Note 9 — Chapter III · ASCENSION.

Daubeny, in his work on Volcanoes (p. 386), remarks that this is the case; and Humboldt, in his “Personal Narrative,” vol. i, p. 236, says “In general, the masses of known primitive rocks, I mean those which perfectly resemble our granites, gneiss, and mica-slate, are very rare in lavas: the substances we generally denote by the name of granite, thrown out by Vesuvius, are mixtures of nepheline, mica, and pyroxene.”