PHYSICAL OCEAKOGRAPHY OF THE GULF OF MAINE 



803 



in the Gulf of Maine region, suggests indrafts from the basin offshore at two levels — 

 one centering at about 50 meters and the other over the bottom. 



In 1917 the autumnal progression of salinity in the Bay of Fundy was of the 

 reverse order (fig. 161), Mavor's (1923) records showing a decrease of about 1.2 per 

 mille at all depths from October to December, as follows:' 



METER 



Fig. 162.— Salinitj' profile crossing the continental shelf off Marthas Vineyard, November 10 and 11, 1916. (From Bigelow, 



1922, fig. 38) 



It is obvious that with salinity increasing in the one year of record, decreasing 

 in the next, neither an increase nor a decrease can be named as normal for the Bay 

 of Fundy in late autumn. Freshening is probably to be expected there in years 

 when the autunmal rains are heavy and the discharges from the St. John and from 

 the other rivers tributary to the bay are correspondingly great, especially if the 

 indraft over the bottom (which varies from year to year) is less active than usual. 

 On the other hand, salting will follow after summers and autumns with light rain- 

 fall or with more than the usual contribution of saline bottom water. This expla- 

 nation is partly corrobated by the fact that the year's precipation showed a defi- 

 ciency of 11.45 inches from the mean at Eastport in 1916 (when the salinity of the 

 bay rose in autumn) , with every month from August to November falling low. 



I Condensed from Mavor (1923, p. 375). 



