272 THEORY OF A MIOCENE ATLANTIS. [Oh. XV. 



agree more closely with those of Japan than does the flora of the in- 

 tervening countries, Oregon and California, west of the Rocky Moun- 

 tains. It would naturally lead us to conjecture that many of the 

 Miocene genera of Europe now found only on the Atlantic side of 

 North America may once have ranged to the Pacific side. In favor, 

 of such an hypothesis, it may he mentioned that in 1859 Lesguereux 

 discovered in a fossil state in Vancouver's Island and in Oregon many 

 of the Miocene genera which are no longer represented in the flora 

 now living on the west side of the Rocky Mountains. Among these 

 there is a Cinnamomum resembling C. Hossmassleri, see fig. 204, a 

 planer-tree, like Planera Hichardi, a Glyptostrobus like G. (Eningensis, 

 Br., and a fan palm, besides willows and maples, the whole assemblage 

 implying a warmer climate in Oregon in the Miocene period, and also 

 pointing to the spread of a similar vegetation across the whole Ameri- 

 can continent in ancient times. 



In support of the Atlantis theory, Heer has pointed out that certain 

 American genera, such as Oreodaphne, closely related to 0. f osteins or 

 the Til, also Clethra, Bystropogon, Cedronella, and others, are com- 

 mon to the Miocene of Europe, and to the flora of Madeira and Porto 

 Santo, and to that of the Canaries and Azores. Had the number of 

 genera proper to these islands, especially to the Azores, been very 

 considerable, this argument would be entitled to have great weight, 

 for such Atlantic islands would then appear to have been the last 

 remnants of a lost continent over which a continuous vegetation once 

 ranged from west to east. But Professor Oliver truly observes that 

 the botanical types having the geological and geographical relations 

 required by the hypothesis are extremely few in the Atlantic islands. 

 Moreover two of those above cited, Clethra and Cedronella, are of lit- 

 tle or no value, as species of both of them now grow in Japan, and 

 some of the other plants may have reached the Atlantic islands at the 

 time when these were united with Barbary, and Barbary with Europe, 

 at which same period many European land-shells and plants now 

 flourishing in Madeira and Porto Santo may have migrated thither. 



The existence of a continuous land communication between East- 

 ern America and Western Europe in the Pliocene period, by means 

 of which many plants migrated, before the Glacial period, from one 

 region to the other, was suggested by Mr. Darwin in his " Origin of 

 Species" (chap, xi., 1859) ; and Dr. Leidy has observed that a like 

 continuity of land from east to west is implied by the identity of some 

 of the extinct Pliocene mammalia of the Niobrara Valley in Nebraska 

 with those of a corresponding geological age in Europe. The ideal 

 map given by Heer of the Atlantis represents a continent as large as 

 Europe precisely in that portion of the Atlantic Ocean which is now 

 the broadest and deepest.* The depth has been lately shown to 



* Heer and Gaudin, Flora Tertiaria Helvetia?, vol. iii. pi. 156, fig. 9, aud Recher- 

 ches sur le Climat, pi. 1, fig. 9. 



