Page:A sketch of the physical structure of Australia.djvu/54

42 shells, at the foot of the cliffs and on the summit of the hills;" and below it, he mentions "picturesque cliffs of limestone varying very much in hardness, containing corallines, spatangi, echini, oysters, pectens, and foraminiferæ," "a thin stratum of compact chert with the same fossils,"—and in another locality, he describes the rocks as containing a nucula and portions of lucina, and turritella or melania. This tertiary formation stretches to Portland Bay, being, however, frequently interrupted by trap and vesicular lava: hills of lava often occur, and one at least, Mount Napier, is described as still exhibiting a perfect circular crater on its rugged summit, with thin walls of lava.

From the description I received I have every reason to believe that this tertiary formation dotted with lava hills, probably only extinct volcanoes, spreads over all the comparatively low country between Sir T. Mitchell's track above described and the sea up to the neighbourhood of Port Phillip. I was told at Geelong that Lakes Colac and Carangamite, about 70 miles west of Geelong, had cliffs of clay and sand abounding in fossil bones, some of which from their great size were supposed by those who had seen them to be the bones of whales.

III. COUNTRY FROM AUSTRALIA FELIX TO THE DARLING RIVER.

Of this great expanse of country our notices are