"Viewing, between the parallels of 34 degrees and 27 degrees, a vast area of depressed interior, subjected in seasons of prolonged rains to partial inundation, by a dispersion of the several waters that flow upon it from the eastern mountains whence they originate; and bearing in mind at the same time, that the declension of the country within the above parallels, as most decidedly shown by the dip of its several rivers, is uniformly to the N.N.W. and N.W., it would appear very conclusive, that either a portion of our distant interior is occupied by a lake of considerable magnitude, or that the confluence of those large streams, the Macquarie, Castlereagh, Gwydir, and the Dumaresq, with the many minor interfluent waters, which doubtless takes place upon those low levels, forms one or more noble rivers, which may flow across the continent by an almost imperceptible declivity of country to the north of north-west coasts, on certain parts of which, recent surveys have discovered to us extensive openings, by which the largest accumulations of waters might escape to the sea." CHARACTER OF THE RIVERS. It is the characteristic of the streams falling westerly from the eastern, or coast ranges, to maintain a breadth of channel and a rapidity of current more immediately near their sources, that ill accords with their diminished size, and the sluggish flow of their waters in the more depressed interior. In truth, neither the Macquarie nor the Castlereagh can strictly be considered as permanent rivers. The last particularly is nothing more than a mountain torrent. The Macquarie, although it at length ceased to run, kept up the appearance of a river to the very marshes; but the bed of the Castlereagh might have been crossed in many places without being noticed, nor did its channel contain so much water as was to be found on the neighbouring plains. There are two circumstances upon which the magnitude, and velocity of a river, more immediately depend. The first is the abundance of its sources, the other the dip of its bed. If a stream has constant fountains at its head, and numerous tributaries joining it in its course, and flows withal through a country of gradual descent, such a stream will never fail; but if the supplies do not exceed the evaporation and absorption, to which every river is subject, if a river dependant on its head alone, falls rapidly into a level country, without receiving a single addition to its waters to assist the first impulse acquired in their descent, it must necessarily cease to flow at one point or other. Such is the case with the Lachlan, the Macquarie, the Castlereagh, and the Darling. Whence the latter originates, still remains to be ascertained; but most undoubtedly its sources have been influenced by the same drought that has exhausted the fountains of the three first mentioned streams.