In the present chapter Dr. Heddle considers the ores of manganese, iron, chromium, and titanium.

He finds that almost all the manganese in Scotland occurs in the form of an ore of little value—psilomelane.

Iron, he has observed in minute laminable specks, in the free or metallic condition, at two localities, but sheathed in both cases in magnetite. The quantity was too small for determining the presence or absence of nickėl, but he conjectures that these specks may have been minute meteorites, which had fallen into the ocean in which the rock was being formed.

He has found two ores of iron new to Britain,—turgite and martite,—the one near Oban, the other in Bute.