in the strata of
the earth, and which had come from the mineral region in a consolidated
state, have, without due consideration, attributed to this cause all the
appearances of petrifaction or mineral concretion. It has been one of
the objects of this work to show that this operation of incrustation,
or petrifaction by means of solution, is altogether ineffectual for
producing mineral concretions; and that, even were it capable of forming
those mineral bodies, yet that, in the solid parts of this earth, formed
by a deposit of travelled materials at the bottom of the sea, the
conditions necessary to this incrustating process do not take place.

Those enlightened naturalists who have of late been employed in
carefully examining the evidences of mineral operations, are often
staggered in finding appearances inconsistent with the received doctrine
of infiltration; they then have recourse to ingenious suppositions, in
order to explain that enigma. In giving examples of this kind. I have in
view both to represent the natural history these mineralists furnish
us with, which is extremely interesting, and also to show the various
shapes in which error will proceed, when ingenious men are obliged to
reason without some necessary principle in their science. We have just
now had an example in Europe; I will next present the reader with one
from Asia.

M. Patrin, in his _Notice Mineralogique de la Daourie_, (Journal de
Physique, Mars 1791) gives us a very distinct account of what he met
with in that region. Describing the country of Doutchersk upon the river
Argun, in Siberia, he proceeds thus:

"Ces colines sont formees d'un hornstein gris qui paroit se convertir en
pierre calcaire par l'action des meteores; car tout celui qu'on prend
hors du contact de l'air donne les plus vives etincelles, et ne fait pas
la moindre effervescence avec les acides, meme apres avoir ete calcine;
et l'on observe celui qui est a decouvert, passer, par nuances
insensibles, jusqu'a l'etat de pierre calcaire parfaite de couleur
blanchatre."

Here M. Patrin has persuaded himself, probably from an imperfect
examination of the subject, that there takes place a mineral
metamorphosis, which certainly is not found in any other part of the
earth, and for which he does not find any particular cause. The natural
effect of the meteors, in other parts of the earth, is to dissolve the
calcareous substance out of bodies exposed to those agents; and the
gradation