586 GLACIAL DEPOSITS IN STJBALPINE SWITZERLAND. [Aug. 1 896. 



reply to Prof. Bonney he observed (1) that, as explained in the paper, 

 the high-level Pliocene Nagelfluh-deposits were, in his view, formed 

 during the recession of the ice-sheet, and the low-level deposits 

 during the subsequent recession of the local glaciers left in the 

 valleys ; (2) that hence it was by no means necessary to assume the 

 Zurich Valley to have been filled with that glacio-nuviatile material 

 to a depth of 1200 feet — indeed, the individual deposits probably in 

 no case exceeded 200 feet in depth ; (3) that he had found distinct 

 evidence of younger, loose gravel being banked against the older 

 calcified conglomerate both at various points near Baden and else- 

 where ; and (4) that the Uetliberg conglomerate was not deposited 

 on the present narrow ridge, but on a flat Molasse dome which 

 afforded ample room for a glacier-stream, and whose flanks were 

 subsequently excavated and sapped by a parallel Postglacial river 

 on each side. In reply to Dr. Hinde, he said that he used the 

 term ' Pliocene ' Nagelfluh (1) because the conglomerate was clearly 

 younger than the Miocene conglomerate and older than the Pleisto- 

 cene gravels ; and (2) because the first glaciation, including the 

 deposition of the conglomerate in question, was by Swiss geologists, 

 too, explicitly and on grounds of palseontological analogy, referred 

 to the Upper Pliocene period. With regard to Mr. Hill's remarks, 

 he regarded the deflection of the Sihl, from its original outlet to 

 the Lake of Zurich, by a stupendous moraine-wall 5 miles in length 

 and 400 feet in depth, as one of the most remarkable instances of its 

 kind in the Swiss Alps. 



