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56 in Mount Pluto, and disemboguing at the head of Spencer's Gulf.

Captain Sturt never mentions the occurrence of any fossils anywhere in this desert interior, but from our knowledge of the tracts of Australia already described and that round the Great Australian Bight, to be now entered on, we can hardly help looking at this vast plain of sand, resting on clay, on sandstone, and on ironstone, so flat and so little elevated above the sea, as having the tertiary formation for its substratum.

Of the remainder of South Australia, we have but little published information. Of the Yorke Peninsula, I can find no mention made. From the head of Spencer's Gulf to Port Lincoln, Mr. Eyre mentions no other rock than quartz, sandstone and sand. In crossing from the head of the same gulf to Streaky Bay, he passes first over a conglomerate and next over some quartzose grits, but the Gawler Range he describes as principally if not entirely formed of granite.

IV.—GREAT AUSTRALIAN BIGHT.

This district extends from the west side of the Port Lincoln peninsula to the neighbourhood of King George's Sound in the colony of Western Australia. The coast was surveyed by Captain Flinders, who describes its aspect from the sea, and it has been traversed by land only by Mr. Eyre, in his most arduous and difficult