360 R. W. ELLS — LAURENTIAN OF THE OTTAWA DISTRICT. 



which forms the upper member of the Laurentian proper, at least east of 

 the Ottawa river. West of that river, in the area north of Kingston, the 

 section of the Archean may be completed upward thus: 



I. A series of schistose rocks, highly metamorphic, comprising talcose, 

 sericitic, chloritic and micaceous schists, described in earlier reports as 

 the Hastings scries. This overlies the crystalline limestone of the 

 upper Laurentian and is believed to represent the lower member of the 

 Huronian system. These schists are the exact lithe-logic equivalent of 

 the Huronian rocks of the anticlinals of the eastern townships, as in 

 Sutton mountain and elsewhere, and also of the lower part of the Huro- 

 nian of New Brunswick. In both the last-named areas they are over- 

 laid by more typically volcanic portions of the Huronian, such as the 

 diorites, felsites, etc., and these in turn are succeeded upward by the 

 conglomerates, quartzites and slates of the lower Cambrian. 



Under the present arrangement of the Laurentian of Quebec the par- 

 allelism with the rocks of the system as displayed in southern New 

 Brunswick is very close. Thus, according to the measurements of Messrs 

 Bailey and Matthew, published in the Report of the Canadian Geologi- 

 cal Survey for 1870-71, the rocks of the system are there divided into a 

 lower and an upper portion; the former comprising the usual variety 

 of grayish and reddish-gray gneiss with syenitic and dioritic rocks, in 

 all estimated at 2,500 feet, the latter consisting of dark-grayish and 

 cream-colorecl dolomitic limestone with rusty grayish quartzose gneiss 

 and quartzite capped by grayish limestone and black graphitic shales. 



North of the Ottawa neither the Huronian rocks of the Hastings series 

 nor the quartzites and other rocks of the lower Cambrian appear. A 

 short distance below the city of Ottawa the gneiss and limestone of the 

 upper Laurentian are overlaid by nearly fiat-lying ledges of Potsdam 

 sandstone, which passes upward gradually and conformably into the 

 Calciferous limestone formation. North of Saint Jerome also a limited 

 outlier of the lower Calciferous is seen to rest upon the Laurentian. 

 Further down the Saint Lawrence toward the city of Quebec the for- 

 mations resting directly upon the Laurentian are the ('hazy and the 

 Trenton, the same general horizontality of the measures being preserved, 

 except where broken by lines of fault. 



