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tertiary formation with fossil shells, as having granitic knobs protruding here and there through it. At the Salt Lakes, east of Cape Le Grand, we still have the fossil formation at an altitude of 150 feet, but after that we have no farther mention of it. About long. 121°, however, we have sandstone and ironstone described as resting on the granite, and I am strongly disposed to look on this sandstone and ironstone as belonging to the same tertiary formation as the fossiliferous limestone, that the two kinds of rocks are either different parts of the same formation, or that they replace each other in the same geological horizon.
On arriving at East Mount Barren, Mr. Eyre speaks of micaceous slate, and we now enter the colony of Western Australia.
V.—WESTERN AUSTRALIA.
As I made an excursion of two or three weeks in Western Australia, I shall first of all give an account of what I myself saw of its structure.
In approaching Swan River you look over a gently undulating plain of some twenty miles in width, backed by a range of hills, called the Darling range, which runs north and south parallel to the coast, and has a mean height of 800 or 1,000 feet. On climbing these hills, however, you find, that instead of being a single ridge, as it appeared from the sea, it is merely the steeply sloping edge of a hilly district, which extends for many miles into the interior of the country. In traversing the plain from the sea, you first pass for about ten miles over a district of loose white and, quite impassable for wheel carriages, but covered by the
