Volume II Part 55 (2/2)
The bottom of several of the bays, on the eastern coast, not having been explored, it is still probable that rivers, or considerable mountain streams, may exist there.
Along this eastern line of sh.o.r.e, granite has been found throughout a s.p.a.ce of nearly five hundred miles; at Cape Cleveland; Cape Grafton; Endeavour River; Lizard Island; and at Clack's Island, on the north-west of the rocky ma.s.s which forms Cape Melville. And rocks of the trap formation have been obtained in three detached points among the islands off the sh.o.r.e; in the Percy Isles, about lat.i.tude 21 degrees 40 minutes; Sunday Island, north of Cape Grenville, about lat.i.tude 12 degrees; and in Good's Island, on the north-west of Cape York, lat.i.tude 10 degrees 34 minutes.
The Gulf of Carpentaria having been fully examined by Captain Flinders, was not visited by Captain King; but the following account has been deduced from the voyage and charts of the former, combined with the specimens collected by Mr. Brown, who has also favoured me with an extract from the notes taken by himself on that part of the coast.
The land, on the east and south of the Gulf of Carpentaria, is so low, that for a s.p.a.ce of nearly six hundred miles--from Endeavour Strait to a range of hills on the mainland, west of Wellesley Islands, at the bottom of the gulf--no part of the coast is higher than a s.h.i.+p's masthead.* Some of the land in Wellesley islands is higher than the main; but the largest island is, probably, not more than one hundred and fifty feet in height;** and low-wooded hills occur on the mainland, from thence to Sir Edward Pellew's group. The rock observed on the sh.o.r.e at Coen River, the only point on the eastern side of the Gulf where Captain Flinders landed, was calcareous sandstone of recent concretional formation.
(*Footnote. Flinders Charts Plate 14.)
(**Footnote. Flinders Volume 2 page 158.)
In Sweer's Island, one of Wellesley's Isles, a hill of about fifty or sixty feet in height was covered with a sandy calcareous stone, having the appearance of concretions rising irregularly about a foot above the general surface, without any distinct ramifications. The specimens from this place have evidently the structure of stalact.i.tes, which seem to have been formed in sand; and the reddish carbonate of lime, by which the sand has been agglutinated, is of the same character with that of the west coast, where a similar concreted limestone occurs in great abundance.
The western sh.o.r.e of the Gulf of Carpentaria is somewhat higher, and from Limmen's Bight to the lat.i.tude of Groote Eylandt, is lined by a range of low hills. On the north of the latter place, the coast becomes irregular and broken; the base of the country apparently consisting of primitive rocks, and the upper part of the hills of a reddish sandstone; some of the specimens of which are identical with that which occurs at Goulburn and Sims Islands on the north coast, and is very widely distributed on the north-west. The sh.o.r.e at the bottom of Melville Bay is stated by Captain Flinders to consist of low cliffs of pipe-clay, for a s.p.a.ce of about eight miles in extent from east to west; and similar cliffs of pipe-clay are described as occurring at Goulburn Islands (see the plate, volume 1) and at Lethbridge Bay, on the north of Melville Island: both of which places are considerably to the west of the Gulf of Carpentaria.
Morgan's Island, a small islet in Blue-Mud Bay, on the north-west of Groote Eylandt, is composed of clink-stone; and other rocks of the trap-formation occur in several places on this coast.
The north of Blue-Mud Bay has furnished also specimens of ancient sandstone; with columnar rocks, probably of clink-stone. Round Hill, near Point Grindall, a promontory on the north of Morgan's Island, is composed, at the base, of granite; and Mount Caledon, on the west side of Caledon Bay, seems likewise to consist of that rock, as does also Melville Island. This part of the coast has afforded the ferruginous oxide of manganese: and brown hemat.i.te is found hereabouts in considerable quant.i.ty, on the sh.o.r.e at the base of the cliffs; forming the cement of a breccia, which contains fragments of sandstone, and in which the ferruginous matter appears to be of very recent production; resembling, perhaps, the hemat.i.te observed at Edinburgh by Professor Jameson, around cast-iron pipes which had lain for some time in sand.*
(*Footnote. Edinburgh Philosophical Journal, July 1825 page 193.)
The general range of the coast, it will be observed, from Limmen's Bight to Cape Arnhem, is from south-west to north-east; and three conspicuous ranges of islands on the north-western entrance of the Gulf of Carpentaria, the appearance of which is so remarkable as to have attracted the attention of Captain Flinders,* have the same general direction: a fact which is probably not unconnected with the general structure of the country. The prevailing rock in all these islands appears to be sandstone.
(Flinders Volume 2 page 158. See hereafter.)
The line of the main coast from Point Dale to the bottom of Castlereagh Bay, where Captain King's survey was resumed, has also a direction from south-west to north-east, parallel to that of the ranges of islands just mentioned. The low land near the north coast in Castlereagh Bay, and from thence to Goulburn Islands, is intersected by one of the few rivers yet discovered in this part of Australia, a tortuous and shallow stream, named Liverpool River, which has been traced inland to about forty miles from the coast, through a country not more than three feet in general elevation above high-water mark; the banks being low and muddy, and thickly wooded: And this description is applicable also to the Alligator Rivers on the south-east of Van Diemen's Gulf, and to the surrounding country. The outline of the Wellington Hills, however, on the mainland between the Liverpool and Alligator Rivers, is jagged and irregular; this range being thus remarkably contrasted with the flat summits which appear to be very numerous on the north-western coast.
The specimens from Goulburn Islands consist of reddish sandstone, not to be distinguished from that which occurs beneath the coal formation in England. On the west of these islands the coast is more broken, and the outline is irregular: but the elevation is inconsiderable; the general height in Cobourg Peninsula not being above one hundred and fifty feet above the sea, and that of the hills not more than from three to four hundred feet.
On this part of the coast, several hills are remarkable for the flatness of their tops; and the general outline of many of the islands, as seen on the horizon, is very striking and peculiar. Thus Mount Bedwell and Mount Roe, on the south of Cobourg Peninsula; Luxmoore Head, at the west end of Melville Island; the Barthelemy Hills, south of Cape Ford; Mount Goodwin, south of Port Keats; Mount c.o.c.kburn, and several of the hills adjacent to Cambridge Gulf, the names given to which during the progress of the survey sufficiently indicate their form, as House-roofed, Bastion, Flat-top, and Square-top Hills; Mount Casuarina, about forty miles north-west of Cambridge Gulf; a hill near Cape Voltaire; Steep-Head, Port Warrender; and several of the islands off that port, York Sound, and Prince Regent's River; Cape Cuvier, about lat.i.tude 24 degrees; and, still further south, the whole of Moresby's flat-topped Range, are all distinguished by their linear and nearly horizontal outlines: and except in a few instances, as Mount c.o.c.kburn, Steep-Head, Mounts Trafalgar and Waterloo (which look more like hills of floetz-trap) they have very much the aspect of the summits in the coal formation.*
(*Footnote. Captain King, however, has informed me, that in some of these cases, the shape of the hill is really that of a roof, or hayrick; the transverse section being angular, and the horizontal top an edge.)
Sketch 1 of some of the islands off Admiralty Gulf (looking southward from the north-east end of Ca.s.sini Island, about lat.i.tude 13 degrees 50 minutes, East longitude 125 degrees 50 minutes) has some resemblance to one of the views in Peron's Atlas (plate 6 figure 7): and the outline of the Iles Forbin (plate 8 figure 5, of the same series) also exhibits remarkably the peculiar form represented in several of Captain King's drawings (Sketch 2).
The red colour of the cliffs on the north-west and west coasts, is also an appearance which is frequently noticed on the sketches taken by Captain King and his officers. This is conspicuous in the neighbourhood of Cape Croker; at Darch Island and Palm Bay; at Point Annesley and Point Coombe in Mountnorris Bay; in the land about Cape Van Diemen, and on the north-west of Bathurst Island. The cliffs on Roe's River (Prince Frederic's Harbour) as might have been expected from the specimens, are described as of a reddish colour; Cape Leveque is of the same hue; and the northern limit of Shark's Bay, Cape Cuvier of the French, lat.i.tude 24 degrees 13 minutes, which is like an enormous bastion, may be distinguished at a considerable distance by its full red colour.*
(*Footnote. Freycinet page 195.)
It is on the bank of the channel which separates Bathurst and Melville Islands, near the north-western extremity of New Holland, that a new colony has recently been established: (see Captain King's Narrative volume 2.) A permanent station under the superintendence of a British officer, in a country so very little known, and in a situation so remote from any other English settlement, affords an opportunity of collecting objects of natural history, and of ill.u.s.trating various points of great interest to physical geography and meteorology, which it is to be hoped will not be neglected. And as a very instructive collection, for the general purposes of geology, can readily be obtained in such situations, by attending to a few precautions, I have thought that some brief directions on this subject would not be out of place in the present publication; and have subjoined them to the list of specimens at the close of this paper.*
(*Footnote. See hereafter.)
In the vicinity of Cambridge Gulf, Captain King states, the character of the country is entirely changed; and irregular ranges of detached rocky hills composed of sandstone, rising abruptly from extensive plains of low level land, supersede the low and woody coast, that occupies almost uninterruptedly the s.p.a.ce between this inlet and Cape Wessel, a distance of more than six hundred miles. Cambridge Gulf, which is nothing more than a swampy arm of the sea, extends to about eighty miles inland, in a southern direction: and all the specimens from its vicinity precisely resemble the older sandstones of the confines of England and Wales.* The View (volume 1 plate) represents in the distance Mount c.o.c.kburn, at the head of Cambridge Gulf; the flat rocky top of which was supposed to consist of sandstone, but has also the aspect of the trap-formation. The strata in Lacrosse Island, at the entrance of the Gulf, rise toward the north-west, at an angle of about 30 degrees with the horizon: their direction consequently being from north-east to south-west.
(*Footnote. I use the term Old Red Sand Stone, in the acceptation of Messrs. Buckland and Conybeare, Observations on the South Western Coal District of England. Geological Transactions Second Series volume 1.
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