54 M. Gh. Maitins on the 



miocene period, and were occasionally filled up with miocene deposits, 

 and afterward re-excavated. It is possible in Auvergne to distin- 

 guish the relative ages of a great variety of alluviums containing the 

 bones of terrestrial quadrupeds, in consequence partly of their pre- 

 servation under lavas of different ages, and partly their position on 

 the sides of valleys which wore gradually deepened ; no flood or re- 

 turn of the ocean having disturbed the surface and mingled the fossils 

 of one period with those of another, as has happened in England and 

 most parts of Europe. The oldest fauna of land quadrupeds in 

 Auvergne, — that found in a fossil state in fresh-water strata of marl 

 and limestone, older than the trachyte of Mont Dor, — consisted of 

 species of Paleotherium, Anoplotherium, Anthracotherium, Opossum, 

 &c., analogous, in great part, to those of the Paris basin, with some 

 miocene forms associated, and belonging, according to Mr Lyell, to 

 an upper eocene group, newer than the Parisian tertiaries, or the 

 uppermost fresh-water of the Isle of Wight. Hence it follows that 

 the whole succession of revolutions in the animate and inanimate 

 creation which have occurred in Central France since the land 

 emerged, vast as they are in duration, as compared to the era of the 

 more modern volcanoes, is, nevertheless, considerably posterior to the 

 marine clay on which London is built ; — this last being one of those 

 tertiary deposits which rank as but the monuments of yesterday in 

 the great calendar of geological chronology. 



On the Ancient Extent of the Glaciers of Chamonixfrom 

 Mount Blanc to the Jura, By M. Ch. MARTINS. 



In the month of August 1815, a geologist returned from a 

 long excursion to the glaciers which occupy the bottom of the 

 valley of Lourtier, a valley lying in a lateral direction to that 

 leading to the Great St Bernard. Wishing to reach the hos- 

 pice on the following day, by a difficult and little known pass, 

 he spent the night in the hut of a chamois-hunter, named 

 Jean-Pierre Perraudin, who was to be his guide next day. 

 Seated before a fire formed of branches of rhododendron, the 

 odoriferous smoke of which escaped from the top of the roof, 

 the geologist and the mountaineer spoke of the elevated re- 

 gion which both of them had so often traversed. The con- 

 versation then fell on those large granite blocks often found 

 at Buch great distances from the rock from which they have 

 been detached. The geologist explained at length to the 



