Davis.] 36 May 3, 



Morlot called attention to stratified gravels between two masses of boul- 

 der clay at the entrance to the valley of the Dranse, south of Lake Geneva, 

 and based his theory of a double glacial period upon this and similar obser- 

 vations elsewhere. (Lausanne, Soc. Vaud. Bull. 1855.) 



Heer describes the subglacial and interglacial gravels and lignites, and 

 decides that there must have been two ice-invasions of the lower ground of 

 Switzerland ; lie does not admit any great glacial erosion. (Die Urwelt der 

 Schweiz, 1865, 532, etc.) 



Lyell gives a general account of these beds in his Antiquity of Man, 

 1873, 365—, 352. 



On the Italian side of the Alps all the outer moraines are found on loose, 

 stratified deposits ; sections showing this superposition are given by — 



Martins et Gastaldi (Sur les terrains superficiels de la vallee du Po, 

 Soc. Geol. Bull, vn, 1849, 554), near Turin. 



B. Gastaldi (Riescavazione dei Bacini lacustri, Milano, Soc. Ital. Mem. 

 i, 1865 ), on the Dora Riparia. 



G. de Mortillet, at foot of Lago d'Iseo. (Soc. Geol. Bull, xvi, 1859, 888. 

 Sur l'affbuillement des anciens glaciers, Milano, Soc. Ital. Atti, v, 1863.) 

 In a comparison between the northern and southern flanks of the Alps, he 

 states that the general order of drift deposits, as seen at many points, is 

 " alluvion ancienne, depots glaciaires, alluvions recentes." (Soc. Geol. Bull. 

 xix, 1862, 849.) Mortillet and Gastaldi believe that the old gravels once 

 filled the lake basins, and have been swept out by glacial erosion ; for rec- 

 ognizing that part of the gravel is derived from the central Alps, and 

 refusing to admit that it might have been washed from glaciers occupying 

 the basins, they are driven to this conclusion. (See these Prcceedings, 

 xxi, p. 336, where the question is further discussed and fuller references 

 given.) Gastaldi later admits that glaciers may have cut out cirques and 

 rock-basins. (On the Effects of Glacial Erosion in Alpine Valleys, Geol. 

 Soc. Journ. xxix, 1873, 396-401.) 



G. Omboni considers the old gravels washed from the glaciers; the lakes 

 exist because occupied by ice to the exclusion of sediment. (I ghiacciai 

 antichi e il terreno erratico di Lombardia, Milano, Soc. Ital. Atti, III, 1861 ; 

 and Halle, Zft. Gesammt. Naturw. xxiv, 1864, 548.) 



B. 6. The Vosges. The same frequent superposition of moraines 

 upon water-worn detritus has long been known in the Vosges. 



E. Collomb. (Quelques observations sur le terrain quarternaire du bassin 

 du Rhin, et des relations d'age qui existent entre le terrain de la plaine et 

 celui de la montagne. Soc. Geol. Bull, vi, 1848-49, 479-499.) It is in this 

 paper that attention was first called to the importance of glacial mud as a 

 source of fine deposits. 



B. 7. Scandinavia and North Germany. In Northern 

 Europe we find Norway and the higher parts of Sweden show- 



