DEPAKl'MENT OF THE NAVAL SERVICE 



THE HYDROGRAPHICAL INVESTIGATIONS. 



A description of the submarine physiography of the Canadian waters lias been 

 given by J. W. Spencer (seo chapter IX of Sub-oceanic Physiography of the North 

 Atlantic Ocean, by E. Hull, London, 1912, and Bull Geol. See. Amer. vol. XIV, 1903, 

 1>. 207), of vphich a brief summary is given by Dr. Huntsman (p. 479 and following 

 pages) which latter I will draw upon here, as it affords an excellent introductory view 

 of the waters investigated. 



As will be seen from Mr. Sandstrom's chart (pi. 1), the continuation of the St. 

 Lawrence river forms " the submerged Laurentian valley cutting across the middle of 

 the St. Lawrence gulf, and passing through Cabot strait and between St. Pierre bank 

 and Banquereau. We have referred to this as the Laurentian channel. Another 

 channel, the Cansan, cuts through between Sable Island bank and Banquereau. Far- 

 ther to the south is the Fundian channel, i)assing out from the Bay of Fundy and 

 through the gulf of Maine. These three channels delimit two portions of the continen- 

 tal shelf off Nova Scotia. That to the north, between the Laurentian and Cansan 

 channels, includes the Banquereau, Misaine, and Cansan banks, and may be called the 

 Breton portion of the shelf, or the Breton bank, since it lies off Cape Breton island. 

 The southern part lies between the Cansan and Fundian channels, and includes La 

 Have and Sable Island banks. It may be called the Scotian bank, since it lies against 

 the main portion of the province of Nova Scotia. 



" In the St. Lawrence gulf we have, to the north of Auticosti island, the Anti- 

 costian channel, and running north towards the straits of Belle Isle, the Esquimau 

 channel. To the south of the Laurentian channel, in the gulf, is an extensive sub- 

 marine plateau, with, for the most part, less than 30 fathoms of water covering it. 

 Cropping up from it are the Magdalen islands and Prince Edward island .... 

 We have referred to it as the Lower Gulf region. It might be called the Magdalen 

 bay." 



Prior to the cruises described in this volume there existed a series of excellent 

 hydrographical investigations carried out by Dr. W. Bell Dawson, p^^blished in the 

 reports of the Tidal and Current Survey of Canada for the years 1894 to 1913. Dr. 

 Dawson made determinations of specific gravity (density), and also some temperature 

 measurements. He has described the current of fresher (lighter) water layers Avhich 

 spreads from the St. Lawrence river along the Gaspe coast and out over the Magdalen 

 bay, as above defined. This current, called the Gaspe current, runs farther out along 

 the south side of Cabot strait as a Cape Breton current. ^ 



From the sea outside another current makes its way into tlie gulf along the north 

 side of Cabot strait off cape Ray, spreading out along the north side of the gulf. Out- 

 side the gulf, the water was far less known. As pointed out by Dr. Huntsman, there 

 was known to exist " a slight westward tendency on the southern coast of Newfound- 

 land, and a southwestward drift along the outer coast of Nova Scotia." 



In the gulf of Maine, on the other hand, the currents have been more thoroughly 

 investigated; there are, as we know, the excellent investigations of many years carried 

 out by Dr. H. B. Bigelow in these waters. Before commencing the present researches, 

 as also during the progress of the same, and afterwards, I had frequent opportunities 

 of diiscussing with Dr. Bigelow himself, the questions involved, and I may say that the 

 present work has greatly profited thereby. 



The fir.st cruise made in connection with the present investigations was, as men- 

 tioned above, that of the C.G.S. Acadia, from the 29th of May to the 4th of June, 

 1915. The vessel started from Halifax, the primary object being to take a section of 

 the westerly drift off the east coast of Nova Scotia, and determine the volume of the 

 mixed layers between the coast and the warmer water of the open ocean. The reader 

 will best be able to follow the course of this cruise by referring to Sandstroms figs, on 



^ For a closer study of the hydrographical features in detail, it will be better to consult Mr. 

 Bjerkan's sections and tables (pp. 379-403). 



