Earths with Inflammables and Metals.
Obvious amongſt the productions of volcanoes, otherwiſe extremely rare.
Salts with Earths, Inflammables, and Metals.
Hardly to be expected but in volcanic mountains.
APPENDIX
THE SECOND.
Foſſils externally reſembling animals or vegetables, originate from foreign matters, which by ſome peculiar proceſs are changed in the boſom of the earth, or are ſo impregnated by mineral particles gradually occupying the place of thoſe which have putrified, that they no longer reſemble organic ſubſtances, except in figure.—Theſe are commonly called Petrefactions.