the Colony. The mouth of the Murray is obstructed by sandbanks, but its lower course is navigable for small craft to Pinjarrah.
The area enclosed between the Murray and Blackwood is drained by the Collie, which receive the Brunswick and Wellesley from the foot of the range in its lower course; the Preston, with its affluent stream, the Dardanup, flowing into Leschenault inlet from the South, as the Vasse and other small streams do into Geographe Bay. The valley of the Margaret opens the the coast range to the "West, as Turner's River does to the South, the interior being accessible from those points. The Blackwood drains the largest area of all the rivers in the South of the Colony, but, in consequence of the secondary elevation of the ranges to the South-West, is confined to a narrow valley in its middle course of some 60 miles in direct distance, through a mountainous and well wooded country, in which there are, however, many fertile flats and well grassed banks. Its lower course for 40 miles is of the same character as the rivers of the West coast; but it has a much greater breadth and depth, and when in flood rises more than 20 feet above its ordinary level. The lateral valleys of the upper basin have an extent of about 75 miles, and from the sources of the Beaufort on the South, to its confluence with the Arthur from the North, may be 50 miles; about 15 miles below this it is joined by the Balgarup, also from the South, from whence to the sea it has no affluent stream worthy of notice, though it is fed by numerous torrents from the mountains on either side. As the lateral valleys of the Murray are separated from those of the Swan, so the head waters of the Arthur and Hillman are separated from those of the Murray and Collie by narrow watersheds, thus
