186 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
SALINITY, CAPE Cop TO CHESAPEAKE Bay. 
1. Surface salinity. The surface salinity (Plate 2) from Cape Cod 
to the southern edge of Nantucket Shoals was 32.2%po-32.6%po. And 
the record of 32.3%po at the eastern end of Vineyard Sound agrees so 
well with Sumner, Osburn, and Cole’s (1913) records for the surface 
waters of that region in August, 1906 (32.2% o to 32.3%p) that we can 
110 
" 
Fic. 29.— Temperature profile lengthwise of the northeastern part of the 
basin from south to north (Stations 10093, 10097). For 42° read 42.5°. 
assume\that value as normal for summer. The few stations in this 
region suggest that the curve of 32.3% swings westward toward the 
mouth of Vineyard Sound, which agrees with their statement (1913, 
p. 36) that there is a dominant westerly movement of the wate? 
through the Sound of about two knots per day. 
From Nantucket light-ship out to the edge of the continental shelf 
there was a steady, and fairly uniform rise in salinity to about 33.4% 
