The outline of the coast about Cape Leveque itself is low, waving, and rounded; and the hue for which the cliffs are remarkable in so many parts of the coast to the north, is also observable here, the colour of the rocks at Point Coulomb being of a deep red: but on the south of the high ground near that Point, the rugged stony cliffs are succeeded by a long tract, which to the French voyagers (for it was not examined by Captain King) appeared to consist of low and sandy land, fronted by extensive shoals. It has hitherto been seen, however, only at a distance; so that a space of more than three hundred miles, from Point Gantheaume nearly to Cape Lambert, still remains to be accurately surveyed.
Depuch Island, east of Dampier's Archipelago, about latitude 20 degrees 30 minutes, is described by the French naturalists as consisting in a great measure of columnar rocks, which they supposed to be VOLCANIC; and they found reason to believe that the adjoining continent was of the same materials.* It is not improbable, however, that this term was applied to columns belonging to the trap formation, since no burning mountain has been any where observed on the coast of New Holland: nor do the drawings of Depuch Island, made on board Captain King's vessel, give reason to suppose that it is at present eruptive. Captain King's specimens from Malus Island, in Dampier's Archipelago (sixty miles farther west) consist of greenstone and amygdaloid.
(*Footnote. Peron volume 1 page 130.)
The coast is again broken and rugged about Dampier's Archipelago, latitude 20 degrees 30 minutes; and on the south of Cape Preston, in latitude 21 degrees, is an opening of about fifteen miles in width, between rocky hills, which has not been explored. From thence to the bottom of Exmouth Gulf, more than one hundred and fifty miles, the coast is low and sandy, and does not exhibit any prominences. The west coast of Exmouth Gulf itself is formed by a promontory of level land, terminating in the North-west Cape; and from thence to the south-west, as far as Cape Cuvier, the general height of the coast is from four to five hundred feet; nor are any mountains visible over the coast range.
Several portions of the shore between Shark's Bay and Cape Naturaliste have been described in the account of Commodore Baudin's Expedition; but some parts still remain to be surveyed. From the specimens collected by Captain King and the French descriptions, it appears that the islands on the west of Shark's Bay abound in a concretional calcareous rock of very recent formation, similar to what is found on the shore in several other parts of New Holland, especially in the neighbourhood of King George's Sound; and which is abundant also on the coast of the West Indian Islands, and of the Mediterranean. Captain King's specimens of this production are from Dirk Hartog's and Rottnest Islands; and M. Peron states that the upper parts of Bernier and Dorre Islands are composed of a rock of the same nature. This part of the coast is covered in various places with extensive dunes of sand; but the nature of the base, on which both these and the calcareous formation repose, has not been ascertained.
The general direction of the rocky shore, from North-west Cape to Dirk Hartog's Island, is from the east of north to the west of south. On the south of the latter place the land turns towards the east. High, rocky and reddish cliffs have been seen indistinctly about latitude 27 degrees; and a coast of the same aspect has been surveyed, from Red Point, about latitude 28 degrees, for more than eighty miles to the south-west. The hills called Moresby's flat-topped Range, of which Mount Fairfax, latitude 28 degrees 45 minutes, is the highest point, occupy a space of more than fifty miles from north to south.
Rottnest Island and its vicinity, latitude 32 degrees, contains in abundance the calcareous concretions already mentioned; which seem there to consist in a great measure of the remains of recent shells, in considerable variety. The islands of this part of the shore have been described by MM. Peron and Freycinet;* and the coast to the south, down to Cape Leeuwin, the south-western extremity of New Holland, having been sufficiently examined by the French voyagers, was not surveyed by Captain King.
(*Footnote. Peron volume 2 page 168 etc.)
Swan River (Riviere des Cygnes) upon this part of the coast, latitude 31 degrees 25 minutes to 32 degrees, was examined by the French expedition, to the distance of about twenty leagues from its mouth; and found still to contain salt water. The rock in its neighbourhood consisted altogether of sandy and calcareous incrustations, in horizontal beds, enclosing, it is stated, shells, and the roots and even trunks of trees. Between this river and Cape Peron, a "great bay" was left unexplored.*
(*Footnote. Peron volume 1 page 179. Freycinet page 5. 170.)