le, qu'il etoit, il redevient chaux, comme il etoit
auparavant."

Here is no question with regard to mere opinion, but to matter of fact;
and, in this case, nothing is more evident, than that upon the surface
of this earth, that is, in the examinable parts above the level of the
sea, there is no transition either of calcareous bodies into flint,
nor of flinty bodies into calcareous substance. Calcareous matter is
constantly dissolved by water, when it is exposed to the washing of
that fluid; and it is even dissolved out of the most perfect union or
combination with siliceous substance, and the most solid composition of
an insoluble body, as may be perceived in the decaying of feld-spar. A
superficial view of flints, which have come out of a body of chalk, may
have created such an opinion, which will not either bear the light of
chemical or mineral investigation. The subject of these chalk flints
will be minutely examined in its proper place.

Our author has carefully examined the subject of flintification; and the
country where he makes his observations would seem to be well disposed
for such a research. He has had great opportunity and inclination to
examine the subject which he writes upon; and he has given a distinct
account of what be has seen. His description of the flintification of
sand-stone is extremely interesting. I will therefore transcribe it,
both as a valuable portion of natural history, and also in order to
contrast this author's opinion, with regard to the means employed by
nature in petrifying bodies, and that which I maintain to be the general
consolidating operation of the globe. It is Section V. _Generation du
Caillou du Silex du Gres, ou Pierre Sablonneuse_.

"Tout gres est susceptible de cette metamorphose quant au grain et quant
a la couleur; depuis la breccia quartzeuse jusqu'a la pierre a rasoir;
et depuis le gres blanc jusqu'au brun et presque noiratre, tient ou non
tient, dur, ou presque friable, c'est indifferent, toutes ces varietes
donnent du silex, et surtout de la calcedoine, de la cornaline, et des
agathes. Quant au ciment je l'y ai toujours remarque calcaire et faisant
effervescence avec les acides dans les endroits de la pierre qui
n'etoient point encore changes; et jamais je n'ai vu ce changement dans
du gres dont le ciment fut ou quartzeux ou argileux et refractaire.
Ainsi le ciment entre pour quelque chose dans ce changement.

"Le commencement de cette metamorphose paroit (autan