A. P. LOW — GLACIAL GEOLOGY OF LABRADOB AND QUEBEC. 410 

 The scientific program was declared in order, and the first paper was : 



NOTES ON THE GLACIAL GEOLOGY OF WESTERN LABRADOR A\~l> NORTHERN 



QUEBEC* 



BY A. P. I.oW 



< 'mill ills. 



Glacial Phenomena of (ho Region page 419 



Pleistocene Changes of Level in Labrador 121 



Glacial Phenomena ofth Region. — As may be supposed, there is no marked differ- 

 ence between the glacial phenomena of the interior of Labrador and those of 

 more southern Canada — they all point to a great mass of ice in motion. As the 

 central divide of the interior 1ms not yet been visited the conditions of the surface 

 there are unknown, but it will probably he found to differ but little from the por- 

 tions already explored. The watershed between the rivers (lowing into the gulf of 

 Saint Lawrence and those of Hudson hay acted as a dividing line to the direction 

 of the later ice movement. This height of land is a marked feature in the region 

 for over fifty miles to the north and south of Lake Mistassini, where it runs 

 roughly north-northeast and south-southwest, or parallel to the longer axis of that 

 lake. The country to the southeast of the divide is from 200 feet to 400 feet higher 

 than that to the north, the descent from the one to the other being quite sharp. 

 Near the summit of the slope toward the Saint Lawrence the liner material of the 

 till is abundant and the surface rock is not deeply grooved or striated. As the 

 slope is descended the stria' are more deeply marked and their course is very per- 

 sistent, being nearly due north and south to beyond Lake Saint John, where the 

 highlands of the Saint Lawrence border appear to have formed an obstruction to 

 the bottom of the moving ice ami caused it to change its course locally, so as to 

 pour out into the Saint Lawrence valley through any convenient pass between the 

 hills. 



North of the divide all rock exposures are deeply scratched and grooved, the 

 direction of the striatum being from N. 30° E. to S. ;50° W., or parallel to the steep 

 escarpment of the watershed. Here the glacial action appears to have been much 

 more intense than on the southern slope; all the finer material being removed, 

 leaving only an innumerable number of bowlders to partly cover t he deeply grooA ed 

 rock. The only place where quantities of the finer drift material remain is along 

 the foot and sides of the escarpment, and this may be the remains of a lateral 

 moraine, but cannot be stated to lie such, as no detailed examination of it has 

 been made. 



The great lakes Mistassini and Mistassinis and the other large lakes strung out 

 in line with them to the southwest lie parallel to the direction of the striae and 

 owe their origin to the action of the ice, which has scooped their deep basins out 

 of the comparatively soft, flat-bedded limestones of Mistassini and the altered 

 hornblende and chlorite slates of the lakes to the southwest. Leaving the granites, 

 gneisses and diorites to Conn the higher lands surrounding them. 



Northward from Mistassini toward the East Main river the stria' hive every- 



* Published by permission of the Director of the ■ ■< ologv il Survej of Canada 

 LXtl— Bum., o'i.'.i. Soc. Am., Vol, I. LS92, 



