NOTES ON THE THICKNESS OF THE LUCERNE GLACIER, ETC. 289 



mountains of the Bernese Oberland and adjoining heights. 

 Similar erratic blocks are to be observed near the Seelisberg 

 (Sonneiiberg) Hotel, resting directly on the surface of the native 

 limestone and amongst the forest trees overlooking the lake. 

 The height to which these erratic blocks extend above the 

 surface of the lake is about 1,400 feet, which may be taken as 

 the limit to which the edge of the former glacier extended. 



That these transported blocks had their origin in the Bernese 

 Oberland, the St. Gotthard and the Finsteraarhorn, at a 

 distance of 20 or 30 miles from the head of the lake, there 

 can be no doubt. The valley of the Eeuss, which is continuous 

 with that in which the upper lake lies, points towards these 

 distant snow- clad masses ; and we know from the observations 

 of geologists that they are formed of granite and varieties 

 of gneiss and schists, similar to those of which the boulders 

 themselves are formed.* From Dr. Baltzer's section, the 

 Finsteraarhorn is shown to be a mass of solid granite called 

 " black granite," while the St. Gotthard mass consists of gneiss 

 and varieties of schist. Such is the composition of the 

 boulders lying on the slopes of the Seelisberg at a distance, as I 

 have stated, of some 20 to 30 miles from their source. Similar 

 blocks occur on the adjoining ridge of Bergenstock ; and by an 

 opening in the moraine matter on the south side of the ridge 

 above Stanz I was able to observe the direction of the glacial 

 striae, indicating clearly that the ice had passed right over 

 the ridge into (what is now) the lake of Lucerne on the other side. 



It may be observed that the promontory above Trieb at 

 Seelisberg very naturally became the site of a moraine during 

 the period when the valley was the channel of a great glacier. 

 Here (as above observed) the glacier coming down from the 

 interior mountains along the Valley of the Eeuss into the 

 upper arm of the present lake called the Urner See, would 

 be forced to change its course to a direction at right angles, 

 owing to the barrier presented by the ridge of the " two 

 mysterious Mythen " as they are called by Lord Aveburyf by 

 which the ice was diverted westward. The ridge of Seelisberg 

 formed the inside of the elbo^v, and the movement of the ice 

 would be here retarded, with the result that the moraine matter 

 with its blocks of granite would be deposited at this spot. 



* See Von Dechen's Geologische Karte von Deutschland ; also Livret- 

 guide Geoloqiqiie de Le Jura et les Alpes (1894), Sheet 9, bv Dr. A. 

 Baltzer. 



t The Scenery of Switzerland, by Sir John Lubbock (Lord Avebury), 

 p. 283. 



