THE GEOLOGICAL AGE OF PALiEOTHERIA, MASTODONS, filC. 243 



evidence of position, that the uppermost beds are the most recent ; 

 and if, in ascending from the lower to the upper part of the series, 

 we find the proportion of the species increase, that are analogous to 

 what now live in the Mediterranean, we obtain the evidence of posi- 

 tion, to support some of the conclusions of M. Deshayes. The evi- 

 dence from position forms, however, the fundamental basis of our 

 conclusions respecting the relative age of the secondary and tertiary 

 formations ; and we can only proceed safely when we have the aid 

 of this evidence. 



M. Elie de Beaumont proposes a division of the tertiary strata into 

 three groups, according to the organic remains of large mammiferous 

 animals which they contain. He supposes that each of these groups 

 indicates a period of tranquillity, intermediate between two periods 

 of change and convulsion; and that each generation of animals was 

 destroyed by a different convulsion. His first period extends to the 

 marls above the gypsum, in the Paris basin. The second to the 

 Fontainebleau sandstone, the upper fresh-water formation, the calca- 

 reous beds at the mouth of the Rhine, and the molasse of Switzer- 

 land. The third period extends to the diluvium {terrain de trans- 

 port) of Bresse, to the beds of GEningen, the sandstone of Aix, the 

 upper marine formation of Montpellier, and the ranges of sub- 

 Apennine hills in Italy, to the tertiary beds of Sicily, and to the 

 Crag of Suffolk. 



The first or lowest group is characterized by the remains of Palae- 

 otheria ; the second, by those of mastodons ; and the third, by the 

 remains of elephants. It is admitted, however, that in marine ter- 

 tiary depositions, these periods seem to pass insensibly into each 

 other. In the marls of the Loire, and the calcareous beds of Mont- 

 pellier, the bones of the Palaeotherium are found mixed with bones 

 of the mastodon and hippopotamus ; and in the Plaisantin, the bones 

 of the elephant are added to the above. Without admitting at pres- 

 ent that the division of M. Elie de Beaumont is supported by suffi- 

 cient evidence, (and the exceptions stated prove that it is not,) yet 

 we may still allow that there is a considerable degree of probability, 

 that each of the three genera of animals, flourished most at the dif- 

 ferent epochs he has stated, but not exclusively of other genera. 

 In England, we have only a few traces of animals of the Palaeothe- 

 rian age ; these occur in the fresh-water formation at Binstead, in 

 the Isle of Wight : and in the second group we have only two known 

 instances ; they occur in the Crag, in which two teeth of the masto- 

 don have been found. In the third, or elephantine group, we have 

 numerous instances ; for teeth and bones of elephants have been 

 found in clay, marl, or gravel, in almost every county in England. 

 The instances cited above, in the two lower groups, are too few to 

 support any hypothesis ; but it is only fair to admit, that, conjointly 

 with the elephants in the third group, they are conformable to the 

 divisions of M. Elie de Beaumont. Should these divisions be more 



