[1] Weinschenk, C. R. _Congrès Géol._, 1900, p. 321, et seq.
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back from admitting views which appeared so extreme. Receptivity
is the first virtue of the scientific mind; but, with every
desire to lay aside prejudice, many felt unequal to the
acceptance of structural features involving a folding of the
earth-crust in laps which lay for scores of miles from country to
country, and the carriage of mountainous materials from the south
of the Alps to the north, leaving them finally as Alpine ranges
of ancient sediments reposing on foundations of more recent date.
The historian of the subject will have to relate how some who
finally were most active in advancing the new views were at first
opposed to them. In the change of conviction of these eminent
geologists we have the strongest proof of the convincing nature
of the observations and the reality of the tectonic features upon
which the recent views are founded.
The lesser mountains which stand along the northern border of the
great limestone Alps, those known as the Préalpes, present the
strange characteristic of resting upon materials younger than
themselves. Such mountains as the remarkable-looking Mythen, near
Schwyz, for instance, are weathered from masses of Triassic and
Jurassic rock, and repose on the much more recent Flysch. In
sharp contrast to the Flysch scenery, they stand as abrupt and
gigantic erratics, which have been transported from the central
zone of the Alps lying far to the south. They are strangers
petrologically,
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stratigraphically, and geographically,[1] to the locality in
which they now occur. The exotic materials may be dolomites,
limestones, schists, sandstones, or rocks of igneous origin. They
show in every case traces of the severe dynamic actions to which
they have been subjected in transit. The igneous, like the
sedimentary, klippen, can be traced to distant sources; to the
massif of Belladonne, to Mont Blanc, Lugano, and the Tyrol. The
Préalpes are, in fact, mountains without local roots.
In this last-named essential feature, the Préalpes do not differ
from the still greater limestone Alps which succeed them to the
south. These giants, _e.g._ the Jungfrau, Wetterhorn, Eiger, etc.,
are also without local foundations. They have been formed from
the overthrown and drawn-out anticlines of great crust-folds,
whose synclines or roots are traceable to the south side of the
Rhone Valley. The Bernese Oberland originated in the piling-up of
four great sheets or recumbent folds, one of which is continued
into the Préalpes. With Lugeon[2] we may see in the phenomenon of
the formation of the Préalpes a detail; regarding it as a normal
expression of that mechanism which has created the Swiss Alps.
For these limestone masses of the Oberland are not indications of
a merely local shift of the sedimentary covering of the Alps.
Almost the whole covering has
[1] De Lapparent, _Traité de Géologie_, p. 1,785.
[2] Lugeon, _Bulletin Soc. Géol. de France_, 1901, p. 772.
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