174 bulletin: museum of comparative zoology. 



west (Stations 10218, 10220, Fig. 5), the temperature was practically 

 uniform from forty meters d^wn to 300 meters. 



The water was considerably warmer on the continental shelf south 

 of Marthas Vineyard than anywhere in the Gulf of Maine, or off Nova 

 Scotia. 



Temperature Profiles. — The relationship of the water of the Gulf of 

 Maine to the Atlantic water is illustrated by profiles across the west 

 and east ends of Georges Bank. Thus the Western Basin of the Gulf, 

 (Fig. 8), with its minimum of 4°-5° at 100 meters, was much colder 

 at all depths than the water south of the Bank; for example to find 

 water on the continental slope, as cold as the 100 meter-level in the 

 Gulf, we must go below 500 meters; while 10° water lay at 40 meters 

 in the Gulf; but only below 150 meters on the slope. And the surface 

 water at Station 10218 was warmer than any water anywhere in the 

 Gulf. But there is much less' difference between the two ends of the 

 profile across the eastern part of the bank, Gulf water being warmer 

 here than further west (Fig. 9), ocean water colder (p. 171). 



The two profiles, combined, reveal the existence of a clearly defined 

 cool band (8°-10°), lying on the middle of the bank at its eastern, 

 over the southern edge at its western end. And they are further 

 interesting for their demonstration that the cold water of the Atlantic 

 abyss (4°-5°), was separated from the bottom water of the Gulf of 

 Maine by a much warmer zone (8°-10°) of bottom water; a phenome- 

 non with which we are already familiar further south (1915), and one 

 of great importance for its bearing on the origin of the Gulf water (p. 

 240). The profile running from Georges Bank to Cape Sable, via the 

 Eastern Channel (Fig. 10) shows that the eastern side of the Channel 

 was appreciably warmer than the western, below 'the level of its con- 

 fining banks, though the waters over the latter were of about the same 

 mean temperature on the two sides. But it is chiefly interesting for its 

 illustration of the sudden change which takes place, east of Brown's 

 Bank, from the moderate temperatures of the banks, and of the upper 

 layers of the Gulf of Maine as a whole, to very much colder water next 

 southern Nova Scotia. 



This cold water, characterized by the almost polar temperatures of 

 l°-2°, extended in a continuous band along the coast from Cape Sable 

 to Halifax (Fig. 11-13). And I may forestall the following discussion 

 (p. 234) so far as to say that it is undoubtedly the product of the Cabot 

 Current. In summer it is limited here to a narrow coastal zone; 

 projecting thence outward like a shelf, along the 50 meter-level, into 

 warmer water offshore. Thus on the Halifax line (Fig. 13) water 



