154 OKTGIJfAL ARTICLES. 



^Polygonum, *Salsola, *Laurus, Persea, *Cinnamomum, '^Emho- 

 thrium, Drijandra, Ficus, *Leptoineria, *Diosp>/ros, *Acerates, 

 Fraximis, *LirioJendron, *Acer, Ilex, Zizyphus, Berchemki, 

 *Jihatnnics, *Paliurus, Pirns, *Juglans, Plerocarya, *Colutea, 

 *Pobinia, *Gleditsckia, Caesalpinia, * Cassia. 



In discussing tlie cliaracter of the Swiss Tertiary Plora,* its 

 general relations to existing Floras are indicated. The methods of 

 comparision employed, Prof. Heer says " incontestably prove that, at 

 the Tertiary period Switzerland was inhabited by types which are 

 now scattered over every part of the world, but of which the ma- 

 jority correspond to American species ; Europe ranks only second, 

 Asia third, Africa fourth, and New Holland fifth. In Europe it is 

 the Mediterranean region ; in America, the Southern United States ; 

 in Asia, Japan, the region of the Caucasus and Asia Minor ; in 

 Africa, in proportion to their area, the small islands of the Atlantic, 

 which support the gi'eatest number of analogous species." Speaking 

 of the distribution in the Tertiary, as compared with the present 

 period, of generic types, he selects Juglandese as offering a marked 

 contrast between their present wide, and former restricted area. 

 Prof. Heer limits the present distribution of Pterocarya to the 

 Caucasus, Juglans to Persia and North America, and JEngelhardtia 

 to the Sunda Islands. Two species of Pterocarya, however, grow 

 in Japan, three species of Juglans are recorded from the same region, 

 where also another generic type is met with in Platycarya {Portuncea, 

 Lindl.), and Engelhardtia occurs in the Himalaya. Carya is not held to 

 be generically distinct from Juglans by Messrs. Hooker and Bentham. 

 Viewed in respect of the sjoecies which contributed most largely 

 to the mass and physiognomy of the tertiary vegetation, he says, "The 

 Elora of Japan with its abundance of Camphor-trees and its Cflyptos- 

 trohi, that of the Atlantic islands with its Laurels, the American Flora 

 with its numerous evergreen Oaks, Maples, Poplars, Plane-trees, 

 Liqiiidavihar, Pohinia, Sequoia, Taxodium, and ternate- leaved Pines, 

 and finally that of Asia Minor with its Planera and Populus miita- 

 lilis occupy the first place." Without distinction of stage in 

 the Swiss deposits, the first rank, in respect to abundance of indi- 

 viduals, Prof. Heer assigns to Lauraceae, second, Cupidiferae. In the 

 first stage, Proteaceae, Khamnaceae and Cupressiueae predominated; 

 in the second, Ehamnaceae and Palmaceae; third Proteaceae; fourth, 

 Salicaceae, Aceraceae, Papilionaceae, Juglandeae and Sapindaceae. 

 The climate of Europe he believes to have been, during the lower 

 miocene, about 13°, and the upper miocene 16° Fahr. warmer than at 

 present, while the large relative proportion of ligneous, evergreen 

 and aquatic species, with layers of lignite, bear testimony to its 

 ample humidity. 



With a view to avoid imnecessary repetition in the following 

 paragraphs, and to save space, I have drawn up the subjoined table, 

 showing the distribution of existing genera of the Swiss Tertiary in 

 the recent Floras of Europe, Japan, of Europe and Asia (including 

 Japan), taken together, and the Southern States of America. 



* Becherches sur le Climat, &c. p. 58. 



