443 
the Polyparia is almost exactly the same as that which has been ob- 
tained from a comparison of the Testacea. Some of the genera of 
corals, fossil in Touraine, as the Astra, Lunulites, and Dendrophyllia, 
have not been found in European seas north of the Mediterranean; ne- 
- vertheless the Polyparia of the Faluns do not indicate a climate warmer 
than that which now prevails on the southern coasts of Europe. 
The next general question considered by Mr. Lyell is, whether 
the Faluns of the Loire and the English crag can be referred to the 
same geological period, eighty-five per cent. both of the corals and 
the shells being of distinct species. ‘‘ Can,” he says, ‘‘such a con- 
clusion be embraced on the ground of the corresponding degree of 
analogy which both deposits bear to the existing fauna, and to the 
extremely wide departure which both the crag and the Faluns make 
from the fossils of the Eocene period ?”’ 
When Mr. Lyell compared in 1839, with the assistance of Mr. 
Searles Wood and Mr. G. Sowerby, the Suffolk crag shells in Mr. 
Wood's cabinet, the proportion of recent species in the red crag was 
found to be about thirty per cent., and in the older or coralline about 
twenty, or, including both, twenty-five per cent., the same amount 
as in the Faluns of Touraine ; the analogy of the recent crag-shells 
being almost entirely to shells of the British seas, and that of those - 
of the Faluns mostly to Mediterranean species. The argument which 
might be derived in favour of the more modern origin of the crag, from 
the recent species being precisely those of the neighbouring seas, 
while the existing species of the Faluns are not to the same extent, 
Mr. Lyell combats by stating that the whole assemblage of English 
crag genera and species departs very widely from that of the ad- 
jacent seas, consisting of northern and southern forms. Thus the 
Glycimeris, Cyprina and Astarte are northern genera, and of the 
‘Astarte there are about fourteen species ; and of genera now known 
as existing only in equatorial latitudes, are Pyrula, Lingula, and some 
others. The fact, that four-fifths of coralline crag Testacea are ex- 
tinct, implies high antiquity ; as well as the sixteen species of Echino- 
derms found inthe crag being unknown as recent species: The 
author therefore refers both the crag and Faluns to the Miocene 
epoch, notwithstanding the specifie-discordance of their fossils, and 
he is of opinion that this disagreement may be diminished when the 
two faunas are better known. ‘The difference between the Testacea 
of the British coasts and of the Mediterranean is pointed out ; and if. 
the greater distance of these seas from each other than of the eastern 
shores of England from the Faluns should be urged as an objection 
to the inference that the crag and Faluns belong to one epoch, Mr. Lyell - 
calls attention to the difference in the Testacea on the opposite sides of 
the isthmuses of Suez and Panama, though these tracts are very incon- 
siderable, both in height and breadth. That landexisted in the imme- 
diate neighbourhood of the Faluns, Mr. Lyell says, is proved, from 
the occurrence of the remains of terrestrial Mammalia, and of land and 
freshwater shells, though they are of rare occurrence, compared with 
the’marine reliquiz ; and if it formed a barrier between the district oc- 
cupied by the crag and that by the Faluns, the more northern charac- 
