22 THE CANADIAN NATURALIST. [Vol. ix. 



" The sandstones in the two areas on the opposite sides of the 

 Riviere du Sud are massive ; on the northern side they are often 

 very coarse grained, and in general of a green color, while the 

 shales which separate the masses are usually red. Very coarse 

 beds are not so frequent on the south side, and there the red 

 color is not confined to the shales, but characterizes the sandstones 

 also, which are as often red as green." ^ 



There are two other distinctions not pointed out by Sir W. 

 Logan. The one is that fossils, oholella and graptolites, charac- 

 terize the northern area, and are apparently absent in the 

 southern area. Another is that the sandstones in the latter 

 frequently present a peculiar schistose structure, not, so far as 

 I know, to be seen in the true Sillery sandstones of the Levis 

 formation, to which the northern of these two sandstone areas 

 clearly belongs. 



I shall now pass on to the consideration of Division 3, which, 

 however, as I have already stated, may be intimately related to 

 the preceding. The rocks composing it are chiefly slaty and 

 schistose, and embrace a great variety of chloritic, micaceous, 

 siliceous and magnesian strata with copper ores, also imperfect 

 gneisses, white and gray micaceous dolomites and magnesian 

 limestones. They constitute the main anticlinal axis of the region, 

 which axis may be traced from Sutton Mountain, east of Lake 

 Memphremagog, on a gently curving line, northeastward to the 

 counties of Montmagny and L' Islet — a distance of 150 miles. 

 Between the St. Francis and the townships of Chester and Wolfes- 

 town, a very considerable dislocation crosses the axis transversely, 

 and the structure here is exceedingly complicated, and is rendered 

 still more obscure by the overlapping of the Upper Silurian rocks, 

 and by the interposition, in the magnesian belt — by a complica- 

 tion of faulting and unconformable superposition — of a long, 

 narrow band of the black shales and dark earthy limestones of 

 the fossiliferous Levis formation. Further north, however, the 

 magnesian belt again assumes its normal relation to the over- 

 lying divisions 1 and 2. And on page 258 of the Geology of 

 Canada, we find its course thus descrebed : " The general course 

 of the magnesian rocks on the south side of the synclinal is, 

 however, pretty well determined by a band of dolomite occasion- 

 ally passing into serpentine, which has been traced from the 



* Geology of Canada, p. 258. 



