156 
OLDER PLIOCENE PERIOD. 
[Ch. XII. 
he added, some species of fossil shells which are found in these 
deposits throughout the whole of Italy. 
In a catalogue, published by Lamarck, of 500 species of 
fossil-shells of the Paris basin, a small number only were enu- 
merated as identical with those of Italy, and only 20 as agreeing 
with living species. This result, said Brocchi, is wonderful, 
and very different from that derived from a comparison of the 
fossil-shells of Italy, more than half of ivhich agree with spe- 
cies now living in the Mediterranean, or in other seas, chiefly of 
hotter climates *. 
He also stated, that it appeared from the observations of 
Parkinson, that the clay of London, like that of the Subapen- 
nine hills, was covered by sand (alluding to the Crag), and that 
in that upper formation of sand in England the species of shells 
corresponded much more closely with those now living in the 
ocean than did the species of the subjacent clay. Hence he 
inferred that an interval of time had separated the origin of the 
two groups. But in Italy, he goes on to say, the shells found 
in the marl and superincumbent sand belong entirely to the 
same group, and must have been deposited under the same 
circumstances f. 
Notwithstanding the correctness of these views, Brocchi con- 
ceived that the Italian tertiary strata, as a whole, might agree 
with those of the basins of Paris and London, and he endea- 
voured to explain the discordance of their fossil contents by 
remarking, that the testacea of the Mediterranean differ now 
from those living in the ocean |. In attempting thus to 
assimilate the age of these distinct groups, he was evidently 
influenced by his adherence to the anciently-received theory of 
the gradual fall of the level of the ocean, to which, and not to 
the successive rise of the land, he attributed the emergence of 
the tertiary strata, all of which he consequently imagined to 
have remained under water down to a comparatively recent 
period. 
Brocchi was perfectly justified in affirming that there were 
* Conch. Foss. Subap., torn. i. p. 148. f Ibid., p. 147. % Ibid., p. 166. 
