The author commences by adverting to a very generally recognised geological difficulty—viz., that of accounting for the disappearance of the mineral from the carbonaceous matter in the processes which have resulted in the formation of coal-beds as we now find them. Coal-beds have undoubtedly their origin from decaying vegetable matter; and the deposition is unquestionably traceable to at least three different sources—viz., the carrying down by rivers of drift wood, and its deposition in deltas and estuaries at their mouths; the accumulations of dead forest trees, &c., falling for successive generations where they had grown; and the growth of peat. But in all of the three methods it is clear that the vegetable matter must have been mixed up to a very large extent with earthy matter, which earthy matter has since disappeared, so as to leave carbonaceous deposits in a comparative state of purity. The explanation of this disappearance has hitherto completely baffled geological ingenuity, and the author, in offering the present solution of the enigma, ventures to hope that he has successfully grappled with the difficulty.