30 
SCENERY OF SWITZERLAND. 
contains. In many places the rocks are ground and 
polished by the glaciers. 
The Rhine at Basle runs on a bed of gravel 30 
V metres at least in thickness, and the hills on each 
side are capped with a yellow, fine, sandy, marl 
known as “loess,” up to a height of 100 metres.* 
Most indeed of the valleys were once much deeper 
than they are now. The bottoms are filled up with 
gravel and alluvium, indicating the presence of bars 
which are now covered up. The alluvial deposits 
often attain a great thickness. Near Travers a pro- 
posed railway bridge had to be abandoned, from 
the difficulty of obtaining any sufficient foundation.** 
r.AKF, OF NeUCHATEL. 
The Lake of NeuchMel is about 24 km. in length, 
and 6 in breadth. It is 432 metres above the sea 
153 in depth. Unless therefore the gravel beds 
of the Aar are 500 feet deep it is also a rock basin. 
It is surrounded by marshes which used to cover 
50,000 acres, but a good deal of the area has now 
been drained. 
The Lake of Neuchatel and of Bienne at one 
time formed a single sheet. Indeed, the former lake 
* Miiller, Beitr. z. Geol. IC d. Schw., L. I. 
** Jaccard, Beitr. z. Geol. K. d. Schw., L. VI. 
