BIGELOW: EXPLORATIONS OF THE COAST WATERS. 



227 



(Fig. 34, 72; 1913, Fig. 29). But this early autumn freshening (if 

 it be a characteristic phenomenon) is confined to the eastern half of 

 the Gulf, just the reverse being true of the western side, where the 

 salinity of the upper layers is at, or near, its lowest in mid-summer 

 (p. 207), with an increase of salinity already apparent on the surface 

 by early September (Fig. 18, 42, 67). And though no great change 

 takes place in the mid-depths from mid-summer to September, the 



Meter 



FiG^73. — Temperature profile across the continental shelf off Shelburne, Nova Scotia, 

 June 23, 1915 (Stations 10291-10295). 



general rise in salinity characteristic of autumn and winter (p. 207) 

 is foreshadowed, at 100 meters, (Fig. 72) by the fact that 33%o water 

 reaches the western slope of the basin in September, instead of being 

 separated from it by a band of fresher water, as in June (Fig. 66). 

 Ever^-where in the depths of the Gulf, at and below 200 meters, the 

 salinity is higher in September than in June, particularly in the 



