372 DEPARTMENT OF THE NATAL SERVICE 



in the channel is carried towards the surface, and pushes its way through the sovithern 

 part of the channel out over the Atlantic slopes down to a depth of 50in. 



Slope water (83-35 ^/m). — At the surface down to 25ni. slope water is only found 

 over the Atlantic depths, close up to the slopes off La Have bank and Great bank, 

 farther out in the larger part of the area between them, though somewhat nearer the 

 slopes south of Sable Island bank. At 50m. the seaward slopes of the Newfoundland 

 and Nova Scotian banks are covered by slope water. Along the southern slopes of St. 

 Pierre bank a tongue of slope water is found, while the southern part of the channel 

 IS occupied by fresher water. At 75 and lOOm. the seaward slopes and the deeper 

 parts of the Newfoundland banks, as well as the outer Nova Scotian banks, are 

 occupied by slope water, and in the Laurentian channel it penetrates as far as off the 

 the western point of St. Pierre bank. At 200m. slope water occupies the submarine 

 channels, the Atlantic slopes and the deeper pits of the Nova Scotian bank area. 



Comparing the spring and summer conditions as regards the slope water we find 

 the difference most marked in the Laurentian channel, where in the summer it is 

 stoved up by a wall of bank water at a line off the western point of St. Pierre bank, 

 at a depth of 75-lOOm., while in the spring it is confined to the mouth of the channel, 

 and only sends a long and narrow offshoot along the northern slopes of the channel as 

 far inward as Cabot strait. 



Atlantic water (above 35 V'joj. — Water of this high salinity is not foinid at the 

 surface in any of the sections, but on the slopes of La Have bank and Sambro bank we 

 find it close up to the slopes at a depth of 150-175m. and downwards. Farther out at 

 sea we find it as close to the surface as 25-50m. south of La Have, Sambro, and Sable 

 Island banks, and off the Laurentian channel it seems to have penetrated farther in 

 towards the channel at a depth of 100 to 200m. than in the spring. 



h. Temperature (Sandstrnui Plate V). 



The surface temperature is naturally much higher in the summer 

 than in the spring; this is mostly due to the influence of the fresher 

 water from the coast, which as we have seen forces its way far out to sea, but 

 also to the force of the Gulf Stream, which especially at some places sets on stronger 

 than in the spring. This circumstance is shown most plainly when we draw in the 16° 

 isotherm. In the gulf it runs from Gaspe to Cape Breton ; south of this line the surface 

 temperature is higher than 16° C. The highest surface temperature in the gulf is 

 found in Northumberland strait (station 28), viz., 18.5° C, and the lowest close up to 

 the north shore (station X 40), viz., 11.65° C. In the main the surface temperature 

 decreases from south to north, and from the Newfoundland coast towards the north 

 shore. In the Atlantic ocean the 16° isotherm runs along the slopes of the bank; only 

 off the mouth of the Laurentian channel the isotherm bends seawards. Out from the 

 slopes we have higher temperatures, the highest temperature being observed at station 

 XIII 44 (19.7° C). The lowest surface temperature observed during the summer 

 cruise is found at station XIII 37, near the coast off Shelburne, viz., 9.7° C. The 

 surface temperature in the Atlantic generally increases from the coast towards the 

 ocean. The lower readings being found very often over the edge of the banks, especially 

 in the northern part of the area. 



Downwards the temperature decreases towards a layer of water of minimum 

 temperature. In the inner part of the gulf of St. Lawrence, the 10° isotherm mostly 

 runs at a depth of about 10m., but in the outer part at a depth of about 20m. The 

 layers of water of negative temperature we mostly find from a depth of 50- 80m. down- 

 wards. The lower 0° isotherm runs deeper in the northern part of the gulf, and the 

 layers of water of Jiegative temperature are thus more extended in the north especially 

 over the Esquimau channel, where the lower 0° isotherm runs at a depth of about 160m. 



