Bulletin, Issues 93-951927 - Geology |
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albite albite porphyry altered appears Ashburton Ashburton River bands basalt basic porphyrite basin beds Blatchford bore Boulder Belt boundary breakaways cale schist Cambrian carbonate Carboniferous chlorite chute cliffs Creek crosscut Darling Fault deep leads deposits depth detritus division dolerite drainage dyke eastern erosion Fault Scarp feet felspar Fitzroy Fitzroyland flow formation Fortescue geological gorge granite greenstone hills hornblende Irwin River Kalgoorlie Kimberley Lake View laterite lease limestone lower miles mineral Murchisonia North Kimberley North-West northern Nullagine occur old plateau Ord River Ordland origin Oroya peneplain Perth physiographic Pilbaraland Poole Range porphyry portion present probably pyrites quartz quartz-dolerite quartz-dolerite greenstone rain rainfall rock-holes rocks Salinaland salt lakes sand ridges Sandland sandstone sea-level sedimentary sericite shaft shale shearing South Kalgurli southern strata streams Sunkland surface Swanland Talbot tion tributaries uplift upper valley vegetation water gaps Western Australia wind
Popular passages
Page 195 - Clarke, in his Presidential Address to the Royal Society of New South Wales, in May, 1870...
Page 124 - ... sand ridges at 26° S. They extended north for 420 miles, were from 30 to 50 feet high, and ran very regularly from east-bysouth to west-by-north. Belts of mulga forming dense thickets and other specimens of acacia, quandong, native poplar, &c., grew sparsely in the hollows. He describes much of it as a great undulating desert of gravel formed largely of pebbles of ferruginous sandstone (Fig. 81). Forrest, in his traverse from west to east, in 1873 crossed near latitude 26° S. Here there seem...
Page 5 - Reach from near Condon to the north of Broome, and on the Nullarbor Plains in the south-eastern corner of the State. The remainder of the country forms the interior drainage area. The interior drainage area is arid and is practically riverless.
Page 180 - Roelands 102 miles farther south, both within the Darling Peneplain area. "During the hot, dry summer, fissures form in the sub-soil, but do not extend to the soil, owing to its binding of vegetation. During the heavy, winter rains, much of the water sinks straight into the dry ground, whieh soon becomes saturated.
Page 5 - ... vast, gently undulating surface. Occasional hills (monadnocks, which are remnants of a previous cycle of erosion) rise above the general surface of the plateau. The Great Plateau may be conveniently subdivided into an area of exterior drainage (where there are definite rivers which flow to the sea), an area of interior drainage (where such water as flows passes into inland basins), and two areas of no surface drainage but which, if they had drainage, would belong to the exterior drainage system....
Page 186 - ... drift are, as at Kanowna, beds of gravel, which indicate more powerful river action in former times; that it may be doubted whether marine rocks exist in the interior, and it, therefore, appears probable that Westralia consists of a great Archaean block or coign, which has never been below the level of the sea, although time after time the sea has washed its borders. 1908. HP Woodward (I). This writer suggests long erosion of the land, in the course of which it is highly probable that wave action...
Page 294 - I1eep sounds and bays (rias) run far into the land, and are manifestly the drowned continuations of the adjacent rivers. This region has been deeply dissected, probably to early maturity, and then submerged. It thus affords excellent illustrations of drowned valleys.
Page 16 - Rainfall, temperature, altitude above sea-level and the lithological character of the surface rocks are the principal factors that control the vegetation of a country. In Western Australia rainfall is the most important factor of all, and as there is great variation in the average annual rainfall throughout the State, there is considerable diversity in the types of vegetation. The Forests Department of Western Australia has issued a valuable vegetation map of the State (published with Bulletin No.
Page 346 - Detritus. The material derived from the waste of the land by erosion. Devonian. The fourth oldest system in the Palaeozoic division of the geological record. It follows the Silurian. Diabase. A basic igneous rock frequently occurring in sheets or dykes. Broadly speaking, it may be called an altered dolerite. Differential Erosion. The more rapid erosion of one portion of the earth's surface than another. Dip. The inclination from the horizontal of a stratificd rock or of a lode.
Page 131 - Plain there exist shallow circular depressions in the surface, and these are called 'dongas.' The dongas vary in diameter from five chains to three miles, and the greatest have a depth of about 20 feet in the centre. They are undoubtedly formed by the caving in of subterranean chambers in the limestone. In the lowest part of the basin there is almost invariably a hole through which the water escapes. The dongas generally carry a good depth of soil, and grasses, buck-bush, etc., grow in great profusion...