and cut off the
Prealpes from their roots, there would have been found sheets, to
the number of eight, superimposed and extending between the Mont
Blanc massif and the massif of the Finsteraarhorn: these sheets
being the overthrown folds of the wrinkled sedimentary covering.
The general nature of the alpine structure

{Fig. 8}

will be understood from the presentation of it diagrammatically
after Schmidt of Basel (Fig. 8).[2] The section extends from
north to south, and brings out the relations of the several
recumbent folds. We must imagine almost the whole of these
superimposed folds now removed from the central regions of the
Alps by denudation,

[1] Lugeon, _loc. cit._

[2] Schmidt, _Ec. Geol. Helvetiae_, vol. ix., No. 4.

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and leaving the underlying gneisses rising through the remains of
Permian, Triassic, and Jurassic sediments; while to the north the
great limestone mountains and further north still, the Prealpes,
carved from the remains of the recumbent folds, now stand with
almost as little resemblance to the vanished mountains as the
memories of the past have to its former intense reality.

These views as to the origin of the Alps, which are shared at the
present day by so many distinguished geologists, had their origin
in the labours of many now gone; dating back to Studer; finding
their inspiration in the work of Heim, Suess, and Marcel
Bertrand; and their consummation in that of Lugeon, Schardt,
Rothpletz, Schmidt, and many others. Nor must it be forgotten
that nearer home, somewhat similar phenomena, necessarily on a
smaller scale, were recognised by Lapworth, twenty-six years ago,
in his work on the structure of the Scottish Highlands.

An important tectonic principle underlies the development of the
phenomena we have just been reviewing. The uppermost of the
superimposed recumbent folds is more extended in its development
than those which lie beneath. Passing downwards from the highest
of the folds, they are found to be less and less extended both in
the northerly and in the southerly direction, speaking of the
special case--the Alps--now before us. This feature might be
described somewhat differently. We might say that those folds
which had their roots farther

153

to the south were the most drawn-out towards the north: or again
we might say that the synclinal or deep-seated part of the fold
has lagged behind the anticlinal or what was originally the
highest part of the fold, in t