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V.—The Zonal Lake Basins of sub-Alpine Switzerland

Published online by Cambridge University Press:  01 May 2009

Extract

In two papers read before the Geological Society in 1904 I showed that the five principal lake basins of sub-Alpine Switzerland lie in a zone which is parallel to the Alps, and that this zone lies almost entirely in the Molasse formation. The conclusions which I drew from these facts as to the age and origin of these basins having, since then, been confirmed by further evidence, it will not be without interest to return to the subject.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1915

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References

page 215 note 1 Cf. Parker, G. H., “The Locomotion of Actinians” : Science, 03 26, 1915, p. 471.Google Scholar

page 215 note 2 Q.J.G.S., vol. lx, pp. 65, 316, 1904.Google Scholar

page 220 note 1 In the other lakes the fluviatile bars were formed by the following rivers: in the Lake of Zurich, by the Sihl ; in the Walensee (an old branch of the Rhine), by the Linth ; in the Lake of Lucerne, by the Emme, which, however, only deflected the Reuss instead of barring the lake ; in the Lake of Thun, by the Kander ; in that of Brienz, by the Lutschinen delta of Interlaken ; in the Lake of Geneva, by the Arve ; and in the Lakes of Neuchatel and Bienne, by the Aare.

page 221 note 1 The most formidable of these deltas is probably that of the Drance at Thonon (Savoy), which projects already 2 kilometres into the Lake of Geneva.

page 221 note 2 Of this, striking evidence is afforded by the interglacial gravel beds near Zurich, the material of which, being strictly fluviatile, can only have been transported across the filled-up lake by a river.

page 221 note 3 Heim, , Gletscherkunde, 1885, p. 542Google Scholar ; also Favre, , Récherches Géol., 1867, p. 210.Google Scholar

page 222 note 1 For instance, a glacier, to traverse a filled-up lake basin 40 kilometres in length, like that of Zurich, at the rate of 0·3 m. = 1 foot per day, would require over 300 years, and in the case of the Lakes of Constance and Geneva double that time.

page 222 note 2 The diagram refers to the area of the junctions of the sub-Alpine rivers between Zurich and Bale. In the Alpine valleys the former higher level of 400 metres would place the then valley floor, e.g. in the Linth Valley, on a level with the present Klōntal Lake, a hanging valley 400 metres above Glarus.

page 223 note 1 Some Swiss lowland Deckenschotter deposits at a somewhat lower level than the typical high-level ones led Mühlberg, Penck, and Brückner to assume a fourth glaciation (in the Tyrol even five), intermediate between the first and maximum glaciations ; but those lower deposits may be, like that of Teufelskeller, near Baden, west of Zurich, due to local subsidence.

page 223 note 2 On the other hand, a big glacier is indirectly a potent factor in valley-making and valley-shaping by the disintegrating action of frost and of the great differences between extreme temperatures on the mountain-sides as well as by its great lateral and vertical pressure. In this action lies obviously the via media between the extreme views pro and contra glacial erosion.

page 224 note 1 Renevier, L’Axe Anticlinal de la Molasse, 1902Google Scholar; Heim, Beitrage, xxv, p. 475, 1891.Google Scholar

page 224 note 2 The retreat of the glaciers must have been of very long duration, for in the Zurich sub-Alpine valley alone there are no less than four successive moraine bars across it, each of which is evidence of a long stage in the recession.

page 224 note 3 A similar instance of zonal subsidence appears to be that of the Cleveland (Yorks) and the Black Combe (South-West Cumberland) “ancient glacier lake” districts, both of which, according to Kendall, P. F. and Smith, B., were in pre-Glacial times at higher levels than at present (Q.J.G.S., vol. lviii, p. 471, 1902CrossRefGoogle Scholar ; vol. lxviii, p. 402, 1912).

page 224 note 4 In 1906 an instructive section was exposed at Clarens at a junction of roads about 60 metres above the lake, showing about 20 metres of moraine with overlying stratified gravel dipping reversely like the rock strata in the immediate vicinity.