Ch. XVI.] MIDDLE AND LOWER EOCENE OF FRANCE. 223 



and two marine, which were supposed to imply that the waters of the 

 ocean, and of rivers and lakes, had Been by turns admitted into and 

 excluded from the same area. Investigations since made in the Hamp- 

 shire and London basins have rather tended to confirm these views, at 

 least so far as to show, that since the commencement of the Eocene 

 period there have been great movements of the bed of the sea, and of 

 the adjoining lands, and that the superposition of deep sea to shallow 

 water deposits (the London clay, for example, to the Woolwich beds) 

 can only be explained by referring to such movements. Nevertheless, it 

 api^ears, from the researches of M. Constant Prevost, that some of the 

 alternations and intermixtures of freshwater and marine deposits, in the 

 Paris basin, may be accounted for by imagining both to have been si- 

 multaneously in progress, in the same bay of the same sea, or a gulf into 

 which many rivers entered. 



To enlarge on the numerous subdivisions of the Parisian strata, would 

 lead me beyond my present limits ; I shall therefore give some examples 

 only of the most important formations enumerated in the foregoing 

 Table, p. 222. 



Beneath the Upper Eocene or " Upper marine sands," A, already 

 spoken of (p. 194), we find, in the neighborhood of Paris, a series of 

 white and green marls, with subordinate beds of gypsum, B. These are 

 most largely developed in the central parts of the Paris basin, and, 

 among other places, in the Hill of Montmartre, where its fossils w^ere first 

 studied by M. Cuvier. 



The gypsum quarried there for the manufacture of plaster of Paris 

 occurs as a granular crystalline rock, and, together with the associated 

 marls, contains land and fluviatile shells, together with the bones and 

 skeletons of birds and quadrupeds. Several land plants are also met 

 with, among which are fine specimens of the fan-palm or palmetto tribe 

 (Flahellaria). The remains also of fi'eshwater fish, and of crocodiles 

 and other reptiles, occur in the gypsum. The skeletons of mammalia 

 are usually isolated, often entire, the most delicate extremities being 

 preserved ; as if the carcasses, clothed with their flesh and skin, had 

 been floated down soon after death, and while they were still swoln by 

 the gases generated by their first decomposition. The few accompany- 

 ing shells are of those light kinds which frequently float on the surface 

 of rivers, together with wood. 



M. Prevost has therefore suggested that a river may have swept away 

 the bodies of animals, and the plants which lived on its borders, or in 

 the lakes which it traversed, and may have carried them down into the 

 centre of the gulf into which flowed the waters impregnated with sul- 

 phate of lime. "We know that the Fiume Salso in Sicily enters the sea 

 so charged with various salts that the thirsty cattle refuse to drink of it. 

 A stream of sulphureous water, as white as milk, descends into the sea 

 from the volcanic mountain of Idienne on the east of Java ; and a great 

 body of hot water, charged with sulphuric acid, rushed down from the 

 same volcano on one occasion, and inundated a large tract of country, 



