310 French National Institute. 



others as a crocodile. M. Ciivier has endeavoured to show 

 that it is a mojiilor, although a giant of its kind. It is up- 

 wards of 25 feet in length ; t!ie tail is short in proportion, but 

 broader than thai of the other species, and .probably formed 

 a powerful rudder ; as every thing favours the suggestion 

 that this animal was strong cnouo.h to live on the surface of 

 the ocean : its bones are generally found among those of 

 large tortoises and shell-fish. 



Mr. Jefferson, president of the united states of America, 

 has sent to the class a fine collection of fossil bones dug up 

 pn the banks of the Ohio in North America : the greatest 

 part belongs to the huge animal improperly called the 

 iiiammolh bv the Americans, and to which M. Cuvier has 

 given the narne of mastodontus ; but there are several bones 

 in the collection belonging to the true mammoth of Siberia. 

 These two gigantic animals seem therefore to have formerly 

 inhabited the whole northern hemisphere. 



We cannot account lor the extirpation of these enor- 

 mous races, and of so many others that have been victims 

 of the same catastrophe, williout being conipletelv acquaint- 

 ed with the strata in which these bones are buried, as well 

 as their succession and nature. This is what has been at- 

 tempted bv Messrs. Cuvier and Brongniarc in the environs 

 of Paris. So far as they have as yet been able to examine 

 the soil in the neighbourhuodj they have found it to be 

 composed of several strata evidently different. The lower- 

 most stratum is an immense body of chalk, which extends 

 to England, an-d contains nothm-j; but unknowii shells, 

 several of which belong to unkno-vn genera. Above this 

 chalk there is a stratum of clay, which does not contain anv 

 organizid body. In several places are to be found those 

 strata of calcareous stones which are employed in building: 

 they are intersper'^ed with shells, most of which are un- 

 known, but they belong to genera with which we are ac- 

 quainted, i. e. they rese.nble the sea-shells of the pre-~ 

 sent day. 



Hillocks of plaistcr-stone are ihrown as if by chance, 

 sometimes on the clay, sometimes on the calcareous stone, 

 and contain abundance of bones of land animals entirely 

 unknown, the skeletons of which have been described by 

 M. Cuvier. In these beds of chalk and the clay which 

 immediately covers them, the shells are those of fresh 

 water, hut the upper strata contam salt-water shells also. 



An inmiense heap of sand without any organized body 



crowns all our eminences j and, what is more remarkable 



than any thing else, the highest stratum, namely, that 



2 \vhich 



