The Quarterly journal of the Geological Society of London (12961147895)

242 1.R0CEEDINGS OF THE GEOLOGICAL SOCIETY. .Maicll 24,
2iid. Santonian stage: the lower part with Ostrea acutirostris,
0. santonensis, Spondylus truncatus, Janira quadricostata, SjphceruUtes
Coquandi, and Radiolites fissicostata.
The upper part, of fluviatile origin, with Unio, CyclaSy Omphalia
Coquandi (Zekeli), and 7 beds of lignite, Cyrena glohosa and Ferussaci,
Math., Melanopsis rugosa, Math., and M. gdllo-provincialis.
Plan d'Aups, near Sainte Baume, and the environs of Mar-
tigues.
This corresponds to the upper portion of the chalk of Gosau.
3rd. Campanian and Dordonian stages, from 400 to 500 metres,
equal to from 1333 to 1666 feet, of Lacustrine limestones, with Cyclas
gardanensis, Brongniartina, and gallo-provincialis, Math.., Ampullaria
prohoscidea, Math., Paludina angulata, Math., Lymnea longissima,
Math., &c., and containing 18 layers of lignites, very different from
those which are worked lower down, in the Santonian stage (fig. 3). It
is evident that these Lacustrine limestones correspond with the "Upper
Chalk " and with my Dordonian stage ; for they are covered by other
Lacustrine limestones, which
, are referred to the level of the ^ig- '^.—Section of the Freshwater
limestone of Rilly, and there- Upper Cretaceous Beds of Fuveau.
fore to the base of the Eocene.
Thus in Lower Provence it is
evident that a complete change
must have been wrought in the
nature of the waters of the
Cretaceous Sea, which, after
the conclusion of the Santonian
period, from being salt became
brackish, and afterwards, from
brackish, fresh — a circumstance
which favoured the develop-
ment of a population of flu-
viatile shells, entirely unknown elsewhere, and which were con-
temporary with the gigantic Eudistes of the Charente, and those
of Provence, which lived in the immediate vicinity of the lake,
at the bottom of which the Carbonaceous deposits were pre-
cipitated.
The classification of these Lacustrine sediments had been, until
very lately, the cause of great confusion and serious errors. They
had been attributed at one time to the Miocene period, at another
to the Eocene, without a single reliable argument, or a single fossil
in support of this opinion. The new method of determining their
chronological order is justified, not only by their position, but also
by the very important fact that in the neighbouring Alps, as well as
in Algeria, where the upper chalk is exclusively of marine origin, we
observe, above the Santonian strata, Ostrea vesicularis and Belem-
nitella mucronata^ species wanting in the corresponding strata of the
Bouches du Rhone, which, as we have seen, having been deposited
in a lake, can only contain Lacustrine shells. My friend M. Mathe-

ron is occupied at the present time in making out a catalogue of this