SECT. 2] 



TOPOGRAPHY OF THE DEEP-SEA FLOOR 



255 



WH6 



WHS 



3000 FATHOMS 





100 200 300 400 



DISTANCE IN NAUTICAL MILES 



500 



600 



Fig. 19. Profiles of abyssal plains and abyssal hills in the western North Atlantic. Profiles 

 are indexed in Fig. 18. (After Heezen et al., 1959.) 



3000 FATHOMS 



.;^yJW\;^^y^Mi-^WJV- 



EH7 



EH8 





'^3000 



100 50 



100 200 300 400 



DISTANCE IN NAUTICAL MILES 



500 



600 



Fig. 20. Profiles of abyssal plains and abyssal hills in the eastern North Atlantic. Profiles 

 are indexed in Fig. 18. (After Heezen et al., 1959.) 



spread in the Atlantic but relatively rare in the Pacific, because turbidity 

 currents cannot flow past island arcs and trenches. (3) The small-scale relief of 

 plains and their approaches can be explained only by the action of bottom- 

 moving turbidity currents (Heezen et al., 1954; Menard, 1955). Submarine 



