Note 1 — Chapter VII · AUSTRALIA; NEW ZEALAND; CAPE OF GOOD HOPE.

I have lately seen, in a paper by Smith (the father of English geologists), in the Magazine of Natural History, that the grains of quartz in the millstone grit of England are often crystallised. Sir David Brewster, in a paper read before the British Association, 1840, states, that in old decomposed glass, the silex and metals separate into concentric rings, and that the silex regains its crystalline structure, as is shown by its action on light.