12 REMARKS ON THE VEGETABLE REMAINS, &C. 



centric layers. The pine forests also at present in existence in many parts 

 of both continents, and on a small scale in this country itself, are accom- 

 panied by numerous species of ferns, as well as occasionally Equisetaceae 

 and Lycopodiacese. The latter vegetables in ancient times had been as- 

 sisted by the heat and moisture which must have invigorated the plants of 

 the islands, from which the early coal-fields were probably formed, when 

 our globe was almost entirely covered by the ocean ; and with the gigantic 

 development which they thus acquired, they would have greatly contri- 

 buted to form those combustible beds, composed of plants belonging to the 

 vascular cryptogamic and phanerogamic classes, having simultaneously pe- 

 rished by some convulsion of nature. 



Whilst, therefore, the strength of the argument in favour of the com- 

 bustible beds of the coal-fields being composed of vascular cryptogamic 

 plants, rests upon the occurrence of the impressions of the latter in great 

 quantity and variety, it appears to me, for the reasons above assigned, that 

 it would not be forcing the argument too far, to claim a large share of the 

 production and consequent composition of these coal-beds, in favour of the 

 gymnospermous phanerogamic class, and of a tribe of vegetables differing 

 little from them in their external appearance, and in their internal texture 

 merely presenting a different disposition of the pores on the walls of the 

 elongated cells constituting the woody fibre, together with frequently the 

 absence of lines marking the union of the woody layers. 



