Part 76

Leaving our camp at 7.25 a.m., steered north 120 degrees east across the plains on the left bank of the river, and at 1.30 p.m. camped at a small pool in the sandy bed of the Gilbert, which is broad, sandy, and retains very little water. Fragments of porphyry, quartz, and black slate are abundant in the drift, and mica, iserine, and minute garnets exist.

Latitude by a Aquilae 17 degrees 25 minutes 50 seconds.

23rd September.

At 7.5 a.m. continued our journey up the river's left bank, the average course south-east by east; at 2.50 p.m., camped at a small pool in the bed of the river; the principal channel is 200 yards wide, and the smaller ones occupy a breadth of half a mile; the banks are low, and the country quite level, thinly wooded with box-trees; the grass good, but not thick; water very scarce, except by digging in the sand of the river.

Latitude by a Cygni 17 degrees 36 minutes; variation of compass 5 degrees east.

24th September.

At 7.0 a.m. steered south-east, and at 8.0 crossed to the right bank of the river, the channel 300 yards wide, with banks fifteen feet high, beyond which the ground gradually declined, so that when the river overflows a great extent of country must be inundated. Continuing our course, the river turned more to the south, and we passed through some poor stunted forest of eucalypti, alternating with grassy box-flats. At noon altered the course south-south-east, and at 12.30 p.m. camped at a chain of small lagoons in the shade of some fine nonda-trees.

Latitude by a Aquilae 17 degrees 45 minutes 10 seconds.

25th September.

At 6.35 a.m. steered south-east through an open melaleuca scrub, the soil sandy loam, thinly grassed; acacia, bloodwood, silver-leafed ironbark, and grevillia forming open patches of wood at intervals. At noon turned south, and at 1.35 p.m. camped at a small lagoon nearly dry and half a mile from the bank of the river; a few hills rose close to the south-west of the river opposite our camp, the lower ridges grassy, the higher hills wooded, but not exceeding 500 feet above the plain. The bed of the river is broad, dry, and sandy, and the box-flats much reduced in width, seldom exceeding a mile. At 5.0 p.m. there was a heavy squall with rain and lightning, followed by a cloudy night and moderate breeze from the south.

26th September.

At 6.45 a.m. resumed our route, and, following up the right bank of the river in a south-east direction till 2.0 p.m., when we camped in the sandy bed of the river, procuring water from a small hole in the sand. The country on the banks of the river consisted of box flats, some parts well grassed, but usually very poor; this extended about half a mile, and then changed gradually to a poor country with little grass and small eucalypti and melaleuca, the soil gravel and sand. The bed of the river continues to be about 300 yards wide, dry, and sandy; a line of melaleuca, morinda, flooded-gum and fig trees, grow along it and mark its course.

Latitude by a Aquilae 18 degrees 10 minutes 10 seconds; variation of compass 5 degrees 20 minutes east.

27th September.

Steered an average south-east course up the river from 6.40 a.m. till 1.0 p.m., when we camped at some pools of water in a side channel of the river, where it was divided by a hillock of slate-rock. The country is inferior in quality, the flats narrowing to an average of half a mile with very dry and thinly scattered tufts of grass. The bed of the river is better defined, and formed at times a single channel 250 yards wide, dry and sandy, as water was only once seen during the day. Low rocky ridges of sandstone gradually approached its banks, and near the camp porphyry, slate, and coarse granite formed detached hills 50 to 100 feet high, seeming to indicate an approach to the ranges in which the stream takes its rise.

Latitude by a Cygni 18 degrees 15 minutes 21 seconds.

GRANITE, PORPHYRY, AND SLATE.

28th September (Sunday).

Walked out from the camp to a low hill about one mile south-south-east. It was composed of granite at the base and capped with horizontal strata of sandstone, some of the beds containing large water-worn pebbles, and the superstratum highly ferruginous. To the south-west of this hill the rock was slate, the strata nearly vertical; the strike north and south, but much contorted, and large pebbles of porphyry, quartz, slate, granite, sandstone, and agate formed banks in the bed of the river. The country, as seen from the hill, was generally level in appearance, but consisted of numerous low ridges and detached hills of granite, with sandstone on the summits. The valley of the river extended to the east and south, and a large branch appeared to join from the south about ten miles lower down, as a valley and some ranges of hills trended in that direction. The whole face of the country had an arid and desolate aspect, as there were no large trees except along the principal watercourses, and many of the hills appeared destitute of any other vegetation besides small acacias and scrub trees, the bare rock showing through its scanty covering.

29th September.

At 7.15 a.m. again steered east up the river, the country level and timbered with stringybark, box, bloodwood, leguminous ironbark, and rusty gum; the soil a red sandy loam, thinly grassed; at 10.30 a.m. came to low hills and ridges of granite and porphyry, timbered with box, leguminous ironbark, terminalia, and the grass somewhat improved. Altered the course at 11.0 a.m. to the south to close in with the river; but after crossing a great number of dry watercourses, and even steering west, only reached the bank of the river at sunset. The channel was dry, and all the vegetation had disappeared, only a barren waste of coarse sand and gravel 180 yards wide, with bare rocky banks, showed that it had once been a running stream. A few small hollows in the rocks retained water from the late rain, but not sufficient for our horses, and though we found a small pool in the sand, it was insufficient for the supply of the party. Encamped at 6.0 p.m. The geological structure of this portion of the country is wholly dissimilar to any other part of North Australia we have yet traversed. Granite, porphyry, and slate are the prevailing rocks. The whole appear to have been subjected to considerable disturbance, as the slate is much broken and contorted, and in several parts altered by contact with the porphyry, and no definite strike or dip appeared to exist. The porphyry is of a red-brown colour, consisting of grey paste with crystal of felspar and angular fragments of slate and granite sometimes one foot in length. The granite contains little mica, and the quartz frequently is arranged in rhomboidal crystals nearly parallel to each other; it readily decomposes, and from the predominance of quartz forms a coarse gritty soil. Quartz-rock forms large beds and veins in the granite, and has a general trend north and south. It often contains crystals of mica, and therefore not likely to contain metals. In washing the sand of the river near Camp 83, only a small quantity of titaniferous iron remained after the removal of the quartz and mica. It was in this locality that the Gilbert Gold Field was afterwards discovered.

Latitude by e Pegasi 18 degrees 25 minutes 33 seconds.

30th September.

Moved the camp about one mile higher up the river to some small pools of water, and then with Mr. H. Gregory ascended the hills to the south of the camp. From the highest ridge the course of the river was visible for nearly twenty miles, trending first seven miles south-south-west and then south-south-east; at the bend a branch appeared to join from west-south-west, in which direction the country appeared very flat for fifteen or twenty miles, as only a few distant hills were visible; from north round to south-east the country was very broken and hilly, rising highest to the north-east, but the view was limited to eight or ten miles; south-east a valley opened through hills, and more distant ranges were indistinctly seen beyond. The whole aspect of the country was barren, rock forming the principal feature. Returning to the camp, collected a quantity of the clustered figs on the bank of the creek; this fruit is rather insipid.

1st October.

Steering an average south-south-east course from 7.40 a.m. till 2.40 p.m., camped on the right bank of the river, which first came from south-west and then from south-east, throwing off two branches to the south-west, and was thereby diminished to 100 yards wide at our camp; only one creek and some gullies joined from the east, although the country in that direction was hilly; the bed of the river was still dry and sandy; water very scarce. Slate, quartz, schist, granite, and trap are the principal rocks, and by their decomposition do not produce a soil favourable to vegetation, the country becoming more desolate as we advanced. The only trees which retain their verdure are those which grow on the banks of the river.

Latitude by a Cygni 18 degrees 40 minutes 29 seconds.

RECONNOITRE TO THE EASTWARD.