From all these facts it is plain that petrified shells are found in Europe, Asia, Africa, and in every place where the observations have been made; they are also found in America, in the Brasils; for example, in Tucumama, in Terra Magellinica, and in such a great quantity in the Antilles, that directly below the cultivable land, the bottom of which the inhabitants call lime, is nothing but a composition of shells, madrepores, astroites, and other productions of the sea. These facts would have made me think that shells and other petrified marine productions were to be found in the greatest part of the continent of America, and especially in the mountains, as Woodward asserts; but M. Condamine, who lived several years at Peru, has assured me he could not discover any in the Cordeliers, although he had carefully sought for them. This exception would be singular, and the consequences that might be drawn from it would be still more so; but I own that, in spite of the testimony of this celebrated naturalist, I am much inclined to suppose, that in the mountains of Peru, as well as elsewhere, there are shells and other marine petrifications, although they have not been discovered. It is well known, that in matter of testimonies, two positive witnesses, who assert to have seen a thing, is sufficient to make a complete proof; whereas ten thousand negative witnesses, and who can only assert not to have seen a thing, can only raise a slight doubt. This reason, united with the strength of analogy, induces me to persist in thinking the shells will be found on the mountains of Peru, especially if we search for them on the rise of the mountain, and not at the summit. The tops of the highest mountains are generally composed of rock, stone granite, and other vitrifiable matters, which contain no shells. All these matters were formed out of the beds of the sand of the sea, which covered the tops of these mountains. When the sea left them, the sand and other light bodies were carried by the waters into the plains, so that there remained only rocks on the tops of the mountains, which had been formed under those beds of sand. At two, three, or four hundred fathoms below the tops of these mountains, are often found marble and other calcinable matter, which are disposed in parallel strata, and contain shells and other marine productions; therefore it is not surprising that M. de la Condamine did not find any shells on these mountains, especially if he sought for them in the elevated parts of those mountains which are composed of rock, free-stone, or vitrifiable sand; but had he examined the lower parts of the Cordeliers, he would undoubtedly have found strata of stone, marble, earth, &c. mixed with shells; for in every country where observations have been made, such beds have always been met with.