1873.] B0NNEY — ALPINE LAKES. 393 



discharge their waters into the Saale, which escapes northward 

 through a narrow glen in the dolomitic range about the head of the 

 Konigsee. Yet the watershed between the Saale and the Zeller 

 See (which enters the Salza) is a low rather irregular plateau, 

 which can hardly rise more than 1 00 feet at most above the bed of 

 the valley. Difficult as this valley-system is to explain*, it seems 

 impossible to attribute the Zeller See to ice-action. No arm from 

 the Pinzgau, or protrusion of the Fuschthal glacier, could have 

 worked it out ; nor, so far as I could see, was there any possibility 

 that a glacier could have come from the north. 



The following, then, is the result of my examination of the Salz- 

 kammergut and its vicinity : — We have here a district whose lakes, 

 though generally inferior in size to those of Switzerland, are more 

 numerous in proportion to its area. Some of them, to say the 

 least, lie in the neighbourhood of glaciers ; others have doubtless 

 been occupied by them. Two of them (the Konigsee and the 

 Hallstadter See) differ from all the Swiss lakes in lying practically 

 at the heads of valleys, just where we might expect a glacier- worn 

 basin to exist, if it did at any place ; and yet the forms of these two 

 are those which it is most difficult to reconcile with any theory of 

 glacier-erosion. Again others — the Fuschel, Wolfganger, Mond, 

 and Atter Seen — lie where it is almost impossible that any very 

 large ice-stream can have passed, or great pressure been exercised ; 

 yet one of these, and that the one most completely protected from 

 glacial action, is the largest and deepest in the whole district, deeper 

 than most of the Swiss lakes f. I think, then, we may safely assert 

 that, when applied to this region, the theory of glacier-erosion fails 

 to account for the phenomena. This being the case, we are led to 

 doubt whether the explanation which seems more specious in the 

 West and Central Alpine regions can, when we regard the general 

 unity of the whole chain of the Alps, be regarded as applicable even 

 there. 



Here I must for a moment refer to my previous communication 

 on the formation of cirques, in which I endeavoured to prove that 

 they were in the main preglacial. Further examination of one of 

 those there mentioned, and of several others, has fu]ly confirmed me 

 in this opinion, and convinced me that the excavating agent to which 

 they were assigned (the erosive action of streams) is the true one — 

 convinced me also that all the principal features of the Alps are of 

 earlier date than the glacial epoch. 



This being the case, it may be asked " What explanation is to be 

 given of the lake-basins ? what agent is capable of excavating these 

 hollows, often more than a thousand feet deep, which indeed some- 

 times descend to the sea-level ? No stream can have done this, no 

 theory of a special subsidence of the area just about the lake can be 



* To this subject I hope to return in a future paper. 



t The Lake of Geneva is not quite so deep at its deepest part. We may note 

 as a further difficulty that there are no signs of great lakes opposite to the 

 openings of the important rivers of the Salza and the Inn, while the great 

 Chiemsee is connected with a com pa rati vely small valley. 



