400 



VEGETATION OF THE CARBONIFEROUS PERIOD 



flourished, we must conclude that the predominance of ferns in general, 

 and of certain species of Pecopteris (a fern apparently allied to our 

 Pteris) over a great area, together with the remarkable similarity of the 

 English fossils with those of North America, are all indications that 

 the Flora of that period was poor in number of species. 



Let it not be supposed that this prevalence of an order, which 

 in point of complexity of structure is low in the system of plants, 

 is a fact favourable to the hypothesis that the vegetation of which 

 it appears to form a large part, was less highly developed than 

 what succeeded it. We know too little of the structure of the ferns 

 of that day, to pronounce them either more or less complete than their 

 allies of the present time; while of the Lycopodiacece* it may be safely 

 asserted, that they were of a form and stature far more noble, and in 

 structure more complicated than any plants of that order now existing. 



ON THE MOST PKEVALENT GENERA OF PLANTS BELONGING TO THE 

 COAL FOEMATION, AND THE CHARACTERS EMPLOYED IN THEIR 

 CLASSIFICATION, AND THAT OF THE SPECIES THEY CONTAIN. 



§ Ferns, General Remarks. 



Numerous as are the dissimilar groups of plants (whether genera 

 or orders) scattered through the various strata of the coal formation, 



Fig. l. 



Pecopteris heterophyUa (Coal-fields, Newcastle). 



* See " Essay on the Structure and Affinities of Lepidostr obus,'' in the present volume 

 of Survey Reports. 



