438 PAL-EOBOTAXY. 



deposits, and there is a marked change in the vegetation of 

 this period as compared "with that of the Carboniferous and 

 Permian epochs. The Zepidodendroids and Sigillarioids have 

 now completely disappeared. The Calamites of the Coal- 

 measures are represented by true Horse-tails {Equisetites). 

 Ferns and Conifers are still abundant, and some of the lat- 

 ter ( Voltzid) are by no means unlike existing forms. Lastly, 

 there is an abundance of remains of Cycadaceous plants 

 {Pterophyllum, Fodoza mites, &c.) 



The Jurassic and Lower Cretaceous deposits are similarly 

 characterised by an abundance of Cycads, Ferns, and Conifers, 

 the first of these in particular constituting a marked feature 

 in the vegetation. 



In the Upper Cretaceous period-^ we have the first ap- 

 pearance, either absolutely, or certainly in any quantity, of 

 ordinary Angiospermous Exogens, similar to those which 

 predominate at the present day in the flora of temperate 

 regions. Besides Ferns and Cycads more or less allied to 

 Jurassic forms, we have now numerous Dicotyledonous trees, 

 such as the Oak, Beech, Fig, Poplar, "Walnut, Willow, Alder, 

 &e., belonging to familiar genera now in existence. Here, 

 also, we have the first appearance, so far as is certainly 

 known, of the group of the Palms. 



Of the vegetation of the Tertiary period, it is sufficient to 

 remark here that now there is a marked predominance of 

 Angiospermous Exogens and of Endogens as compared with 

 Cryptogams and Gymnospermous Exogens. Xot only is tliis 

 the case, but many of the Tertiary plants approximate closely 

 to existing forms, this approximation becoming more and 

 more marked as we recede from the Eocene and approach 

 the Eecent period. 



Before closing this brief review of the succession of plants 

 upon the globe, it may be well to notice shortly a general- 

 isation which was long since made by M. Adolphe Brongniart. 



^ It is impossible here to enter into the question as to whether the so-called 

 " Lignitie Series" of Xorth America, which rests upon undoubted Cretaceous 

 strata, and is overlaid by unquestionable Lower Tertiary beds, and which has 

 pelded such a number of Angiosperms of Tertiary type, is itself really refer- 

 able to the Cretaceous or to the Eocene formation. It will here, on the 

 strength of its animal remains, be regarded as of Cretaceous age. 



