised mica slate, and by the addition of hornblende, un- 

 dergoes a still greater change in the east of Malbay- This 

 appearance has been rarely noticed by authors. Dr. Ma- 

 culloch met with it in the Isle of Sky in the West of Scot- 

 land, and considers it to be of difficult explanation, but 

 ishews it to occur in other formations. Professor Kidd 



