196 SCENERY OF SWITZERLAND. 
Walen, the other continues along the left bank of the 
Rhine valley to and beyond Winterthur. 
The Green Julier Granite occupies the centre. 
It comes from the mountains over the Upper Enga- 
dine, down the Oberhalbstein Rhine and the Albula, 
is scattered over the Canton of Thurgau, along the 
west of the Lake of Constance, and far away to the 
north and east. 
The Brown Gneiss of Montafun lies to the east. 
It comes down the valley of the 111 to the Rhine at 
Feldkirch, extends to the east of the Lake of Con- 
stance, and is abundant at Lindau, reaching far 
beyond Ravensburg. 
Thus the Puntaiglas Granite is found only on the 
west, the Julier Granite in the centre, and the Brown 
Montafun Gneiss on the east. 
The Lake of Constance is 400 metres above the 
sea and 276 metres in depth; it is 40 miles long 
and covers 208 square miles. At its west end it is 
dammed up to a certain height by the deposits of 
the ancient Rhine glacier. These, however, would 
not, as Prof. Penck has been good enough to inform 
me in a letter, account for more than say a quarter 
of its depth. 
It is therefore a rock basin. 
