16 
TERTTARY STRATA OF THE PARIS BASIN, 
[Ch. II. 
points in the history of the discovery and classification of the 
tertiary strata. 
Paris Basin. The first series of deposits belonging to this 
class, of which the characters were accurately determined, were 
those which occur in the neighbourhood of Paris, first described 
by MM. Cuvier and Brongniart*. They were ascertained to 
fill a depression in the chalk (as the beds d, in diagram No. 2, 
rest upon c), and to be composed of different materials, some- 
No. 2. 
a. 
a, Primary rocks. 
b, Older secondary formations, c, Chalk. 
d, Tertiary formation. 
times including the remains of marine animals, and sometimes 
of freshwater. By the aid of these fossils, several distinct alter- 
nations of marine and freshwater formations were clearly shown 
to lie superimposed upon each other, and various speculations 
were hazarded respecting the manner in which the sea had 
successively abandoned and regained possession of tracts which 
had been occupied in the intervals by the waters of rivers or 
lakes. In one of the subordinate members of this Parisian 
series, a great number of scattered bones and skeletons of land 
animals were found entombed, the species being perfectly dis- 
similar from any known to exist, as indeed were those of almost 
all the animals and plants of which any portions were discovered 
in the associated deposits. 
We shall defer, to another part of this work, a more detailed 
account of this interesting formation, and shall merely observe 
in this place, that the investigation of the fossil contents of 
these beds forms an era in the progress of the science. The 
* Environs de Paris, 1811. 
