FOSSIL BOTANY. 



237 



muat have existed at this time in great quantity ; prohably, 

 too, in great variety. For animals depend on the vege- 

 table kingdom for their subsistence, each animal consuming 

 many times its own weight of vegetable food. That fossil, 

 animals are in every age found more abundantly than 

 fossil plants is not to be taken as proof that there were 

 fewer of the latter ; it must be borne in muid that the hard 

 parts of animals are much less destructable than any vege- 

 table tissue, and are, therefore, oftener preserved in the 

 fossil state. The plants which have up to the present 

 tjme been found and described are a number of cellular 

 (marine Algse) and a few vascular cryptogams. Many of 

 them were marine plants, apparently related to the genus 

 Fucus (division Oosporecs) ; a branching form of the 

 Lower Silurian has received the generic name of Butho- 

 trephis (Fig. 342). A 

 representative of the 

 division Carposporem, a 

 plant of the genus Go- 

 rallina, has been found 

 in this age. In the 

 Upper Silurian, besides 

 many marine species, 

 there were a number 

 of true Land-plants, 

 among which may be 

 mentioned the genus 

 Fsilophyton, which is a representative of the Club-Mosses 

 or Lycopods (class lAeopodiacece ; division Pteridophyta). 



202. A very marked advance is exhibited in the vege- 

 tation of the Devonian Age. The fucoidal plants 



Fig. 342. Sathotre^his siicculens (Silurian Age). 



342 



