Page:A sketch of the physical structure of Australia.djvu/82

70 covered with masses of sandstone," p. 168. The red and white sandstones with ferruginous concretions I should conclude to be the same as the rocks of Port Essington, which I suppose to be tertiary: but the "coarse sandstone" and the "rugged ranges" I take to belong to the rocks of the district about to be described.

This district extends from Collier Bay to Victoria River, and has been described by Captain King in the account of his first arduous and important surveying voyages round the coasts of Australia, and more recently by Captains Stokes and Grey. This district is wholly different from any other part of the north coast of Australia, which is generally low and level, whereas here we have lofty hills rising fully 1000 feet above the sea, arid bold rocky headlands, with deep bays bounded by broken and precipitous cliffs. Captain King says that in passing through the eastern part of Port George IV. into Roger Strait, he landed on an island which was found to be granite, p. 189, and speaks of some islets of grey slate in Doubtful Bay. Captain Grey likewise speaks of porphyry and basalt in Port George IV., and after crossing the sandstone ranges, he describes a volcanic cone with lava and other hills of basalt in the valley of his Glenelg River, pp. 162 and 168. With these exceptions, the whole of this district appears to be composed of sandstone in thick and massive beds, Apparently identical in lithological character with the