CHAP. XVI. 



THE POSITION OF THE LOESS. 333 



almost every variety of rock, and will therefore exhibit an 

 average result nearly the same in all countries. Thus, the 

 loam which fills to a great depth the wide valley of the 

 Saone, which is bounded on the west side by an escarpment 

 of inferior oolite, and by the chain of the Jura on the east, is 

 very like the loess found in the continuation of the same 

 great basin after the junction of the Ehone, by which a large 

 supply of Alpine mud has been added and intermixed. 



In the higher parts of the basin of the Danube, loess of the 

 same character as that of the Ehine, and which I believe to be 

 equally of Alpine origin, attains a far greater elevation above 

 the sea than any deposits of Ehenish loess. Mr. Stur informs 

 me that it also fills the valleys of the Carpathians almost to 

 the height of the watershed between Austria and Hungary. 



Oscillations of Level required to explain the Accumulation and 

 Denudation of the Loess. 



A theory, therefore, which attempts to account for the 

 position of the loess cannot be satisfoctory unless it be 

 equally applicable to the basins of the Rhine and Danube. 

 So far as relates to the source of so much homogeneous loam, 

 there are man}^ large tributaries of the Danube which, during 

 the glacial period, may have carried an ample supply of 

 moraine-mud from the Alps to that liver; and in regard to 

 grand oscillations in the level of the land, it is obvious that 

 the same movements, both downward and upward, of the 

 jrreat mountain-chain would be attended with analogous 

 effects, whether the great rivers flowed northwards or east- 

 wards. In each case fine loam would be accumulated during 

 subsidence, and removed during the upheaval of the land. 

 Changes, therefore, of level, analogous to those on which we 

 have been led to speculate when endeavoring to solve the 

 various problems presented by the glacial phenomena, are 



