354 M. Brongniart on the different Floras which 



6. Tertiary Period. 



The collective nature of the plants of this period, contempo- 

 raneous with all the tertiary deposits and surviving even yet in 

 the vegetation clothing the present surface of the earth, is one of 

 the most characteristic. The abundance of augiospermous Dico- 

 tyledons, of Monocotyledons of various families, but especially of 

 Palms, during at least a portion of this period, distinguishes it at 

 once from the more ancient. The observations made upon the 

 cretaceous epoch, however, have established a kind of transition 

 between the forms of the secondary epochs and those of the ter- 

 tiaries, which some years ago was not supposed to have existed. 

 But while in that epoch the Angiosperms appeared almost to 

 equal the Gymnosperms, they exceed them much in the tertiary 

 period ; while in the cretaceous epoch there still existed Cyca- 

 dacese and Coniferse allied to the genera inhabiting tropical re- 

 gions, the Cycadacese appear to be wholly wanting in Europe, 

 and the Coniferse belong to genera of temperate regions during 

 the tertiary period. 



In spite of this ensemble of characters common to the whole 

 tertiary period, there are evidently notable differences in the 

 generic and specific forms, and in the predominance of certain 

 families at different epochs of this long period. But we here fre- 

 quently experience grave difficulties in establishing the synchro- 

 nism of the numerous local formations which constitute the dif- 

 ferent tertiary rocks. In this attribution of the different loca- 

 lities, where fossil plants have been observed, to the principal 

 divisions of the tertiary series, I have not followed exactly the 

 bases received by M.Unger in his ' Synopsis' ; I have approached 

 very near to the distribution adopted by M. Raulin in his memoir 

 on the transformations of the flora of central Europe during the 

 tertiary period (Ann. des Sc. Nat. x. 193, Oct. 1848), which re- 

 fers to the pliocene or most recent epoch, several of the forma- 

 tions classed by M. Unger in the middle or miocene division. 

 Nevertheless, on the advice of M. Elie de Beaumont, I have not 

 placed all the beds of the lignite of Germany in the pliocene di- 

 vision, as M. Raulin did, nor all in the miocene, like M. Unger ; 

 but, in agreement with the old opinion of my father, I have left 

 the lignites of the shores of the Baltic, containing amber, in the 

 inferior divisions of the old basins of Paris, London and Brussels, 

 regarding them as contemporary with the Soissonnese lignites ; 

 the lignites of the banks of the Rhine, of Wetterau and West- 

 phalia, are arranged in the middle or miocene division ; those, on 

 the contrary, of Styria and of a portion of Bohemia, among the 

 recent or pliocene beds. 



This distribution agrees generally well enough with the nature 



