Page:A sketch of the physical structure of Australia.djvu/22

10 or between Cape Upstart and Cape Melville, the loftiest and most massive mountain ranges strike out upon the very coast as if the heart or central axis of the chain was here actually washed by the sea. Thus far several of the highest points still attain the height of 4,000 feet above the level of the sea, and its mean elevation cannot be much less than in New South Wales. North of Cape Melville the chain rapidly diminishes in height and importance, few parts being higher than 1,000 feet, and at Cape York we have only insignificant hills of 300 or 400 feet high. As in Bass's Straits, however, so also in Torres' Straits, the submarine continuation of the chain may still be traced in a line of steep, rugged, and often peaked islands, several of which are 7 and 800 feet high, which run in a north and south direction up to Mount Cornwallis, which is close to the coast of New Guinea. The distance in a straight line between the S. Cape of Tasmania in 43 35', and Mount Cornwallis in 9° 45', is 43° 35' of latitude, or about 2050 geographical, 2370 statute miles; following the slightly curved line of the chain itself, its extreme length will be about 2,400 geographical, or 2,780 statute miles.

We have now to describe the geological structure of this chain. It cannot be said to have any one well-defined axis of granitic or other rocks, or if it has, that axis is often deep-seated, and is not apparent at the surface. Large granitic masses,