68 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 30, 



above the Batlis of Pfeffers, where this ancient striation, imdistin- 

 guishable from that caused by existing glaciers, has, by a very recent 

 shde of a heavy mass of gravel from the upper slope of the same 

 rock, been crossed by fresh scorings and striae, transverse to those 

 of former date, from which the markings made in the preceding 

 year only differ in being less deeply engraved. He also adverts to the 

 choking up of some valleys, particularly of the Yorder or Upper Rhine 

 below Dissentis, by the fracture, in situ, of mountams of limestone, 

 which constitute masses of enormous thickness, made up of innumera- 

 ble small fragments, all of which have been heaped together since the 

 dispersion of the erratic blocks ; and he further indicates the effects 

 of certain great shdes or subsidences within the historic aera. 



In considering the distribution of the erratic detritus of the Rhone, 

 the author having denied that it can ever have been carried down the 

 chief valley to the Lake of Geneva in a solid glacier, he still more 

 insists on the incredibihty of such a vast body of ice having issued 

 from that one narrow valley, as to have spread out over all the low 

 country of the cantons Vaud, Friburg, Berae and Soleure, and to have 

 protruded its erratics to the slopes of the Jura, over a region of about 

 100 miles in breadth from north-east to south-west, as laid down in 

 the map of Charpentier. He maintains, that in the low and undu- 

 lating region between the Alps and the Jura, the small debris derived 

 from the former has everywhere been water-worn, and that there is 

 in no place which he saw anything resembling a true moraine ; and he 

 therefore believes, that the great granitic blocks of Mont Blanc were 

 translated to the Jura by ice-floats, when the intermediate country 

 was under water. He further appeals to the water-worn condition 

 of all the detritus of the high plateaux around IMunich, 1 600 and 1 700 

 feet above the sea, to show that a subaqueous condition of things must 

 be assumed, for the whole of the northern flanks of the Alps, when the 

 great erratic blocks were carried to their present positions. 



Prof. Guyot of Neufchatel has endeavoured to show, that the de- 

 tritus of the rocks of the right and left sides of the upper valley of 

 the Rhone have also maintained their original relative positions in 

 the great extra Alpine depression (Lake of Geneva), and that these re- 

 lations are proofs, that nothing but a sohd glacier could have arranged 

 the blocks in such linear directions. But the author meets this ob- 

 jection by suggesting that there are notable examples to the contrary. 

 He also refers to the great trainees of similar blocks which preserve 

 hnear directions in Sweden and the low countries south of the Baltic, to 

 show that as this phsenomenon was certainly there produced by power- 

 ful streams of water, so may the Alpine detritus have been arranged 

 by similar agency. In alluding to the drainage of the Isere, he fm'ther 

 points to the admission of Prof. Guyot, that nearly all its erratic de- 

 tritus, both large and small, is rounded and has undergone great at- 

 trition ; and he quotes a number of cases in which such boulders and 

 gravel, derived from the central ridges of Mont Blanc, have been 

 transported across tracts now consisting of lofty ridges of limestone 

 with very deep intervening valleys ; and therefore he infers that the 

 "whole configuration of these lands has been since much changed, in- 



