Ch. XV.] THEORY OF A MIOCENE. ATLANTIS. 271 



Miocene flora of Central Europe and the Recent flora of .North 

 America, and that the analogy is greater than between the same fossil 

 flora and that now existing in Europe. But in the first place it is 

 remarked by Dr. Asa Gray that the Swiss Miocene plants are more 

 like those of Japan than they are like those now living in Europe, 

 which at once suggests the idea that the American plants may have 

 taken a westerly instead of an easterly route. In the next place it is 

 remarked that, if we travel from Europe to the east, the farther we go 

 the more we find the living vegetation putting on the characters of 

 the Old Miocene flora. Thus in passing from the Mediterranean to 

 the Levant, the Caucasus, and Persia, we meet, says Professor Oliver, 

 with Chamcerops, Platanus, Liquidamhar, Pterocarya, Juglans, &c, 

 &c, then we trace along the Himalaya and through China other 

 Miocene genera, the eastern part of the Asiatic continent forming 

 with Japan one great botanical region. In the Southern American 

 States eighty-eight of the Miocene genera are now represented ; but Pro- 

 fessor Oliver gives a table to show that if we take Europe, Asia, and 

 Japan together, as before suggested, there are no less than 120 Recent 

 genera which are common to the Swiss Miocene flora. Moreover 

 there are some general features in which the living flora of Japan is 

 more like the Old Miocene vegetation of Europe than is the living 

 flora of xlmerica. For example, the nine Tertiary orders which are 

 numerically the largest are the following: — 1. Graminece (grasses) ; 2. 

 Compositse ; 3. Cyperacese (sedges) ; 4. Salicacese (willows) ; 5. Con- 

 iferse (pines) ; 6. Leguminosss ; 7. Laurinese (laurels) ; 8. Acerinese 

 (maples) ; and 9. Proteaceae. The six first of these are included in 

 the nine largest orders of Japan, and only four of them, namely, 

 the three first and the sixth, in the largest orders of the Southern 

 States of North America ; and farther, the three last of the nine are 

 much more developed in Japan than in the Southern States. 



Heer estimates the proportion of ligneous species in the Swiss 

 Miocene as exceeding 60 per cent, of all the plants. Professor Oliver 

 remarks on this subject that in Japan they constitute 40 per cent, of 

 the whole flora, and only 22 per cent, in that of the Southern United 

 States. There are seventy-seven genera common to the recent flora of 

 Japan and to the European Miocene strata, and nearly the same num- 

 ber are common to the tertiary and the living flora of Europe ; but 

 the genera which are common in these two instances are by no means 

 the same, and no less than twenty-six of the Japanese list are wanting in 

 Europe, having become extinct there since the Miocene period. Not 

 a few of these, such as Cinnamomum and Glyptostrobus, play a con- 

 spicuous part among the fossils. 



In order to understand the disappearance of so many forms, we 

 have only to call to mind the great geographical changes already 

 alluded to, which are known to have taken place in Eastern Europe 

 and Western Asia since the Miocene era. It seems at first sight an 

 anomaly that the plants on the eastern side of North America should 



