THE 



QUARTERLY JOURNAL. 



January, 1826. 



Art. I. — On the Lignites. By J. Mac Culloch, M.D., 

 F.R.S., Src. 8fc. 



[Communicated by the Author.] 



The substances included under this term, form the link which, in 

 some measure, unites coal and peat, so distant in geological time 

 and place ; partaking at one extreme of the mineral nature of the 

 former, as much as at the other they approximate to the vege- 

 table character of the latter. 



The gradation of geological relations among these three com- 

 bustible families is not indeed very perfect ; for while peat is 

 absolutely superficial in position, or covered with very slender 

 deposites of recent soil, the lignites are found under alluvia of a 

 high antiquity, or else are imbedded in the strata which succeed 

 to the coal series. Thus, from the lignites to the proper coal, 

 there is a regular gradation of geological relations ; just as by 

 means of the coal of the old red sandstone, we continue an ana- 

 logous gradation through the primary strata. The mineralogical, 

 or chemical transition is more perfect : and, in this respect, the 

 lignites hold a station more nicely intermediate between coal and 

 peat ; some of the varieties approaching as nearly to the submerged 

 wood of peat in their chemical characters, as they do in their ap- 

 pearance ; while, in both these respects, there are varieties at the 



Vol. XX. Q 



