Narrative of a Survey of the Intertropical and Western Coasts of Australia Volume II Part 57

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 pegmat.i.tes (granites graphiques) qui cunst.i.tuent 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 rama.s.ses a la terre de Van Diemen, dans les environs du port Dalrymple, et pres du Cap Barren, indiquent, 1. Des terrains de pegmat.i.te, 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 a.s.sociation. 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 const.i.tute large ma.s.ses, seems to be of more frequent occurrence as a component of rocks than has. .h.i.therto 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 ma.s.s 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 sh.o.r.e. 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, ma.s.ses of strata highly inclined.

The outlines on the contrary, on the north, north-west, and western sh.o.r.es, 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 cla.s.s 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 sh.o.r.es, except that of the recent breccia; and although negative conclusions are hazardous, it would seem probable, from this circ.u.mstance, 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 s.p.a.ce of no less than twenty-five degrees of lat.i.tude, 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 sh.o.r.es 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 sh.e.l.ls, which abounds on the sh.o.r.es 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 sh.o.r.e; and other calcareous acc.u.mulations, 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 sh.o.r.e at Madagascar, and consists of a firmly-compacted cream-coloured stone, composed of granular fragments of sh.e.l.ls, 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 sh.e.l.ls of Bermuda, described by Captain Vetch,*** which pa.s.s 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 ma.s.ses 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 gra.s.s, 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 Inst.i.tution, 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 sh.e.l.ls, 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 const.i.tutes 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 sh.o.r.e, 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 sh.e.l.ls from Bermuda, described by Captain Vetch, and already referred to:* and the rock in both these cases, nearly approaches to some of the coa.r.s.er 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 sh.e.l.ls, 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 acc.u.mulation which occurs at St.

Hospice, about sixty feet above the present level of the sea, as containing marine sh.e.l.ls in a scarcely fossil state (a peine fossiles) and he describes the ma.s.s in which they occur, as belonging to a formation still more recent than the upper marine beds of the environs of Paris.***

(*Footnote. Prevost ma.n.u.scripts. 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 Oss.e.m.e.ns 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. .h.i.therto been a.s.signed to the crag beds of Suffolk, Ess.e.x, 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 sh.e.l.ls, is considered,** the continual deposition of which, at the present time, cannot be questioned (though probably the greater part of the ma.s.ses 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 sh.e.l.ls 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 Ess.e.x 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 sh.e.l.ly 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 sh.e.l.ls are found in the cemented ma.s.ses, at heights above the sea, to which no ordinary natural operations could have conveyed them, the elevation of these sh.e.l.ls 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 sh.e.l.ls, their great quant.i.ty, 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 sh.e.l.ls, 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 sh.e.l.ls 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 sh.e.l.ls in such situations may often be ascribed to the birds, which feed on their inhabitants. At Madeira, where recent sh.e.l.ls 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 sh.e.l.ls 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 s.p.a.ce 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-sh.e.l.l 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 sh.e.l.ls 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 s.h.i.+NGLE MIXED WITH Sh.e.l.lS, extending, in a parallel direction to the sh.o.r.e, to the height of fifty feet above the sea." Such an acc.u.mulation of geological evidence, from different quarters and distinct cla.s.ses 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 ill.u.s.trated by a valuable paper in the Journal of the Royal Inst.i.tution for April 1824 volume 17 page 38 etc.) The writer of this latter article a.s.serts 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 sh.o.r.e. 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, princ.i.p.ally in the form of comminuted sh.e.l.ls, which is diffused through the siliceous sand of the sh.o.r.es 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 princ.i.p.ally 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 lat.i.tudes. 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 a.n.a.logous 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 sh.o.r.e 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 Perths.h.i.+re, which present a great variety of stalact.i.tic forms, generally more or less complicated, and often exceedingly intricate and strange,*** and which appear to be a.n.a.logous 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 stalact.i.tes 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 Inst.i.tution 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 a.n.a.logous 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 circ.u.mstances, 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 ma.s.s 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.