The western side of LETHBRIDGE BAY, on the north of MELVILLE ISLAND, consists of a range of cliffs like those at Goulburn's Island; the upper part being red, the lower white and composed of pipe-clay. The western extremity of BATHURST ISLAND, between CAPE HELVETIUS and CAPE FOURCROY, is also formed of cliffs of a very dark red colour.
LACROSSE ISLAND, at the mouth of CAMBRIDGE GULF, about one hundred miles from Port Keats. Reddish, very quartzose sandstone; from a stratum which dips to the south-east, at an angle of about ten or fifteen degrees. Micaceous and argillaceous fissile sandstone, of purplish and greenish hues, in patches, or occasionally intermixed; precisely resembling the rock of Brecon, in South Wales, and, generally, the old red sandstone of the vicinity of Bristol and the confines of England and Wales. Fine-grained thin-slaty sandstone, resembling certain beds of the coal formation, or of the millstone grit, is found in large masses, under an argillaceous cliff, on the north side of Lacrosse Island.
The specimens from the interior of Cambridge Gulf are from ADOLPHUS ISLAND, and consist of reddish and grey sandstone, more or less decomposed.
VANSITTART BAY, about one hundred and forty miles north-west of Cambridge Gulf. Reddish quartzose sandstone, or quartz-rock. Indistinct specimens of greenstone, with adhering quartz; apparently a primitive rock.
PORT WARRENDER, at the bottom of Admiralty Gulf, about forty miles south-west of Vansittart Bay (Narrative volume 1). Epidote and quartz, in small crystals confusedly interlaced; apparently from veins, or nests, but unaccompanied by any portion of the adjacent rock. The structure in one of these specimens approaches to the amygdaloidal. A compact greenish stone, with disseminated crystalline spots of epidote, and of quartz, and apparently consisting of an intimate mixture of those minerals, is also among the specimens from Port Warrender.
All these specimens are from detached water-worn masses at the foot of Crystal Head, on the south-west of the port. The summit of the head is flat and tabular, and the rocks in the vicinity are described by Captain King as consisting of siliceous sandstone. Chalcedony, apparently from amygdaloid of the trap formation, was also found at Port Warrender.
The epidote of this place is in general of a pale-greenish colour, but is mixed with, and sometimes appears to pass into, spots of a rich purplish-brown. The specimens resemble generally the epidote of Dauphiny and Siberia; but Mr. Levy, who has been so good as to examine them, informs me that the crystals exhibit some modifications not described either by Hauy, or by Mr. Haidinger in his paper on this mineral, and which are probably peculiar to this locality.
WATER ISLAND, on the west side of CAPE VOLTAIRE, at the south-west entrance of Port Warrender, is described (volume 1) as consisting of quartzose sandstone; as is also KATER ISLAND, in Montagu Sound. And the same rock appears to occur throughout the islands on this part of the coast. (Narrative 1.)
MONTAGU SOUND, about five-and-twenty miles south-west of ADMIRALTY GULF (Narrative 1). Greyish granular quartz; like that of the Lickey Hill, in Worcestershire. Fine-grained quartzose sandstone, of a purplish hue, resembling a rock on the banks of the Severn, near Bridgenorth. Grey and reddish sandstone; apparently composed of the debris of granite, and very nearly resembling that of Simms Island above-mentioned.
HUNTER'S RIVER, falling into YORK SOUND, on the north-east side. Somewhat coarse reddish-white sandstone; like that of the coal formation, and some varieties of millstone grit. Fine-grained, reddish-grey quartzose sandstone, having the appearance of stratification, and resembling the rocks of Cambridge Gulf.