COAL. 297 



Admitting even the hypothetical supposition of the 

 absence of dry land in those remote conditions of the 

 globe which produced the more antient marine ani- 

 mals, the existence of marine vegetables would explain 

 the formation of carbonaceous matter ; as these are 

 known to be now forming deposits of peat. That 

 these vegetables actually occur, and even in the older 

 schists, is now well known. 



Primary coal thus offers an analogy to the lignites 

 of the upper secondary strata, rather than to the proper 

 coal series ; nor, if I have succeeded in showing that 

 vegetables might have existed in some antient states 

 of the globe, is there any difficulty in accounting for 

 its occurrence. Organic animal remains might have 

 been utterly destroyed by the revolutions which they 

 have undergone ; but the indestructible nature of 

 charcoal, when protected from air, explains, without 

 difficulty, how vegetable ones should have been pre- 

 served, so as to have produced the coal of the primary 

 rocks. 



But as long as the true nature of elementary carbon 

 "remains unknown, this question must also remain 

 obscure, or subject, at least, to dispute. If the 

 diamond be a mineral production from elementary 

 carbon, primary coal may have the same origin. The 

 existence of plumbago offers a parallel difficulty ; 

 occurring, as is well known, like coal, among the pri- 

 mary strata, in gneiss and in argillaceous schist. If 

 it be of mineral origin, 1 primary coal, or anthracite, 

 differing but slightly from it in its essential nature, 

 may have been derived from the same sources. Yet 

 the coal of secondary origin, containing vegetable 

 remains, is converted into plumbago by the influence 

 of trap; as wood has been in iny experiments, and as 

 coal is, daily, in the iron-furnaces ; so that even the 



