319 

 GEOLOGY OF THE REGION AROUND NANAIMO. 



PHYSIOGRAPHY. 



The region around Nanaimo (5) is a part of the east 

 coast lowland of Vancouver island. Since the sedimentary 

 rocks underlying the lowland are varyingly resistant, 

 as well as moderately disturbed, their predominating strike 



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Basal unconformity, shore west of Neck point, Wellington district, showing the 

 irregularities of the surface on which the Nanaimo series was deposited. 



being northwest and their dip northeast, the lowland has 

 considerable relief, extensive valleys having been developed 

 in belts of soft rocks, between ridges composed 

 of more resistant beds. The hard rock ridges are of the 

 cuesta type with very steep, in places nearly vertical, front 

 slopes and gentle dip or back slopes. Tongues of the crys- 

 talline rocks extend eastward from the upland to the west, 

 and form low eastward trending ridges increasing in eleva- 

 tion to the westward. One of the ridges in the northern 

 part of the region forms the northern boundary of the 

 sedimentary rock basin, and another west of Nanaimo is 



