344 Dr. C. S. Da Riche Preller — Alpine, Lowland, and 



Switzerland, I shall confine myself to those lake basins from whose 

 glacial or hydrographic features definite conclusions may be drawn. 

 The illustrations (Sheets Nos. 1-4, Figs. I-X), having to cover the 

 large area of Central and Northern Switzerland, are necessarily 

 drawn to a small scale, but all particulars may be gleaned from the 

 Swiss 1 : 25,000 contour map, to which the metric altitudes and 

 dimensions in this paper correspond. 



I. Lakes with Gouge Exit Channels. 



1. Lake Klontal (Sheet No. 1, Fig. I), one of the most picturesque 

 though least known of the smaller Alpine lakes, lies in a Cretaceous 

 basin between the Glarnisch and Wiggis massifs at altitude 826 metres, 

 about 80 metres above Glarus in the Linth "Valley. The present lake 

 has shrunk from its original length of 6 km. to 2 - 5 km., its average 

 width being 500 metres and its greatest depth 31 metres. Its two 

 main affluents are the Klon and the Rosematter streams, the latter 

 of which rises in one of the Glarnisch glaciers. Its exit is by a steep 

 and narrow gorge channel through which the Lontsch, in a series of 

 cascades about 2 km. in length, reaches the Linth Yalley and 

 discharges into the Linth at Nettstall, a short distance below Glarus, 

 at altitude 440 metres, the average fall in the total length of 3 km. 

 being thus 1 in 8. The lake has probably reached its present greatest 

 depth by solution ; the hanging valley in which it lies is of special 

 interest in that its altitude indicates the former level of the Lintli 

 Yalley floor, which, like that of the Zurich Valley in the same drainage 

 area at the time of the Deckenschotter being deposited on Utliberg 

 after the first glaciation, was subsequently eroded to its present level, 

 about 400 metres lower. 



2. Lake Aegeri (Sheet No. 1, Fig. I) occupies a basin in the Molasse 

 area at the western base of Rossberg, at altitude 725 metres. Its 

 present length of 5 km. is barely one-half of its former extent, 

 while its average width is now 1 km. and its greatest depth 

 80 metres. As a storage basin it is of great industrial importance to 

 Canton Zug. It derives special interest from the moraine wall 

 which, beginning at its lower end, extends down to the Zug Valley. 

 After overflowing this wall at a much higher level than now, the 

 Lorze cut through it, as well as through the older glacial deposits 

 below, down to the Molasse, thus forming the Lorze ravine, 6 km. 

 in length at a fall of 1 in 20. Beyond this moraine and gravel bank 

 fully 100 metres in depth, the Lorze built up an extensive cone in 

 the direction of its flow towards the Reuss, of which it was then 

 a direct affluent. The present Lake Aegeri, as a moraine-barred 

 basin with a steep exit channel, was obviously formed during the 

 recession of the Reuss Glacier, which, in its last advance, impinged 

 upon Rigi and Rossberg, and then flowed round them in three 

 branches. 



3. Ancient Sihl and Waeggi Lakes (Sheet No. 1, Fig. I). — These two 

 basins, although their lakes are extinct, may be grouped with the 

 preceding ones as having moraine bars and steep exit channels, and 

 as such may be termed "ancient glacier lakes in overflow valleys". 

 As is seen from the sketch-plan, they lie in the Molasse area on the 



