532 
BULLETIN OF THE BUREAU OF FISHERIES 
eastern end of the bank (fig. 16), however, shows much less contrast in temperature 
between the two sides of the latter, with the oceanic water (warmer than 8° and 
salter than 34 per mille) so much farther out from the edge of the continent that 
even the outermost station (20069) did not touch it, leaving the bottom down the con- 
tinental slope bathed with water colder than 5° at all depths. The profiles thus 
corroborate the temperature charts (figs. 12 and 13), to the effect that the warm 
bottom zone was obliterated somewhere between longitudes 67° and 68° W. (about 
midway the length of Georges Bank) in February and March by the “cold wall” 
Temperature, Centigrade 
2 ° 3 ° 4 ° 5 ° 6 ° 7 ° 8 ° 9 ° 10 ° 11 ° 12 ° 13 ° 14 ° 15 ° 
Fig. 10 —Vertical distribution of temperature near Lurcher Shoal in various months. A, March 23, 1920 
(station 20082); B, April 12, 1920 (station 20101); C, May 10, 1915 (station 10272); D, August 12, 1913 
(station 10096); F, August 12, 1914 (station 10245); G, January 4, 1921 (station 10500) 
that wedges in between the slope and the oceanic water. As it is the existence of 
this warm zone that permits the year-round existence of warm-water subtropical 
invertebrates and of the tilefish along this stretch, the definite location of its eastern 
limit is a matter of some biological importance. The contrast between the graph 
for our outermost station off the western end of Georges Bank and two other deep 
stations off its eastern end and off Shelburne, Nova Scotia (fig. 18), is an addi- 
tional illustration of the sudden dislocations about midway of the bank, with a 
