44 Messrs Lyell and Murchison 07i the 



flowed as far down the bed of the Couze d'Issoire, instead of 

 that of the Couze de Chambon. This evidence, however, is of 

 a nature best appreciable by those who have visited the district, 

 and are famihar with the geological phenomena of Auvergne. 

 To such it will appear clear, that one of the modern lava-streams 

 of Auvergne, passing by Pardines, Perrier, and the Farm of 

 Boulade, would merely share with the river the lowest level of 

 the valley, and would not reach so high as the lowest beds of 

 alluvium and trachytic breccia, which last would then hold the 

 same relative position to the recent lava as does the ancient pho- 

 nolitic current before mentioned, below Besse, to the modern 

 " cheire " beneath. 



The fossil remains of animals discovered near the Farm of 

 Boulade, were imbedded in alluvial gravel and sand subjacent to a 

 great mass of trachytic breccia. Now, the diffex-cnt varieties of 

 this rock occurring at Mont Perrier are undistinguishable from 

 those which enter into the composition of Mont Dor and the 

 Cantal, where they are seen in the ridgy prolongations branch- 

 ing off from those mountains, to alternate with ancient volcanic 

 products of different eruptions ; and near the Cascade of Mont 

 Dor, and at the foot of the Puy Gros, they are traversed by 

 basaltic dikes. One of the masses of trachytic breccia at Perrier 

 is no less than 60 feet in thickness, and encloses fragments of 

 trachyte of enormous magnitude, cemented by a tufaceous base, 

 as hard as the rock itself. Since these fragments are fully as 

 angular and large as any of those in similar rocks laid open in 

 the interior of Mont Dor, there is not a shadow of pretence for 

 regarding those at Perrier as regenerated, and as having result- 

 ed from the breaking up of more ancient breccias. 



And when we identify these breccias with those of Mont Dor, 

 it must be recollected that such a conclusion is in perfect har- 

 mony with their height above the river at Perrier, which corre- 

 sponds, as we before remarked, to that of lava-currents of the 

 intermediate age in Auvergne. From such considerations, 

 therefore, we must infer, that the alluvium, from whence the 

 remains of quadrupeds were disinterred, near the Farm of Bou- 

 lade, and at Perrier, was of very high antiquity ; nor is this in- 

 ference at varianci; with the character of these remains, since the 

 individuals belonged for the most part, if not entirely, to extinct 



