THE SEVEN AGES OF PLANT LIFE 39 



the main groups now known were represented. The 

 flora of the Devonian was very similar in essentials. 



If that be so, it may seem unsatisfactory to place 

 all the preceding aeons under one heading, the OLDER 

 PALEOZOIC. And, indeed, it is very unsatisfactory to 

 be forced to do so. We know from the study of 

 animal fossils that this time was vast, and that there 

 were several well-defined periods in it during which 

 many groups of animals evolved, and became extinct 

 after reaching their highest development; but of the 

 plants we know so little that we cannot make any 

 divisions of time which would be of real value in help- 

 ing us to understand them. 



Fossil plants from the Early Palaeozoic there are, 

 but extremely few as compared with the succeeding 

 period, and those few but little illuminative. In the 

 later divisions of the Pre- Carboniferous some of the 

 plants seem to belong to the same genera as those of 

 the Carboniferous period. There is a fern which is 

 characteristic of one of the earlier divisions, and there 

 are several rather indefinite impressions which may be 

 considered as seaweeds. There is evidence also that 

 even one of the higher groups bearing seeds (the Cor- 

 daitece) was in full swing long before the Carboniferous 

 period began. Hence, though of Older Palaeozoic plants 

 we know little of actual fact, we can surmise the salient 

 truths; viz., that in that period those plants must have 

 been evolving which were important in the Devonian 

 and Carboniferous periods; that in the earlier part of 

 that period they did not exist, and the simpler types 

 only clothed the earth; and that further back still, even 

 the simpler types had not yet evolved. 



Names have been given to many fragmentary bits 

 of fossils, but for practical purposes we might as well 

 be without them. For the present the actual plants of 

 the Older Palaeozoic must remain in a misty obscurity, 

 their forms we can imagine, but not know. 



On the other hand, of the more recent periods, those 



