g extent of desert lying between any of the known portions
of Australia, and what may be considered as having been the next island,
can be ascertained and crossed over, new and valuable regions may yet be
offered for the extension of the pastoral interest of our Colonies,
and for the general spread of civilization and improvement.

[Note 34: "An hundred miles above this, I passed a curious feature, called
the "Square Hills" (plate 123 ). I landed my canoe and went ashore, and to
their tops to examine them. Though they appeared to be near the river, I
found it half a day's journey to travel to and from them; they being
several miles from the river. On ascending them I found them to be two or
three hundred feet high, and rising on their sides at an angle of 45 deg.
and on their tops, in some places for half a mile in length perfectly
level, with a green turf, and corresponding exactly with the tabular
hills spoken of above the Mandans, in plate 39, vol. 1. I therein said
that I should visit these hills on my way down the river; and I am fully
convinced from close examination, that they are a part of the same
original superstratum, which I therein described, though 7 or 800 miles
separated from them. They agree exactly in character, and also in the
materials of which they are composed; and I believe that some
unaccountable gorge of waters has swept away the intervening earth,
leaving these solitary and isolated, though incontrovertible evidences,
that the summit level of all this great valley, has at one time been
where the level surface of these hills now is, two or three hundred feet
above what is now denominated the summit level."--Catlin's American
Indians, Vol. 2. pp. 11 and 12.]

[Note 35: Similar banks of fossil shells and oyster beds, are found in the
Arkansas.--Vide Catlin, Vol. 2. p. 85. At page 86, Mr. Catlin describes
banks of gypsum and salt, extending through a considerable extent of
country, and which apparently was of a very similar formation to some of
the localities I was in to the north of Spencer's Gulf.]

I have already observed that several circumstances connected with my own
personal experience have led me to the conclusion, that there is no
inland sea now occupying the centre of New Holland; it will be sufficient
to name three of the most important of these.

First. I may mention the hot winds which in South Australia, or opposite
the centre of the continent, always blow from the north, to those,