Page:A Voyage of Discovery and Research in the Southern and Antarctic Regions Vol 1.djvu/147

] of very frequent occurrence, and are usually of basalt.

"Several conical hills, with crater-shaped summits, have evidently once been volcanic vents. Three or four very singular isolated hills, composed of an igneous kind of arenaceous rock which occur in Cumberland Bay, present a very smooth outline; they consist of pieces of broken fragments, through which the mass protrudes in places in prismatic columns.

"The vast quantities of debris which have accumulated at the base of the hills, in many places to the height of 200 or 300 feet and upwards, afford strong evidence of the rapid disintegration which this land is undergoing from the sudden atmospheric vicissitudes to which it is exposed.

"The whole island appears to be deeply indented by bays and inlets, the surface intersected by numerous small lakes and watercourses. These becoming swollen by the heavy rains which alternate with the frost and snow, accompanied by violent gusts of wind, rush down the sides of the mountains and along the ravines in countless impetuous torrents, forming in many places beautiful foaming cascades, wearing away the rocks, and strewing the platforms and valleys below with vast fragments, and slopes of a rich alluvium, the result of their decomposition.

"Quartz, in beautiful crystals, forming drusy cavities in the trap rocks in Cumberland Bay, occurs in great abundance, whilst zeolites predominate in the rocks about Christmas Harbour.