594 THE FRESH-WATER LOCHS OF SCOTLAND 
would have been much lower if the Rhine had been running in its 
former bed. 
The course of the Aar, which joins the Rhine on the left bank 
between Schaffhausen and Rasle, is interrupted by rapids caused by 
the uplift of ridges across the course of the river. Below Innert- 
kirchen is a ridge of rock, above which it has been supposed the river 
once formed a lake in the depression known as " Hasli-im-Grund,"" 
There is no direct evidence of this, however, and the river may have 
formed the famous Aar gorge by cutting through the ridge as it rose. 
Below Meiringen the river flows through a broad, flat valley, with 
terraces on each side, which was evidently once much deeper, and 
formed part of the I^ake of Brienz, but has gradually been filled up 
by the river. 
Lake of Brienz is 9 miles in length, by 2 miles in maximum 
breadth, and covers an area of 11 square miles. It lies 1857 feet 
above sea-level, has a maximum depth of 856 feet, a mean depth of 
577 feet, and is estimated to contain about 182,600 million cubic feet 
of water. The Lakes of Brienz and Thun were originally one, the 
level plain upon which Interlaken stands having been formed by the 
deposits of the River Llitschine, coming from Grindelwald on the 
south, and of the River Lombach, draining the valley of Habkern 
on the north. To judge from the depth of the lake, these deposits 
must be at least 1000 feet in thickness.^ 
The Aar follows a winding course on the plain of Interlaken, 
being first directed to the right by the cone of the Liitschine, and 
then to the left by that of the Lombach. The lower end of the Lake of 
Thun is dammed up in part by the deposits of the Simmen and the 
Kander, but the lower end of the valley has risen relatively. 
Lake of Thun lies 1837 feet above sea- level, and covers an 
area of about 18 square miles. The greatest depth is 712 feet, and 
the mean depth 443 feet. The volume of water contained in it is 
estimated at about 229,600 million cubic feet. 
The Thiele (Zihl) rises under the neve of Orbe in the valley of the 
Joux, in the Jura, and after flowing for some miles in an underground 
channel passes through the Lakes of Neuchatel and Bienne to join 
the Aar. The Jura range consists mainly of calcareous strata, often 
much fissured, so that the rain sinks into the ground and reappears 
after a longer or shorter course underground. Thus the River Orbe 
commences in a closed valley. The upper part, or Vallee de Joux, is 
double, one branch being without any river, except a little streamlet 
which flows into the Lake of Ter. The southern valley is traversed 
by the Upper Orbe, which falls into the Lake of Joux, and its 
continuation, the Lake of Brenet. Neither of these lakes has any 
^ Lubbock, oj). cit., p. 382, 
