m that which fill'd the cavities, and exactly of the same kind with that
which covered the outside, being for the most part whitish, or
_mother-of-pearl_ colour'd.

As for the cavities between those _Diaphragms_, I found some of them fill'd
with Marle, and others with several kinds of stones, others, for the most
part hollow, onely the whole cavity was usually covered over with a kind of
_tartareous petrify'd_ substance, which stuck about the sides, and was
there shot into very curious regular Figures, just as _Tartar_, or other
dissolv'd Salts are observ'd to stick and _crystallize_ about the sides of
the containing Vessels; or like those little _Diamants_ which I before
observed to have covered the vaulted cavity of a Flint; others had these
cavities all lin'd with a kind of _metalline_ or _marchasite-like_
substance, which with a _Microscope_ I could as plainly see most curiously
and regularly figured, as I had done those in a Flint.

From all which, and several other particulars which I observ'd, I cannot
but think, that all these, and most other kinds of stony bodies which are
found thus strangely figured, do owe their formation and figuration, not to
any kind of _Plastick virtue_ inherent in the earth, but to the Shells of
certain Shel-fishes, which, either by some Deluge, Inundation, Earthquake,
or some such other means, came to be thrown to that place, and there to be
fill'd with some kind of Mudd or Clay, or _petrifying_ Water, or some other
substance, which in tract of time has been settled together and hardned in
those shelly moulds into those shaped substances we now find them; that the
great and thin end of these Shells by that Earthquake, or what ever other
extraordinary cause it was that brought them thither, was broken off; and
that many others were otherwise broken, bruised and disfigured; that these
Shells which are thus _spirallied_ and separated with _Diaphragmes_, were
some kind of _Nautili_ or _Porcelane shells_; and that others were shells
of _Cockles_, _Muscles_, _Periwincles_, _Scolops_, &c. of various sorts;
that these Shells in many, from the particular nature of the containing or
enclos'd Earth, or some other cause, have in tract of time rotted and
mouldred away, and onely left their impressions, both on the containing and
contained substances; and so left them pretty loose one within another, so
that they may be easily separated by a knock or two of a Hammer. That
others of these Shells, acco