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LETTER XX.

EXAMINATION OF OPINIONS, INSPECTING THE ORIGIN OF PEAT....ABORIGINAL FORMATION....A MARINE DEPOS IT.. ..MINER A LORIGIN....FLOATING ISLANDS....A RECENT VEGETABLE SUB-STANCE.

Although I encourage the hope, that the circumstances adducedare such as will be likely to be successful, in establishing the opi-nions I have offered, respecting the origin and nature of this sub-stance ; yet something more remains to be done. The opinionsalready advanced, on this subject, have a claim upon our attention;and although the greater part of them may not require a formalrefutation, others will require to be examined, that it may be de-termined whether they offer a satisfactory explanation of the pro-perties which are possessed by this substance. It is likewise incum-bent to determine whether those particular circumstances, whichhave been supposed most powerfully to support the hypotheseswhich have been already advanced, militate against, or favour,that which is here attempted to be established.

The first opinion I shall notice is that which supposes peat tohave existed, in its present form and state, from the creation of theworld. In opposition to this opinion it must be sufficient to ob-serve, that peat is composed of substances which bear the indu-bitable marks of having existed in another state; also that thereis an abundance of instances of its formation going on, even atthe present day.

The hypothesis, which supposes it to have been formed by a bitu-minous deposit from the waters of the sea, must be rejected, fromits being impossible thus to account for the prodigious quantity