• Thus we conclude, that the strata both primary and secondary, both those of ancient and those of more recent origin, have had their materials furnished from the ruins of former continents, from the dissolution of rocks, or the destruction of animal or vegetable bodies, similar, at least in some respects, to those that now occupy the surface of the earth.

    John Playfair, James George Playfair (1822). “Biographical memoir. Illustrations of the Huttonian theory of the earth”, p.32