and Lake Basins of Northern Italy. 405 



Riparia (Mt. Cenis) ; at Ivrea that of the Dora Baltea (Mt. Blanc and 

 Mt. Rosa) ; at the lower end of Lakes Maggiore and Yarese, that of 

 the Ticino and Toce (St. Gothard and Simplon) ; near Comoand Lecco 

 that of the Adda ; at the lower end of Lake Isco that of the Oglia ; 

 and at Lake Garda the terminal moraine of the Mincio glacier. 



The most formidable of these moraine walls are those of Ivrea and 

 at the lower ends of Lakes Maggiore, Como, and Garda. South of 

 Ivrea the Monte Rosa glacier, descending through the lower Dora 

 Baltea Valley, has left two stupendous marginal moraine walls, the 

 " Serre" of Andrate and Brosso, which reach a height of no less than 

 450 metres above the present river-level and, with the frontal moraine 

 broken up into hillocks and interspersed with morainic lakelets, form 

 a circumference of at least 50 kilometres. Again, south of Lakes 

 Maggiore and Varese, the concentric moraine belts of the Ticino and 

 Toce glaciers extend to 10 kilometres from the lake-end, with 

 a circumference of 50 kilometres and a height of 150 metres above 

 Lake Maggiore. South of Como the moraine deposits form, in 

 a distance of barely 10 kilometres, three separate concentric ridges 

 about 20 kilometres in length, rising to 152, 157, and 165 metres 

 above the level of Lake Como. Similarly, at the lower end of Lake 

 Garda, the moraine walls extend in concentric semicircles and an 

 extraordinary agglomeration of morainic hills 12 kilometres into the 

 Lombardy plain, with a circumference of at least 30 kilometres, and 

 rising to 23, 62, and 141 metres above the lake-level. 



The points where marine shells were found embedded in glacial 

 deposits are situated about 6 kilometres south and north-west of Como ; 

 the former near Fino, on the second of the three concentric moraine 

 ridges, about 160 metres above the present lake-level, and the latter 

 between Chiasso and Mendrisio in the Breggia Yalley, by which the 

 former Lugano fiord communicated with that of Como. 1 The most 

 northerly of the latter deposits is that of Pontegana, near Balerna, 

 about 90 metres above the present lake-level, which, being glacial 

 clay, corresponds to similar deposits near Yarese and to others in the 

 Ivrea district. In Lombardy the shell-bearing deposits rest directly 

 on Pliocene marl and are overlain by morainic material of sand, 

 gravel, and conglomerate, known as ceppo and ferretto, while in 

 Western and Southern Piemont many of the glacial deposits exhibit 

 intermediate flu vio- glacial alluvia, whose origin was at the time 

 a subject of keen controversy between Stoppani and Gastaldi. These 

 alluvia are, in fact, the southern equivalent of the ' ' alluvion ancienne " 

 and Deckenschotter north of the Alps, and, as such, the product of 

 a pre-maximum glaciation which in Upper Piemont, but not in 

 Lombardy, reached to the foot of the Alps. As regards the stupendous 

 Moraine Amphitheatre of Piemont and Lombardy as a whole, it can 

 only be the product of the maximum glaciation, while any pre- 

 maximum, as also the post-maximum or last glaciation, probably did 

 not descend much beyond the heads of the present lakes, or, roughly, 

 beyond a limit 30 to 40 kilometres distant from the Lombardy 



1 Most of these deposits are now obliterated, but ample specimens of the 

 marine shells are preserved in the Geological Museum of Milan. 



