60 



Physiography 



120* 



Figure 57. Regional varia- 

 tions in topography of the 

 abyssal sea floor. From 

 Menard (1955, Fig. 2). 



• PLEISTOCENE OR 

 RECENT VOLCANOES 

 (INCLUDING ISLANDS) 



-ij>-GUYOTS, FORMER 

 VOLCANIC ISLANDS 



X SEAMOUNTS, SUBMARINE 

 VOLCANOES NOT KNOWN 

 TO BE GUYOTS 



Figure 58. Fracture zones, sea- 

 mounts, guyots, and known 

 volcanoes of abyssal sea floor. 

 From Menard (1956, Fig. 2). 



f 



