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era. A collection of 345 species of Coralline Crag shells in Mr. 
Wood’s cabinet was then compared in like manner, and sixty-seven 
were determined to be identical with recent species, being about 19 
per cent. Mr. Lyell, therefore, considers that the Coralline Crag is also 
Miocene, although belonging to a more remote part of that period 
than the Red Crag. Having obtained from M. Dujardin a collection 
of 240 shells from the Faluns of Touraine, he found with Mr. George 
Sowerby’s assistance that the recent shells were in the proportion of 
twenty-six per cent., so that he has now come round to the opinion 
long ago announced by M. Desnoyers, that upon the whole the Crag 
of Suffolk corresponds in age with the Faluns of Touraine, both be- 
ing Miocene, although the species in the two countries are almost 
entirely distinct, those of England having a northern and those of 
France a sub-tropical character. I am also informed by Mr. Lyell, 
that out of 400 marine and freshwater species, from the Kocene strata 
of the London and Hampshire basins, Mr. G. Sowerby was scarcely 
able to identify two per cent. with living shells. It is satisfactory 
therefore to observe that the test of age derived from the relative 
approach to the recent Fauna is in perfect accordance with the in- 
dependent evidence drawn from superposition. We ascertain for 
example by superposition that the freshwater strata of the mud cliffs 
of East Norfolk rest on Norwich crag, and are the newest forma- 
tion of all. They are then followed in the descending series by, Ist, 
the Norwich, 2ndly, the Red, and 3rdly, the Coralline Crag, beneath 
which is the London Clay. The same order of sequence is indi- 
cated by the organic remains considered independently, and simply 
with reference to the degree of their correspondence with the ex- 
isting Fauna. 
It has been known for many years, that near Bridlington, in York- 
shire, sand and clay containing marine tertiary shells had been ex- 
posed on the coast. From an examination of the shells collected 
there by Mr. Bean, Mr. Lyell finds the deposit to agree in age with 
the Norwich Crag. 
I cannot conclude these remarks without observing, that some 
part of the confusion and apparent inconsistency of the opinions of 
different conchologists, respecting the age of the Crag, must have 
arisen from the intermixture of fossils derived equally from 
