regarding it as the highest point of the McDonnell Range, which is the
natural centre of this part of the continent. Mr. Waterhouse only saw
Chambers Pillar from a distance, but he had an opportunity of examining a
smaller hill of the same character, and found it to be composed of a soft
loose argillaceous rock, at the top of which was a thin stratum of a hard
siliceous rock, much broken up. "The isolated hills appear to have been
at some remote period connected, but from the soft and loose nature of
the lower rock meeting with the action of water, had arisen a succession
of landslips. These have been washed away and others have followed in
their turn; the upper rock, from being undermined, has fallen down and
broken up, supplying the peculiar siliceous stones so widely distributed
on parts of the surface of the country."

The vegetation of this district is poor; the myall is scarce, but the
mulga (Acacia aneura) generally plentiful. Both these shrubs are species
of acacia, the myall being of much larger growth and longer lived than
the mulga. Nutritious grass is seldom found except in the immediate
vicinity of the creeks, and the scrubs are very extensive.

Mr. Waterhouse collected a great number of specimens of natural history,
but, from want of the convenience for carrying them, many of the more
delicate objects were broken.

In the Appendix will be found some remarks by Mr. John Gould, F.R.S.,
etc., on the birds collected by Mr. Waterhouse during Mr. Stuart's
expedition, including a description of a new and beautiful parrakeet.
There are also descriptions of new species of Freshwater Shells from the
same expedition, by Mr. Arthur Adams, F.L.S., and Mr. G. French Angas, to
the skill of which latter gentleman this work is indebted for its
admirable illustrations.