442. 
Lyell :found here the first) specimens of the shell, generally con- 
sidered to be the Voluta Lamberti of the English crag, but which he 
believes to differ from it. During his researches at Pontlevoy he 
procured 163 species of shells, forty-five of which, or twenty-five per 
cent., have been identified with existing Testacea ; and on comparing 
the whole number with a collection’ of 180 from Louans, 106 were 
found to be common to the two localities: Only thirty-four of the 
Pontlevoy shells were not procured by Mr. Lyell, at some other Fa- 
lun locality. Not more than six species of corals have yet been as- 
certained to occur in this district. The other localities near Pont- 
levoy examined by Mr. Lyell are Sambin and Contres. At the 
former the white Falun, containing hard flags, is covered by a great 
deposit of red, ferruginous, stratified gravel, with grains of quartz and 
flint derived from the Eocene freshwater formation ; and it bears a 
striking resemblance’ to the gravel-beds which overlie the red crag 
in Suffolk... Immediately east of Sambin, as well as between Conrtres 
and Soing,: Mr. Lyell found specimens of the Ostrea virginica asso- 
ciated with fragments of other Testacea, which identified the deposits 
from which they were obtained with those of Touraine. ‘These ide- 
tached Faluns imply, ‘he says, that a large part of France, now 
drained by the Loire and its tributaries, was submerged during the 
Miocene period, although it is only at.a few isolated points that the 
evidence can be detected of the long time this submergence must 
have lasted, and of the distinctness of the fauna which then lived, 
both from that now existing, and still more from that of the ante- 
cedent Eocene epoch. 
General Remarks.—Previously to his tour, Mr. Lyell considered 
that the collections which he had seen from the Loire might be di- 
vided into two groups, the larger resembling a Mediterranean or even 
@ more northern fauna, and the smaller a tropical one; and that some 
of the shells composing the latter came from inferior beds of the de- 
_ posit, or from patches of Falun of more ancient date than others : 
he also suspected, that where the tropical forms abounded, there 
would be found asmaller proportion of recent shells: He is, how- 
ever, now convinced that all the shells belong to one group, or that 
the forty-four crag species were really contemporaneous in Touraine 
with the large! cones, Cypreeas, Fasciolarias, and other tropical forms 
of '‘Testacea. At Bossée, where he found these large-univalves, as well 
as the Astrea, Lunulites, and Dendrophyllia, most fully developed, he 
obtained the greatest proportion of recent shells, or thirty-two per 
cent., the average being twenty-five. In making the examinations 
upon which these results depend, Mr. Lyell states that he always 
had recourse: to ithe assistance of Mr. G. Sowerby, and in doubtful 
cases to that of Mr. E. Forbes, or some other conchologist ; and that 
he excluded from his calculations:a great many species-of which he 
did not possess perfect’ specimens, or a sufficient number: to enable 
the» specific identification to be confidently proved. _ Of the corals 
collected. by the author,:forty-three spécies have been determined by 
Mr. Lonsdale; only seven of which, or fifteen per cent., agree spe-— 
cifically with those found in the Suffolk crag. This per- centage in 
