SOUTH CHETICAMP, CAFE BRETON ISLAND. — -'JRANDIN. 351 



The courses of the principal streams appear to l.ave been 

 mainly determined b}' the orioinal slopes of the surface ; but 

 those of the smaller brooks and torrents have been influenced 

 chiefly b}^ fault lines, the disposition and lie of the schists and 

 the relative resistant power of the rocks. 



Two great systems of rocks are represented in the district — 

 the pre-Cambrian and the Carboniferous. The classification of 

 the former into series has not yet, on account of tlie complexity 

 of the problem, been attempted. The Carboniferous are divided 

 into two series : — the Lower and the Middle. Broadlj' viewed, 

 it may be said that the pre-Cambrian rocks occup}' the plateau, 

 and the Lower Carboniferous the fringe of hummocks and 

 ridges along the foot of the escarpment, and the plain. The 

 rocks of the Cheticamp Island are regarded b}' Mr. Hugh 

 Fletcher as Middle Carboniferous. 



The pre-Cambrian formation consists mainly of granites, 

 .syenites, felsites, gneisses and schists. Granitic rocks, cut b}' 

 •dikes of trap, predominate along the edge of the plateau. 

 These give place towards the intei'ior of the district to patches 

 and belts of schistose rocks alternating with or surrounded by 

 massive igneous rocks. The whole formation has been nuich 

 plicated, sliced horizontally and vertically by shear and thrust 

 planes, and in conseijuence of these mechanical movements and 

 the chemical action thereby set up, most of its rocks have been 

 converted into varieties of gneisses, schists and other foliated 

 rocks. 



The massive igneous rocks are frequently metalliferous, but 

 it is the schists that have so far proved the principal ore-bearing 

 rocks of the district and in them the important deposits have 

 been located. 



A powerful fault, traversing the district from north-east to 

 south-west and following the course of the escarpment, separates 

 the pre-Cambrian from the Carboniferous. The latter is repre- 

 sented by conglomerates, sandstones, shales, gypsum and lime- 



