314 CHAP. XL1II. Lignites. In conformity to an accepted arrangement, which I do not approve, yet do not at present choose to depart from, the present chapter includes every combustible deposit following the magnesian limestone. It com prises many which are undistinguishable from the former coal, both in general disposition and in mineral character, together with the several substances which are lignites in the mineral sense of that term : the latter forming an important object in the theory of coal, as being the link by which it is connected with peat. The gradation of geological relations from the “in dependent” coal to the most superficial woody lignite in the upper alluvia, and thence to peat, is sufficiently perfect ; while from that through the old red sandstone, we can pursue this gradation into the primary strata. But the mineralogical or chemical gradation is even more complete: and, in this respect, the woody lig nites hold a station more nicely intermediate between coal and peat; some of them approaching as nearly to the submerged wood of peat in chemical characters as in their appearance ; while, in both these respects, there arc varieties at the other extremity of the series, scarcely differing from coal, and finally identical with it. I must however remark, that while almost every ligneous sub stance found beneath alluvial soil, and bearing marks of bituminization, is here ranked as a lignite, I have found it more expedient to class with peat the sub merged wood of the most recent alluvia, even though it should be slightly bituminized; on account of its different connexions with that substance. While the superior antiquity of the woody lignite to