base of the main range to the East, there are superficial masses of gravel containing fossil bones of large animals which have not yet been examined. The line of this coast range is apparently continued in the reefs which fringe the coast, the outer one being known as the Five Fathom Bank, possibly terminating in Houtman's Abrolhos.
The great granitic mass of the South-Western Ranges slopes downward to the North, where the strata of sandstones and limestones about Moore River and the rivers of the Victoria district to the North, and which rest upon it, give a distinct character to that portion of the Colony. The formation of these is not sufficiently well known, but it would seem that they are related to the schistose deposits on the Irwin and the South coast. The Blackwood, having had its lower course directed Southward by the interposition of the rock masses on the West Coast, from Cape Leeuwin to Cape Naturaliste, assumes an intermediate position in the South, as the Gascoigne, falling into Shark's Bay, does to the North. The rivers Murchison, Greenough, Swan, and Murray, the basins of which open to the West coast, have their sources in the main watershed, and mark the principal divisions of the Coast district; while the Hutt, Bowes, and Chapman, the Irwin and Moore, the Serpentine, Harvey, and Collie, have their sources in the outer slopes of the ranges which form the upper basins of the larger rivers, as other inferior rivers, so called, have their sources still nearer the Coast line. The rivers of the Colony are indeed, for the most part, water courses, down which torrents rush in wet seasons, which occur only occasionally and sometimes at long intervals; and their courses are at other times marked by sand and gravel, brought down by the floods, and pools formed in
