Ch. XVIII.] 
PARIS BASIN — GYPSUM. 
253 
of them belonging to a division of the order Pachydermata, 
which is now only represented by four living species, namely 
by three tapirs and the daman of the Cape. A few carni- 
vorous animals are associated;, among which are a species of 
fox and gennet. Of the Rodentia, a dormouse and a squirrel ; 
of the Insectivora, a bat ; and of the Marsupialia, (an order 
now confined to America, Australia, and some contiguous 
islands,) an opossum, have been discovered. 
Of birds about ten species have been ascertained, the ske- 
letons of some of which are entire. None of them are referable 
to existing species *. The same remark applies to the fish, 
according to MM. Cuvier and Agassiz, as also to the reptiles. 
Among the last are crocodiles and tortoises of the genera 
Emys and Trionix. 
The tribe of land quadrupeds most abundant in this forma- 
tion is such as now inhabits alluvial plains and marshes and 
the banks of rivers and lakes, a class most exposed to suffer by 
river inundations. Whether the disproportion of carnivorous 
animals can be ascribed to this cause, or whether they were 
comparatively small in number and dimensions, as in the indi- 
genous fauna of Australia, when first known to Europeans, is 
a point on which it would be rash perhaps to offer an opinion 
in the present state of our knowledge. 
We have no reason to be surprised that all the species of ver- 
tebrated animals hitherto observed are extinct, when we recollect 
that out of 1122 species of fossil testacea obtained from the Paris 
basin, 38 only can be identified with species now living. We 
have more than once adverted to the fact that extinct mam- 
malia are often found associated with assemblages of recent 
shells, a fact from which we have inferred the inferior duration 
of species in mammalia as compared to the testacea ; and it is 
not improbable that the higher order of animals in general may 
more readily become extinct than the marine molluscs. Some 
of the thirty-eight species of testacea above alluded to, as having 
survived from the Eocene period to our own times, have now a 
* Cuvier, Oss. Foss. torn. Hi. p. 255. 
