568 DE. C. S. DTJ RICHE PEELLER Off GLACIAL [Aug. 1 896, 



view, Deckenschotter, while the former, which constitutes the upper 

 portion of the peninsula, is probably the indirect product of the second 

 glaciation. The contact of the old conglomerate with the Molasse 

 is not disclosed, but is probably some 20 metres below the level of 

 the lake, which near this point attains its maximum depth of about 

 142 metres. The occurrence of Deckenschotter on this quasi- 

 promontory, and even below the lake-level, is, at first sight, ex- 

 tremely puzzling ; but the phenomenon admits, in my opinion, of an 

 adequate explanation, namely, that the submerged Molasse-floor of 

 the present peninsula was originally, that is, before the first glacia- 

 tion, at a higher level ; that on this Molasse-floor the Deckenschotter 

 was deposited during the recession of the glacier ; that during the 

 following Interglacial period it was, by erosion, reduced to an island 

 which shared the general subsidence of that part of the valley, as I 

 shall show farther on ; that the superposed younger gravel, which 

 also filled the gap between the island and the mainland, was 

 deposited during the recession of the glacier of the second Ice- 

 period, and that the gap was re-eroded after the third glaciation, 

 the island thus reconstituted being, by subsequent alluvial deposit, 

 again connected with the mainland, and assuming the form of a 

 peninsula, as it appears at the present day. 



Albishorn. — On the Albis range, which flanks the left side of the 

 Zurich lake- and Sihl valleys, and extends from the Uetliberg to the 

 Albishorn, the Molasse is generally overlain by moraine and an 

 abundance of erratic blocks of the second or maximum glaciation ; 

 but above and below this moraine there occur, more especially near 

 the southern end, various deposits of glacio-fluviatile conglomerate, 

 of which those of the Albishorn and Biirglenstutz may serve as 

 typical examples. Below the inn on the summit of the Albishorn, 

 which is at contour 915, or 45 metres higher than the summit of 

 the Uetliberg, a spring issues at the contact of the Deckenschotter 

 and the underlying impervious, boulder-bearing, glacial clay. The 

 latter can be traced some distance down the brook, but its contact 

 with the Molasse is indistinct and lies somewhere near contour 850. 

 The cliff of well- cemented, coarse, and horizontally stratified Caver- 

 nous Nagelfluh which overlies the glacial clay is about 5 metres 

 in depth. The pebbles, occasionally striated and coarser at the top 

 than at the bottom, are, however, remarkably fresh, and the con- 

 glomerate, although obviously Deckenschotter, differs from the 

 Uetliberg deposit just as much as the latter differs from that of Au, 

 in striking confirmation of my former conclusion that the difference 

 observable between various deposits of this conglomerate is not of 

 kind, but of degree. Upon the Albishorn Deckenschotter rests, to 

 a depth of about 15 metres, a much looser conglomerate, in which 

 scratched pebbles, as evidence of the proximity of the glacier, are 

 numerous, and which, moreover, contains small lumps of the old 

 conglomerate ; while farther on, towards the end of the range, the 

 same gravel overlies an extensive exposure of loose surface-moraine 

 about 20 metres in depth. On both sides of the Albishorn inn 

 the Deckenschotter crops out at various points of the narrow ridge, 



