the Tertiary Formations. 267 



tiary deposites are not raised higher, it is because, during the 

 time of their precipitation, the waters of the Mediterranean 

 which produced them in each basin, did not rise to the height 

 of the counterforts, and that, in proportion as that sea withdrew 

 within the hmits which it now occupies, the mass of its waters, 

 flowing towards its present basin, gradually diminished. It 

 would also appear that the tertiary deposites precipitated in the 

 basin of the ancient sea did not rise in the south of France to 

 a height of more than 400 yards above the present level of the 

 Mediterranean *. 



The tertiary formations, with the exception of the upper 

 fresh-water deposites (comprehending the deposites of lacustrine 

 and fluviatile limestone, with the marls and lignites peculiar to 

 this system, in which marine fossils are never seen, unless those 

 which may have been detached from previously existing forma- 

 tions and from the diluvium), being the last relics of the seas, 

 when the Ocean and the Mediterranean were already separated, 

 seem so much the older the more distant they are from the pre- 

 sent seas, and so much the newer the nearer they are to them. 

 They appear, moreover, to have this peculiarity, that most of 

 those depending upon the ocean are older than the tertiary de- 

 posites depending upon inland littoral basins. 



One is involuntarily led to this inference, on observing the 

 difterence of position which the marine rocky banks occupy in 

 the two orders of these basins. In fact, the tertiary rocky ma- 

 rine limestones of the oceanic basins are in general inferior to 

 the gypsum containing bones, while those of the inland basins 

 are for the most part not only superior to the gypsums, but 

 also to the subappenine blue marls. Both are as distinct in re- 

 spect to their geological position as in the fossils which they con- 

 tain, — a fact on which we have insisted in our papers on the cal- 

 caire moellon. 



Thus, setting out from the positive fact, that the second tei'- 

 tiary limestone of the South of France is newer than the cal- 

 caire grossier, or the first tertiary limestone, since the calcaire 



" The tertiary formations deposited after the retreat of the seas from our 

 continents, are the only ones which rise to all kinds of levels, and which rest 

 indiscriminately upon rocks of the most discordant ages. 



3 



