102 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 5, 



2. On the Last Elevation of the Alps ; with Notices of the 

 Heights at which the Sea has left Traces of its Action on 

 their Sides. By Daniel Sharpe, Esq., F.R.S., F.G.S. &c. 



[Contents.] 



Introduction. 



Traces of Erosion on the Sides of the Mountains. 



1st Line of Erosion. 



2nd Line of Erosion. 



3rd Line of Erosion. 



General Results. 

 Lines of Water-level traceable in the Excavation of the Valleys. 

 Terraces of Alluvium in the Alpine Valleys. 



Valleys of the Rhone and its Tributaries. 



Valleys of the Rhine and its Tributaries. 



Valleys of the Inn and its Tributaries. 



Valleys on the South of the Alps. 



General Results. 

 Theoretical Conclusions. 

 Erratic Blocks. 

 Tables of the Altitudes of Heads of Valleys, Terraces, and Erosions. 



Introduction. — In the following pages I have attempted to show, 

 that, after the Alps had assumed their present form, and when they 

 already stood as much above the surrounding lowlands as at present, 

 they must have been nearly submerged below the sea, out of which 

 their rise must have been, by a series of steps or starts of unequal 

 amount, separated by long intervals of time. The evidence on which 

 these views rest is derived from three sources ; 1st, from the traces 

 of erosion on the sides of the mountains, ending upwards in lines of 

 uniform level ; 2ndly, from the levels to which the valleys have been 

 excavated ; 3rdly, from the elevation of the terraces of alluvium in 

 the valleys ; and lastly, from the harmony of the results obtained 

 from these three sets of observations, when compared together*. 



Traces of Erosion on the Sides of the Mountains, 



In reading Prof. James Forbes' s interesting description of Norway, 

 I was much struck with his remarks on the frequent occurrence of 

 rugged and precipitous mountain-ranges rising, at the same elevation, 

 from a comparative level of gentle undulations destitute of angular 

 prominences, where this change of form cannot be due to different 

 powers of resistance in the rocks, which are of the same character 

 both above and below the changes. Prof. Forbes states that, " as a 

 general rule, the surfaces of erosion (whether produced by glaciers or 

 otherwise) have a tolerably definite superior limit, as in the Alps, only 

 here [in Norway] at somewhere about 1.500 to 2000 feet above the 



* Mr. R. Chambers has brought forward evidence, in some respects similar, 

 to prove that Great Britain was submerged beneath the sea during the Pleistocene 

 period; * Ancient Sea Margins,' 1818. 



