78 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 19, 



Tapir f Sus^ Bos (2 species), Cervus (about 20 species), Antihpe, 

 Capra (2 species), Felis (7 species), Hycena (2 species), Martes^ 

 Lutra, Canis^ Ursus, JErinaceus, Marmot, Castor^ Arvicola (2 spe- 

 cies), and Lepus, all referable to extinct species. Next in age 

 come two other alluvial deposits, Nos. 6 and 7? in which fossil mam- 

 malia of other species, according to M. Bravard, occur, the bones 

 of Hippopotamus in particular having been met with in No. 6. Passing 

 then to the south-east of Issoire, and crossing the Allier, we arrive 

 at No. 8, the celebrated bone-bed of the Tour de Boulade, in which 

 a great many other mammalia have been collected by the labours of 

 MM. Bravard and Pomel ; among others the Elephant, Rhinoceros 

 {R,tichorhinus), Equus, Bos, Cervus {mc\\xd.\wg Reindeer), Antilope, 

 Felisy and Canis. This assemblage differs considerably in its species 

 from any other in the neighbourhood, and may be considered as more 

 ancient in character than No. 9, alluded to in the beginning of this 

 paper, or the bed which underlies the lava at Nechers. In regard to 

 the Tour de Boulade bed. No. 8, its base is about sixty feet above the 

 level of the Allier. It consists in great measure of angular pieces of 

 freshwater limestone and basalt, which seem to have fallen from the 

 steep slope of the hill above, or which at least are unrounded, and 

 have not been brought from a distance. Some of the angular blocks 

 are three feet in diameter. There is an intercalated sandy bed with 

 bones such as may have been deposited in a river or sheet of water, 

 into which these fragments of rock, detached by frost from the pre- 

 cipice, have rolled down. In this sandy stratum two marine shells 

 have been found by MM. Bravard and Pomel, belonging decidedly 

 to the genera Nntica and Pleurotoma. Although too imperfect to 

 allow of the species being positively determined, they both approach 

 closely to shells which I have from the faluns of Touraine. As no 

 marine tertiary shells had been previously observed nearer to this 

 part of Auvergne than the valley of the Loire, and as the deposit 

 under consideration has a purely terrestrial or supra-marine aspect, 

 I should not have given credit to this discovery if not attested by 

 geologists, who are so cautious, and who were so alive to the novelty 

 and importance of the phsenomenon at the time when they found 

 them, as were the naturalists above mentioned. They have been 

 as much perplexed as I am to conceive how any current of water 

 could have brought such shells from the north ; and we can hardly 

 suppose the Miocene sea to have ascended the valley of the Allier 

 without leaving there some more decided monuments of its sojourn. 

 There is only one other subject on which I shall offer a iew ob- 

 servations. It has long been announced, that in the celebrated 

 mountain of Gergovia M. Bouillet had found the Melania inquinata 

 in some argillaceous marls in the north flank of the hill. I examined 

 the spot with attention, and obtained by digging many specimens of 

 the Melania in question, and of a Unio and Melanopsis which ac- 

 companied it in abundance. Some doubts had been raised by M. 

 Bouillet whether the strata containing these shells belonged merely 

 to a local deposit, or really formed an integral part of the great 

 freshwater formation of Auvergne, of which the mass of the hill of 



