738 THE JOURNAL OF GEOLOGY. 
bands of black and white running horizontally. It will be seen 
that the East Alps do not begin at once at the Rhine, but there 
is a promontory-like wedge of Helvetian strata (fine black hori- 
zontal lines) projecting along in front of their north border a 
considerable distance. In this wedge occur the enigmatical 
exotic bowlders by Bolgen (A of the map). 
lt will be noticed that) the’ clitts) and) exotic blocksmanre 
scattered with considerable irregularity along the north border 
of the Alps over a belt of Helvetian strata (indicated by the light 
horizontal lines) from about two to nearly nine kilometers broad. 
The exotic masses do not extend anywhere south of this strip. 
In the vicinity of Iberg, which has been studied with especial 
thoroughness, may be seen how the whole region between the 
southern border of the cliff belt and the northern border of the 
Helvetian chains is covered with exotic material. Abundant as 
is this exotic material here, every trace of it disappears a short 
distance south of the cliffs. This most striking limitation of the 
distribution of the exotic strata southward all along the Thun- 
Rhine cliff belt is precisely what we would expect if there had 
been an overthrust like that hypothecated. 
Summary and conclusion—To recapitulate, we have found 
Alpine facies in the Freiburg Alps at the west end of the cliff 
zone, Alpine facies again at the east end in the ‘East Alps,” 
Alpine facies also in the superficial cliffs and exotic blocks 
between these two points. In the Nagelfluh we have evidence 
of a former much greater extent of the cliff masses. In the 
cliffs themselves and in the fact that cliffs and exotic blocks lie 
invariably in Flysch we find evidence that they were thrust over 
Flysch; lastly, in the supposed Vindelicic system beneath the 
Miocene plains north of the cliffs we have a place—and appar- 
ently the only place—from which it seems possible that the 
cliffs could have been derived. These conclusions afford us the 
most satisfactory explanation of the cliff belt and the Freiburg- 
Chablais region as a whole and their relations to the East Alps, 
and render intelligible the presence of the Swiss plains —sunken 
between the “horsts” of the Alps and the Jura—and the isolated 
position of the Jural mountains on the far side of them. 
