Page:A sketch of the physical structure of Australia.djvu/77

65"of the season. How these holes were produced with their regular shape, their depth, their occupying for different distances the whole width of the river bed, and their sudden endings in each direction, was a difficulty I could not solve."

I have now to speak of what is known of the remainder of Western Australia. The steep edge of the hill country runs north and south for many miles north of Swan River, and south of it as far as the sea at Point d'Entrecasteaux; the rocks of which the hills are composed seem likewise to be much the same as in the neighbourhood of the Swan, but the hills must sometimes assume loftier and bolder features, as Mount William in lat. 33&deg; is said to be 3000 feet high. Granitic and metamorphic rocks appear to form all the country from York to King George's Sound, but there the tertiary sand with concretionary limestone seems in places to rest upon them to a height of 400 feet above the sea at least. It is probable, also, that these tertiary accumulations occur at intervals all along the coast to the eastward till we reach the great tertiary district of the Australian Bight. The tertiary plain of Swan River likewise appears to stretch to the southward till it reaches the south coast, but south of the Swan I believe the white sand band gets narrower, and the plain is partly composed of clay and red sandstone. The projecting piece of land between Cape Leeuwin and Port Naturalist exhibits, I believe, granite on the coast beneath the tertiary rocks.

From the descriptions of Captain Grey and others