to
be but one uninterrupted slope by which it descends to the shore of the
lake. It will, however, be noticed by the most careless observer that this
slope is divided by the difference in vegetation into two strongly marked
bands of color: the lower and more gradual descent being of a lighter
green, while the upper portion is covered by the deeper hue of the
forest-trees, the Beeches, Birches, Maples, etc., above which come the
Pines. When the vegetation is fully expanded, this marked division along
the whole side of the range into two broad bands of green, the lighter
below and the darker above, becomes very striking. The lighter band
represents the cultivated portion of the slope, the vineyards, the farms,
the orchards, covering the gentler, more gradual part of the descent; and
the whole of this cultivated tract, stretching a hundred miles east and
west, belongs to the Cretaceous epoch. The upper slope of the range, where
the forest-growth comes in, is Jurassic. Facing the range, you do not, as
I have said, perceive any difference in the angle of inclination; but the
border-line between the two bands of green does in fact mark the point at
which the Cretaceous beds abut with a gentler slope against the Jurassic
strata, which continue their sharper descent, and are lost to view beneath
them.

This is one of the instances in which the contact of two epochs is most
directly traced. There is no question, from the relation of the deposits,
that the Jura in its upheaval carried with it the strata previously
accumulated. At its base there was then no lake, but an extensive stretch
of ocean; for the whole plain of Switzerland was under water, and many
thousand years elapsed before the Alps arose to set a new boundary to the
sea and inclose that inland sheet of water, gradually to be filled up by
more modern accumulations, and transformed into the fertile plain which
now lies between the Jura and the Alps. If the reader will for a moment
transport himself in imagination to the time when the southern side of the
Jurassic range sloped directly down to the ocean, he will easily
understand how this second series of deposits was collected at its base,
as materials are collected now along any sea-shore. They must, of course,
have been accumulated horizontally, since no loose materials could keep
their place even at so moderate an angle as that of the present lower
slope of the range; but we shall see hereafter that there were many