196 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
most striking feature, apart from the separation into comparatively 
fresh water on the continental shelf, and much salter oceanic water 
on the slope, is a succession of zones of comparatively uniform salinity 
alternating with zones in which there is a rapid change in salinity both 
vertical and horizontal. Next the shore there is first a mass of bottom 
water of 33.2%o, fifteen fathoms thick (Station 10063), separated 
by a zone of rapid transition from a much fresher though hardly less 
uniform surface zone of about 33% (Station 10062), some twenty-five 
fathoms thick. This, in turn, gives place to much salter water, over 
the edge of the shelf (Station 10061), where salinity increases only by 
2% (33.41% -33.62%po) from the surface down to fifty fathoms; 
below which there is a sudden rise. Since some of these masses of 
uniform water reappear in other profiles, it is convenient to designate 
them from the shore seaward, as A, B, and C. 
On the profile from the neighborhood of New York to the slope, in 
about latitude 40° (Fig. 39), the salt ocean water is much more in 
evidence than it is further east, water of 35%p bathing the slope nearly 
to the fifty fathom curve, although the surface water at the shore 
end is about the same salinity as in the last profile (Station 10067, 
31.2% o). ‘Two of the bands, which were noted in the preceding profile, 
reappear here, 2. e., A and B, with about the same salinities which 
characterized them further east. Band A is as well defined as in the 
preceding profile, occupies the same relative position on the shelf; 
and has the same salinity (33.2%). But in the present profile the 
transition to the fresher water near shore is less sudden than it was 
further east. Band B is less clearly defined than in the preceding 
profile, and its salinity is less uniform, both vertically and transverse to 
the continental shelf, though of the same general value (about 33%p); 
nor does it so nearly reach to bottom, but overlies a layer of much 
salter water. Nevertheless the band is distinctly more uniform than 
the water immediately below, or on either side of it; hence its indi- 
viduality still deserves recognition. But the third band, C, which 
characterized the outer part of the preceding profile, can not be dis- 
tinguished in this one. As a whole the surface is fresher along this 
profile than the preceding; and this is true even of its off shore end, 
although the bottom water near the edge of the shelf is much salter 
than further east. And not only is water salter than 33.2%p nearer the 
surface over the middle of the shelf, but water with salinity of 33% 
and higher washes the bottom to the fifteen fathom, instead of only 
to the twenty-five fathom curve. All this shows that off New York 
shore water was more in evidence on the surface, Atlantic water on 
