COMPAEISONS OF CEAG AND FALUNS. 
213 
of a type now characteristic of equatorial seas, and wholly 
unlike any Mediterranean forms. These proofs of a more 
elevated temperature seem to imply the higher antiquity of 
the faluns as compared with the Suffolk Crag, and are in per¬ 
fect accordance with the fact of the smaller proportion of 
testacea of recent species found in the faluns. 
Out of 290 species of shells, collected by myself in 1840 at 
Pontlevoy, Louans, Bossee, and other villages twenty miles 
south of Tours, and at Savigne, about fifteen miles north-west 
of that place, seventy-two only could be identified with re¬ 
cent species, which is in the proportion of twenty-five per 
cent. A large number of the 290 species are common to all 
the localities, those peculiar to each not being more numer¬ 
ous than we might expect to find in different bays of the 
same sea. 
The total number of species of testaceous mollusca from 
the faluns in my possession is 302, of which forty-five only, or 
fourteen per cent., were found by Mr. Wood to be common 
to the Suffolk Crag. The number of corals, including bryo- 
zoa and zoantharia, obtained by me at Done and other lo¬ 
calities before adverted to, amounts to forty-three, as deter¬ 
mined by Mr. Lonsdale, of which seven (one of them a zoan- 
tharian) agree specifically with those of the Suffolk Crag. 
Some of the genera occurring fossil in Touraine, as the corals 
Astrea and Dendrophyllia^ and the bryozoan Lunulites^ have 
not been found in European seas north of the Mediterranean ; 
nevertheless, the zoantharia of the faluns do not seem tb in¬ 
dicate, on the whole, so warm a climate as woufd be inferred 
from the shells. 
It was stated that, on comparing about 300 species of Tou¬ 
raine shells with about 450 from the Suffolk Crag, forty-five 
only were found to be' common to both, which is in the pro¬ 
portion of only fifteen per cent. The same small amount of 
agreement is found in the corals also. I formerly endeavored 
to reconcile this marked difference in species with the sup¬ 
posed co-existence of the two faunas, by imagining them to 
have severally belonged to distinct zoological provinces or 
two seas, the one opening to the north and the other to the 
south, with a barrier of land between them, like the Isthmus 
of Suez, now separating the Red Sea and the Mediterranean. 
But I now abandon that idea for several reasons; among 
others, because I succeeded in 1841 in tracing the Crag fauna 
southward in l^ormandy to within seventy miles of the Fa- 
lunian type, near Dinan, yet found that both assemblages of 
fossils retained their distinctive characters, showing no signs 
of any blending of species or transition of climate. 
