mineralogists, as occurring in the oldest serpentine, as much as that at Chiavenna and elsewhere.
There is a little way below the Pass-d'Olen, a ridge connected with the main body of Monte Rosa itself, a bed of magnetic iron[1] which is worked, though situated at the height of eight thousand eight hundred and fourteen feet above the level of the sea, so that without going out of the boundary of this mountain we find arguments supported by certain facts, proving that the characters which have been pointed out as distinguishing the two kinds of formation, are not well founded. Cornwall furnishes an example no less conclusive, as we find at the most southern point of the Lizard, the serpentine resting on mica slate, though it appears as if occurring there in mass.
Of all the characters which have been considered, I see only one, upon which we can rely in establishing a division in the serpentine formation, if such a division be at all necessary, viz. that the serpentine is found either stratified; or in mass, in balls, and forming subordinate beds. All the other circumstances which have been hitherto thought to characterize the one or the other of these formations, appear to me to belong to both indifferently. It is probable that there may be some reason for admitting a difference of age in the serpentine formation, but on what ground this distinction is to be admitted, does not appear. It is a subject which among a great many others ought to excite the attention of those who are interested in the study of the physical structure of our globe. Let us imitate the example of the most skilful geologists, of Pallas, and of Saussure, who without ever losing
- ↑ Brochant also mentions this mine; he calls the Pass-d`Olen the Col d'Olingade. Traité de Minéralogie, tom. ii. p. 278.
