Hypothetical Continents. 91 



affinity of certain- aniinals, or of certain plants,, implies their 

 common origin, and in the case of terrestrial organisms, an 

 almost if not a quite continuous land-connection "between the 

 habitats of the allied organisms. This principle is perfectly 

 sound, according to mynotions, and of infinite value in palseonto- 

 logical reasoning ; but the , upheaval of these various hypo- 

 thetical continents is by no means the only way of explaining 

 known phenomena in accordance with it. It therefore seems 

 reasonable to expect some physical evidence in confirmation of 

 their former existence, and unless this evidence is forthcoming- 

 I should much prefer another explanation if supported in that 

 way. 



I shall now endeavour to make clear an explanation of the 

 phenomena which have hitherto required the aid of an Atlantis 

 and a Lemuria, treating them as belonging to one category. 

 This hypothesis will also explain certain facts requiring- 

 elucidation by any theory framed to account for the peculiarities 

 of the Swiss miocene flora, and will, I hope to be able to show, 

 accord with others which have, apparently, no necessary 

 connection with the subject. 



I have stated that the Atlantis theory was founded on the 

 similarity of the miocene flora of Europe to the recent flora of 

 America. According to Dr. Oswald Heer, 186 species of 

 miocene Swiss plants have their nearest allies living in the 

 United States, 40 in tropical America, 6 in Chile, 58 in Central 

 Europe, 79 in the Mediterranean region, 108 in Asia, 25 in the* 

 Atlantic Islands, 26 in the rest of Africa, and 24 in Australia. 

 This analysis, by a strenuous and able advocate of the Atlantis- 

 theory, shows that there are other facts to be explained besides 

 the preponderance of American types. Dr. Asa Gray, there- 

 fore suggested that the plants had travelled by way of Japan,. 

 Northern Asia, and Asia Minor to Europe, instead of across the- 

 Atlantic over a great island-continent, and this theory has been 

 received with great favour by geologists like Sir Charles Lyell^ 

 and botanists like Professor Oliver. The latter gentleman,, 

 indeed, has ably seconded Professor Asa Gray in attempting to 

 show that the plants travelled by the longer rather than the- 

 shorter route, and in comparatively high latitudes.* It will 

 be unnecessary for me to do more than mention some of the- 

 chief features of his analysis of the three recent floras, namely,, 

 of Europe, Japan, and the Southern United States, in so far as 

 they are allied to the Swiss miocene flora. 



Of the miocene plants of Switzerland there are 76 genera 



common to the recent flora of Europe, 88 to that of the 



Southern United States, 77 to that of Japan, and 123 which 



occur in the united floras of Europe and Asia. The 77 genera 



* Nat. Hist. Review, 1862, p. 149. 



