The various heights and situations at which Pebbles are found have
led to many erroneous conclusions as to the period of changes of the
earth’s surface. All the banks of rivers and lakes, and the shores of
the sea, are covered with pebbles, rounded by the waves which have
rolled them against each other, and which frequently seem to have
brought them from a distance. There are also similar masses of pebbles
found at very great elevations, to which the sea appears never to
have been able to reach. We find them in the Alps at Valorsina, more
than 6000 feet above the level of the sea; and on the mountain of Bon
Homme, which is more than 1000 feet higher. There are some places
little elevated above the level of the sea, which, like the famous
plain of Crau, in Provence, are entirely paved with pebbles; while in
Norway, near Quedlia, some mountains of considerable magnitude seem to
be completely formed of them, and in such a manner that the largest
pebbles occupy the summit, and their thickness and size diminish as you
approach the base. We may include in the number of these confused and
irregular heaps most of the depositions of matter brought by the river
or sea, and left on the banks, and perhaps even those immense beds of
sand which cover the centre of Asia and Africa. It is this circumstance
which renders so uncertain the distinction, which it is nevertheless
necessary to establish, between alluvial masses created before the
commencement of history, and those which we see still forming under our
own eyes.
A charming monograph, entitled “Thoughts on a Pebble,” full of playful
sentiment and graceful fancy, has been written by the amiable Dr.
Mantell, the geologist.