[Note 41: From the description given in this treatise, and from the
drawings both of M. de Carosi and M. Macquart, I find a very valuable
inference to be made, so much the more interesting, as I have not found
any example of the like before. This arises from the intimate connection
which is here to be perceived between agate and gypsum. Now, upon this
principle, that the agate-calcedony had been formed by fusion, a truth
which, from the general testimony of minerals, I must presume, it is
plain, that those nodules of gypsum had been in the fluid state of
fusion among those marly strata, and that the gypseous bodies had been
penetrated variously with the siliceous substance of the calcedony.
The description of those siliceous penetrations of gypsum is followed by
this conclusion: "En voila assez, je crois pour faire voir que le silex
ci-decrit est effectivement une emanation du gypse, et non pas une
matiere heterogene amenee d'autre part et deposee, ou nous la voyons."
In this instance our author had convinced himself that the calcedony
concretions had not been formed, as he and other mineralists had before
supposed, by means of infiltration; he has not, however, substituted
any thing more intelligible in its stead.
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