324 LIGNITES. 



stems of dicotyledonous and monocotyledonous plants. 

 The hitherto imperfect arrangement of fossil vegeta- 

 bles, has referred them to terms, rather than genera, 

 under the names of Carpolithes, Phyllites, Lycopodio- 

 lithes, Palmacites, Endogenites, &c. ; nor need I quote 

 the more minute distinctions under which they have 

 been arranged. The large list of fossil animal remains 

 will be found in the often printed catalogues. 



The last division of the lignites is that which occurs 

 in alluvial soils, and which seems necessarily limited 

 to the more antient alluvia. The scattered specimens, 

 of various character, dispersed in the upper alluvial 

 portions of the tertiary strata, must be ranked in this 

 division ; but we are not well furnished \vith recorded 

 examples of this nature. I must follow the prevailing 

 opinions, in referring the well-known case of Bovey 

 to this division, though not satisfied that it is a real 

 instance of an alluvial lignite. For want therefore of 

 satisfactory observations, we can only conjecture gene- 

 rally what the characters of such a deposit ought to 

 be, and what are the accompanying substances. It is 

 to be suspected that many of the supposed alluvia, 

 containing amber and jet, described by authors, are 

 rather cases of the tertiary strata beneath : the sands 

 perhaps of the plastic clay, or other portions of these 

 deposits, having been mistaken for alluvial formations. 



There is another difficulty respecting the recorded 

 descriptions of the alluvial lignites, lying at the oppo- 

 site extreme. Among the numerous examples of fo- 

 rests submerged under alluvial soils, observers have 

 not often 'enquired whether the wood was a true lig- 

 nite, or was only that unbituminized substance which, 

 essentially, is but a mode of Peat: being unacquainted 

 with the chemical distinctions, which I first pointed 

 out in the Geological Transactions. But in the un- 



