DIRECTIONS OF RIVERS. 
227 
and is at one place not more than 14 feet across. 
There are reasons, moreover, as we shall see pre- 
sently, for considering the defile to be of com- 
paratively recent origin. Moreover, at various points 
round the Lake of Geneva, remains of lake terraces 
show that the waters once stood at a level much 
higher than at present. One of these is rather more 
than 76 metres above the lake. 
The low tract between Lausanne and Yverdun 
has a height of 76 metres (250 feet) only, and 
corresponds with the above-mentioned lake terrace. 
The River Venoge, which rises between Rolle and 
the Mont Tendre, runs at first towards the Lake of 
Neuchatel, but near La Sarraz it divides; the valley 
continues in the same direction, and some of the 
water joins the Nozon, which runs to the Lake of 
Neuchatel at Yverdun; but the river itself turns 
sharply to the south, and falls into the Lake of 
Geneva to the east of Morges. 
It is probable, therefore, that when the Lake of 
Geneva stood at the level of the 76 metres terrace 
the waters ran out, not as now at Geneva and by 
Lyons to the Mediterranean, but near Lausanne by 
Cissonay and Entreroches to Yverdun, and through 
the Lake of Neuchatel into the Aar and the Rhine. 
But this is not the whole of the curious history. 
15* 
