XCIV PEOCEEDINGS OP THE GEOLOGICAL SOCIETY. 



theory of aMiocene Atlantis. The remarkable resemblance of many 

 of the numerous types which form the fossil Miocene Mora of 

 Switzerland (richer even than the modern flora) to living West- 

 ern American types, suggested first to linger, and subsequently 

 to Heer, that the present basin of the Atlantic was once occupied 

 by land, over which the Miocene plants passed freely. This view 

 is combated by Dr. Asa Gray, who argues that it is far more pro- 

 bable that the plants, instead of reaching Europe by the shortest 

 route, over an imaginary Atlantis, emigrated in an opposite direc- 

 tion, and took a course four times as long, across America and the 

 whole of Asia. The objections to the Miocene Atlantis theory 

 are confirmed by the evidence shown by the study of the fossil 

 shells and corals of that period. Mr. J. Carrick Moore has 

 pointed out that certain Tertiary shells of St. Domingo show a 

 gi-eat affinity to the Miocene shells of Europe. Dr. Duncan has 

 done the same with regard to the corals, thereby inferring that 

 there was no great barrier of land or Atlantic continent separating 

 the Miocene seas of Europe from those of the West Indies. 



If I might be allowed to hazard an opinion on this subject, I 

 would say that, even on the showing of the advocates of the re- 

 spective theories, there is such a manifest want of a connecting- 

 link in the chain of evidence, that both the contending theories 

 must be dismissed from consideration. In the first place, the 

 floras which are compared are not contemporaneous, it is the 

 Miocene flora of Switzerland which is compared with the existing 

 flora of North America, and there is no evidence that the Miocene 

 flora of America was the same as the living one. In the next 

 place, both theories assume that the plants travelled from America 

 to Switzerland, that is to say, from the recent flora to that of the 

 Miocene period — a physical impossibility. Moreover in France 

 we have evidence of an intervening Miocene sea extending to the 

 Atlantic. Again, all that is assumed in comparing the two Floras 

 is rather analogy of type than identity of species. I cannot, 

 therefore, think that either of these theories will be permanently 

 established. Would it not be a more probable solution or ex- 

 planation of the typical resemblance to suppose that the con- 

 ditions of climate and of soil were so nearly similar during the 

 Miocene period in Switzerland to that which now prevails on the 

 American continent, that analogous forms were introduced in the 

 respective floras independently of each other, rather than to look 

 upon one as the direct descendant of the other ? Such an ex- 

 planation may not suit the views of those who have adopted the 

 Darwinian theory ; but this is not the time to discuss the law of 

 species, or the causes which have led to the creation of new 

 forms. 



But I cannot go through the whole of this interesting work, 

 although many other important points remain to be noticed, as in 

 the 31st chapter, where Sir C. Lyell publishes for the first time 

 the results of his own observations and those of others on the 

 Miocene rocks of Madeira and Grand Canary, and on the fossils 



