GEOLOGICAL REMARKS.
1. The rocks, of which specimens occur in the collections of Captain King and Mr. Brown, are the following:
Granite: Cape Cleveland; C. Grafton; Endeavour River; Lizard Island; Round Hill, near C. Grindall; Mount Caledon; Island near C. Arnhem; Melville Bay; Bald-head, King George's Sound.
Various Slaty Rocks:
Mica-State: Mallison's I.
Talc-State: Endeavour River.
Slaty Clay: Inglis' I., Clack I., Percy I.
Hornblende Rock ?: Pobassoo's Island; Halfway Bay, Prince Regent's River.
Granular Quartz: Endeavour River; Montagu Sound, North-west Coast.
Epidote: C. Clinton ?; Port Warrender; Careening Bay.
Quartzose Conglomerates, and ancient Sandstones: Rodd's Bay; Islands of the north and north-west coasts; Cambridge Gulf; York Sound; Prince Regent's River.
Pipe-clay: Melville Bay; Goulburn I.; Lethbridge Bay.
ROCKS OF THE TRAP FORMATION.
Serpentine: Port Macquarie; Percy Isles.
Sienite: Rodd's Bay.
Porphyry: C. Cleveland.
Porphyritic Conglomerate: C. Clinton, Percy I., Good's I.
Compact Felspar: Percy I., Repulse Bay, Sunday Island.
Greenstone: Vansittart Bay, Bat I., Careening Bay, Malus I.
Clinkstone: Morgan's I., Pobassoo's I.
Amygdaloid, with Chalcedony: Port Warrender; Half-way Bay; Bat Island; Malus I.
Wacke ?: Bat Island.
Recent calcareous Breccia: Sweer's Island, N. coast. Dirk Hartog's and Rottnest Islands, etc., West coast. King George's Sound, South coast.
The only information that has been published respecting the geology of New Holland, besides what is contained in the Voyages of Captain Flinders and Commodore Baudin, is a slight notice by Professor Buckland of some specimens collected during Mr. Oxley's Expedition to the River Macquarie,* in 1818; and a brief outline of a paper by the Reverend Archdeacon Scott, entitled A Sketch of the Geology of New South Wales and Van Diemen's Land, which has been read before the Geological Society.** On these authorities, the following may be added to the preceding list of rocks:
Limestone, resembling in the character of its organic remains the mountain limestone or England: Interior of New Holland, near the east coast; Van Diemen's Land (Buckland; Prevost manuscripts; Scott).
The Coal-formation: East coast of New Holland; Van Diemen's Land. (Buckland-Scott.)
Indications of the new red-Sandstone (Red-Marl) afforded by the occurrence of Salt: Van Diemen's Land. (Scott.)
Oolite: Van Diemen's Land. (Scott.)
(*Footnote. Geological Transactions volume 5 page 480.)
(**Footnote. Ann. of Phil. June 1824. I am informed that Mr. Von Buch also has published a paper on the rocks of New Holland; but have not been so fortunate as to meet with it.
Since this paper has been at the press, a Report presented to the Academy of Sciences at Paris, on the Voyage of Discovery of M. Duperrey, performed during the years 1822 to 1825, has been published; from whence I have subjoined an extract, in order to complete the catalogue of the rocks of Australia, according to the present state of our information.
Les echantillons recueillis tant dans les contrees voisines du Port Jackson, que dans les Montagnes-Bleues, augmentent beaucoup nos connoissances sur ces parties de la Nouvelle Hollande. Les echantillons, au nombre de soixante-dix, nous offrent, 1. Les granites, les syenites-quartziferes, et les pegmatites (granites graphiques) qui cunstituent le second plan des Muntagnes-Bleues. 2. Les gres ferrugineux, et renfermant d'abondantes paillettes de fer oligiste, qui couvrent non seulement une vaste etendue de pays pres des cotes, mais encore le premier plan des Montagnes-Bleues; et 3. Le lignite stratiforme qu'on exploite au Mont-Yorck, a 1000 pieds au-dessus du niveau de la mer, et dont la presence ajoute aux motifs qui portent a penser que les gres ferrugineux de ces contrees appartiennent au systeme des terrains tertiaires.
Vingt-sept echantillons ramasses a la terre de Van Diemen, dans les environs du port Dalrymple, et pres du Cap Barren, indiquent, 1. Des terrains de pegmatite, et de serpentine. 2. Des terrains intermediaires coquilliers, formes du grauwacke-schistoide, et de pierre calcaire. 3. Des terrains tres-recens, composes d'argile sablonneuse et ferrugineuse, avec geodes de fer hydrate, et du bois fossile, a differens etats. On distingue en outre des belles topazes blanches ou bleuatres, parmi les galets quartzeux, qui ont ete recueillis au Cap Barren: Bulletin des Sciences Naturelles, Octobre 1825 page 189.)
2. The specimens of Captain King's and Mr. Brown's collections, without any exception, agree with those of the same denominations from other parts of the world; and the resemblance is, in some instances, very remarkable: The sandstones of the west and north-west of New Holland are so like those of the west of England, and of Wales, that the specimens from the two countries can scarcely be distinguished from each other; the arenaceous cement in the calcareous breccia of the west coast is precisely the same with that of Sicily; and the jasper, chalcedony, and green quartz approaching to heliotrope, from the entrance of Prince Regent's River, resemble those of the Tyrol, both in their characters and association. The Epidote of Port Warrender and Careening Bay, affords an additional proof of the general distribution of that mineral; which, though perhaps it may not constitute large masses, seems to be of more frequent occurrence as a component of rocks than has hitherto been supposed.* The mineral itself, both crystallized and compact, the latter in the form of veins traversing sienitic rocks, occurs, in Mr. Greenough's cabinet alone, from Malvern, North Wales, Ireland, France, and Upper Saxony. Mr. Koenig has found it extensively in the sienitic tract of Jersey;** where blocks of a pudding-stone, bearing some resemblance to the green breccia of Egypt, were found to be composed of compact epidote, including very large pebbles of a porphyritic rock, which itself contains a considerable proportion of this substance. And Mr. Greenough has recently received, among specimens sent home by Mr. J. Burton, junior, a mass of compact epidote, with quartz and felspar, from Dokhan, in the desert between the Red Sea and the Nile. When New Holland is added to these localities, it will appear that few minerals are more widely diffused.
(*Footnote. See Cleaveland's Mineralogy 1816 page 297 to 300.)
(**Footnote. Plee's Account of Jersey quarto Southampton 1817 page 231 to 276.)
3. The unpublished sketches, by Captain King and Mr. Roe, of the hills in sight during the progress of the survey of the Coasts of Australia, accord in a very striking manner with the geological character of the shore. Those from the east coast, where the rocks are primitive, representing strongly marked and irregular outlines of lofty mountains, and frequently, in the nearer ground, masses of strata highly inclined. The outlines on the contrary, on the north, north-west, and western shores, are most commonly uniform, rectilinear, the summits flat, and diversified only by occasional detached and conical peaks, none of which are very lofty.
4. No information has yet been obtained, from any of the collections, respecting the diluvial deposits of Australia: a class of phenomena which is of the highest interest, in an island of such vast extent, so very remote in situation, and of which the existing animals are so different from those of other parts of the globe. It is remarkable, also, that no limestone is among the specimens from the northern and western shores, except that of the recent breccia; and although negative conclusions are hazardous, it would seem probable, from this circumstance, that limestone cannot be very abundant or conspicuous at the places visited. No eruptive mountains, nor any traces of recent volcanic eruption, have yet been observed in any part of Australia.
5. The recent calcareous breccia, of which a detailed description will be found in the subjoined list of specimens, is one of the most remarkable productions of New Holland: It was found, during the expedition of Commodore Baudin, to exist throughout a space of no less than twenty-five degrees of latitude, and an equal extent of longitude, on the southern, west, and north-west coasts;* and from Mr. Brown's specimens it appears to occur also on the shores of the Gulf of Carpentaria. The full account which M. Peron has given of this formation, sufficiently shows its resemblance to the very recent limestone, full of marine shells, which abounds on the shores of the Mediterranean, the West India Islands, and in several other parts of the world: And it is a point of the greatest interest in geology, to determine, whether any distinct line can really be drawn, between those concretions, unquestionably of modern formation, which occur immediately upon the shore; and other calcareous accumulations, very nearly resembling them, if not identical, both in the fossils they contain, and in the characters of the cementing substances, that are found in several countries, at considerable heights above the sea.
(*Footnote. Voyage 2 page 168, 169 to 216 etc.)
Dr. Buckland has described a breccia of modern formation, which occurs upon the shore at Madagascar, and consists of a firmly-compacted cream-coloured stone, composed of granular fragments of shells, agglutinated by a calcareous cement.* The stone of Guadaloupe, containing the human skeletons, is likewise of the same nature; and its very recent production cannot be doubted, since it contains fragments of stone axes, and of pottery.** The cemented shells of Bermuda, described by Captain Vetch,*** which pass gradually into a compact limestone, differ only in colour from the Guadaloupe stone; and agree with it, and with the calcareous breccia of Dirk Hartog's Island, in the gradual melting down of the cement into the included portions, which is one of the most remarkable features of that rock.**** A calcareous compound, apparently of the same kind, has been recently mentioned, as of daily production in Anastasia Island, on the coast of East Florida;***** and will probably be found to be of very general occurrence in that quarter of the globe. And Captain Beaufort's account of the process by which the gravelly beach is cemented into stone, at Selinti, and several other places on the coast of Karamania, on the north-east of the Mediterranean,****** accords with M. Peron's description of the progress from the loose and moveable sands of the dunes to solid masses of rock.******* In the island of Rhodes, also, there are hills of pudding-stone, of the same character, considerably elevated above the sea. And Captain W.H. Smyth, the author of Travels in Sicily, and of the Survey of the Mediterranean recently published by the Admiralty, informs me, that he has seen these concretions in Calabria, and on the coasts of the Adriatic; but still more remarkably in the narrow strip of recent land (called the Placca) which connects Leucadia, one of the Ionian Islands, with the continent, and so much resembles a work of art, that it has been considered as a Roman fabric. The stone composing this isthmus is so compact, that the best mill-stones in the Ionian Islands are made from it; but it is in fact nothing more than gravel and sand cemented by calcareous matter, the accretion of which is supposed to be rapidly advancing at the present day.
(*Footnote. Geological Transactions volume 5 page 479.)
(**Footnote. Linnean Transactions 12 page 53 to 57.)
(***Footnote. Geological Transactions 2nd Series volume 1 page 172.)
(****Footnote. Koenig Philosophical Transactions 1814 page 107 etc.)
(*****Footnote. Bulletin des Sciences Nat. Mars 1825.)
(******Footnote. Beaufort's Description of the South Coast of Asia Minor etc. Second edition. London 1818: pages 180 to 184 etc. In the neighbourhood of Adalia the deposition of calcareous matter from the water is so copious that an old watercourse had actually crept upwards to a height of nearly three feet; and the rapidity of the deposition was such that some specimens were collected on the grass, where the stony crust was already formed, although the verdure of the leaf was as yet but imperfectly withered (page 114): a fact which renders less extraordinary M. Peron's statement that the excrements of kangaroos had been found concreted by calcareous matter. Peron volume 2 page 116.)
(*******Footnote. Voyage 2 116.)
The nearest approach to the concreted sand-rock of Australia, that I have seen, is in the specimens presented by Dr. Daubeny to the Bristol Institution, to accompany his excellent paper on the geology of Sicily;* which prove that the arenaceous breccia of New Holland is very like that which occupies a great part of the coast, almost entirely around that island. Some of Dr. Daubeny's specimens from Monte Calogero, above Sciacca, consist of a breccia, containing angular fragments of splintery limestone, united by a cement, composed of minute grains of quartzose-sand disseminated in a calcareous paste, resembling precisely that of the breccia of Dirk Hartog's Island: and a compound of this kind, replete with shells, not far, if at all, different from existing species, fills up the hollows in most of the older rocks of Sicily; and is described as occurring, in several places, at very considerable heights above the sea. Thus, near Palermo, it constitutes hills some hundred feet in height; near Girgenti, all the most elevated spots are crowned with a loose stratum of the same kind; and the heights near Castro Giovanni, said to be 2880 feet above the sea, are probably composed of it. But although the concretions of the interior in Sicily much resemble those of the shore, it is still doubtful whether the former be not of more ancient formation; and if they contain nummulites, they would probably be referred to the epoch of the beds within the Paris basin.
(*Footnote. Edinburgh Philosophical Journal 1825 pages 116, 117, 118, and 254 to 255.)
The looser breccia of Monte Pelegrino, in Sicily, is very like the less compacted fragments of shells from Bermuda, described by Captain Vetch, and already referred to:* and the rock in both these cases, nearly approaches to some of the coarser oolites of England.
(*Footnote. These specimens are in the Museum of the Geological Society.)
The resemblance pointed out by M. Prevost,* of the specimens of recent breccia from New Holland, in the museum at the Jardin du Roi, to those of St. Hospice near Nice, is confirmed by the detail given by Mr. Allan in his sketch of the geology of that neighbourhood;** in which the perfect preservation of the shells, and their near approach to those of the adjoining sea at the present day, are particularly mentioned; and it is inferred that the date of the deposit which affords them, is anterior to that of the conglomerate containing the bones of extinct quadrupeds, likewise found in that country. M. Brongniart also, who examined the place himself, mentions the recent accumulation which occurs at St. Hospice, about sixty feet above the present level of the sea, as containing marine shells in a scarcely fossil state (a peine fossiles) and he describes the mass in which they occur, as belonging to a formation still more recent than the upper marine beds of the environs of Paris.***
(*Footnote. Prevost manuscripts. See hereafter.)
(**Footnote. Transactions of the Royal Society of Edinburgh volume 8 1818 page 427 etc. See also the previous publications of M. Risso Journal des Mines tome 34 etc.)
(***Footnote. Brongniart in Cuvier Ossemens Fossiles; 2nd Edit. volume 2 page 427.)
The geological period indicated by these facts, being probably more recent than the tertiary beds containing nummulites, and generally than the Paris and London strata, accords with the date which has hitherto been assigned to the crag beds of Suffolk, Essex, and Norfolk:* but later observations render doubtful the opinion generally received respecting the age of these remarkable deposits, and a full and satisfactory account of them is still a desideratum in the geology of England. When, also, our imperfect acquaintance with the travertino of Italy, and other very modern limestones containing freshwater shells, is considered,** the continual deposition of which, at the present time, cannot be questioned (though probably the greater part of the masses which consist of them may belong to an era preceding the actual condition of the earth's surface) it would seem that the whole subject of these newer calcareous formations requires elucidation: and, if the inferences connected with them do not throw considerable doubt upon some opinions at present generally received, they show, at least, that a great deal more is to be learned respecting the operations and products of the most recent geological epochs, than is commonly supposed.
(*Footnote. Conybeare and Phillips Outlines etc. page 11, Geological Transactions 1 page 327 etc. Taylor in Geological Transactions 2nd series Volume 2 page 371. Mr. Taylor states the important fact that the remains of unknown animals are buried together with the shells in the crag of Suffolk; but does not mention the nature of these remains. Since these pages have been at the press, Mr. Warburton, by whom the coast of Essex and Norfolk has been examined with great accuracy, has informed me that the fossil bones of the crag are the same with those of the diluvial gravel, including the remains of the elephant, rhinoceros, stag, etc.)
(**Footnote. Some valuable observations on the formation of recent limestone, in beds of shelly marl at the bottom of lakes in Scotland, have been read before the Geological Society by Mr. Lyell, and will appear in the volume of the Transactions now in the press. See Annals of Philosophy 1825 page 310.)
Since it appears that the accretion of calcareous matter is continually going on at the present time, and has probably taken place at all times, the stone thus formed, independent of the organized bodies which it envelopes, will afford no criterion of its date, nor give any very certain clue to the revolutions which have subsequently acted upon it. But as MARINE shells are found in the cemented masses, at heights above the sea, to which no ordinary natural operations could have conveyed them, the elevation of these shells to their actual place (if not that of the rock in which they are agglutinated) must be referred to some other agency: while the perfect preservation of the shells, their great quantity, and the abundance of the same species in the same places, make it more probable that they lay originally in the situations where we now find them, than that they have been transported from any considerable distances, or elevated by any very turbulent operation. Captain de Freycinet, indeed, mentions that patellae, worn by attrition, and other recent shells, have been found on the west coast of New Holland, on the top of a wall of rocks an hundred feet above the sea, evidently brought up by the surge during violent storms;* but such shells are found in the breccia of Sicily, and in several other places, at heights too great, and their preservation is too perfect, to admit of this mode of conveyance; and to account for their existence in such situations, recourse must be had to more powerful means of transport.
(* Freycinet page 187. The presence of shells in such situations may often be ascribed to the birds, which feed on their inhabitants. At Madeira, where recent shells are found near the coast at a considerable height above the sea, the Gulls have been seen carrying up the living patellae, just taken from the rocks.)
The occurrence of corals, and marine shells of recent appearance, at considerable heights above the sea, on the coasts of New Holland, Timor, and several other islands of the south, was justly considered by M. Peron as demonstrating the former abode of the sea above the land; and very naturally suggested an inquiry, as to the nature of the revolutions to which this change of situation is to be ascribed.* From similar appearances at Pulo Nias, one of the islands off the western coast of Sumatra, Dr. Jack also was led to infer, that the surface of that island must at one time have been the bed of the ocean; and after stating, that by whatever means it obtained its present elevation, the transition must have been effected with little violence or disturbance to the marine productions at the surface,** he concludes, that the phenomena are in favour of a HEAVING UP OF THE LAND, BY A FORCE FROM BENEATH. The probable nature of this force is indicated most distinctly, if not demonstrated, by the phenomena which attended the memorable earthquake of Chili, in November, 1820,*** which was felt throughout a space of fifteen hundred miles from north to south. For it is stated upon the clearest evidence, that after formidable shocks of earthquake, repeated with little interruption during the whole night of the 19th of November (and the shocks were continued afterwards, at intervals, for several months) IT APPEARED, on the morning of the 20th, THAT THE WHOLE LINE OF COAST FROM NORTH TO SOUTH, TO A DISTANCE OF ABOUT ONE HUNDRED MILES, HAD BEEN RAISED ABOVE ITS FORMER LEVEL. The alteration of level at Valparaiso was about three feet; and some rocks were thus newly exposed, on which the fishermen collected the scallop-shell fish, which was not known to exist there before the earthquake. At Quintero the elevation was about four feet. "When I went," the narrator adds, "to examine the coast, although it was high-water, I found the ancient bed of the sea laid bare, and dry, with beds of oysters, mussels, and other shells adhering to the rocks on which they grew, the fish being all dead, and exhaling most offensive effluvia. And I found good reason to believe that the coast had been raised by earthquakes at former periods in a similar manner; several ancient lines of beach, consisting OF SHINGLE MIXED WITH SHELLS, extending, in a parallel direction to the shore, to the height of fifty feet above the sea." Such an accumulation of geological evidence, from different quarters and distinct classes of phenomena, concurs to demonstrate the existence of most powerful expansive forces within the earth, and to testify their agency in producing the actual condition of its surface, that the phenomena just now described are nothing more than what was to be expected from previous induction. These facts, however, not only place beyond dispute the existence of such forces, but show that, even in detail, their effects accord most satisfactorily with the predictions of theory. It is not, therefore, at all unreasonable to conceive, that, in other situations, phenomena of the same character have been produced by the same cause, though we may not at present be enabled to trace its connexion with the existing appearances so distinctly; and though the facts, when they occurred, may have been unnoticed, or may have taken place at periods beyond the reach of historical record, or even beyond the possibility of human testimony.
(*Footnote. Peron Voyage etc. volume 2 pages 165 to 183.)
(**Footnote. Geological Transactions Second Series volume 1 page 403, 404.)
(***Footnote. The statements here referred to, are those of Mrs. Graham, in a letter to Mr. Warburton, which has been published in the Geological Transactions Second Series volume 1 page 412, etc.; and the account is supported and illustrated by a valuable paper in the Journal of the Royal Institution for April 1824 volume 17 page 38 etc.) The writer of this latter article asserts that the whole country, from the foot of the Andes to far out at sea, was raised by the earthquake; the greatest rise being at the distance of about two miles from the shore. The rise upon the coast was from two to four feet: at the distance of a mile, inland, it must have been from five to six, or seven feet, pages 40, 45.)
M. Peron has attributed the great abundance of the modern breccia of New Holland to the large proportion of calcareous matter, principally in the form of comminuted shells, which is diffused through the siliceous sand of the shores in that country;* and as the temperature, especially of the summer, is very high on that part of the coast where this rock has been principally found, the increased solution of carbonate of lime by the percolating water, may possibly render its formation more abundant there, than in more temperate climates. But the true theory of these concretions, under any modification of temperature, is attended with considerable difficulty: and it is certain that the process is far from being confined to the warmer latitudes. Dr. Paris has given an account of a modern formation of sandstone on the northern coast of Cornwall;** where a large surface is covered with a calcareous sand, that becomes agglutinated into a stone, which he considers as analogous to the rocks of Guadaloupe; and of which the specimens that I have seen, resemble those presented by Captain Beaufort to the Geological Society, from the shore at Rhodes. Dr. Paris ascribes this concretion, not to the agency of the sea, nor to an excess of carbonic acid, but to the solution of carbonate of lime itself in water, and subsequent percolation through calcareous sand; the great hardness of the stone arising from the very sparing solubility of this carbonate, and the consequently very gradual formation of the deposit--Dr. MacCulloch describes calcareous concretions, found in banks of sand in Perthshire, which present a great variety of stalactitic forms, generally more or less complicated, and often exceedingly intricate and strange,*** and which appear to be analogous to those of King George's Sound and Sweer's Island: And he mentions, as not unfrequently occurring in sand, in different parts of England (the sand above the fossil bones of Norfolk is given as an example) long cylinders or tubes, composed of sand agglutinated by carbonate of lime, or calcareous stalactites entangling sand, which, like the concretions of Madeira, and those taken for corals at Bald-Head, have been ranked improperly, with organic remains.
(*Footnote. Peron Voyage etc. 2 page 116.)
(**Footnote. Transactions of the Geological Society of Cornwall volume 1 page 1 etc.)
(***Footnote. On an arenaceo-calcareous substance, etc. Quarterly Journal Royal Institution October 1823 volume 16 page 79 to 83.)
The stone which forms the fragments in the breccia of New Holland, is very nearly the same with that of the cement by which they are united, the difference consisting only in the greater proportion of sand which the fragments contain: and it would seem, that after the consolidation of the former, and while the deposition of similar calcareous matter was still in progress, the portions first consolidated must have been shattered by considerable violence. But, where no such fragments exist, the unequal diffusion of components at first uniformly mixed, and even the formation of nodules differing in proportions from the paste which surrounds them, may perhaps admit of explanation, by some process analogous to what takes place in the preparation of the compound of which the ordinary earthenware is manufactured; where, though the ingredients are divided by mechanical attrition only, a sort of chemical action produces, under certain circumstances, a new arrangement of the parts.* And this explanation may, probably, be extended to those nodular concretions, generally considered as contemporaneous with the paste in which they are enveloped, the distinction of which, from conglomerates of mechanical origin, forms, in many cases, a difficulty in geology. What the degree may be, of subdivision required to dispose the particles to act thus upon each other, or of fluidity to admit of their action, remains still to be determined.
(*Footnote. The clay and pulverized flints are combined for the use of the potter, by being first separately diffused in water to the consistence of thick cream, and when mixed in due proportion are reduced to a proper consistence by evaporation. During this process, if the evaporation be not rapid and immediate, or if the ingredients are left to act on each other, even for twenty-four hours, the flinty particles unite into sandy grains, and the mass becomes unfit for the purposes of the manufacturer. I am indebted for this interesting fact, which, I believe, is well known in some of the potteries, to my friend Mr. Arthur Aikin. And Mr. Herschel informs me, that a similar change takes place in recently precipitated carbonate of copper; which, if left long moist, concretes into hard gritty grains, of a green colour, much more difficultly soluble in ammonia than the original precipitate.)
6. As the superficial extent of Australia is more than three-fourths of that of Europe, and the interior may be regarded as unknown,* any theoretic inferences, from the slight geological information hitherto obtained respecting this great island, are very likely to be deceitful; but among the few facts already ascertained respecting the northern portion of it, there are some which appear to afford a glimpse of general structure.
Captain Flinders, in describing the position of the chains of islands on the north-west coast of Carpentaria, Wessel's, the English Company's, and Bromby's Islands, remarks, that he had "frequently observed a great similarity both in the ground plans, and the elevations of hills, and of islands, in the vicinity of each other, but did not recollect another instance of such a likeness in the arrangement of clusters of islands."* The appearances which called for this observation, from a voyager of so much sagacity and experience in physical geography, must probably have been very remarkable; and, combined with information derivable from the charts, and from the specimens for which we are indebted to Captain King and Mr. Brown, they would seem to point out the arrangement of the strata on the northern coasts of New Holland.
(*Footnote. The following are the proportions assigned by Captain de Freycinet to the principal divisions of the globe. Voyage aux Terres Australes page 107.
COLUMN 1: DIVISION OF THE GLOBE.
COLUMN 2: AREA IN FRENCH LEAGUES SQUARE.
COLUMN 3: PROPORTION.Asia : 2,200,000 : 17.
America : 2,100,000 : 17.
Africa : 1,560,000 : 12.
Europe : 501,875 : 4.
Australia : 384,375 : 3.The most remote points from the coast of New South Wales, to which the late expeditions have penetrated (and the interior has never yet been examined in any other quarter) are not above 500 miles, in a direct line from the sea; the average width of the island from east to west being more than 2000 miles, and from north to south more than 1000 miles.)
(*Footnote. Flinders 5 2 page 246; and Charts, Plates 14 and 15. King's Charts, Plate 4.)
Of the three ranges which attracted Captain Flinders' notice (see the Map) the first on the south-east (3, 4, 5, 6, 7) is that which includes the Red Cliffs, Mallison's Island, a part of the coast of Arnhem's Land, from Cape Newbold to Cape Wilberforce, and Bromby's Isles; and its length, from the mainland (3) on the south-west of Mallison's Island, to Bromby's Isles (7) is more than fifty miles, in a direction nearly from south-west to north-east. The English Company's Islands (2, 2, 2, 2) at a distance of about four miles, are of equal extent; and the general trending of them all, Captain Flinders states (page 233) is nearly North-East by East, parallel with the line of the main coast, and with Bromby's Islands. Wessel's Islands (1, 1, 1, 1) the third or most northern chain, at fourteen miles from the second range, stretch out to more than eighty miles from the mainland, likewise in the same direction.
MAP OF THE CHAINS OF ISLANDS ON THE NORTH-WEST COAST OF CARPENTARIA
It is also stated by Captain Flinders, that three of the English Company's Islands which were examined, slope down nearly to the water on their west sides; but on the east, and more especially the south-east, they present steep cliffs; and the same conformation, he adds, seemed to prevail in the other islands.* If this structure occurred only in one or two instances, it might be considered as accidental; but as it obtains in so many cases, and is in harmony with the direction of the ranges, it is not improbably of still more extensive occurrence, and would intimate a general elevation of the strata towards the south-east.
(*Footnote. Flinders Volume 2 page 235.)
Now on examining the general map, it will be seen, that the lines of the coast on the mainland, west of the Gulf of Carpentaria, between Limmen's Bight and Cape Arnhem--from the bottom of Castlereagh Bay to Point Dale--less distinctly from Point Pearce, latitude 14 degrees 23 minutes, longitude 129 degrees 18 minutes, to the western extremity of Cobourg Peninsula, and from Point Coulomb, latitude 17 degrees 20 minutes, longitude 123 degrees 11 minutes, to Cape Londonderry, have nearly the same direction; the first line being about one hundred and eighty geographical miles, the second more than three hundred, and the last more than four hundred miles, in length.* And these lines, though broken by numerous irregularities, especially on the north-west coast, are yet sufficiently distinct to indicate a probable connexion with the geological structure of the country; since the coincidence of similar ranges of coast with the direction of the strata, is a fact of very frequent occurrence in other parts of the globe.** And it is observable that considerable uniformity exists in the specimens, from the different places in this quarter of New Holland which have been hitherto examined; sandstone, like that of the older formations of Europe occurring generally on the north and north-west coasts, and appearing to be extensively diffused on the north-west of the Gulf of Carpentaria, where it reposes upon primitive rocks.***
(*Footnote. It is deserving of notice, that the coast of Timor, the nearest land on the north-west, at the distance of about 300 miles, is also nearly straight, and parallel to the Coast of New Holland in this quarter: part of the mountainous range, of which that island consists, being probably more than 9000 feet high; and its length, from the north-eastern extremity to the South-West of the adjoining island of Rottee, about 300 miles. But, unfortunately for the hypothesis, a chain of islands immediately on the north of Timor, is continued nearly in a right line for more than 1200 miles (from Sermatta Island to the south-eastern extremity of Java) in a direction FROM EAST TO WEST. This chain, however, contains several volcanoes, including those of Sumbawa, the eruption of which, in 1815, was of extraordinary violence. See Royal Inst. Journal volume 1 1816 page 248 etc.
At Lacrosse Island, in the mouth of Cambridge Gulf, on the north-west coast of New Holland, the beds rise to the North-West: their direction consequently is from South-West to North-East; and the rise towards the high land of Timor. The intervening sea is very shallow.)
(**Footnote. A remarkable case of this kind, which has not, I believe, been noticed, occurs in the Mediterranean; and is conspicuous in the new chart of that sea, by Captain W.H. Smyth. The eastern coast of Corsica and Sardinia, for a space of more than two hundred geographical miles being nearly rectilinear, in a direction from north to south; and, Captain Smyth has informed me, consisting almost entirely of granite, or, at least, of primitive rocks. The coast of Norway affords another instance of the same description; and the details of the ranges in the interior of England furnish several examples of the same kind, on a smaller scale.)
(***Footnote. The coastlines nearly at rightangles to those above-mentioned--from the South-East of the Gulf of Carpentaria to Limmen's Bight, from Cape Arnhem to Cape Croker, and from Cape Domett to Cape Londonderry--have also a certain degree of linearity; but much less remarkable, than those which run from South-West to North-East.)
The horn-like projection of the land, on the east of the Gulf of Carpentaria, is a very prominent feature in the general map of Australia, and may possibly have some connexion with the structure just pointed out. The western shore of this horn, from the bottom of the gulf to Endeavour Straits, being very low; while the land on the east coast rises in proceeding towards the south, and after passing Cape Weymouth, latitude 12 degrees 30 minutes, is in general mountainous and abrupt; and Captain King's specimens from the north-east coast show that granite is found in so many places along this line as to make it probable that primitive rocks may form the general basis of the country in that quarter; since a lofty chain of mountains is continued on the south of Cape Tribulation, not far from the shore, throughout a space of more than five hundred miles. It would carry this hypothesis too far to infer that these primitive ranges are connected with the mountains on the west of the English settlements near Port Jackson, etc., where Mr. Scott has described the coal-measures as occupying the coast from Port Stevens, about latitude 33 degrees to Cape Howe, latitude 37 degrees, and as succeeded, on the eastern ascent of the Blue Mountains, by sandstone, and this again by primitive strata:* But it may be noticed that Wilson's Promontory, the most southern point of New South Wales, and the principal islands in Bass Strait, contain granite; and that primitive rocks occur extensively in Van Diemen's Land.
(*Footnote. Annals of Philosophy June 1824.)
The uniformity of the coastlines is remarkable also in some other quarters of Australia; and their direction, as well as that of the principal openings, has a general tendency to a course from the west of south to the east of north. This, for example, is the general range of the south-east coast, from Cape Howe, about latitude 37 degrees, to Cape Byron, latitude 29 degrees, or even to Sandy Cape, latitude 25 degrees; and of the western coast, from the south of the islands which enclose Shark's Bay, latitude 26 degrees, to North-west Cape, about latitude 22 degrees. From Cape Hamelin, latitude 34 degrees 12 minutes, to Cape Naturaliste, latitude 33 degrees 26 minutes, the coast runs nearly on the meridian. The two great fissures of the south coast, Spencer's, and St. Vincent's Gulfs, as well as the great northern chasm of the Gulf of Carpentaria, have a corresponding direction; and Captain Flinders (Chart 4) represents a high ridge of rocky and barren mountains, on the east of Spencer's Gulf, as continued, nearly from north to south, through a space of more than one hundred geographical miles, between latitude 32 degrees 7 minutes and 34 degrees. Mount Brown, one of the summits of this ridge, about latitude 32 degrees 30 minutes, being visible at the distance of twenty leagues.
The tendency of all this evidence is somewhat in favour of a general parallelism in the range of the strata, and perhaps of the existence of primary ranges of mountains on the east of Australia in general, from the coast about Cape Weymouth* to the shore between Spencer's Gulf and Cape Howe. But it must not be forgotten, that the distance between these shores is more than a thousand miles in a direct line; about as far as from the west coast of Ireland to the Adriatic, or double the distance between the Baltic and the Mediterranean. If, however, future researches should confirm the indications above mentioned, a new case will be supplied in support of the principle long since advanced by Mr. Michell,** which appears (whatever theory be formed to explain it) to be established by geological observation in so many other parts of the world, that the outcrop of the inclined beds, throughout the stratified portion of the globe, is everywhere parallel to the longer ridges of mountains, towards which, also, the elevation of the strata is directed. But in the present state of our information respecting Australia, all such general views are so very little more than mere conjecture, that the desire to furnish ground for new inquiry, is, perhaps, the best excuse that can be offered for having proposed them.
(*Footnote. The possible correspondence of the great Australian Bight, the coast of which in general is of no great elevation, with the deeply-indented Gulf of Carpentaria, tending, as it were, to a division of this great island into two, accords with this hypothesis of mountain ranges: but the distance between these recesses, over the land at the nearest points, is not less than a thousand English miles. The granite, on the south coast, at Investigator's Islands, and westward, at Middle Island, Cape Le Grand, King George's Sound, and Cape Naturaliste, is very wide of the line above-mentioned, and nothing is yet known of its relations.)
(**Footnote. On the Cause of Earthquakes. Philosophical Transactions 1760 volume 51 page 566 to 585, 586.)