﻿248 Canadian Record of Science, 



These facts are not mentioned in adverse criticism of 

 the work already done, but to indicate the vast amount yet 

 to be performed before the map can be completed, even 

 with as much detail as its present scale, four miles to one 

 inch, admits. The map of 1896 marks an important step 

 in the geological investigation of this section of the prov- 

 ince. It should be in the hands of every local naturalist, 

 to whom it affords an almost indispensable basis for more 

 minute investigation than its scope allows. 



The area represented on this map extends from the 

 vicinity of Ste. Agathe to Warwick, in the County of 

 Drummond, on the north, and to the international bound- 

 ary line, from Huntingdon to Stanstead, at the south. It 

 comprises more than 7;000 square miles. 



Towards the north-western and south-eastern corners 

 of this district the country is mountainous, while the 

 central portion, which is much greater in extent, is occu- 

 pied by the basin of the St. Lawrence Eiver. This is a 

 uniformly level area, extending in a south-west and 

 north-east direction beyond the limits of the sheet. The 

 mountainous portions on the opposite sides of this basin 

 are of older formation than the interior, and hence the 

 strata, whose geological position is the lowest, form most 

 of the higher landscape features of the district. Occur- 

 rences of the following geological systems are described in 

 descending order : 



Devonian. — Consisting of slates and shales at Sargent's 

 Bay, and limestones at Owl's Head, Lake Memphremagog. 



Silurian. — Comprising the dolomitic conglomerate of 

 St. Helen's Island ; reddish sandstones and shales in 

 Wendover and Pierreville on the lower part of the St. 

 Lawrence Kiver, and the limestones and dolomitic slates, 

 which nearly surround Lake Memphremagog. 



Cambho-Silurian. — This consists of 



1. The Lorraine or Hudson Eiver formation, which 



