7i8 NATURAL SCIENCE. sov.. 



possibly understand — and to prefer to bridge across an ocean between 2,000 and 

 3,000 fathoms deep, in order to reduce the distance to about three-quarters of the 

 other route, is again to hold \ lews totally inconsistent with the theory of ocean- 

 permanence. 



Even in the passage from his " Address " quoted by Dr Blanford, there is more 

 antagonism than agreement ; for I cannot admit that " there is no evidence what- 

 ever . . . that every ocean-bed now more than 1,000 fathoms deep, has always been 

 ocean." If by "every ocean-bed" we mean the great oceanic basins as distin- 

 guished from deep seas within continental areas, and if we admit those very rare and 

 hmited encroachments of old continents on the margins of these oceans, which, as I 

 have shown, I have always admitted, then I maintain that ,^iere is very strong 

 evidence indeed of the permanence of all the gr^at ocean-basins, and that the 1,000- 

 fathom line still gives us the best indication of the general limits of the old 

 continental areas. This is so, because the facts adduced in my last paper show 

 that any extension of the continents into the oceanic areas much beyond the 1,000- 

 fathom line would necessitate the submergence to great depths of many times their 

 area of existing land. 



Before concluding, I must briefly notice a very extraordinary claim of Mr. 

 Jukes-Browne. He says (" Evolution of Oceans and Continents," p. 510) : — " Those 

 who oppose the doctrine of permanence say that the present continents are the out- 

 come of a long series of geographical mutations," each phase being " an episode in 

 a long process of geographical evolution." 



But this is exactly what those who uphold permanence have always said. Dana 

 taught the evolution of the American continent nearly forty years ago ; Sir 

 Archibald Geikie has discus ed " Geographical Evolution " with permanence of 

 continental areas ; and I myself, following these great masters, have endeavoured to 

 sketch out the process of this evolution and its results. This " process of evolution " 

 necessarily implies permanence of position of the continental as regards the adjacent 

 oceanic areas —the only permanence that has ever been postulated by myself or 

 others, and it is simply amazing to find this very process now claimed as if it were 

 the discovery and the distinctive teaching of those who oppose permanence ! 



In conclusion, I may say that, while admitting with pleasure the growing approxi- 

 mation of views on this subject, I cannot forget that it has been, and still is with 

 many writers, the practice to assume former continental extensions across the great 

 oceans in order to explain difficulties in the distribution of single ger.era or families ; 

 that geologists of repute have claimed the Dolphin bank in the Atlantic trough as 

 the relic of a chain of mountains comparable with the Andes ; that oceanic islands 

 have been recently claimed to be merely the tops of submerged mountains, which 

 can only be properly compared with the highest points of continents, and that a 

 geological critic so late as 1879 considered the idea that the oceans had always been 

 in their present positions " a funny one." If such extreme views are now less 

 common than they were, I hope that I may, without presumption, claim to have 

 had some share in bringing about the change in scientific opinion now in progress. 



Alfred R. Wallace 



Museums and Specialists. 



1 DESIRE to raise a slight objection to the kindly notice of my account of 

 the Fossil Crinoids in the British Museum (Natural Science, vol. i., p. 474), a 

 notice that has just been reprinted verbatim in the A inen'cun Geologist for October. It 

 is stated that I accept as my rule the American maxim, that a museum is a 

 collection of labels illustrated by specimens ; but this gives an entirely erroneous 

 impression. The paper referred to began with Professor Flower's words, " a well, 

 arranged educational Museum has been defined as a collection, &c.," and it 

 further stated in so many words that it dealt solely with the specimens exhibited 

 for the diftusion of scientific knowledge. 



The excuse for this protest is that the comments appeared shortly after a 

 leading article on a similar subject, in which comparisons were instituted between 

 the Storehouse-type of museum, disarrarged and thick in dust, with its keys half 



