FLORA OF THE CAINOZOIC PERIOD. 87 



FOSSIL FLORA OF THE TERTIARY OR 



CAINOZOIC PERIOD, 



(including the cretaceous epoch). 



Reign of Angiosperms. 



This reign is characterised bj the appearance of Angio- 

 spermous Dicotyledons, plants which constitute more than 

 three-fourths of the species of the existing flowering plants 

 of the globe, and which appear to have acquired the pre- 

 dominance from the commencement of the Tertiary epoch. 

 They are plants with seeds contained in seed-vessels, and 

 each seed with two cotyledons. These plants, however, 

 appear even at the beginning of the Cretaceous period. 

 In this reign, therefore, Brongniart includes the upper 

 Secondaiy period, or the Cretaceous system, and all the 

 Tertiary period. The Cretaceous may be considered as a 

 sort of transition period between the reign of Gymnosperms 

 and Angiosperms. The Chalk flora is characterised by the 

 Gymnospermous almost equalling the xVngiospermous Dicoty- 

 ledons, and by the existence of a considerable number of 

 Cycadacea3, which do not appear in the Tertiary period. The 

 genus Credneria is one of the characteristic fomis. In this 

 period we find Alg^ represented by Cystoseirites, Confervites, 

 Sargassites, and Chondrites; Ferns by peculiar species of 

 Pecopteris and Protopteris ; Naiadaceas by Zosterites ; Palms, 

 by Flabellaria and Palmacites; Cycadace^e by Cycadites, 

 Zamites, Microzamia, Fittonia, and Bennettites ; Coniferas, 

 by Brachyphyllum, Widdringtonites, Cryptomeria, Abietites, 

 Pinites, Cunninghamites, Dammarites, Araucarites ; and An- 

 giospennous Dicotyledons, by Comptonites, Alnites, Carpi- 

 nites, Salicites, Acerites, Juglandites, and Credneria. At the 

 base of the Tertiary period there are deposits of Algce of a 

 very peculiar form, belonging to the genera Chondrites and 

 Munsteria. No land plants have been found mingled with 

 these marine species. 



