PHYSICAL OCEANOGRAPHY OF THE GULF OF MAINE 
713 
In the same way, a March reading of only 32.91 per mille at 175 meters in the 
trough west of Jeffreys Ledge (station 20061) mirrors the hindrance of free circula- 
tion at the bottom (p. 691) by the barrier rim to the north. 
Salinities at depths greater than 150 meters did not demonstrate any inflow as 
actually taking place into the bottom of the gulf in February and March, 1920. 
Thus we find a general and comparatively uniform gradation at 175 meters from 
33.5 to 33.8 per mille around the inner slope of the basin generally (but only 33. OS 
