THE JURA. 
19 
the figure 72, which represents the junction of the 
two at the Botzberg tunnel, near Brugg. 
Fig. 73 gives a section of the Wannenfluh, the 
mountain on the east of the cluse which leads from 
Balstatt to Oensingen between Soleure and Olten, 
and it is evident that the strata to the south have 
been thrust somewhat over those to the north. 
This “Zone de recouvrement,” as it is termed by 
the Swiss geologists, is shown by the belt marked 
with cross-lines in Fig. 71. It extends from Meltingen 
(S.E. of Laufen) by Reigoldswil, Oltingen, and Botz- 
berg, to near Baden in Aargau. The overthrust in- 
dicates that the pressure came from the south. 
Folded Jura. 
The Folded Jura is thrown into some 160 un- 
dulations and about fifteen main folds nearly parallel 
to one another. These however do not extend the 
whole length of the district; they are most numerous 
to the SW., where there are as many as twelve, but 
gradually coalesce towards the N.E., others from time 
to time making their appearance, but still the number 
gradually diminishing to a single anticlinal, which 
crosses the Reuss forming the Cluse south of Brugg, 
and finally disappears at Regensberg, to the north of 
Zurich. 
2 
