MODK III. BASALT1N. 



" After having given a preliminary idea of 

 the topographical position of Auvergne, and the 

 mineralogical structure of this country, M. 

 Daubuisson has successively and in detail de- 

 scribed the volcanoes and basalts of the country 

 of Puy de Dome, Mont Dor*, and of Cantal, he 

 concludes his memoir by a general review of his 

 observations. We shall here give an extract 

 from this latter part. 



" Auvergne (Departments of the Puy de Dome 

 and of Cantal) is in the middle of that great 

 slope, or inclined plane, whose bottom lies to- 

 wards the center of France, and which terminates 

 in the upland that directs the course of the 

 Rhone to the westward. The primitive soil (an- 

 terior to the volcanoes) is of granite, covered 

 in some places with a marly limestone. The 

 valleys excavated in this soil render the country 

 unequal, and give it a mountainous appearance, 

 although there are in fact only excrescences or 

 volcanic mountains, which rise above the genera! 

 plane of the slope, 



" Nearly all this soil has been covered with 

 volcanic productions: they are of three kinds, 

 and their formation seems to date from three 

 distinct epochs. The most recent and least 



* This is the proper spelling, derived from the river Dor, which, 

 joining the Dogne, forms the Dordogne. See Le Grand. 





