Page:A sketch of the physical structure of Australia.djvu/60

48"and S.S.W., seemed to form the limit of the copper ore in one direction. The most singular thing respecting these mines appears to me to be the softness of the rock in which they lie. I believe this rock to be part of the surrounding clay slate formation, but either it can never have been metamorphosed into clay slate, or some agency has remetamorphosed it back again into its original condition, or something like it. Can that agency be in any way connected with the production of the mineral veins and masses? I regret that my time was too limited to allow of my making further observations on these interesting points. My search for organic remains was unsuccessful, but it was necessarily very imperfect."

Of the remainder of this hilly chain of South Australia, we only get a few other geological notices from Mr. Eyre's travels. He describes Flinders' Range, near Mount Arden, as consisting of clay slate, argillaceous stone and quartz; Mount Deception (lat. 30&deg; 48') as 3000 feet high, and composed of micaceous slate; and the rocks N.E. of Mount Eyre as quartz and ironstone. Mr. Kingston of Adelaide informed me that he knew of no true granite in this South Australian chain, but Mr. Dutton, in his "South Australia and its Mines," page 259, mentions granite as occurring in the beds of the rivers and forming the peaks of the hills of the Barossa range. Its appearance is at all events rare.

We have now to speak of the country intermediate between the South Australian chain, and the region of Australia Felix before described. We saw that all the lower part of the river Glenelg was occupied