Soon after entering this remarkable sheet of water, we noticed a rock formation in its western banks; this we found to be a coarse-grained red sandstone, with fragments of quartz, and extended for nearly a quarter of a mile along the edge of the water.  Over many parts of it was a coating of a dark and metallic appearance, about three inches thick; and the surface in places presented a glazed or smelted appearance.  Mr. Darwin, in his work upon volcanic islands, page 143, alludes to this formation, under the head of “Superficial ferruginous beds,” and thus concludes his observations:  “The origin of these superficial beds, though sufficiently obscure, seems to be due to alluvial action on detritus abounding with iron.”

As we proceeded along this canal, for such was the appearance of the reach we were now ascending, we surprised a small party of natives.  They were at the water’s edge, beneath a high mound of loose white sand, over which the children were some time in making their escape, struggling and screaming with anxiety and fear, as they half buried themselves beneath its treacherous surface; and sometimes, after almost gaining the summit, sliding back again to the base.  All parental care seemed for the moment lost in the overwhelming sense of present danger, caused by the strange and unknown spectacle thus suddenly presented to the gaze of these poor savages.  Our white faces, curious garments, moving boats, the regular motions and unaccustomed sounds of our heavy oars, must indeed have filled them with amazement.  I have since frequently remarked, that our oars created more wonder, or alarm, among the various tribes who first learnt through us the existence of their white brethren, than almost any other instrument of which they could at all understand the use; perhaps, as they propel their frail rafts with a spear, they jumped to the conclusion, that our oars were also immense spears, which, being their chief weapons, must have given us a formidable appearance.  We noticed, among the trees on the banks of this natural canal, two varieties of the palm; both kinds had been observed by Mr. Brown in the Gulf of Carpentaria, during Captain Flinders’ voyage.

At the end of this reach, which extended for a mile and a half in a South-East by South direction, the river was scarcely 50 yards wide, and the depth had decreased from 12 to 6 feet; the current, scarcely perceptible in the deep water, now ran with a velocity of from one to two miles per hour.  Here, therefore, the Fitzroy may be said to assume all the more distinctive features of an Australian river:  deep reaches, connected by shallows, and probably forming, during the droughts which characterize Australia, an unlinked chain of ponds or lagoons; and in places, leaving no other indication of its former existence than the water-worn banks and deep holes, thirsty and desolate as a desert plain.  At this point, the river divided into two branches, one having an East-South-East,