Page:A Voyage of Discovery and Research in the Southern and Antarctic Regions Vol 1.djvu/148

1840

"The most remarkable geological feature in the island is the occurrence of fossil wood and coal, and, what is still more extraordinary, imbedded in the igneous rocks. The wood, which for the most part is highly silicified, is found enclosed in the basalt, whilst the coal crops out in ravines, in close contact with the overlying porphyritic and amygdaloidal greenstone.

CHRISTMAS HARBOUR,

"In which the ships were moored during the period the expedition remained at the island, is bounded on the south side by a ridge of basaltic rocks, disposed in terraces and platforms, dipping slightly to the N.W., and surmounted by a remarkable block of basalt, rising to about 1000 feet above the harbour. It has in some places a conglomerate structure, the enclosed fragments being excessively hard and ponderous. It is beneath this rock that the fossil wood is found, I having discovered the first fragment whilst ascending the hill on the day after the ships were secured in the harbour, and on a further search it was found in considerable abundance, both imbedded in the basalt and in the debris below, or scattered on the surface amongst the fragments of rock. A portion of the trunk of a large tree, seven feet in circumference, and much silicified, was dug out of the soil immediately below the rock. About 400 feet from the summit is a bed of shale, nearly horizontal, averaging six feet in thickness; but in some