228 
SCENERY OF SWITZERLAND. 
caused by parts of these terraces slipping down 
bodily into the valley. 
The best preserved terrace is that which belongs 
to the level of the Bedrettothal. It diverges from 
the present valley level at Madrano, and bears also 
the villages of Altanca (1392 metres), Ronco (1373), 
Deggio (1214), and Catto (1244). It corresponds 
with the terrace of Andermatt on the Reuss. In 
spite of the destructive glacial action it can be traced 
round Monte Piottino, and below it again forms a 
broad terrace, visible even on small maps as bear- 
ing the villages of Osco (1164), Mairengo (923), 
Primadengo (975), Rossura (1056), Calonico (987), 
Cavagnano (1021), and Sobrio {1095). Calonico is 
celebrated as the seat of the terrible catastrophe of 
28th September 1868. From Atlanca to Sobrio this 
terrace drops 300 metres, while the present river 
valley falls 900 metres. Here also, therefore, the 
figures closely correspond with those of the Ander- 
matt terrace in the valley of the Reuss. 
The terrace, though not so continuous, can also 
be traced on the right side of the valley, where it 
supports the hamlet of Nante, and the Alps of Ravina, 
Prato, etc., as far as Chironico. 
Above this terrace is a yet higher one, (Fig. 145), 
specially well marked to the south of Monte Piottino. 
