74 EOYAL SOCIETY OF CANADA 



The origin of the Strait of Canseau has been a subject of some 

 (Speculation as a product of erosion in the comparatively recent Pleis- 

 tocene period, but I ask consideration of a supposition that would make 

 the origin of the strait a rivec channel in much earlier times w*hen a 

 course was found between the old rocks of Cape Porcupine and the 

 Craignish hills of Cape Breton. Personally I am with those who hold 

 that the erosion of the surface by the moyements of an ice cap and iti 

 glaciers has been by some writers greatly exaggerated, and that in part* 

 of ISTova Scotia it was insignificant and insufficient even to rub off all 

 the inequalities left by the preceding denudation effected by the agents 

 of the air. 



To account for the origin of the strait of Canseau by river action it 

 is submitted that the deposits of the Permian and Triassic periods, rem- 

 nants of which still occupy the Gulf, were subjected to the denuding 

 influences of the atmosphere on their emergence from the sea during the 

 Cretaceous period: That then the drainage from the northern slopes 

 of the highlands along the range of the Cobequid hills and their exten- 

 sion to Cape George gathered near their base and forming a stream 

 palrallel to (the general) course of the! hills found exit along faulting by 

 the strait of Canseau to the sea. The deposits in Chedabucto Bay 

 opposite the mouth of the strait take the form of a delta with water 

 deeper on the sides than in the middle of the bay. The drainage of the 

 hills flowed down their slopes until it met the new and less coherent 

 beds and in them was made the lateral and combined stream. The pre- 

 sent Northumberland straits were then part of the river system of this 

 Cretaceous drainage. As time rolled on, and the newer rocks yielded 

 more readily than the old to the action of the streams, the beds of the 

 rivers in them deepened. The flow off the western slopes of the Cape 

 Breton hills formed at first an independent river finding outlet to the 

 eastward and eating deeper and deeper into the softer rocks, its forks 

 and branches eroded backwards and at length cut through the barrier 

 that divided it from some lower branch of the current flowing from the 

 west round Cape George to the strait of Canseau. When this was once 

 effected the deeper and swifter stream flowing by Cape Breîon lost no 

 time in making a way in addition for the waters of the stream thus cut 

 ofi" and which hitherto had gone south about to the ocean. Such a re- 

 sult of river action is no fanciful supposition but it is a recognized and 

 accepted explanation by geographers for the presence of dry and unused 

 channels of many existing streams. 



This result achieved when subsidence in due course again lowered 

 the region to sea level the remnant of the newer rocks lying north and 



