112 



THE GEOLOGICAL HISTORY OF PLANTS. 



place to vast swampy flats, and which, instead of the oil- 

 bearing shales of the Erian, were destined to produce 

 those immense and wide-spread accumulations of vege- 

 table matter which constitute our present beds of bitu- 

 minous and anthracite coal. The 

 atmosphere of these great swamps 

 is moist and warm. Their vege- 

 tation is most exuberant, but of 

 forms unfamiliar to modern eyes, 

 and they swarm with insects, 

 millepedes, and scorpions, and 

 with batrachian reptiles large 

 and small, among which we look 

 in vain for representatives of the 

 birds and beasts of the present 

 day. 



Prominent among the more 

 gigantic trees of these swampy 

 forests are those known to us as 

 SigillaricB (Fig. 33). They have 

 tall, pillar-like trunks, often sev- 

 eral feet in diameter, ribbed like 

 fluted columns, but in the re- 

 verse way, and spreading at the 

 top into a few thick branches, 

 which are clothed with long, 

 grass-like leaves. They resem- 

 ble in some respects the Lepi- 

 dodendra of the Erian age, but 

 are more massive, with ribbed in- 

 stead of scaly trunks, and longer 

 leaves. If we approach one of 



them more closely, we are struck with the regular ribs of 

 its trunk, dotted with rows of scars of fallen leaves, from 

 which it receives its name Sigillaria, or seal-tree (Figs. 

 34-37). If we cut into its stem, we find that, instead of 



FIG. BS.SwiUarice, restored. 



A, Sigillaria JSrownii. 



B, Sigillaria elegans. 



