134 
THE GROWTH OF CONTINENTS. 
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 Ju- 
rassic. Facing the range, you do not, as I have 
said, perceive any difference in the angle of in- 
clination ; 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 be- 
neath them. 
This is one of the instances in which the con- 
tact of two epochs is most directly traced. There 
is no question, from the relation of the deposits, 
that the J ura 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 enclose that inland sheet of water, 
gradually to be filled up by more modern accu- 
mulations, and transformed into the fertile plain 
which now lies between the Jura and the Alps. 
If the reader will for a moment transport him- 
self in imagination to the time when the south- 
