at present is not, in what manner those collections of calcareous relics
have become a perfect solid body, and have been changed from an animal
to a mineral substance; for this is a subject that will be afterwards
considered; we are now only inquiring, if such is truly the origin of
those mineral masses.

That all the masses of marble or limestone are composed of the
calcareous matter of marine bodies, may be concluded from the following
facts:

1_st_, There are few beds of marble or limestone, in which may not be
found some of those objects which indicate the marine origin of the
mass. If, for example, in a mass of marble, taken from a quarry upon the
top of the Alps or Andes[2], there shall be found one cockle-shell, or
piece of coral, it must be concluded, that this bed of stone had been
originally formed at the bottom of the sea, as much as another bed which
is evidently composed almost altogether of cockle-shells and coral. If
one bed of limestone is thus found to have been of a marine origin,
every concomitant bed of the same kind must be also concluded to have
been formed in the same Manner.

[Note 2: "Cette sommité élevée de 984 toises au dessus de notre lac, et
par conséquent de 1172 au dessus de la mer, est remarquable en ce que
l'on y voit des fragmens d'huîtres pétrifiés.--Cette montagne est
dominée par un rocher escarpé, qui s'il n'est pas inaccessible, est du
moins d'un bien difficile accès; il paroît presqu'entièrement composé
de coquillages pétrifiés, renfermés dans un roc calcaire, ou marbre
grossier noirâtre. Les fragmens qui s'en détachent, et que l'on
rencontre en montant à la Croix de fer, sont remplis de _turbinites_ de
différentes espèces." M. DE SAUSSURE, _Voyage dans les Alpes_, p. 394.]