266 M. Marcel de Serres on the Deposition of 



seas were already sepai'ated when they were formed ; the seas 

 and the ocean having the place which they now occupy, and 

 the continents a configuration nearly the same as that which 

 they have at the present day. 



This last fact results from the observation of the numerous 

 differences which are remarked among the tertiary basins de- 

 pending upon the Ocean and the Mediterranean ; and from the 

 striking similarity which exists between the tertiary deposites and 

 the fossils which they contain in basins depending upon the 

 same seas, or upon different seas not at great distances from 

 each other. This does not prevent some particular basins, 

 depending upon the ocean, from having yet communicated 

 with the Mediterranean, or with other seas, when the tertiary 

 depositions took place, especially when their level was low, and 

 coincided with their line of inclination towards the other seas. 

 It is probably on account of this latter circumstance that we 

 find recurring, in the two basins of Lower Austria and Hun- 

 gary, the formations of the Subappenine Hills and Languedoc, 

 or the marine sands, the calcaire mcellon, or second tertiary 

 limestone, associated with the Swiss nagelfliih, which, repre- 

 senting the middle fresh-water formations, covers the first ter- 

 tiary limestone, these basins possessing the characters of both 

 oceanic and Mediterranean basins at the same time. 



A proof of it will also be found in a multitude of other facts, 

 which we shall proffer in another memoir on the tertiary forma- 

 tions of the south of France, and which is at this moment in the 

 press. It especially results from the constant position of these 

 tertiary deposites in the bottom of valleys never rising to the 

 height of the counterforts, when these attain any considerable 

 elevation. This position of the tertiary deposites, formed in the 

 ancient sea at the foot and base of the secondary counterforts, 

 and without rising with them, is so constant in the tertiary ba- 

 sins dependent upon the Mediterranean, that, in proportion as 

 we rise toward the culminating point of a counterfort, the se- 

 condary formations are alone seen, while the tertiary deposites 

 are again found on the opposite side of the same counterfort, 

 which separates two contiguous tertiary basins. This fixed 

 situation at the foot and on each side of the counterforts which 

 separate the contiguous tertiary basins, proves that if the ter- 



