Page:A sketch of the physical structure of Australia.djvu/66

54 in height, running in parallel lines to the horizon in each direction. A little scanty grass grew here and there, nourished at rare intervals by thunder showers. Permanent water there was none, and Captain Sturt made one expedition of 180 miles on the strength of a single shower of rain; the puddles of which had not wholly dried up on his return. The heat was intense, "lucifer matches," he told me, "took fire if dropped upon the sand, and the thermometer on one occasion reached 153&deg; in the coolest spot they could find." In the centre of this terrible plain of sand ridges is a remarkable " stony desert" round lat. 26&deg; 30', long. 139&deg; 30'. This is the lowest and most depressed part of the interior; it is so thickly covered by stones as wholly to exclude vegetation; the stones are fragments of quartz which are said to he rounded by attrition. Its known dimensions are 35 miles by 80. He elsewhere speaks of its surface as a great expanse of solid dark ironstone on which the horse's hoof rang and left no impression.

To the N.W. of the Stony Desert, the sand ridges ran in lines bearing N.N.W. and S.S.E., and from his farthest point he saw no hope of their cessation. Between the Stony Desert and Grey's Range the sandy ridges ran in lines bearing N.N.E. and S.S.W. Between the north end of Grey's Range and the depression of Lake Torrens, which was struck in lat. 29&deg; 10', long. 139&deg; 50', the sand ridges curve from N.E. and S.W. (their direction near the