62 THE ROYAL SOCIETY OF CANADA 



and in the Laurentian channel, which runs along the north side of 

 these shallows, there is, below these two, a third which fills up the 

 bottom of the channel. 



The uppermost layer consists of warm water of low salinity, 

 the result of the heating action of the spring and summer as well 

 as of the influx of large quantities of fresh water from the St. Lawrence 

 and other rivers of the region. The layer below this is of somewhat 

 higher salinity, and with a very low temperature, much of it being 

 below 32 degrees F. The low temperature has been derived from the 

 cold of the previous -winter. The third and deepest layer is of still 

 higher salinity and of intermediate temperature from 39 degrees to 

 42 degrees F. It appears to originate from the open Atlantic, the 

 "cold wall" of water which is banked up against the side of the con- 

 tinent flowing very slowly into the gulf by way of the bed of the 

 Laurentian channel. 



These three layers of water were discovered early in the last 

 century. Kelley, who worked with Admiral Bayfield in the gulf and 

 river St. Lawrence during 1831, 1832 and 1836, took a series of tem- 

 peratures at the surface, and in addition took the temperature of 

 water from various depths down to as deep as 150 fathoms, brought 

 to the surface in Woolaston's machine. The small number of observa- 

 tions taken by this imperfect method was nevertheless sufificient to 

 demonstrate the presence at a depth of from about thirty to ninety 

 fathoms of a layer of very cold water, with slightly warmer water 

 below and much warmer water near the surface. These observations 

 were published in the Transactions of the Literary and Historical 

 Society of Quebec, and remained in obscurity until used by Hind in 

 1877. The latter drew diagrams to show the temperature zones and 

 the seasonal changes in a section from Anticosti to Prince Edward 

 Island. 



Whiteaves, while dredging in the gulf during the years 1871 and 

 1872, took the temperature and the mud brought up from the various 

 depths in the dredge, and was puzzled to find the mud from the 

 greatest depths warmer than that from lesser depths. This method 

 was equally imperfect. In 1895 Dr. Dawson with modern apparatus 

 determined carefully the temperatures and densities of water at 

 various depths down to as much as 200 fathoms, both in Cabot strait 

 and in the channel between the Gaspé peninsula and Anticosti island. 

 During 1915 Dr. Hjort, on the Canadian Fisheries expedition, made 

 a very thorough hydrographie survey of the gulf both in June and 

 again in August, the results of which have not yet been published. 

 Last year we investigated the Magdalen shallows off Cheticamp, 

 C.B., and also the Cape Breton side of Cabot strait. The stratified 



