DAVIS STRAIT AND LABRADOR SEA 6 



the im})ortaiit contours from this map in the questionable region 

 have been incorporated in our frontispiece. As a result of the 

 General Greene\ survey it now can be definitely stated that there 

 is no Newfoundland Ridge in the vicinity of the fiftieth parallel, 

 but Heykjanes Kidge and Flemish Cap are separated by a tortuous 

 channel deeper than 4,500 meters. This depression which lies closer 

 to the American side of the Labrador Sea than the Greenland side 

 can be followed with decreasing depths in a northwesterly direction 

 for a considerable distance. Although tliere is no bar to the deeper 

 circulation of the Labrador Sea, as formerly suspected, the winding 

 and narrow features of the entering channel, however, may con- 

 siderably restrict the freer movement of the bottom water and par- 

 tially explain the temperature gradient recorded in footnote 3 (p. 2). 

 Secondary bathymetric features which have an important bearing 

 on some of the subjects under discussion, and to which brief atten- 

 tion should be called, include a trough-like embayment across the 

 American slope in the latitude of Hudson Strait, the 600-meter con- 

 tour penetrating to within a few miles of Resolution Island. An- 

 other topographic feature is an elliptical depression about 60 miles 

 long by 15 miles wide, its deepest parts more than 200 meters below 

 the surrounding shoal, in latitude 56 N., longitude 59 W. (See 

 frontispiece.) A larger and more irregularly shaped depression, but 

 not so deep a scarp, is found farther south, about 120 miles north- 

 east of Newfoundland. The Grand Banks, as bounded by the 100- 

 meter contour, are separated from St. Pierre Bank, Green Bank, 

 and Newfoundland by an equal number of channels, the one between 

 Cape Race and the Grand Banks cutting to a depth of 100 meters 

 below the main block of the Banks themselves. In practically every 

 one of the seven sections across the Labrador shelf (figs. 50 and 5l) 

 the presence of a longitudinal depression is indicated. 



HISTORY OF OCEANOGRAPHIC EXPLORATION 



The northwestern North Atlantic witnessed the voyages of the 

 Norse Vikings colonizing Greenland and reaching North American 

 (Vinland) shores as early as 1000 A. D. Existing written accounts 

 of the sea in the northwestern North Atlantic date from 1266, when 

 a Norse expedition sailed northward in west Greenland waters to the 

 region of Smith Sound. The first recorded crossing of the Labrador 

 Sea was made by Martin Frobisher in 1576. 



Surface temperature data from the northwestern North Atlantic, 

 as material incidental to exploration, fisheries, and trade, together 

 with accounts of ice, were made the subject of an oceanographic 

 paper by Petermann (1867). He found evidence of a warm current 

 from the Atlantic that reached even the headwaters of Baffin Ba3^ 



In 1872 Bessels, a scientist on board the Polaris of the LTnited 

 States North Polar Expedition, recorded the first sub-surface tem- 

 peratures in the northwestern North Atlantic. Bessels' (1876) ob- 

 servations from depths of several meters in Kane Basin, north of 

 Baffin Bay, refuted the popular theory of Petermann of a warm 

 Atlantic current. 



In 1875 Moss, staff surgeon with Nares on H. M. S. Alert of the 

 British North Polar Expedition, carried out a program of tempera- 



