LAKES. 
24I 
one of the side streams is often cut off, and forms a 
curved piece of standing water. 
6. Subsidence lakes, as already mentioned, occur 
principally in Triassic areas. The gypsum or salt is 
dissolved away in places, and eventually the ground 
gives way, leaving funnel-shaped hollows. 
Such a pool was actually formed near the village 
of Order in the Chablais in the year i860. There 
had previously been a strong spring giving rise to a 
stream. Suddenly the ground fell in, forming a pond 
about 20 metres long and 8 wide. Three fine chest- 
nut trees were engulfed, and the pool was so deep 
that at 20 metres no bottom was found, nor were 
even the tops of the trees touched.* 
These hollows are generally small, though in some 
cases, as for instance the Konigssee, the Lakes of 
Cadagno and Tremorgia in the Ticino, they are of 
considerable dimensions. Our Cheshire Meres are 
mainly due to the same cause. 
7. Lakes occupying craters are far from infrequent 
in Volcanic regions, as for instance in the Auvergne, 
the celebrated Lake Avernus in the district of Naples, 
and the Maare of the Eifel. There are, however, no 
crater lakes in Switzerland. 
* Favre, Rech . Geol vol. II. 
Scenery of Switzerland. I. 
6 
