﻿492 



Canadian Record of Science. 



In Newfoundland similar rocks to those seen at Phillips- 

 burgh and Levis are recognized, and the sequence of strata 

 in that province is supposed lo be nearly the same as in 

 Quebec. The red sand-rock division, or the Georgia 

 group, was styled the Potsdam formation, and this, along 

 the Strait of Belle-isle, was established as the base of the 

 whole series. These rocks were overlain by the Calcifer- 

 ous, which was represented by rocks regarded as the 

 equivalents of the Phillipsburgh limestones, and these in 

 turn were supposed to be succeeded by the slates and 

 sandstone of the Sillery, which was still regarded as 

 constituting the upper member of the group. 



In 1866 the Quebec Group was divided into three parts, 

 a new term, the Lauzon, being added, which comprised 

 the greater portion of the red, green and purple slates in 

 which fossils were rarely found, and which was held to be 

 intermediate between the Levis and Sillery. This arrange- 

 ment was, however, soon discarded and the rocks of the 

 group were included under the two original heads. 



In 1866-69, Pichardson, after a study of the red and 

 green slates, sandstones and conglomerates of the country 

 to the south of the St. Lawrence, and between that river 

 and the mountain chain of crystalline rocks, assumed that 

 the division styled the Sillery was separable into three 

 portions and should be referred to the Potsdam formation 

 as representing its upper part. In 1870, however. Hunt, 

 after a study of the crystalline rocks of New Brunswick 

 and of their relations to the overlying Cambrian, and by 

 a comparison of these with the rocks of the mountain area 

 in the province of Quebec, became " convinced that the 

 latter should be separated from the fossiliferous formations 

 and assigned to a much lower position, being in fact the 

 equivalent of the Huronian. This change of view on the 

 part of Hunt naturally met with much dissent from those 

 who had been so long at work in this field. It, however, 

 gradually acquired weight, and after a careful study of the 



