PKINCIPLES OF CLASSIFICATION. 
141 
ed because they were all posterior in date to the Secondary 
series, of which last the Chalk of Cretaceous, No. 9, Fig. 86, 
constitutes the newest group. The whole of them were at 
first confounded with the superficial alluviums of Europe; 
and it was long before their real extent and thickness, and 
the various ages to which they belong, were fully recognized. 
They were observed to occur in patches, some of fresh-water, 
others of marine origin, their geographical area being usual¬ 
ly small as compared to the secondary formations, and their 
position often suggesting the idea of their having been de¬ 
posited in difierent bays, lakes, estuaries, or inland seas, after 
a large portion of the space now occupied by Europe had al¬ 
ready been converted into dry land. 
The first deposits of this class, of which the characters 
were accurately determined, were those occurring in the 
neighborhood of Paris, described in 1810 by MM. Cuvier and 
Brongniart. They were ascertained to consist of success^ive 
sets of strata, some of marine, others of fresh-water origin, 
lying one upon the other. The fossil shells and corals were 
perceived to be almost all of unknown species, and to have 
in general a near affinity to those now inhabiting warmer 
seas. The bones and skeletons of land animals, some of them 
of large size, and belonging to more than forty distinct spe¬ 
cies, were examined by Cuvier, and declared by him not to 
agree specifically, nor most of them even generically, with 
any hitherto observed in the living creation. 
Strata were soon afterwards brought to light in the vicin¬ 
ity of London, and in Hampshire, which, although dissimilar 
in mineral composition, were justly inferred by Mr. T. Web¬ 
ster to be of the same age as those of Paris, because the 
greater number of the fossil shells were specifically identi¬ 
cal. For the same reason, rocks found on the Gironde, in 
the South of France, and at certain points in the North of 
Italy, were suspected to be of contemporaneous origin. 
Another important discovery was soon afterwards made 
by Brocchi in Italy, who investigated the argillaceous and 
sandy deposits, replete with shells, which form a low range 
of hills, flanking the Apennines on both sides, from the plains 
of the Po to Calabria. These lower hills were called by him 
the Subapennines, and were formed of strata chiefly marine, 
and newer than those of Paris and London. 
Another tertiary group occurring in the neighborhood of 
Bordeaux and Dax, in the South of France, was examined by 
M. de Basterot in 1825, who described and figured several 
