not that those countries of
inferior hardness and elevation have been spared in the course of
time, but because we have not, in those levelled countries, such great
remainders, by which we are to judge the quantity of what is lost. In
the alpine country, again, though it be the same system of things with
that which takes place in the lower country, the revolution of things
is more marked for our view; and the ravages of time, in destroying
the solid parts of the globe, in order to make soil of that which is
removed, may be seen in all the steps of that important operation;
whereas, in the more level countries, the scale of elevation is
imperceptible, and that of time is so slow as renders our examination
fruitless. It is the Alps, therefore, chiefly that we are to take for an
example, in tracing this operation of nature upon the surface of this
earth, and forming some idea of the course of time that must have
flowed during that operation in which the height of our land had been
diminished.

On whatever side we approach the Alps, we find some great river
discharging the waters which had been gathered above, and with that
water all the waste of earth and stone which had been made among those
lofty masses of decaying rock. Now, we find this river running in a
valley proportioned, in general, to this vehicle, in which is travelled
the wreck of ruinous mountains. Spacious plains attend those mighty
streams; and, tho' sometimes we find the greatest rivers much confined
between approaching hills of solid rock, the valley opens again, and,
on the whole, is always corresponding to the current of water which has
successively run in all the quarters of this plain. Here a question
occurs; Has this valley been made by the operation of the river itself,
or has it been the effect of other causes? Let us now resolve that
question.

If the valley was made for the river by any other natural cause, either
we should tell by what means this work had been performed, or all
reasoning upon the subject is at an end, and fancy substituted in its
place. If again the river be considered as the means employed by nature
in making this valley, then all the solid parts between the bounding
mountains must have been removed, and the fertile plains must have been
formed by the water depositing those materials which we find in the
soil, and which had come originally from the solid mountains. There is
no occasion to enter into any argument to prove this