THEORY OF THE EARTH. 



may be considered as intimately connected with 

 the present discourse ; at the same time, that it 

 is, without a doubt, one of the best ornaments of 

 my work *. 



In it there is presented the history of the most 

 recent changes that have taken place in a particu- 

 lar basin, and it descends so far as the Chalk forma- 

 tion, the extent of which over the globe is vastly 

 more considerable than that of the materials of 

 the basin of Paris. The chalk, which has been 

 considered so modern, is thus found to be ad- 

 vanced in antiquity among the ages of the great 

 period preceding the last catastrophe. It forms 

 a sort of limit between the most recent formations, 

 those to which the name of Tertiary may be re- 

 served, and the formations which are named Se- 

 condary, which have been deposited before the 

 Chalk, but after the Primitive and Transition 

 formations. 



Recapitulation of the Observations upon the Succession 

 of the Tertiary Formations. 



The most superficial strata, those deposits of 

 mud and clayey sand, mixed with rolled pebbles, 



* Copies have been printed separately, under the title of 

 Description Geologique des Environs de Paris, par MM. G. 

 Cuvier et Al. Brongniart. Second edition. Paris, 1822, 4to. 



