OLITER ON THE ATLANTIS HYPOTHESIS. 



153 



second stages Ehamnacese rank as tlie Gth and 5tli order respectively. 

 In the fourth stage, Proteacese are not included among the first eight 

 orders, while Compositfe take the foiu'th place. In the third stage, the 

 remains of but three Coniferse are recorded. The proportion of 

 ligneous to herbaceous species is considered to have been very large, 

 there being upwards of 530 of the former, of which number more than 

 one half were arborescent. 327 are reckoned to have been evergreen.* 

 The groups which, either in number of species or individuals, espe- 

 cially gave a character to the Tertiary epoch vegetation, are 



Coniferae, in" El. Tert. Helvetise" referred to 9 gen. 23 species. 



Palmae 8 „ 15 „ 



Populus .,...,. „ 8 „ 



Salix . 



Myrica 



■Quercus 



Ulmus and Planera 



Ficus 



Platanus 



Liquidambar 



Aceracae 



Lauraceae 



Proteaceae 



Ehamnaceae 



Legumiuosae 



Juglandeae 



Prof. Heer in a chapter entitled " Comparison of Plants of the 

 Swiss Tertiary Plora with species now existing," f enumerates 41 

 species, exclusive of cellular plants, based upon both leaf and fruit or 

 flower remains (marked * in the following list), and in a second list 

 SO species resting upon leaf remains only, sufficient, however, to enable 

 him to indicate for each species a living analogue. Although I should 

 probably differ as to the specific counterparts in some cases, there 

 can be but little doubt as to many of the generic identifications. 

 These genera are, ^Woodwardia, *Pteris, *Aspidium, Osmunda, 

 *Juneus, *Arm>do, ^Sparganium, ^Potmnogeton, Smilax, Sabal, 

 ^Gli/ptostrohus, *Taxodium, * Sequoia, Myrica, Carpimis, *Populus, 

 ^Salix, *Quercus, *Ulmus, * Planera, * Platanus, ^Liquidambar, 



* This is Professor Heer's estimate, and I have not the means of analysing 

 it. Dr. Hooker has directed my attention to the importance of ascertaining satis- 

 factorily the exact proportions generally prevailing between ligneous and herbaceous 

 plants, and the proportion of evergreens in tnily tropical floras. I presume all the 

 Lauracece to have been reckoned among evergreens by Professor Heer. He 

 says (Recherches, &c., p. 60) " * * • les Lam-iers et les Camphriers gardaient 

 sans interruption leur verdoyante panire." — In th-e South United States, of the six 

 species of Lauracese which occur there, four are deciduous, and in the Himalaya 

 Dr. Hooker informs me some of the oi-der are commonly bare in winter. To the 

 absolute numbers given by Professor Heer, I think comparatively little value can 

 be attached, though probably the relative proportions in, for example, his table of 

 the sequence of orders, may be sustained, 

 t Recherches sur le Climat, &c. p. 5.5, 

 N. H. K— 1862. M 



