26 
SCENERY OF SWITZERLAND. 
which pass by Delle, Porrentruy, and St. Ursanne, 
continuing possibly by Sonceboz to Biel. 
The selection of Pontarlier for the line of railway 
has been determined by one of the geological events 
which has most profoundly affected^ tlie chain of the 
Jura. The displacement, commencing in the direc- 
tion of the valley of the Loue, and passing through 
it to the eastern end of Mont Tendre, has been 
utilised by rivers, roads, and railway lines. It passes 
nearly due S.N., and all the anticlinal and synclinal 
folds on the two sides of the line show a dislocation, 
sometimes amounting to 2 or 3 km. 
The Jura is very poor in rivers and streams. It 
consists mainly of calcareous strata, often much fis- 
sured, so that the rain sinks into the ground and 
reappears often in copious springs — named from one 
of the most celebrated “sources vauclusiennes” — 
where the water is brought to the surface by some 
more impervious stratum. 
In several cases the disposition of the ridges and 
the character of the rock is such, that the streams 
have no natural issue, and after a longer or shorter 
course under ground, reappear at some distance. 
Thus the 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 
