142 !>• H. Scott. 



in the liglit of modem knowledge. It is only when we come to the 

 Carboniferous that tlie evidence becomes abundant and satisfactory, 

 and it is from this formation that our conception of Palaeozoic floras 

 has been essentially derived. In the present article a sj^stematic 

 order will be followed, as most convenient for our purpose, while 

 the geological range of the plants discussed will be indicated under 

 each group. 



In considering the Plant-world at such a remote epoch we are 

 prepared to find that the limits and relative development of the 

 various classes were very different from those to which we are 

 accustomed in the recent flora. There is no evidence that the 

 Angiosperms, now the dominant class in the Vegetable Kingdom, 

 existed in Paleozoic times; on the contrary their first traces only 

 appear far on in the Mesozoic epoch. Palaeontological research has 

 as yet thrown little or no light on the question of the derivation of 

 the Angiosperms. Although their history may probably extend much 

 further back than is shown by our present records, there is no 

 reason to suppose that their evolution, as a distinct phylum, had 

 begun in Palaeozoic times. On the other hand Gymnosperms, and 

 more primitive seed-plants allied to Gymnosperms, were immensely 

 abundant, though belonging, with few exceptions, to families now 

 extinct. The Pteridophyta, while not so predominant as has commonly 

 been supposed, played an important part, and some of their families 

 attained a development far exceeding anything that their recent allies 

 can show. As regards the lower classes of plants, while we have 

 scarcely any knowledge of Palaeozoic Bryophyta, there is evidence 

 that Fungi were abundant, though their remains have not as yet 

 proved of any great botanical interest. The Algae are somewhat 

 better known, but here also well-characterized specimens are few. 

 Though the Palaeozoic Thallophyta are thus of subordinate interest, 

 in the present state of our knowledge, a few of the chief points 

 relating to them may be mentioned before going on to the more 

 important parts of our subject. 



As regards the Algae, the great majority of the published records 

 are worthless. The investigations ofNathorst, Williamson and 

 others have shown that a large proportion of the casts and impressions 

 formerly attributed to Algae were in reality of a totally different 

 nature, often representing the tracks or burrows of marine animals 

 or even mere markings on sand or mud, due to rills of water or 

 other purely mechanical agencies. 



It is only where there is evidence of structure that remains of 

 supposed fossil Algae are worth consideration. A few cases of this 

 kind are of interest from the great antiquity of the organisms in 



