172 PROP. E. J. GARWOOD ON THE P^&y I906, 



patches of snow, which lie throughout the greater part of the year in 

 hollows near the watershed ; but one, the lowest, occupying the centre 

 of the cirque, originates in the little La go Taneda mentioned on 

 p. 168. This cirque is a good example of an escarpment-cirque, 

 formed by a series of streams which derive a constant supply from 

 lakes and melting snow. The water from Cadagno winds through 

 the alluvial and morainic material mentioned on the previous page, 

 to the edge of the rock-escarpment of quartz-calc-garnet schist ; but 

 the fall is very slight, probably not more than a few feet. The 

 rock-basin of Cadagno must, therefore, be at least 50 feet deep. 

 From the edge of the escarpment the water plunges abruptly into 

 the Ritom basin, down a cliff 100 feet high, near the centre of the 

 synclinal fold. 



Lago Scuro (see Pis. XII & XIX) is undoubtedly one of the 

 most interesting of the lakes in this district. It lies at a height of 

 8048 feet, and is situated almost on the watershed between the 

 Ticino and the Reno di Medels (or Medelser Rhein), its exact 

 position being some 150 or 160 feet below the summit of the ridge 

 on the northern side. It drains through the Yal Cadlimo into the 

 Medelser Rhein, and occupies a true rock-basin, which lies along the 

 junction between the schist and the northern mass of gneiss. 



It is roughly oval in shape, and has a longer diameter of 404 yards, 

 which runs north-north-east and south-south-west. The only 

 drainage that it receives is derived from the melting snow round its 

 sides, and it discharges its surplus water down a rocky channel into 

 the Cadlimo River. The bathymetrical chart (PI. XIX) shows it 

 to have a maximum depth of 138 feet. The contours run roughly 

 parallel to the shore, and the axis of greatest depth lies east-north- 

 east and west-south-west, in the general direction of the junction 

 of the gneiss and the crystalline schists. The shore is entirely 

 formed by rock in situ with occasional loose blocks, while a patch 

 of snow permanently occupies a portion of the eastern bank. The 

 dip of this schist is about 40° northward, but it can be seen sweeping 

 round in a basin-like curve across the southern end of the lake. 

 Soundings show that ridges of rock continue under water for some 

 distance out, and thin bands of harder material have weathered out 

 so sharply as to cause considerable trouble in using the sounding- 

 line. 



Lago Taneda (for contour-map, see PI. XX) occupies a rock- 

 basin, lying at a height of 7740 feet, and is situated along the same 

 line of strike as Lago Scuro. According to Dr. Eritsch, who mapped 

 the district in detail, the junction between the northern mass of 

 gneiss and the underlying schist runs down the middle of the lake. 

 The relation between these rock-masses at the exit is not very 

 clear ; but the gneiss is well seen, forming the watershed above 

 the north side of the lake, where it appears to be iceworn. The 

 southern shore is formed of a gneissose mica-schist dipping about 

 40° northward ; but immediately below this, on the track leading 



