MIOCENE ATLANTIS. 31 



tlie Sequoia sempervirens having apjDarently continued in existence from the miocenc times 

 until now. 



The relative prejDonderance of tj-pe in tlie European miocene flora at that epoch was, first, 

 that of North America, especially the southern part of the United States, as Louisiana, Florida, 

 Georgia, and the Carolinas ; second, of Europe, particularly the Mediterranean district ; third, of 

 Asia ; fourth, of Africa ; and fifth, of Australia. The Australian types had been diminishing in 

 numbers as we ascend from the oolite and the lower eocene to the upper miocene. The American 

 element is esi^ecially remarkable in the number of evergreen oaks, maples, planes, poplars, liquid- 

 amber, Robinias, Sequoias, and Ta^das, that is, pines with leaves in clusters of three. The con- 

 clusions drawn from insects, of which no less than 1322 fossil tertiary species, or supposed species, 

 have been found in Switzerland, correspond in the main with the conclusions derived from 

 plants. 



These facts suggested to Unger and Goppert the speculation which is known as the " Atlantis 

 theorj'," or the " Miocene Atlantis," viz. that the present basin of the Atlantic was occupied 

 by land, over which the miocene plants could pass freely, and this hypothesis has been enlarged 

 and advocated with great abilitj- bj' Heer and other eminent men. To use the words of Sir- Charles 

 Lyell : " The existence of a continuous land communication between Eastern America and Western 

 Europe in the pliocene period, by means of which many plants migrated before the glacial epoch, 

 from one region to the other, was also suggested by Mr. Darwin, in his Origin of Species; 

 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 fact that it is the Eastern or Atlantic side of America, or that which is nearest to 

 Europe, which presents the greatest number of vegetable forms analogous to the miocene flora, 

 woidd be an additional argument in favour of the Atlantis, if the present distribution of species 

 and their relative proportion in America gave any clue to those in the miocene age, but if, as 

 I imagine, they do not, the hypothesis must stand upon more general grounds. 



On the other hand, Dr. Asa Gray, Professor Oliver, and others, following up a hint thrown 

 out by Bentham, have argued that it is more probable that the plants, instead of reaching Europe 

 by the shortest route over an imaginary Atlantis, migrated in an opposite direction, and took a 

 course four times as long across America and the whole of Asia. 



It rather appears to me, however, that their hypothesis does not apply so much to the miocene 

 epoch as to a subsequent period. When the glacial epoch was at its height, ice covered the wliole 

 of North America, as far south as the north of Georgia and Texas (see Map 4) (that, as is proved 

 by the tertiary deposits to the south of them, being the then southern termination of the North 

 American contuaent), and the ice there ran into the sea in miglity glaciers. In its progress 

 south it must, of course, have driven every plant or animal before it, making a clean sweep of all 

 life wherever it came ; and wherever it rested, covering the land as it did, for thousands and thou- 

 sands of years (whether intermittently or not), it must have left the surface a tabtda rasa for the 

 reception of new impressions. Wliere there was an extension of land before it, as in the south-west 

 corner of North ^\merica, the plants and animals would take refuge in i1. Where there was no 

 extension of land, and the glacier ice terminated in the sea, of course every living thing woidd 

 be annihilated. 



In Eui-ope, on the other hand, although the drift or glacial ice did not reach so far south as 



