the substance of it long-ways, that breaking it off a-cross, I found it to look very like an Honey-comb; but as for any of the second, or bigger kind of pores, I could not find that it had any; so that it seems, whatever were the cause of its production, it was not without those small kind of pores which we have onely hitherto found in Vegetable bodies:  and comparing them with the pores which I have found in the Charcoals that I by this means made of several other kinds of Wood, I find it resemble none so much as those of Fire, to which it is not much unlike in grain also, and several other proprieties.

And therefore, what ever is by some, who have written of it, and particularly by Francisco Stelluto, wrote a Treatise in Italian of that Subject, which was Printed at Rome, 1637, affirm’d that it is a certain kind of Clay or Earth, which in tract of time is turn’d into Wood; I rather suspect the quite contrary, that it was at first certain great Trees of Fir or Pine, which by some Earthquake, or other casualty, came to be buried under the Earth, and was there, after a long time’s residence (according to the several natures of the encompassing adjacent parts) either rotted and turn’d into a kind of Clay, or petrify’d and turn’d into a kind of Stone, or else had its pores fill’d with certain Mineral juices, which being stay’d in them, and in tract of time coagulated, appear’d, upon cleaving out, like small Metaline Wires, or else from some flames or scorching forms that are the occasion oftentimes, and usually accompany Earthquakes, might be blasted and turn’d into Coal, or else from certain subterraneous fires which are affirm’d by that Authour to abound much about those parts (namely, in a Province of Italy, call’d Umbria, now the Dutchie of Spoletto, in the Territory of Todi, anciently call’d Tudor; and between the two Villages of Collesecco and Rosaro not far distant from the high-way leading to Rome, where it is found in greater quantity then elsewhere) are by reason of their being encompassed with Earth, and so kept close from the dissolving Air, charr’d and converted into Coal.  It would be too long a work to describe the several kinds of pores which I met withall, and by this means discovered in several other Vegetable bodies; nor is it my present design to expatiate upon Instances of the same kind, but rather to give a Specimen of as many kinds as I have had opportunity as yet of observing, reserving the prosecution and enlarging on particulars till a more fit opportunity; and in prosecution of this design, I shall here add: 

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Observ.  XVII. Of Petrify’d wood_, and other Petrify’d bodies._

Of this sort of substance, I observ’d several pieces of very differing kinds, both for their outward shape, colour, grain, texture, hardness, &c. some being brown and redish; others gray, like a Hone; others black, and Flint-like:  some soft, like a Slate or Whetstone, others as hard as a Flint, and as brittle.  That which I more particular examin’d, was a piece about the bigness of a mans hand, which seem’d to have been a part of some large tree, that by rottenness had been broken off from it before it began to be petrify’d.