t things we may perceive a certain gradation, which
here takes place among the works of nature, and forms three steps
distinguishable by a naturalist, although in reality nothing but the
variable measure of similar operations.

We are now to assimilate the primary and tertiary masses, which are so
extremely different, by means of the secondary masses, which is the
mean. The primary and tertiary differ in the following respects: The one
of these contains the relicts of organised bodies which are not observed
in the other. But in the species containing these distinguishable
bodies, the natural structure and position of the mass is little
affected, or not so much as to be called into doubt. This, however, is
not the case with the other; the species in which organised bodies do
not appear, is in general so indurated or consolidated in its structure,
and changed in its position, that this common origin of those masses is
by good naturalists, who have also carefully examined them, actually
denied. Now, the secondary masses may be considered, not only as
intermediate with respect to its actual place, as M. Pallas has
represented it, but as uniting together the primary and tertiary, or as
participating of the distinguishing characters of the other two. It
is homologated with the primitive mountains, in the solidity of its
substance and in the position of its strata; with the tertiary species,
again, in its containing marks of organised bodies. How far this view
of things is consistent with the theory of the earth now given, is
submitted to the consideration of the unprejudiced.

Let us see what our learned author has said farther on this subject,
(page 65).

"Je dois parler d'un ordre de montagnes tres-certainement posterieur aux
couches marines, puisque celles-ci, generalement lui servent de base.
On n'a point jusqu'ici observe une suite de ces _montagnes tertiaires_,
effet des catastrophes les plus modernes de notre globe, si marquee
et si puissante, que celle qui accompagne la chaine Ouralique ou cote
occidentale fur tout la longueur. Cette suite de montagnes, pour la
plupart composees de grais, de marnes rougeatres, entremelees de couches
diversement mixtes, forme une chaine par-tout separee par une vallee
plus ou moins large de la bande de roche calcaire, dont nous avons
parle. Sillonnee et entrecoupee de frequens vallons, elles s'eleve
souvent a plus de cent toises perpendiculaires, se repand vers les
plaines de la Rus