Page:A sketch of the physical structure of Australia.djvu/31

19 to Liverpool plains, whence they again expand to the north, and occupy a wide band of country as, far north as lat. 28°. On the western or inland flank of the chain, limestone and other rocks of the palæozoic formation are mentioned by Sir T. Mitchell as occurring about Yass plains near the sources of the Murrumbidgee, between the heads of the Lachlan and Macquarrie rivers, and about the head of the Namoy or Peel river. On the eastern flank of the chain, the rocks on the coast of Twofold Bay appeared to me to be palæozoic, in which case they probably form part of a large tract of such rocks spreading over that district. North of this a granitic spur from the main chain with porphyry and other igneous rocks reaches the coast about the Shoalhaven river. North of that again is the largest and best known district of palæozoic rocks in New South Wales, stretching from Illawarra to the flanks of the Liverpool range, and traversed by the rivers Nepean and Hawksbury on the south, and the Hunter river on the north, with their various tributaries. From the descriptions of my friend the Rev. W. B. Clarke, of Sydney, and from some excursions made either alone or in his company, as well as from the published accounts of Count Strzelecki, Mr. Darwin, and others, I am enabled to give a more