This creek also ran on the line of contact of primitive and basaltic rocks; the primitive side was cut by gullies and ravines, whilst the basalt formed a steep uninterrupted slope, though covered with boulders which had been carried down even into the sandy bed of the creek, where they were intermingled with those of granite and pegmatite.

I called this creek "Separation Creek," in allusion to its geological relations: at the point where we met it, it turned to the north and north-west, which made me believe that it was a westerly water; but in this I was mistaken.
We had some slight showers of drizzling rain during the afternoon.

The wind veered towards evening to the northward, and the night was clear.
We saw several kangaroos, and their tracks to the water showed that they were numerous.

One of them, which we saw in the creek, was of a light grey colour, with rich fur and a white tail.
May 19 .-- We returned to the camp.

A cold easterly wind continued during the day; low rainy clouds in the morning formed into heavy cumuli during the afternoon.
My geological observations lead me to the conclusion, that an immense valley between granitic ranges has here been filled by a more modern basaltic eruption, which (supposing that Mount Lang is basaltic in the centre of elevation) rose in peaks and isolated hills, but formed in general a level table land.