FosmI Bone^ of SamUPrivaUd'Allier- 281 



is only at some paces from thence, that we see issuing from 

 below the soil the first mentioned flow, which is that upon 

 which it reposes. These scoriae, which contain a certain quan- 

 tity of crystals of black or greenish pyroxene, have moreover 

 all the characters of those to which we have given the name 

 of " scoriae of craters," from the immense quantity of them 

 which volcanic mouths hurl into the air. Their black colour is 

 concealed by an earthy cement, commonly of a brick-red colour, 

 rarely yellow, which is in a great measure the product of their 

 decomposition ; and this is sometimes so abundant, that the 

 breccia assumes an earthy or tufaceous aspect. And when, on 

 the contrary, the scoriae are only feebly agglutinated, we learn, 

 from the perfect preservation of the most delicate of their vesi- 

 cles, that they have suffered no transport, and that they are 

 still upon the same place in which they fell. 



" This bed is here covered over by a layer from two to four 

 decimetres thick, of grayish volcanic cinders, with fine grains, 

 feebly agglutinated, above which reposes the second flow, which 

 is about four metres thick. It presents here the same charac- 

 ters of structure and composition that it has exhibited above 

 the bridge, where we first perceived it. Lastly, a third flow, 

 the lava of which is well distinguished from the lower ones 

 by a larger quantity of grains of pyroxene and of peridote, is 

 immediately superimposed upon it. 



"It is from thence, that, in a space of two square metres, 

 being from the higher portion of the bed of scoriae, there has 

 been extracted, by the care of M. Deribier and myself, well 

 characterized remains of many animals belonging to the orders 

 of carnassiers, of pachydermata, and of ruminantia." 



[From the above account it appears, that the order of su- 

 perposition, in tracing the rocks from above downwards, is as 

 follows : 



Third and last flow of Basaltic Lava. 



Second flow, four metres thick. 



Greyish Volcanic Cinders two to four decimetres thick. 



Agglutinated Scoriae and Tufa one or more metres thick, in 

 the upper layer of which the fossil bones were discovered. 



Oldest plateau of Basaltic lava. 



Gneiss. 



k 



