modifications the methods and procedures were those reported by 

 Harvey.^ 



Figm'es 15, 16, 18, and 19 show, in chronological order, the current 

 charts resulting from the four surveys made during the season. 

 Figure 15 shows that at the time of the first survey, although the 

 dynamic heights in the lowest part of the area were about normal, 

 the highs of 971.72 in the Atlantic Current and 971.18 on the Grand 

 Banks were exceptionally high and indicated a very active circulation 

 both in the Labrador Current along the eastern slope of the Grand 

 Banks and in the margins of the Atlantic Current shown in the south- 

 eastern part of the surveyed area. In the area south-southeastward 

 of the Tail of the Banks, a pool of colder mixed water of undetermined 

 extent was indicated beyond the southwestern limits of the survey. 

 In the northeastern part of the survey there was a slow clockwise 

 circulation arovnid Flemish Cap, with a diversion of some of the Lab- 

 rador Current water northward of it. This pattern persisted through- 

 out the season and was probably responsible for the early season 

 drift of bergs to the vicinity of Flemish Cap. 



Comparison of figures 15 and 16 shows the extent to which the in- 

 trusion of Atlantic Current water spread northward between the first 

 and second surveys. In the second survey, water of Atlantic Current 

 characteristics was found as far north as 45°20' N., and at single 

 levels at stations 5411 and 5412 just north of 46° N. The Labrador 

 Current along the eastern edge of the Grand Banks continued to feed 

 the cold mixed-water pool which extended south of the southern 

 limits of the survey. Labrador Current water did not extend west- 

 ward of about 50°20' W., and warm salty water had reached to the 

 Grand Banks at 43° N., westward of 50°15' W. This intrusion of 

 water of the Gulf Stream w^as most in evidence at the section extend- 

 ing southwestward from station 5468. Figure 17 shows the tem- 

 perature distribution along this section. 



Figure 18, showing the results of the third survey, does not com- 

 pletely enclose all of the cold mixed-water pool even though the survej^ 

 was extended unusually far to the south. The probable southern 

 hmit of berg drift was judged to be the 971.36-dynamic meter contour 

 line, the course of which has been estimated in figure 18. Comparing 

 figures 16 and 18 permits of following changes in pattern features 

 common to both. The axis of the major valley in the southern part 

 of the chart remained at about the 48th meridian. The branch valley 

 which extended southwestward from the Tail of the Banks in the 

 second survey moved southeastward, and in the third survey ex- 

 tended southwestward from about 42° N., 49° W. The topography 

 along the southeastern edge of the surveyed area straightened out 

 and the minor salients between it and the valley, only hinted at in 



^Harvey, H. W., "The estimation of phosphate and of total phosphorus in sea waters." Journ. Mar. 

 Biol. Assoc, vol. XXVII, pp. 337-359 (1948), Plymouth, Eng. 



84 



