Chapter Ii—Fernando Noronha; Terceira; Tahiti, Etc.

FERNANDO NORONHA.—Precipitous hill of phonolite. TERCEIRA.—Trachytic rocks: their singular decomposition by steam of high temperature. TAHITI.—Passage from wacke into trap; singular volcanic rock with the vesicles half-filled with mesotype. MAURITIUS.—Proofs of its recent elevation.—Structure of its more ancient mountains; similarity with St. Jago. ST. PAUL’S ROCKS.—Not of volcanic origin.—Their singular mineralogical composition.