th
which, the perfect impression either of the inside or outside of such
Shells seem'd to be left, but for the most part, those impressions seem'd
to be made by an imperfect or broken Shell, the great end or mouth of the
Shell being always wanting, and often times the little end, and sometimes
half, and in some there were impressions, just as if there had been holes
broken in the figurating, imprinting or moulding Shell; some of them seem'd
to be made by such a Shell very much brused or flaw'd, insomuch that one
would verily have thought that very figur'd stone had been broken or brused
whilst a gelly, as 'twere, and so hardned, but within in the grain of the
stone, there appear'd not the least sign of any such bruse or breaking, but
onely on the very uttermost superficies.

Fourthly, they were very different, as to their outward covering, some
having the perfect Shell, both in figure, colour, and substance, sticking
on upon its surface, and adhering to it, but might very easily be separated
from it, and like other common _Cockle_ or _Scolop-shels_, which some of
them most accurately resembled, were very dissoluble in common _Vinegar_,
others of them, especially those _Serpentine_, or _Helical stones_ were
cover'd or retained the shining or Pearl-colour'd substance of the inside
of a Shel, which substance, on some parts of them, was exceeding thin, and
might very easily be rubbed off; on other parts it was pretty thick, and
retained a white coat, or flaky substance on the top, just like the
outsides of such Shells; some of them had very large pieces of the Shell
very plainly sticking on to them, which were easily to be broken or flaked
off by degrees: they likewise, some of them retain'd all along the surface
of them very pretty kind of _sutures_, such as are observ'd in the skulls
of several kinds of living creatures, which _sutures_ were most curiously
shap'd in the manner of leaves, and every one of them in the same Shell,
exactly one like another, which I was able to discover plainly enough with
my naked eye, but more perfectly and distinctly with my _Microscope_; all
these sutures, by breaking some of these stones, I found to be the
_termini_, or boundings of certain _diaphragms_, or partitions, which
seem'd to divide the cavity of the Shell into a multitude of very
proportionate and regular _cells_ or _caverns_, these _Diaphragms_, in many
of them, I found very perfect and compleat, of a very distinct substance
fro