50°N 



40° 



30° 



20° 



I0°N 



80°W 



70° 



60° 



30°W 



80°W 



70° 



60° 



50° 



40° 



30° W 



50°N 



40° 



30° 



20° 



I0°N 



Figure 16. Depth of 10°C isothermal surface, according to Iselin (1936, fig. 47). Depths are given in meters. 



15 



