30TH SEPTEMBER.--Thermometer, at 7 A.M., 67 deg.. I found, by my map, that I might very much shorten the homeward route to next camp (that of 18th September), by travelling towards it in a straight line across the downs. We accordingly set out on the bearing of 51/2 deg. S. of E., and hit the spot exactly at a distance of eighteen miles; arriving early, so as to afford some good rest to our horses. We crossed open downs chiefly, passed through a narrow belt of brigalow (about a mile wide), and twice crossed a tributary to the river, which tributary we thus discovered. The water- course on which we had again encamped, arose in open downs of fine firm clay, and it was pleasant to see a great river thus supplied by the waters collected only amongst the swelling undulations and valleys of the country through which it passed, like the rivers of Europe. The river we had discovered, seemed, in this respect, essentially different from others in Australia, which usually arise in mountains, and appear to be rather designed to convey water into regions where it is wanting, than to carry off any surplus from the surfaces over which they run. 1ST OCTOBER.--Our track back across the downs, brought again into view the Northern range, and I now named the prominent mountain at its salient, Mount Northampton, in honour of the noble marquis at the head of the Royal Society. The range to the southward also appeared above the trees of the valley, and I gave the name of Mount Inniskillen to the salient mountain, which appeared so remarkable a feature to us on first advancing into that region, from the eastward. We again reached the river this day, after traversing the wide plains. Its woods still resounded with the plaintive cooing of a dove, which I had not seen elsewhere. At a distance, the sound resembled the distant cooy of female natives, and we at first took it for their voices until we ascertained whence these notes came. I had arrived at a fine reach of the river, and while watering the horses, preparatory to leaving its banks, (to make a short cut on our former route,) when a pair of these birds appeared on a bough over head, so near that I could take a drawing, by which I have since ascertained the bird to have been GEOPELIA CUNEATA.