302 P. Chalmers— Pleistocene Marine Shore-Lines 



Art. XXX Y. — Pleistocene Marine Shore-Lines on the South 

 Side of the St. Lawrence Valley / by Robert Chalmers, 

 of the Geological Survey of Canada. 



[Published by permission of the Director of the Geological Survey of Canada ] 



Although it has been known for many years that a con- 

 siderable rise of the land took place in the St. Lawrence Valley 

 in the later Pleistocene period, the facts on which this conclu- 

 sion was based have been few and disconnected. Sir J. "W. 

 Dawson first showed that marine deposits of Pleistocene age, 

 containing fossils, occur on Mount Royal, at Montreal, 470 feet 

 above the sea.* Later, the same author found evidences of 

 ancient shore-lines at the same place at a height of 550 feet ;f 

 and Adams and de Geer discovered beaches there also at an 

 elevation of 600 feet and upwards. Along the lower St. 

 Lawrence, between Sainte Flavie and Riviere du Loup, marine 

 shore-lines were observed by the writer in 1885 at heights 

 varying from 345 to 375 feet. During the seasons of 1894 and 

 1895, however, an opportunity was afforded me of examining 

 the evidences of the Pleistocene upheaval along the south side 

 of the St. Lawrence in much greater detail than has heretofore 

 been done, and data have been obtained showing the extent of 

 a differential uplift there with some approach to accuracy. The 

 observations referred to, it may be stated, are in continuation 

 and extension of those relating to changes of level made in 

 New Brunswick, Nova Scotia, Prince Edward Island and the 

 Gaspe peninsula, the results of which have appeared from 

 time to time in the reports of the Geological Survey of Canada 

 and are shown on the maps accompanying them .J In a report 

 recently issued, § the whole of the work relating to this sub- 

 ject in the eastern maritime provinces is summarized, and it 

 will be seen that the highest Pleistocene marine shore-lines 

 have been traced continuously along the coast from the Inter- 

 national boundary between the State of Maine and New 

 Brunswick northward to the mouth of the St. Lawrence River, 

 also around Prince Edward Island and the Magdalen Islands. 

 On the maps accompanying this report these shore-lines are 

 laid down, and in the text their elevations are tabulated and 

 the differential movements they indicate described. This 

 investigation is now in progress along the south side of the 



. *The Post-Pliocene Geology of Canada, Can. Naturalist, vol. vi, 1812. 



\ The Canadian Ice Age, p. 63. 



% Annual Report Geol. Survey Can., vol. ii, 1886, Part M; ibid., vol. iii, 1887, 

 Part N; ibid., vol. iv, 1888-89, Part N, with accompanying maps. 



§ Annual Report Geol. Survey .Can., vol. vii, 1895, Part M, with accompanying 

 maps. 



