Four miles to the south-east we came upon a pool of brackish water, surrounded with bulrushes, in a channel coming from the south of the Hamersley Range, again apparently offering us a chance of getting to the southward. We accordingly struck for the gorge out of which this stream came, and succeeded in penetrating for three miles up a very rocky gully, filled with some of the harshest triodia we had yet encountered, and had to halt for the night in a narrow pass, where there was scarcely room to tie up our horses. Camp 18. Latitude 22 degrees 12 minutes 52 seconds. ASCEND THE RANGES. 12th June. One of the horses having slipped his halter during the night, Messrs. Brown and Brockman returned down the gully to track it up, while we made an attempt to follow up the deep defile in which we were hemmed, but a quarter of a mile brought us to an impassable barrier of cliffs. Retracing our steps about a mile, we again made an attempt more to the eastward, and this time succeeded in reaching a considerable stream-bed, which ultimately proved to be the main channel of the Fortescue, and led us through the range. Resting till noon, Messrs. Brown and Brockman overtook us with the missing horse, when we resumed our route up the bed of the river to the southward, until again brought to a dead stand by the whole bed of the stream being occupied by deep pools of water, fed by numerous strong springs. As it was getting late in the day, I left the party to form a camp, while I climbed the hills to get a view of the country in advance. A laborious ascent of nearly an hour brought me to one of the highest summits of the range, at an elevation of about 2700 feet above the sea, and 700 above the bed of the river. From this hill I had a fine view to the southward, and observed that by following up a small dry ravine to the south-east there would be a fair prospect of reaching a large extent of open level plain that came within two or three miles of the camp in that direction. To the east and south-east the range was lofty and mountainous, while to the south and south-west stretched open grassy plains, occasionally interrupted by bold detached hills, apparently of the same formation as the Hamersley Range. On descending to the camp, I started a fragment of rock of a few tons weight, which rushed with fearful velocity towards the deep gorge in which the horses were feeding. After carrying all before it for a quarter of a mile, it made a clear spring over a cliff 200 feet in depth, and plunged into the waters below with a sound like thunder, inducing a belief at the camp that a large portion of cliff had fallen. Fortunately it did not produce an estampede, which I had known to have been caused on another occasion by a similar occurrence. Camp 19. Latitude 22 degrees 15 minutes; longitude 118 degrees 4 minutes 30 seconds. 13th June.