With reference to a supply of fresh water, so indispensably necessary in every settled country, the researches made by Captain Stirling and Mr. Fraser were attended with the most satisfactory results. The former observes, that the clouds which are impelled against the western side of the range of mountains are condensed into rain, the water of which is conducted across the plain to the sea, in numerous streams, but chiefly by three principal rivers, terminating in estuaries, or salt-water lakes. These are—the Swan River, opposite the Island Rottenest; the Rivière Vasse, and Port Leschenault, in Geographer's Bay. "We found," says Captain Stirling, "a great number of creeks, or rivulets, falling into Swan River, more particularly on the eastern side; and I am inclined to think, that the country generally is much divided by such water-courses. Its supply of fresh water, from springs and lagoons, is abundant; for we found such wherever we thought it necessary to ascertain their existence. At Point Heathcote," he adds, "we met with a remarkable instance; for there the beach of a narrow rocky promontory is a bed of springs, and by tracing the finger along any part within four inches of the edge of the salt water, pure and fresh water instantly occupied the trace."
Mr. Fraser's testimony leaves no doubt of the abundance of fresh water. "I was astonished," he says, "at the vivid green of the Eucalyptus, and other trees and shrubs, so distinct from those of New South Wales; but, on digging the soil to the depth of two feet, I found the cause to arise apparently from the immense number of springs with which this country abounds; for, at the depth above mentioned, I found the soil quite moist, although evidently at the latter end of an exceedingly dry season; and from the same cause must arise the great luxuriance of the herbaceous plants on the banks, which exceeds any thing I ever saw on the east coast. They consist principally of the senecia and the sonchus, which here attain the height of nine feet."
He further observes, that numerous active springs issue from the rocks of the limestone ridge, and particularly in Geographer's Bay, the whole coast of which, he says, "is a perfect source of active springs, discharging themselves on the beach in rapid rills of considerable extent, every six or seven yards."
Between the two heads which form the entrance into Swan River, there is, unfortunately, a bar, made by the continuity of the limestone ridge. Over this bar, the depth, at low water, is but six feet, and is therefore practicable only for boats or rafts. About a mile inside the heads, the water deepens; and then commences a succession of cliffs, or natural wharfs, with four, five, and six fathoms at their bases. The same depths are extended over a magnificent expanse of salt water, to which Captain Stirling has given the name of "Melville Water;" and which, in his opinion, wants only a good entrance to make it one of the finest harbours in the world, being seven or eight miles in length, by three or four in width, and having a depth of water from four to seven fathoms. This narrow entrance of the river, he thinks, might be made navigable by ships of burthen, without difficulty or great expense.
When the town begins to rise, and substantial buildings are required, the blocks of stone procured by quarrying this entrance will go far towards paying the expense of excavation.
Into this expansive sheet of water fall two rivers; one from the north-east, which is properly the Swan River; the other from the south-east, called Canning's River. Captain Stirling examined them both: the former to its source, the latter beyond the point where the water ceased to be brackish. They are both sufficiently convenient for boat navigation, even at the end of the dry season; and any obstruction might easily be removed to make them more so, by which the productions of an immense extent of country might be transported by water-carriage.
Mr. Fraser remarks that nothing of the mangrove appears along the banks of the Swan River, the usual situation of this plant being here occupied by the genus Metrosideros. The first plain, or flat, as it is called, contiguous to the river, commencing at Point Fraser, is formed of a rich soil, and appears, by a deposit of wreck, to be occasionally flooded to a certain extent. Here are several extensive salt marshes, which Mr. Fraser thinks are admirably adapted for the growth of cotton. The hills, though scanty of soil, are covered with an immense variety of plants; among others, a magnificent species of Angophera occupied the usual place of the Eucalyptus, which, however, here as on the eastern side, generally forms the principal feature in the botany of the country, accompanied by Mimosa, Correa, Melaleuca, Casuarina, Banksia, and Xanthorea. The brome, or kangaroo glass, was most abundant. On a more elevated flat, a little further up the river, the botanist observes that the "magnificence of the Banksia and arborescent Zamia, which was here seen thirty feet in height, added to the immense size of the Xanthorea near this spot, impart to the forest a character truly tropical." He says that about five miles to the eastward of the river, there is an evident change in the character of the country: extensive plains of the richest description, consisting of an alluvial deposit, equalling in fertility those of the banks of the River Hawkesbury in New South Wales, and covered with the most luxuriant brome grass. The Casuarina, so common near the limestone ridge of the coast, here disappears, and is succeeded by a pendulous species of Metrosideros, which continues to the source of the river.
"From this point," says Mr. Fraser, "the country resembles, in every essential character, that of the banks of those rivers which fall to the westward of the Blue Mountains in New South Wales, varying alternately on each bank from hilly promontories of the finest red loam, and covered with stupendous Angopheras, to extensive flats of the finest description, studded with magnificent blue and water gums, and occasional stripes of Accacias and papilionaceous shrubs, resembling the green wattle of New South Wales."
The higher the river is ascended, the more extended the flats become, and the better is the quality of the soil. Here the country is said to resemble in character that on the banks of the Macquarrie River, west of Wellington valley; and though marks of occasional floods appeared on the lower plains, the upper flats had evidently never been flooded. The sides of the mountains were bare of underwood, and their summits covered with large masses of iron stone, among which were growing enormous trees of Angophera, and some straggling plants of Hakea. On a careful examination of this part of the country bordering the two rivers from the sea-coast to the mountains, Mr. Fraser says, "In giving my opinion of the land seen on the banks of the Swan River, I hesitate not in pronouncing it superior to any I ever saw in New South Wales, east of the Blue Mountains, not only in its local character, but in the many existing advantages which it holds out to settlers. These advantages I consider to be,
"First, the evident superiority of the soil.