THE ANCIENT ATLANTIS 275 



Archibald Geikie, we are led to the conclusion that the pre- 

 sent continental areas must have been terrestrial regions 

 of the earth's surfa.ce from a remote geological period. 

 Subject to repeated oscillations, continues Sir Archibald 

 Geikie. so that one tract after another has disappeared 

 and reappeared from beneath the sea, the continents.; 

 though constantly varying in shape and size, have yet 

 maintained their individuality. So far, I think, most 

 geologists will agree with Sir Archibald Geikie. It is his 

 inference, that the existing ocean basins have probably always 

 been the great depressions of the earth's surface, which has 

 not met with such general approval. Dr. Wallace supports 

 Sir Archibald Geikie's view on the grounds, not only of the 

 enormous depths and great extent of the oceans, and of the 

 circumstance that the deposits now forming in them are 

 distinct from anything found upon the land surface, but also 

 owing to the supposed extraordinary fact that the countless 

 islands scattered over their whole area (with one or two ex- 

 ceptions) never contain any Palaeozoic or Secondary rocks, 

 that is, have not preserved any fragments of ancient con- 

 tinents, nor of the deposits which must have resulted from 

 their denudation during the whole period of their existence ! 

 The exceptions alluded to by Dr. Wallace* are New Zealand 

 and the Seychelles islands, both situated near to continents 

 and, according to the same writer, not really oceanic. "The 

 Vast areas of the Atlantic, Pacific, Indian and Southern 

 Oceans are thus left almost without a solitary relict of the 

 great islands or continents which some naturalists believe to 

 have sunk beneath the waves of these oceans." Thus writes 

 Dr. Wallace. Another argument in favour of the permanence 

 of ocean basins has recently been brought forward by Pro- 

 fessor Joly.f It is based on the facts of solvent denudation. 

 He regards the sodium in the ocean as the key to the history 

 of solvent denudation, arguing that it was derived from the 

 igneous rocks of the earth by the processes of weathering and 

 solution progressing throughout geological time. He shows 

 that the quantity of oceanic sodium agrees with the sediments 



* Wallace, A. E., " Island Life," p. 105. 



t Joly, J., " Radioactivity and Geology," pp. 127131. 



T 2 



