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APPENDIX, No. IV.
GEOLOGICAL REMARKS ON THE ANTARCTIC CONTINENT AND SOUTHERN ISLANDS, BY ROBERT McCORMICK, ESQ., SURGEON OF H.M.S. EREBUS.
The earth's crust, as we approach towards the pole in the southern hemisphere, presents, in a remarkable degree, the most striking indications of the vast subterranean fires pent up within it, and, as we now find, having vents in both the frigid zones: the volcano of Jan Mayen, actively burning within the Arctic circle; and Mount Erebus, rising from the lofty mountain range of the newly-discovered continent of Victoria, to an altitude of more than 12,000 feet above the Antarctic Ocean, and sending forth its smoke and flame to the height of 2000 feet above its crater, the centre of volcanic action in those regions of eternal snow.
On our first voyage south, after sailing from the River Derwent, Tasmania, on the 12th of November, 1840, we proceeded to the Auckland Group, and Campbell Island, the former situated in about the latitude of 51° S., and longitude 166° E., and the latter in the 53rd degree of latitude. Both are of igneous formation, being chiefly constituted of basalt and greenstone, forming hill ranges, nowhere exceeding an altitude of 2000 feet. The basalt frequently occurs in the prismatic form. At Deas Head, a promontory 300 feet in height, in Auckland Island, these prismatic pillars were highly magnetic.
Pebbles of quartz and agate occur amongst the shingle on the beach at Campbell Island, and some traces of limestone; the only indication of the sedimentary class of rocks which we met with after our departure from the Australian Lands.
