.134 



and 18. The bottom intrusions of Arctic water were found in 

 general to be the same relative position as shown bj' previous record- 

 of the patrol and the area of freshest and warmest bottom watc; 

 lay as a cover over the south-central part of the Bank, as an iso- 

 lated circuit often referred to as a tidal reservoir. 



It has long been known tbat the water in this vicinity of the 

 Grand Bank promontory, especially the surface layers, although 250 

 miles from the nearest land, was of decidedly coastal character and 

 it was believed that in order that such water be so fresh it must 

 receive continual coastal contributions, but the actual manner in 

 which such a movement took place was not proven heretofore. 

 Sketches 17 and 18 conclusively show that coastal water moves off- 

 shore in the surface layers in the vicinity of Cape Race, southeast- 

 ward to the south-central Grand Bank region via its western side. 

 The continual contributions accumulating in the central Grand 

 Bank region finally flood this place from surface to bottom with 

 fresh water and give it a truly coastal character in spite of its dis- 

 tance, 250 miles at sea. 



This water mass is isolated from all except its contributions which 

 it receives from the westward, and possessing a rotary tidal motion, 

 with its accumulations increasing, it spreads outward on all sides, 

 most markedly toward the north and northeast, where by virtue of 

 its fresher and warmer character it is continually swamping arctic 

 intrusions from that direction. 



The offshore movement on the west side of the bank is at a maxi- 

 mum during the summer and fall, when the arctic circulation is at 

 a minimum, but intermittent communication takes place the year 

 round, particularly in the surface layers. In the spring such offshore 

 progression may be occurring, while in the deeper layers frigid arctic 

 water may be cieej)ing in over the bottom. 



GENERAL SCHEME OF CIRCULATION IN ICE REGIONS 



For some years it has been an ambition to present a current chart 

 of the ice regions of the North Atlantic based upon the scientific 

 investigation of the ice patrol, but as more and more evidence was 

 accumulated it was found increasingly difficult to represent the varied 

 movements for which the water masses of these regions are famous. 

 At no other part of the world do such diametrically opposed bodies 

 abut each other with a consequent complexity of circulation. It has 

 been concluded, therefore, that the only correct manner to satisfy a 

 current scheme of charting is to trace the average boundary of the 

 three classified types of water, viz, Arctic, Banks, and Atlantic 

 sketches, and. wherever it lias been possible, to illustrate a more or 



