Permanence of Continents 301 



His position still remains inexpugnable that it is not permissible to 

 invoke geographical change to explain difficulties in distribution 

 without valid geological and physical support. Writing to Mellard 

 Reade, who in 1878 had said, " While believing that the ocean-depths 

 are of enormous age, it is impossible to reject other evidences that 

 they have once been land," he pointed out " the statement from the 

 Challenger that all sediment is deposited within one or two hundred 

 miles from the shores 1 ." The following year Sir Archibald Geikie 2 

 informed the Royal Geographical Society that "No part of the 

 results obtained by the Challenger expedition has a profounder 

 interest for geologists and geographers than the proof which they 

 furnish that the floor of the ocean basins has no real analogy among 

 the sedimentary formations which form most of the framework of the 

 land." 



Nor has Darwin's earlier argument ever been upset. "The fact 

 which I pointed out many years ago, that all oceanic islands are 

 volcanic (except St Paul's, and now that is viewed by some as the 

 nucleus of an ancient volcano), seem to me a strong argument that 

 no continent ever occupied the great oceans 3 ." 



Dr Guppy, who devoted several years to geological and botanical 

 investigations in the Pacific, found himself forced to similar con- 

 clusions. " It may be at once observed," he says, " that my belief in 

 the general principle that islands have always been islands has not 

 been shaken," and he entirely rejects "the hypothesis of a Pacific 

 continent." He comes back, in full view of the problems on the 

 spot, to the position from which, as has been seen, Darwin started : 

 " If the distribution of a particular group of plants or animals does 

 not seem to accord with the present arrangement of the land, it is 

 by far the safest plan, even after exhausting all likely modes of 

 explanation, not to invoke the intervention of geographical changes ; 

 and I scarcely think that our knowledge of any one group of organ- 

 isms is ever sufficiently precise to justify a recourse to hypothetical 

 alterations in the present relations of land and sea 4 ." Wallace 

 clinches the matter when he finds "almost the whole of the vast 

 areas of the Atlantic, Pacific, Indian, and Southern Oceans, without 

 a solitary relic of the great islands or continents supposed to have 

 sunk beneath their waves 5 ." 



Writing to Wallace (1876), Darwin warmly approves the former's 

 "protest against sinking imaginary continents in a quite reckless 



1 More Letters, n. p. 146. 



2 "Geographical Evolution," Proc. E. Geogr. Soc. 1879, p. 427. 



3 More Letters, n. p. 146. 



* Observation* of a Naturalist in the Pacific between 1896 and 1899, London, 1903, 

 i. p. 380. 



8 Island Life, p. 105. 



