It seems to me to be a clayey sandstone (Psammite) penetrated by silica.

A coarse-grained sandstone and quartzite cropped out in that part of the river situated between the two camps.

The melon-holes of the box-flats were frequently over-grown with the polygonaceous plant, mentioned at a former occasion; and the small scrub plains were covered with a grey chenopodiaceous plant from three to four feet high.

The stiff-leaved Cymbidium was still very common, and two or three plants of it were frequently observed on the same tree; its stem is eatable, but glutinous and insipid.
The morning of Easter Sunday was very clear and hot; the wind from E.N.E.
As soon as we had celebrated the day with a luncheon of fat damper and sweetened tea, I rode with Charley about seven or eight miles down the river, and found abundance of water, not only in the bed of the river, but in lines of lagoons parallel to it.

Charley shot several ducks, which were very numerous upon the water.