LOWER MOLASSE OF SWITZERLAND. 
235 
vergne, and there are many other points of agreement which 
the discordance of nomenclature tends to conceal. A re¬ 
markable carnivorous genus, the Hyaenodon of Laizer, is 
represented by more than one species. The same genus has 
also been found in the Upper Eocene marls of Hordwell Cliff, 
Hampshire, just below the level of the Bembridge Limestone, 
and therefore a formation older than the Gypsum of Paris. 
Several species of opossum [Didelphis) are met with in the 
same strata of the Limagne. The total number of mamma¬ 
lia enumerated by M. Pomel as appertaining to the Lower 
Miocene fauna of the Limagne and Velay falls little short 
of a hundred, and with them are associated some large croc¬ 
odiles and tortoises, and some Ophidian and Batrachian rep¬ 
tiles. 
Lower Molasse of Switzerland. —The two upper divisions 
of the Swiss Molasse—the one fresh-water, the other marine 
—have already been described in the preceding chapter. I 
shall now proceed to treat of the third division, w^hich is of 
Lower Miocene age. Nearly the whole of this Lower Mo¬ 
lasse is fresh-water, yet some of the inferior beds contain a 
mixture of marine and fluviatile shells, the Cerithium mar- 
garitaceum^ a well-known Lower Miocene fossil, being one of 
the marine species. Notwithstanding, therefore, that some 
of these Lower Miocene strata consist of old shingle-beds 
several thousand feet in thickness, as in the Rigi, near Lu¬ 
cerne, and in the Speer, near Wesen, mountains 5000 and 
7000 feet above the sea, the deposition of the whole series 
must have begun at or below the sea-level. 
The conglomerates, as might be expected, are often very 
unequal in thickness, in closely adjoining districts, since in a 
littoral formation accumulations of pebbles would swell out 
in certain places where rivers entered the sea, and would thin 
out to comparatively small dimensions where no streams or 
only small ones came down to the coast. For ages, in spite 
of a gradual depression of the land and adjacent sea-bottom, 
the rivers continued to cover the sinking area with their 
deltas; until finally, the subsidence being in excess, the sea 
of the Middle Molasse gained upon the land, and marine 
beds were thrown down over the dense mass of fresh-water 
and brackish-water deposit, called the Lower Molasse, which 
had previously accumulated. 
Flora of the Lower Molasse.— In part of the Swiss Molasse, 
which belongs exclusively to the Lower Miocene period, the 
number of plants has been estimated at more than 500 species, 
somewhat exceeding those which were before enumerated as 
occurring in the two upper divisions. The Swiss Lower Mio- 
