THE SURFACE OF THE GLOBE. 135 



at present, in the eyes of all geologists, the most evident proof of the 

 immense inundation which was the last catastrophe of this globe *. 



Between this diluvium and the chalk are formations alternately 

 filled with the productions of fresh water and salt water, which mark 

 the irruptions and retreats of the sea, to which, since the deposition 

 of the chalk layer, this portion of the globe has been subjected; first, 

 marls and mill-stones and hollow silex, filled with fresh-water shells, 

 like those of our marshes and pools ; under them are marls, sand- 

 stones, and limestone, all the shells of which are marine ; oysters, &c. 



Still deeper are fresh-water formations of a much more remote pe- 

 riod, and particularly those famous gypsum deposites in the vicinity of 

 Paris, which have afforded the means of adorning the edifices of this 

 fine city with so much facility, and where we have discovered entire 

 genera of land animals, of which no traces have been elsewhere de- 

 tected. 



They rest on those equally remarkable beds of limestone, of which 

 our capital is built, and in the more or less close composition of which 

 the patience and sagacity of the savans of France have already de-. 

 tected more than eight hundred species of shells, all marine, but the 

 great part unknown in the seas now existing. They also contain bones 

 of fishes, of cetaceous and other marine mammiferous animals. 



Under the marine limestone is anotlier fresh- water deposite, formed 

 of clay, in which are interposed great layers of lignite (brown coal), 

 or that fossil coal of more recent origin than the common coal. Amongst 

 the shells, always of fresh water, there are also some bones ; but it is 

 remarkable that they are bones of reptiles, and not of mammifera. It 

 is filled with crocodiles and tortoises, but the genera of extinct mam- 

 mifera, which are deposited in the gypsum, are not there to be found. 

 They did not as yet exist in that country when these clays and lignites 

 were formed. 



This fresh-water formation, the most ancient that has been with cer- 

 tainty detected in our neighbourhood, and which supports all the for- 

 mations which we have just enumerated, is itself supported and en- 

 vironed entirely by chalk ;- a formation, vast from its thickness and by 

 its extent, which shows itself in very distant countries, such as Pome- 

 rania, and Poland ; but which, in our environs, pervades with a sort of 

 continuity Berri, Champagne, Picardy, Upper Normandy, and a part 

 of England, and also forms a great circle, or rather basin, in ■which 



* See Professor Buckland's great work, called ' Reliquiae Diluvianee,' London, 

 1S23, in 4to. pp. 185, et seq. ; and the article ' EAU ' by M. Brongniart, in the 

 14th volume of the Dictionary of Natural Sciences. 



