THE CLASSIFICATION OF THE TERTIARY DEPOSITS. 
125 
and Lamarck discussed the characters of the invertebrate fauna 
found therein. In a catalogue of five hundred species of shells 
found in the Paris Basin, Lamarck showed that only twenty 
could be identified with living species. 
In England, Brander, as early as the year 1766, had 
described the beautiful fossil shells found at Barton Cliff, in 
Hampshire, though without discussing their relation to living 
forms. In 1811 Parkinson described the Crag beds of Suffolk 
as overlying the London Clay, and as containing numerous 
fossil shells, of which a considerable proportion could be iden- 
tified with species now inhabiting the neighbouring seas. 
About the same time Webster was engaged in studying the 
Tertiary strata of the Isle of Wight and Hampshire, and in 
1813 he established the general parallelism of these beds with 
those described by Cuvier and Brongniart in the Paris Basin. 
In 1820 M. Constant Prevost described the strata of the 
Yienna Basin, the study of which had occupied his attention 
during four years, and announced, as his conclusion concerning 
their age, that they are either younger than the beds of the 
Paris Basin or equivalent to the upper portion of them. 
In the year 1825, I)e Basterot published an account of a 
large Tertiary deposit which he had discovered in the basin of 
the Gironde and the district of the Landes in the south-west 
of France, and he described more than three hundred species 
of shells as occurring there. These, as he proved, differ, for the 
most part, both from the shells of the Subapennine beds, and 
from those of the Paris Basin. A little later, M. Desnoyers 
showed that beds with a similar fauna to that collected by 
De Basterot about Bordeaux and Dax, are found at Touraine, 
in the valley of the Loire, while Bonelli recognized the same 
fauna in the hill of the Super ga, near Turin. 
At the time when Lyell took up the investigation of the 
subject, the state of the problem was as follows. Three distinct 
sets of Tertiary strata had been discovered. First, the Subapen- 
nine beds of Italy and the Crags of England, in which a majority 
of the shells were found to belong to living species. Secondly , 
the series of strata of the London, Paris, and Hampshire Basins, 
in which only a very small minority of the shells belong to 
living species. Thirdly , the strata of the Landes, and the 
Faluns of Touraine (with which those of the Yienna Basin 
and of the Superga in Piedmont were identified), in all of which 
the fossils were in great part distinct alike from those of the 
t Subapennine beds, on the one hand, and from those of the 
Paris and London strata on the other. 
One other very important step had been taken by M. Des- 
noyers, who showed that in the valley of the Loire the beds of 
Touraine distinctly overlie others containing the same fossils as 
