July 30.—The geological formation of the country we had passed through, consisted in the higher ranges of an argillaceous rock, of quartz, or of ironstone. Upon some of the hills the small loose stones had a vitrified appearance—in others they looked like the scoria of a furnace, and appeared to be of volcanic origin, but nowhere did I observe the appearance of anything like a crater. In the lower or front hills the rock was argillaceous, of a hard slaty nature, and inclined at an angle of about 45 degrees from the horizontal. This formation was frequently traversed by dykes of grey limestone of a very hard texture.
Upon watering the horses at the hole in the rock, I was much disappointed to find that they had already sunk it eighteen inches, and now began to fear that it would not last them so long as I had anticipated, and that I should still be obliged to cross over the hills to the very rocky channel where I had found permanent water on the 15th of July. This I was desirous, if possible, to avoid, both from the difficult nature of the road by which that water must be reached, and from the circumstance that it was going so much out of our way into an all but impracticable country, and that consequently, when we did move on again to the north, we should be obliged to come all the way back again over the same bad road to gain the open country under Flinders range, where alone we could hope to make any progress with the drays.