VII RIVERS AND LAKES 307 
The Vorder and Hinter Rhine united then 
(Fig. 43) as they do now at Reichenau, but at 
a much higher level, and ran to Mayenfeld, 
not by Chur, but by the Kunckel Pass to Sar- 
gans, and so on, not to the Lake of Constance, 
but to that of Zurich. The Landwasser at 
that time rose in the Schlappina Joch, and 
after receiving as tributaries the Vereina and 
the Sardasca, joined the Albula, as it does now 
at Tiefenkasten ; but instead of going round 
to meet the Hinter Rhine near Thusis, the 
two together travelled parallel with, but at 
some distance from, the Hinter Rhine, by 
Heide to Chur, and so to Mayenfeld. 
In the meanwhile, however, the Land- 
quart was stealthily creeping up the valley, 
attacked the ridge which then united the 
Casanna and the Madrishorn, and gradually 
forcing the passage, invaded (Fig. 44) the 
valleys of the Schlappina, Vereina, and Sar- 
dasca, absorbed them as tributaries, and, 
detaching them from their allegiance to the 
Landwasser, annexed the whole of the upper 
province which had formerly belonged to that 
river. 3 
