SECT. 2] 



ABYSSAL PLAINS 



341 



45 



43 



42 



43 



42 



40 



39 



38 



HORIZONTAL AND VERTICAL 

 SCALE OF PROFILES 



5n2500 



5 10 



15 



NAUTICAL MILES 

 VERTICAL EXAGGERATION 15.1 



,2700 FATHOMS 



AY- 

 AZ — 



■■■■/~ 

 AX 



AA 



43 



42 



41 



2700 



.N.- 



AH 



-AJ 

 -AK 



-AI 



-AL 



-AM 

 —AN 



,K 



•.'•V- — AO 



-AP 



-AG 



AT 

 'AU 



^AR 



AS 



h A ZI ^ I 



40 



39 



38 



45 



Fig. 22. Forty-eight profiles across the Northwest Atlantic Mid-Ocean Canyon. (After 

 Heezen et al., 1959.) 



is associated with an abyssal gap through a ridge dividing the northwest arm 

 of the Sohm Plain from the rest. 



In the Indian Ocean, soundings taken by the Swedish Deep-Sea Expedition 

 in the Albatross have shown the existence of trough-shaped features in an 

 otherwise flat and featureless floor, which have been interpreted as grabens 



