BIOLOGICAL STUDY OF CHESAPEAKE BAY WATERS 
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at Z (August cruise, 1920). On 10 of the 15 cruises for which we have data during 
1916, 1920, 1921, and 1922 the bottom salinity increased, passing from T to Z — that is, 
toward the head of the bay. While there is not much difference in depth from T to 
Z, yet it will be seen that the latter is a little deeper than the former and this is prob- 
ably enough to account for the condition mentioned. At the surface the salinity 
decreases almost invariably from T to Z. 
CAPE HENRY _ _ _ CAPE CHARLES 
VARIATION OF BOTTOM SALINITY ACROSS BAY 
It will be remembered that there seems to be a strong tendency for the most 
saline surface water to lie near the eastern shore of the bay but that this tendency 
decreases in the upper part until at Z, Y the saltier water occurs with more nearly an 
equal frequency on the eastern and western sides. The most saline bottom water, 
however, as might be expected, owing to its higher density finds its way into the deep- 
water channel of the bay and may be traced during every cruise along the eastern 
Figure 8. — Salinity profile from New Point Comfort to Cape Charles City, August 22, 1920 
shore and almost invariably through Y, X, S, and R, then to the middle of the bay 
through L, then nearer the western shore through J, again on the eastern shore through 
Q and A, and finally out through the mouth of the bay at G. (See map showing deep- 
water channel, fig. 1.) 
VERTICAL DISTRIBUTION OF SALINITY 
Profiles across the bay show that especially along the deep-water channel, some- 
times in the region of the mouths of rivers, and usually at the mouth of the bay, a 
sharp increase in salinity occurs somewhere between the surface and about the 20- 
meter level. (Figs. 7, 8, 9.) This phenomenon, which is a well-known one for regions 
