84 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
of the flood near shore, is N. N. E. toward the Grand Manan Channel 
and the Bay of Fundy, and along this coast the velocity increases 
steadily from west to east, the rate in the channel being two knots. 
Along the west coast of Nova Scotia the mean direction of the flood- 
current is nearly north. ‘The flood is weakest in the northern part 
of Massachusetts Bay, and along shore from Cape Ann to Portland, 
as shown in the Table (p. 143), though there are strong tidal currents 
off the mouths of large rivers, and tide rips off Portsmouth (Station 11). 
In the central part of the Gulf (Stations 7, 27) the current is about .5 
knot; but along the Nova Scotian Coast and off the mouth of the Bay 
of Fundy it occasionally attains velocities of more than two knots, with 
extensive and dangerous tide-rips on the various shoals, for example 
the Grand Manan Bank. 
In a general way the ebb is the reverse of thé flood, flowing out of 
the Bay of Fundy ina generally S. W. to S. S. W. direction, and around 
the coast of Nova Scotia to the S. and S. E. Along the coast of Maine 
from the Grand Manan Channel to Mt. Desert the ebb flows about 
S.W. But the current in the central part of the Gulf is about S. by E. 
Off Casco Bay the ebb is southerly; along the coast from Portland 
to Cape Ann it sets in general toward the E. S. E. but there aré various 
local currents here, yet to be explained. The strength of the ebb 
current is proportional to that of the flood, strongest off the mouth of 
the Bay of Fundy and along the coast of Nova Scotia; progressively 
weaker to the westward. 
The data is insufficient to show whether the tidal currents result in 
any definite eddy movement of the waters of the Gulf, nor have I 
been able to find in them any evidence of an inflow, or alongshore 
flow within the Gulf, such as might be credited to a branch of any 
constant ocean current. This question was thoroughly studied by 
Dawson (1910) for the Bay of Fundy and for the Nova Scotian Coast, 
between the mouth of the St. John and Cape Sable, in 1904 and 
1907. And his general conclusion is that ebb and flood are almost 
opposite, veering at slack water only, if at all; and that there is 
little indication of any movement of water in a dominant direction. 
The mean compass-bearings and strengths of the currents on Brown’s 
and George’s Banks as given on the U. 8S. Coast Survey charts suggest 
a drift from northeast to southwest. But the data on the tidal cur- 
rents of George’s Bank given by Mitchell (Rept. U. S. Coast and Geo- 
detic Survey, 1881, p. 175) show that there is a slight easterly drift, 
and it is so represented on the current chart.in the coast pilot. (U.S. 
Coast Pilot, part 3, 1912, chart facing p. 9). And although most of 
