144 ON THE REVOLUTIONS OF 



deposites of fresh water, covered by the marine beds of Alsace, the 

 province of Orleans, and of Berri. 



This animal population has a very remarkable character in the 

 abundance and variety of certain genera of pachydcrmata, which are 

 unknown amongst the quadrupeds now existing, and the character- 

 istics of which are more or less nearly related to tapirs, rhinoceroses, 

 and camels. 



The genera, whose discovery is entirely due to me, are — the pa- 

 Iceotheria, the lophiodonta, the anoplotheria, the anthracotheria, the 

 c7icropotami, and the adapis. 



The paleeotheria resemble the tapirs in the general form, in that of 

 the head, and particularly in the shortness of the bones of the nose, 

 which proves that they had, like the tapirs, a small proboscis ; and 

 also in having six incisores and two canine teeth in each jaw ; but 

 they resembled the rhinoceros in their grinders, of which the upper 

 ones were square, with prominent ridges differently shaped, and the 

 lower ones shaped like double crescents, and their feet in like manner 

 were divided into three toes, while the fore feet of the tapir have four 

 divisions. 



It is one of the genera, the most distributed and numerous in 

 species, that are found in the layers of its particular period. Our 

 gypsum quarries in the environs of Paris are crowded with them. The 

 first (P. magnum) as large as a horse. Three resemble swine, but one 

 (P. medium) has narrow and long feet ; one (P. crassmn) with larger 

 feet ; one (P. latum) with feet still larger and much more short ; the 

 fifth species (P. curtimi) of the size of a sheep, is much lower, and has 

 feet still larger and shorter in proportion than the last ; a sixth (P. 

 minus) is of the size of a small sheep and has slim feet, the lateral 

 toes of which are shorter than the others ; and finally there is one 

 (P. minimum) not larger than a hare, which has also long and slender 

 feet. 



They have also been found in other provinces of France ; at Puy in 

 Velay, in the beds of gypseous marl, one species (P. velaunum), very 

 similar to the (P. medium), but differing from it in the formation of 

 the lower jaw; in the vicinity of Orleaus, in the layer of marly stone, 

 a species (P. aurelianense) distinguished from the others by having 

 the returning angle of the lower grinders with the crescent cleft into 

 a double point, and by some difference in the prominences of the upper 

 grinders ; near Issel, in a layer of gravel, or molasse, "along the decli- 

 vities of the Black Mountain, a species (P. isselanuni) characterised 

 like those of Orleans, but smaller ; but principally in the molasse of 



