DERIVATION OF THE FLORA AND FAUNA 



381 



Table VII . 



The Chaigneau Ridge. 

 r = rock, s = sand. 



Juan Fernandez situated on a "lobe" with somewhat shallower water, less than 

 3000 m deep, extending NW. from the coast and suggesting a possible former 

 connection, but recent charts are less unambiguous. The 2000 m curve makes, 

 however, a bulge around lat. 38°, where a depth of only 1238 m is indicated 

 while deeper water, 1400-1500 m, is met with near the coast. Soundings be- 

 tween the islands and the line where the trough stops are too few to be of much 

 value, but in all probability the connection, if it did exist, should be looked 

 for farther south. This is, as we shall see, also the opinion of the geologists. 

 They do not hesitate to regard the banks just described as an extension from 

 the continent. Nobody will, I suppose, argue that every marked rise of the ocean 

 floor is a sign of sunken land; the majority of oceanographers prefer to call 

 them independent products of volcanic action. Some, perhaps most of them, 

 never reached the surface, some have done so, but were broken down, but many 

 are still above the water and form the Pacific islands. But even the advocates 

 of the permanence of this largest of basins admit that its margins are zones of 

 considerable disturbance. If it can be proved, or at least be made probable, that 



