Page:A sketch of the physical structure of Australia.djvu/45

33 to approach that part of the coast of New Guinea composed of alluvial materials, and coloured pale green in the chart. This results from the well-known inability of the coral polyps to live in sea water charged with mud, or at all mingled with fresh water. Inasmuch, however, as the large reef of Warrior's Islet runs up to the New Guinea Coast west of Bristow Island, it would appear that no fresh water is discharged there, nor if the Hormuzeer and Chesterfield Shoals be really coral reefs, for a considerable distance to the westward. This inference is likewise strengthened by the submarine continuation of the eastern chain of Australia striking this part of the coast, since if it do not absolutely stretch into the interior of New Guinea in the shape of high land or mountains it will very likely have a tendency so to do, and thus raise the land above the average level and deflect the waters to the northward and eastward. The fact of Murray Island, Darnley Island, and Bramble Key being of volcanic origin, renders it rather probable that Aird's Hill is likewise volcanic. Now we know that along" the north coast of New Guinea runs a lofty volcanic chain, from which these look like offshoots, in which case there is probably a range of high land, or sufficiently high to cause a water-shed, proceeding from the north coast of New Guinea to the south, somewhere about long. 146&deg; or 147&deg;. If