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HEEZEN AND MENARD 



[chap. 12 



Fig. 1. Major basins of the North Atlantic Ocean. Heavy solid lines indicate boundaries 

 formed by the axis of the Mid-Atlantic Ridge. Light solid lines indicate boundaries 

 formed by shelf break and submarine ridges. Dashed lines indicate arbitrary 

 boimdaries. (After Wiist, 1940.) 



Fig. 2. Major morphological divisions of the North Atlantic Ocean. The profile is a repre- 

 sentative profile from New England to the Sahara Coast. (After Heezen et al., 1959.) 



The Meteor profiles were constructed from closely spaced echo-soundings taken 

 by extremely diligent workers. Continuous-recording echo-sounders were 

 developed in the 1920's but none of these early instruments was suitable for use 

 in the deep sea. It was not until World War II that continuously recording deep- 

 sea echo-sounders were developed. Although the information shown on such 



