ST.HELENA.
Lavas of the feldspathic, basaltic, and submarine series.--Section of Flagstaff Hill and of the Barn.--Dikes.--Turk's Cap and Prosperous Bays.--Basaltic ring.--Central crateriform ridge, with an internal ledge and a parapet.--Cones of phonolite.--Superficial beds of calcareous sandstone.--Extinct land-shells.--Beds of detritus.--Elevation of the land.--Denudation.--Craters of elevation.
