SUBMARINE MOUNTAINS 



79 





Vertical Scale 



= 10 X Horizontal Scale 



\ I 



FIGURE 45. GRAVITY ANOMALIES OVER AND NEAR THE NERO DEEP. 

 AFTER F. A. VENING MEINESZ. 



involved, experiments of this kind are not easily conclusive, 

 but already they have made it highly probable that a true crust 

 40 or 50 miles thick would be at least twice as strong as rock 

 in the quarry, whether granite or thoroughly crystallized ba- 

 salt. Accordingly there seems to be good warrant for assuming 

 the actual crust to be competent to carry the loads indicated 

 by the volcanic islands and by the ocean deeps. The substratum 

 need not be called upon to take any part in the support. If this 

 be true, we find in the weak substratum the primary condition 

 for the earth's plasticity, crustal complexity, and ruggedness 

 of surface. 



The Mountain Ra?iges 



Some principal facts and conclusions have been gathered 

 from the simatic, volcanic islands. What, in their turn, have 



