LIGNITES. 317 



have thus named it among the following more conspi- 

 cuous examples of this substance. 



The lowest in order is that which belongs to the 

 lias and oolithe series, which, for the present purpose, 

 may rank as one. Though some geologists have been 

 unwilling to admit of more than one such deposit be- 

 neath the chalk, there can be no question that there is 

 a second, which may be referred to the green sand. 

 The third is situated above the chalk, in the plastic 

 clay, and the last is that which occurs in the antient 

 alluvia. I might indeed refine on this division, by se- 

 parately enumerating those which have been described 

 in the red marl, in the muschelkalk, and in other posi- 

 tions, through the whole series above the miignesian 

 limestone, as we might also mid other deposits in the 

 strata above the plastic clay. But such refinement ap- 

 pears unnecessary, except for local purposes ; and it 

 will be sufficient to have thus indicated such less im- 

 portant and marked examples. To these must be 

 added those which, though not forming extended de- 

 posits, are important from their characters and posi- 

 tions, while not falling into any of the preceding divi- 

 sions. Occurring among the trap rocks, they have 

 been called basaltic coal ; but as this term, equally ap- 

 plied to the ordinary coal series where interrupted by 

 trap, has produced confusion, the name of basaltic lig- 

 nite is preferable. Volcanic lignites, such as that of 

 Iceland, need not be distinguished from this kind. 



From the confusion which has been made between 

 the coal beds here classed with lignite, and those of 

 the proper coal series, it is not possible, or not safe, 

 to quote examples in illustration of some of them ; 

 nor is it even in my power to produce adequate de- 

 scriptions. A more perfect set of observations is yet 

 wanting, and, till then, this sketch must be doubtful or 



