Page:A sketch of the physical structure of Australia.djvu/87

75 pebbles, &c. (p. 274 to 277). The coast south of Melville's Island as low deep red coloured cliffs all along the land (p. 147). Lethbridge Bay in Melville's Island argillaceous sandstone, upper part red, lower white (p. 108). East of Port Essington, he describes the coast all about Goulbourn's Island as having cliffs forty feet high, upper stratum red indurated clay, lower whitish pipeclay (p. 64). He speaks of an argillaceous cliff, bright yellow, at Copeland Island (p. 77). And says generally that the coast was exactly of the same character thence all the way to Cape Wessel.

From Dr. Fitton's Appendix to Captain King's Voyage, we gather that there is granite in the country about Melville Bay and Cape Arnhem, that at Morgan's Island and an islet in Blue Mud Bay there is chinkstone and trap, and that in Caledon Bay there is likewise granite, but that these rocks are covered with a brown hæmatite and concretionary ironstone, and that all along Limmen's Bight there is a range of low hills of which the base is "primitive;" the upper part reddish sandstone. Groote Eylandt is said to be composed principally of sandstone and conglomerate. I believe that here as on the south coast on each side of the Great Australian Bight, we have tertiary rocks resting on granite, and the other rocks formerly called primitive.

Of the interior of this tract of country we know nothing except from the accounts of the adventurous