24 PRELIMINARY INQUIRIES. 



Professor Ungcr in his " New Holland in Europe,"* puts it wholly beyond dispute. lie has 

 there enumerated 173 plants discovered in the eocene beds of Europe analogous to species now 

 livino- in New Holland or in the southern hemisiDhere. In his interesting paper on this subject, 

 Professor linger also points out that the representatives of a certain proportion of the eocene 

 plants are now found in China and other parts of Asia, and the analogues of a third portion in 

 North America. He might have added that another proportion occurs in the Indo-Malayan region, 

 for Mr. Bowerbank has described no fewer than thirteen fruits of palms from the eocene beds in the 

 Island of Sheppy, aU of the recent type, now foimd only in India, and in the Moluccas and 

 Philii^pine Islands. 



The conclusion to which Professor Ungcr arrives from these premises is that Europe was not 

 a centre of creation, but that it received the impress of the peculiarities of three continents ; and 

 he supposes that it did so by means of a land communication existing between Australia and 

 Europe, through Asia, by way of the Moluccas, and by one from America across the Atlantic. Of 

 course, it is part of his hj'pothesis that at that time the climate of all these coimtries was the same. 



Professor TJnger's explanation is open to the objection that he assumes, without the smallest 

 warrant, that the floras of Australia, of Asia, and of America, were each of the same character 

 in. the eocene epoch as they are now. Europe is the only country with whose flora in the eocene 

 epoch we are at all acquainted. With that of Australia we shall probably never be acquaiated, 

 because it apparentlj^ has no eocene formations. The eocene fossils hitherto found in America are 

 extensive, but entirely marine, and consequently our knowledge of the fossil flora of that epoch 

 there, is nil, and we know as little of the eocene flora of Asia. 



The character, therefore, of the existing vegetation in the only country (Europe) with whose 

 flora during the eocene epoch we are acquainted, is different from that which then grew in it, 

 and therefore, so far as we can draw any conclusions from that solitary fact, they should certainly 

 not be that the eocene flora of all the other countries was the same as their existing flora. There 

 are groimds for making an exception in favour of Australia whose present flora is so largely 

 analogous to the European eocene flora. The very extent of the analogy is in itself an argu- 

 ment for doing so, but there are no grounds for supposing this either for America or Asia, 

 of whose elements only a small proportion appears in the eocene flora of Europe. The m^ore 

 generally adopted view accords better with facts, viz. that (whether as a consequence of the more 

 uniform heat which then extended over the whole globe or not) organic life during the secondary 

 and eocene epoch was more homogeneous than it became afterwards, or is now. The elements 

 out of which the American, Asiatic, Indo-Malayan, and Australian floras have sprung, were doubtless 

 intermingled then not only in Europe, but in America, in Asia, in the Tropics, and Australia ; 

 but since then, through the changes arising from altered conditions of life, the uniformity has 

 been broken up, and the j^resent distribution of species established. 



There can be no dovibt that laud communication between Australia must then have existed, 

 and the route suggested by Professor Unger seems as likely as any other. At the same time, it must 

 be remembered that the present arrangement of the flora or fauna of any part of the northern 

 hemisphere is not the slightest criterion of what it was in the eocene epoch, because the whole of 

 the old relations of species there must have been completely overturned by the clearance of life 

 which the glacial epoch brought about. 



* Unger, Dr. F. " Nou Holland in Europa," and Translation in Seeman's " Journal of Botany," Feb. 1S65, p. 39. 



