404 Br. Bu Riche Preller — The Moraine Walls 



suddenly came into prominence through the discovery, chiefly hy 

 Stoppani, of several glacial clay, sand, and gravel deposits in the 

 vicinity of Como, which contained marine shells, and therefore 

 demonstrated the presence of the sea in contact with the Alpine 

 glaciers. Stoppani' s conclusions, expounded in two brilliant memoirs, 1 

 were endorsed not only by his Italian confreres, Spreafico 2 and 

 Sordelli, 3 but also by distinguished geologists north of the Alps, 

 notably by Desor of Neuchateh/ Renevierof Lausanne, 5 and Rutimeyer 

 of Bale, 6 the revealing memoirs more especially of the two last-named 

 being models of classical and closely reasoned exposition. Since then 

 the subject has been enlarged upon chiefly by discoveries of interglacial 

 deposits in various sub- Alpine valleys debouching into the Lombardy 

 plain, and more recently Penck and Bruckner have dealt with it from 

 their point of view in their latest monumental work, 7 whose salient 

 features have been summarized by G. W. Wright. 8 But the evidence 

 adduced by the various Italian and other writers, including Penck's 

 somewhat laboured endeavour to work out his four glaciations for the 

 Alps en bloc, is as yet so conflicting that it is almost refreshing to 

 turn to the earlier and more conclusive views of Stoppani and his 

 contemporaries as a point of departure for considering the subject 

 mutatis mutandis, in order to arrive at some independent conclusions 

 from personal observation. 



I. The Moraine "Walls. 



As will be seen from the sketch-map, Sheet No. 1, Fig. 1, the belt of 

 double, in many places triple concentric moraine walls which fringes 

 the southern base of the Alps, forms roughly a semicircle extending 

 from Cuneo in the south of Piemont to Lake Garda in Lombardy, 

 a distance of about 400 kilometres, and from the last-named point to 

 the Frioul, another 200 kilometres. The most striking feature of this 

 belt consists not only in its remarkable extent but in the enormous 

 accumulations of glacial material, compared with which the morainic 

 deposits north of the Alps, notably in Switzerland, almost sink into 

 insignificance. The moraine walls were all formed, like so many 

 bars, in front of the exits of the principal valleys. Thus, near Cuneo 

 we find the terminal moraine of the Stura glacier ; west of Savigliano, 

 that of the Po (Monte Yiso) ; at Rivoli, near Turin, that of the Dora 



1 Stoppani, " II mare glaciale ai piedi delle Alpi " : Eivista Italiana, Agosto, 

 1874. " Sui Eapporti del terreno glaciale col Pliocenico nei dintorni di 

 Como" : Atti Soc. Ital. di Scienze naturali, Aprile, 1875. 



2 Spreafico, " Conchiglie marine nel terreno erratico di Cassina Bhizzardi 

 (Fino, Prov. di Como) " : Atti Soc. Ital., 1874. 



3 Sordelli, " La Fauna marina di Cassina Bhizzardi, Fino " : Atti Soc. Ital. , 

 1875. 



4 Desor, Le Paysage m'orainique et son origine glaciaire, Neuchatel, 1875. 



5 Benevier, " Belations du Pliocene et du Glaciaire aux environs de Come " : 

 Bull. Soc. Geol. France, s&r. Ill, tome iv, 1876. 



6 Butimeyer, Ueber Pliocan und Eisjoeriode auf beiden Seiten der Alpen, 

 Bale, 1876. 



7 Penck and Bruckner, Die Alpen im Eiszeitalter , 1909. 



8 G. W. Wright, The Quaternary Ice Age, 1914. 



