The command was given to A. C. Gregory, who had with him the celebrated botanist, Dr. Mueller, and his brother H. C. Gregory. Mr. Elsey, surgeon and naturalist, Mr. Baines, artist, and the requisite number of men made the party up to a total of eighteen. Their live stock consisted of horses and sheep.
The plan of the expedition was to proceed north to the Victoria River, which from the report of Captain Stokes was then considered an important stream, and probably a means of easily gaining the interior.
On the 18th July, 1855, they left Sydney for Moreton Bay, in the barque MONARCH, attended by the schooner TOM TOUGH. At Moreton Bay they took on board the remainder of the party, with fifty horses and two hundred sheep, and after some accidents caused by the MONARCH running on a reef, reached Point Pearce at the mouth of the Victoria River, on the 24th September. Here the horses were landed, much weakened by their voyage, and Gregory, Dr. Mueller, and seven men proceeded to the upper part of the Victoria overland, leaving the schooner to work her way up the river with the sheep on board. The land party first made the Macadam Range, so named by Stokes, thence they went to the Fitzmaurice River, where their horses were attacked by alligators and three of them severely wounded; and on the 10th of October they reached the Victoria, and rejoined the remainder of the party. Unfortunately, troubles had now set in, the schooner was aground on a bank eight miles below the camp, and having sprung a leak a considerable quantity of stores were damaged; the sheep, too, had been foolishly kept penned up on board, and so many had died that when finally landed the number was reduced to about forty. All this considerably weakened Gregory's resources.
An attempt to ascend the river in an india-rubber boat was a failure, the craft not being adapted to surmount the obstacles encountered in the shape of rocky bars. On the 24th of November, Gregory, with his brother, Dr. Mueller, and Wilson, followed the Victoria to the south, on horseback. The party reached latitude 161 south, finding the tributary sources of the river to flow from fine open plains, and level forest country, all well grassed. From this point they returned to camp.
On the 3rd January, 1856, another start was made, with a much larger party, consisting of eight men and thirty horses. On reaching their old point below the 16th parallel, a depôt camp was formed, and accompanied by Dr. Mueller, his brother, and one man, Gregory advanced south. The head of the Victoria was found sooner than expected, and crossing the watershed, and following down some small creeks running south through the tableland, they reached a grassy plain in which these watercourses were lost; beyond, the country was sandy and barren. A westerly course was then kept, and on the 15th the head of a creek was reached, which turning at first northerly, afterwards kept a distinct S.W. course for about three hundred miles. The country passed through for a large portion of the upper part was good available pastoral land, but as the lower part of the creek was reached a more desert formation took its place, and at last the creek terminated in extensive salt lakes. Beyond this point no continuation of the channel could be found, and Gregory too easily recognised the aspect of the desert country that had baffled him before. The creek was named Sturt's Creek, and a prominent hill, parallel with the lowest salt lake was called Mount Mueller. The party then retraced their steps; the water on which they depended in Sturt's Creek drying up so rapidly as to render more extended exploration very hazardous. They rejoined their companions at the depôt camp on the Victoria, and making a detour to the eastward, followed down the Wickham, a considerable tributary of the Victoria, to its junction with that river.
Arrangements were now made for the homeward journey by way of the Gulf of Carpentaria; the TOM TOUGH having been repaired and caulked, started for Timor, to obtain more provisions, and then return and meet the party at a rendezvous appointed on the Albert River. The land party consisted of the leader and his brother, Dr. Mueller, Elsey, and three men. They started on the 21st June.
Following up an eastern tributary of the Victoria, they crossed on to a creek running into the Roper, which was called the Elsey, and on this creek a camp was found, which suggested the idea that it had been occupied by whites. It consisted of the framework of a substantial-looking hut, of a different shape to that usually made by the natives; but no marked trees were found, nor anything more seen to confirm the supposition. Thence the party followed down the Roper for some distance, and then crossing the head waters of the Limmen Bight River, skirted the Gulf at some considerable way south of Leichhardt's track, crossing the same rivers that he did, only higher up on their courses. They struck the Nicholson far above where it had been so named by Leichhardt, and following it down reached the rendezvous at the Albert River (which is the outlet of the Nicholson), but the schooner had not arrived.
Gregory determined not to wait, but to proceed home overland. He buried a note at the foot of a marked tree for the information of the schooner people when they should arrive, and on the 3rd of September started. Two days' journey from the true Albert, they reached a stream which Leichhardt had erroneously taken for that river, and many of the errors in his map may be traced as being due to this cause.
This also has led to a good deal of confusion about the Plains of Promise so much vaunted by Captain Stokes, Leichhardt mistaking the level country on the river that bears his name for the spot. Gregory, who rightly identified the place, professes great disappointment with them compared to what he had been led to expect. Since then many conflicting opinions have been given as to their value. Settlement, however, as it generally does, decided the question; they have been found to be very suitable for cattle, but quite unadapted for sheep breeding. Stokes gave them a taking name, which probably led to a false estimate being entertained, as the country is in no way superior to the district to the eastward.
On the morning Gregory left the Leichhardt his party was attacked by the blacks, who were, however, easily repulsed, the leading native being shot in the short struggle. The Flinders was crossed on the 9th of September, but Gregory did not think that it gave promise of draining a very large extent of country. Instead, therefore, of following it up, and thereby lessening his journey, and discovering the beautiful pastoral downs that this most important river flows through, he wandered away to the north, and followed up the Gilbert River, thus duplicating, only further to the south, the eccentric course of Leichhardt. The dividing watershed was crossed on the basaltic plateau at the head of the Burdekin, and this stream was traced to the Suttor junction, where Leichhardt first struck it. They travelled on up the Suttor, and also up the Belyando, connecting with Major Mitchell's track. Their course then lay through the country traversed by Leichhardt on both his expeditions, watered by the Mackenzie and the Comet, and on the 22nd November the party reached a station on the Dawson owned by Messrs. Fitz and Connor.