IN THE STRATA OF THE CARBONIFEROUS SERIES. 49 



which the fossils contain much siliceous matter, the probability would be, 

 that the deposit in question must be part of the mountain-limestone group, 

 subjacent to the coal formation properly so called, and that, therefore, any 

 search for extensive beds of combustible matter would prove unsuccessful. 



Having now completed my investigation of the fossil vegetables retaining 

 organic tissue, that have been found in the shale and sandstone beds of the 

 carboniferous series, I may remark generally, that exogenous trees, or those of 

 the Dicotyledonous Class, so far from being excluded from that series, exist 

 in an abundance which farther examination will probably shew to be still 

 greater than we are at present aware of. These fossil trees all present a 

 texture very intimately allied to that of our present Conifera? ; but, as has 

 been shewn, differing in certain respects, namely, in most instances the 

 want of concentric circles, and in all cases in having reticulations or areola?, 

 in two or three series, on two opposite walls of the elongated cellules. In 

 one or two instances, the areola? approach very closely to those of our pines. 

 It is, however, certain, that hitherto no structure precisely resembling that 

 of the Coniferae in every respect, has been found in the mountain limestone 

 series or in the coal formation ; but the alleged absence of phanerogamic 

 trunks in these deposits has been fully, and, I trust, most satisfactorily, 

 refuted. 



REMAINS OF ORGANIC TEXTURE DISCOVERED IN COAL. 



The vegetable origin of coal has, in the more perfectly fossilized varie- 

 ties, been rather inferred than demonstrated. Peat, we know, from actual 

 observation, to consist of decayed vegetables. The process is going on un- 

 der our eyes ; we can watch its progress, distinguish its degrees, and observe 

 its results. The lignites of the upper deposits are so analogous to peat, and 

 so decidedly present traces of woody tissue, that we can have no reasonable 

 doubts respecting their origin. Thus Bovey Coal, of which a fragment is 

 represented in Plate XI. Fig. 1, is evidently dicotyledonous wood partially 

 altered. In the coal beds of the lower formations, however, we cease to re- 



G 



