24 
SCENERY OF SWITZERLAND. 
at Court, and find an exit northwards by Moutier to 
Delemont. The valley of Delemoiit itself is another 
case. Two streams, one from the east, another, the 
Some, from the west, meet the Birse near Delemont, 
and run through another cluse to the N.E. 
The Jura is thus crossed by four principal trans- 
verse valleys or cluses. 
The longitudinal valleys were probably filled at 
one time by mollasse, and some perhaps formed 
lakes, as, for instance, the flat plains near Pontarlier, 
Delemont, the Val St. Imier, etc. Between Delemont 
and Soleure are several ridges, which are cut through 
by the “cluses” of the Birse and the Some. If we 
imagine these “cluses” abolished, the result would 
be to form lakes; these would gradually fill up, and 
eventually run over where the “cluses” now are, 
which would thus be re-excavated. This throws 
light on the cases, not othenvise easily explicable, 
where in neighbouring and parallel valleys the streams 
run in opposite directions. The valley of Etraches, 
for instance, N.E. of Pontarlier, runs parallel to that 
of the Doubs, but the Etraches runs from N.E. to 
S.W., the Doubs from S.W. to NE. Nay, the Doubs 
itself, after running north-eastward to St. Ursanne, 
between rocks 250 to 300 metres high, makes an 
extraordinary turn. Its course so far had been in 
