s le plaines au contraire, et a
l'embouchure des vallees, qui aboutissent aux plaines et meme assez haut
sur les pentes des montagnes qui bordent ces plaines, on trouve des
cailloux et des blocs que l'on diroit tombes du ciel, tant leur nature
differe de toute ce que l'on voit dans les environs."

Here are facts which can only be explained in supposing that the valleys
have been hollowed out of the solid mass, by the gradual operation of
the rivers. In that case stones, travelled from a far, will be found at
considerable heights, upon the sides of the valleys at their under end,
or where, as our author says, they terminate in plains.

We have a striking example of the operation of time and the influences
of the atmosphere, in wasting the surface of the rocks, and forming soil
upon the earth; this is the kaolin of the Chinese, or the true porcelain
earth, which is the produce of granite countries. The feldspar of the
granite rock exposed to the atmosphere is corroded very slowly indeed,
by the effects of air and moisture, and in having the soluble earth or
calcareous part of its composition dissolved; the surface of this stone,
thus, in a long course of time, becomes opaque in having the white
siliceous earth exposed to view, and thus appears like a calcined
substance. The snows and rain detaches from this surface of the rock the
white earth, which being deposited in the plain below, forms a stratum
of kaolin more or less pure, according to the circumstance of the place.

As this operation of the atmosphere upon the surface of granite is so
extremely slow as to be altogether unmeasurable to man; and as there are
in many places of the earth inexhaustible quantities of this kaolin,
notwithstanding a small portion only of the ablution of the rock had
been retained upon the surface and deposited by itself, it must appear
that much time had been required for amassing those beds of kaolin, and
that these operations, which in the age of a continent is nothing, or
only as a day, are, with regard to the experience of man, unmeasurable.

For approbation of this theory, it is not necessary to show, that
wherever there is granite found, there should be also kaolin observed;
but it is necessary that wherever kaolin is found, there should be also
granite or feldspar to explain its origin; and to this proof the theory
is most willingly submitted. The following are the places which have
come to my knowledge. First Loch Dune in the shi