LAKES GENEVA ANT) LUCERNE 377 



and Porto Ceresio, the shallows grown with reeds seem to suggest a back- 

 ing up of the water. The delta fronts at Lugano and Porlezza stand 3 or 

 4 feet above the water. Nothing more definite was found. 



A more promising subject, and the onty remaining promising one in 

 Italy for studies of this kind, is lake Iseo, but this was not visited. 



Lake Geneva 



My observations on lake Geneva were fewer than on the Italian lakes, 

 but, so far as the}' go, seem to indicate a similar direction of deformation, 

 though less in amount. At the time of my visit I was not acquainted 

 with Forel's great work, and so, unfortunately, did not profit by his 

 studies. Forel mentions two principal sets of terraces, one at about 10 

 meters altitude and the other at about 30 meters* with a few scattered 

 ones at higher levels. I saw some of these near Vevay, Lausanne, and 

 Thonon. I did not observe wave-made features in connection with them, 

 and so regarded them as products of ice-border drainage rather than true 

 deltas made in the margin of open water. The breadth of lake Geneva 

 in its broader part seems, by comparison with the broader part of lake 

 Garda, to justify the expectation of a recognizable wave-made shoreline, 

 provided the lake stood long enough at one level. 



Besides the deltas described by Forel, I found near Lausanne a feature 

 which appeared to be a true old shoreline in the form of a sandy bench 

 12 to 14 feet above the lake. There appeared to be a faint wave-cut ter- 

 race also at Evian and Thonon on the south shore, but at these places 

 only 7 or 8 feet above the water. Faint marks supposed to belong to the 

 same stage of the lake were seen near Nyon and Rolle on the west shore. 

 If these features are of the character supposed, they seem to show an old 

 lake surface rising northward 12 to 14 feet in about 20 miles. Lake 

 Geneva, like the lakes studied in Italy, has its outlet to the south, though 

 its greatest extent in a north and south direction is only 20 miles. 

 Forel's observations suggest no deformation, though the fragments above 

 30 meters altitude were said to be at discordant heights. A slight differ- 

 ential tilt like that here recorded would be hard to determine in so short 

 a distance as 20 miles b}' the study of old delta deposits. So small a 

 factor might easily have been overlooked. 



Lake Lucerne 



The remaining larger Swiss lakes — Neuchatel, Lucerne, Zurich, and 

 Constance — have their outlets to the north. If they have suffered 

 changes of attitude in the same direction as the Italian lakes and lake 

 Geneva, the change has been equivalent to a depression of their south- 

 ward parts, and, except at their outlets, their waters must now stand at 



* F. A. Forel : Le Leman, Monographie Limnologiqae, pp. 175-179. 

 LI— Bull. Geol. Soc. Am., Vol. 15, 1903 



