th is composed, we still find evident proofs, that those
beds had their origin from materials deposited at the bottom of the sea;
and that they have the calcareous substance which they contain, from the
same source as the marbles or the limestones.

2_dly_, In those calcareous strata, which are evidently of marine
origin, there are many parts that are of a sparry structure, that is
to say, the original texture of those beds, in such places, has been
dissolved, and a new structure has been assumed, which is peculiar to
a certain state of the calcareous earth. This change is produced by
crystallisation, in consequence of a previous state of fluidity, which
has so disposed the concreting parts, as to allow them to assume a
regular shape and structure proper to that substance. A body, whose
external form has been modified by this process, is called a _crystal_;
one whose internal arrangement of parts is determined by it, is said to
be of a _sparry structure_; and this is known from its fracture.

3_dly_, There are, in all the regions of the earth, huge masses of
calcareous matter, in that crystalline form of sparry state, in
which perhaps no vestige can be found of any organised body, nor any
indication that such calcareous matter had belonged to animals; but
as, in other masses, this sparry structure, or crystalline state, is
evidently assumed by the marine calcareous substances, in operations
which are natural to the globe, and which are necessary to the
consolidation of the strata, it does not appear, that the sparry masses,
in which no figured body is formed, have been originally different from
other masses, which, being only crystallised in part, and in part still
retaining their original form, leave ample evidence of their marine
origin[3].

[Note 3: M. de Saussure, describing the marble of Aigle, says, "Les
tables polies de ce marbre presentent frequemment des coquillages, dont
la plupart sont des peignes stries, et de tres-beaux madrepores. Tous
ces corps marins on pris entierement la nature et le grain meme
du marbre, on n'y voit presque jamais la coquille sous sa forme
originaire."]

We are led, in this manner, to conclude, that all the strata of the
earth, not only those consisting of such calcareous masses, but others
superincumbent upon these, have had their origin at the bottom of the
sea, by the collection of sand and gravel, of shells, of coralline
and crustaceous bodies, and of earths and clays, various