718 
BULLETIN OF THE BUEEAU OF FISHERIES 
that its deeper strata show almost no effect of overflows from the deeps of the neigh- 
boring basin. A profile running out from the Isles of Shoals would show a contrast 
of this same sort, and due to the same cause, between the trough to the west of 
Jeffreys Ledge (station 20061) and the basin to the east of it, though with the actual 
difference in salinity not so great between the two sides of this rather steep ridge 
because this particular trough is open to the north. 
The two phases of the salinity of the gulf that claim most attention in the first 
days of spring, before the Nova Scotian current has spread westward past Cape 
Sable, are the vernal freshening from the land, already mentioned (p.704), and the 
state of the water in the eastern side, where the inflowing bottom current is chiefly 
concentrated. The latter is illustrated graphically in east-west profile (fig. 98) by 
a very evident banking up of the saltest bottom water (salter than 33.5 per mille) 
to within about 80 meters of the surface on the eastern slope of the gulf (station 
20086), when it lay nearly 100 meters deeper in the western side of the profile 
(station 20087, March 23), and by the contrast between its high salinity and the 
considerably less saline masses of water on either hand. 
Unfortunately the three eastern stations (20084 to 20086) on this profile were 
occupied about 3 weeks later, in date, than those immediately to the westward of 
them, allowing the possibility that a cumulative development of the saline core 
during the interval may have been partly responsible for the contrasting salinity. 
But even if the most saline band was not as definitely limited on its western side, 
at any given date, as it is represented, the profile certainly does not exaggerate the 
gradation in salinity between the eastern and western sides of the basin, because 
water samples were taken in both at the same date (March 23 and 24, stations 
20086 and 20087) . A variation of at least 1 per mille in salinity is therefore to be 
expected from west to east across the gulf at the 40 to 100 meter level during the 
last week of March, but one decreasing with increasing depth from that stratum 
downward to virtually nil in the bottom of the trough. It is also probable that 
the whole western side of the basin remained decidedly uniform in salinity through- 
out the month at any given level (p. 722). 
Had vernal freshening affected either end of this profile up to the date of obser- 
vation (to March 24) , the surface would have been much less saline than the deeper 
water at the inshore stations off Massachusetts, on the one side, or off Nova Scotia 
on the other, just as was actually the case off the Kennebec Kiver on March 4 
(p.706, fig. 91). Instead of a distribution of this sort, however, the water at these 
stations was nearly homogeneous in salinity from surface to bottom, evidence that 
values somewhat lower there than in the basin merely represented the gradation of 
this sort that always exists between the coastal and the offshore waters of the gulf. 
Consequently the precise values recorded on Figure 98 represent the prevailing state 
just prior to the date when surface salinity begins to decrease. 
This profile also corroborates the horizontal projections of salinity (fig. 91 and 
93) to the effect that in 1920 the cold Nova Scotian current did not begin to flood 
westward past Cape Sable into the gulf before the end of March in volume sufficient 
to affect the salinity of the latter appreciably, because the band less saline than 32.5 
per mille (correspondingly low in temperature) was then narrower in the eastern side 
of the gulf than in the western, or elsewhere around its periphery for that matter. 
