Page:A sketch of the physical structure of Australia.djvu/69

57 journey from South Australia to Western Australia. Near Coffin Bay he says the hills are of oolitic limestone, with granite protruding through it in one of the gorges. This oolitic limestone belongs to the "fossil formation" which he subsequently mentions, and is no other than part of the great tertiary formation previously described. Mount Hope near Coffin Bay is granite, thence to Streaky Bay nothing is seen but limestone and sand, except Mount Hall near Streaky Bay, which is granite. From Streaky Bay to Fowler's Bay it is all tertiary, masses of marine shells were found in it, and the country is said to be crusted with oolitic limestone. From this point round the head of the Great Australian Bight to the neighbourhood of Cape Arid, a distance of about 600 miles, both Flinders and Eyre speak of an unbroken line of cliffs of horizontally stratified rock varying in height from three to five hundred feet. At the head of the Bight Mr. Eyre gives us the following section.

1. Oolitic limestone in a crust probably of no great thickness.

2. Hard concrete sand with pebbles and marine shells.

3. Hard coarse grey limestone.

4. White substance like chalk.