288 



HISTORICAL GEOLOGY. 



We shall therefore dismiss them for the present with one 

 or two remarks. 



1. In Nova Scotia, in direct connection with the plant- 

 beds, have also been found many fossil forest-grounds. 

 These are marked by dark seams with stumps and roots 

 in place just as the trees grew. In some cases, also, thin 

 seams of coal lie upon the forest-grounds. Thus, there- 

 fore, we have here in the Devonian an anticipation not 

 only of coal vegetation, but also of the conditions neces- 

 sary for the formation and preservation of coal. 



2. We have here a somewhat sudden appearance of 

 land-plants, as if they came without progenitors. But 

 we must remember that we have a feeble beginning of 

 land-plants in the Silurian. It seems probable that in 

 the Devonian we had more favorable conditions, and 

 therefore a rapid development of new forms. 



Animals. 



If we bear in mind what we said about Silurian ani- 

 mals, it will be necessary here only to note the great 

 changes, i. e., what old forms pass out, what new forms 

 come in, and what advances are made in the progress of 

 life, dwelling only on the great characteristic of the age, 

 viz., the fishes. 



FIG. 200. FIG. 201. 



FIGS. 200, 201. Devonian corals : 200. Favosites hemispherica. 201. Zaphrentis 

 Wortheni. (After Meek.) 



