212 
FOREIGN EQUIVALENTS. 
were no longer found except in latitudes lower by 10 degrees 
than those which they had attained during the Miocene period. 
At last the period closed with a flora which, though still suffi¬ 
ciently rich to funish abundant food for gigantic herbivora, no 
longer contained, at each point, species which it is easy to-day 
to rediscover by approaching some degrees nearer towards the 
equator. 
In this outline of the climatic changes in the Mediterranean 
region Prof, de Lapparent traces a gradual refrigeration of the 
climate corresponding to that which we have seen is so marked 
in England. It appears, therefore, that a classification of the 
Tertiary strata founded on important climatic changes, ought to 
be of more than local value. It ought also to yield a better 
standard for the correlation of isolated deposits than can possibly 
be found in the variable and uncertain per-centage of recent 
mollusca discovered at each locality. 
The Pliocene system in the south of France is commonly thus 
divided* :— 
Upper [Arnusian) ■ 
Middle {Astian) 
Lower {Plaisancian) 
Mio-Pliocene P {Mes- 
sinian). 
The lowest of these divisions scarcely comes within the limits 
of this Memoir, for the horizon is unrepresented in Britain, 
though found in Belgium, where deposits apparently of about 
this age are generally referred to the Miocene period. In the 
basin of the Rhone, the Messinian strata rest unconformably on 
the older deposits, including the Miocene. They certainly in 
that district are more naturally grouped with the Pliocene 
series than with the older deposits, which according to M. Fon- 
tannes’ sections have been greatly disturbed and eroded in the 
interval. The Messinian strata yield a brackish-water fauna, 
characterised by several species of CongeHa and Melania^ and 
the thickness of this division is small. 
Above the brackish-water Messinian deposits come those known 
as Plaisancian—equivalent approximately to our Coralline Crag. 
These are separated by IVl. Fontannes into two groups ; a lower 
series of marine strata with Nassa semistriata; and an upper 
* See Fontannes, Etudes Stratigraphiques et Paleontologiques pour servir a 
I’Histoire de la Periode Tertiaire dans le Bassin du Rhone. 8vo. Paris, 187.5-1889 ; 
and Deperet, Description Geol. du Bassin Tertiaire du Roussillon. Ann. Sc. 
GeoL, vol. xvii. 1885. The beds with Potamides Basteroti in the above table are 
sometimes classed with the Astian. 
=Forest-bed. 
=Norwich Crag and 
Upper Red Crag. 
{ Horizon ot oaint-Prest with \ 
Elephas meridionalis - J 
Horizon of Perrier with Mas¬ 
todon arvernensis - 
[ Freshwater beds with 
nopithecus and Mastodon I- =Lower Red Crag ? 
arvernensis - - J 
rEstuarine beds with Pota-l 
J mides Basteroti - - ^ ^ 
Marine beds with iVassa Crag. 
L semistriata - - J 
r Brackish-water deposits with 'X Missing in 
\ Conqeria - - -J 
land. 
Eng- 
