Narrative of an Expedition into Central Australia. Charles Sturt

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СКАЧАТЬ being then 200 miles distant from the south coast in a direct line, I was less than 100 feet above the level of the sea; circumstances prevented my examining this new river however for many miles above its junction with the main stream, but coming, as I have elsewhere remarked, direct from the north, and possessing, as it did, all the character and appearance of the Upper Darling, I had no doubt as to its identity; in which case no stronger fact could have been adduced to prove the southerly fall or dip of the interior as far as it had been explored. Proceeding down the Murray, I reached at length the commencement of the great fossil formation, through which that river flows. This immense bed rose gradually before me as I pushed to the westward, until it gained an elevation of from 2 to 250 feet, but on my turning southward, it presented an horizontal and undulating surface, until at the point at which the river enters the Lake Victoria, it suddenly dipped and ceased. The lower part of this formation was entirely composed of Serritullae, but every description of shell with the bones and teeth of sharks and other animals, have subsequently been found in the upper parts of the bed, the summit of which is in many places covered with oyster shells so little changed by time, as to appear as if they had only just been thrown in a heap on the ground they occupy.

      The general appearance of the country through which I had passed, and the numerous deposits of fine sand upon the face of it, like sea dunes, still more convinced me, that, when the events which had produced such a change in the physical structure of the continent took place, a current of some description or other must have swept over the interior from the northward; and that this current had deposited the great fossil bed where it now rests; for I cannot conceive that such a mass and mixture of animal remains could have been heaped together in any other way. From the outline of this bed, it struck me that some natural obstacle or other had checked the detritus, brought down by the current, as sand and gravel are checked and accumulated against a log or other impediment athwart a stream, presenting a gradual ascent on the side next the current and a sudden fall on the other. Such, in truth, is the apparent form of the great fossil bed of the Murray. This idea, which struck me as I journeyed down the river, was strengthened, when at a lower part of it I observed a ridge of coarse red granite, running across the channel of the river, and disappearing under the fossil formation on either side of it. It appeared to me to be probable that this ridge of granite might rise higher in other places, and that stretching across the current as it did, that is to say from west to east, the great accumulation of fossil and other remains had been gradually deposited against it, forming a gradual ascent on the northern side of the ridge, and a precipitous fall upon the other.

      I have already observed that at a particular point the rivers of the interior, which I had traced on my first expedition, appeared to lose their character as such, and that they soon afterwards ceased in some extensive marsh, the evaporation and absorption over such extensive surfaces being greater than the supply of water they received. This point is about 250 or 300 feet above the level of the sea, and if we draw a line eastward, from the summit of the fossil formation, and prolong it to the western base of the Blue Mountains, we shall find that it will pass over the marshes of the several rivers falling into the interior, and will strike these rivers where their channels appear to fail, as if that had been the former sea-level.

      The impressions I have on this interesting subject are clear enough in my own mind, but they are difficult to explain, and I fear I have but ill expressed myself so as to be understood by my readers. I only wish however to record my own ideas, and if I am in error in any particular, I shall thank any one of the many who are better versed in these matters than myself to correct me.

      I have stated in a former part of this chapter, that I undertook a journey to South Australia in 1838. I advert to the circumstance again because it is connected with the present inquiry. After I had turned the north-west angle of the Murray, and had proceeded southwards to latitude 34 degrees 26 minutes (Moorundi), where Mr. Eyre has built a residence, I turned from the river to the westward, along the summit of the fossil formation, which, at the distance of a few miles, was succeeded by sandstone, and this rock again, as we gained the hills, by a fine slate, and this again, as we crossed the Mount Barker and Mount Lofty ranges, by a succession of igneous rocks, of a character and form such as could not but betray to a less experienced geologist even than myself the abundant mineral veins they contained. On descending to the plains of Adelaide I again crossed sandstone, and to my surprise discovered that the city of Adelaide stood on the same kind of fossil formation I had left behind me on the banks of the Murray, and it was on the discovery of this fact that the probability of the Australian continent having once been an archipelago of islands first occurred to me.

      A more intimate acquaintance with the opinions of Flinders, as to the probable character of the interior of the continent, from the character and appearance of the coast along the Great Australian Bight; the information I have collected as to the extent of the fossil bed, and my own past experience, have led me to the following general conclusions. That the continent of Australia has been subjected to great changes from subigneous agency, and that it has been bodily raised, if I may so express myself, to its present level above the sea; that, as far as we can judge, the north and N.E. portions of the continent are higher than the southern or S.W. parts of it, and that there has consequently been a current or rush of waters, from the one point to the other--that this current was divided in its progress into two branches, by hills, or some other intervening obstacle, and that one branch of it, following the line of the Darling, discharged itself into the sea, through the opening between the western shores of Encounter Bay and Cape Bernouilli; that the other, taking a more westerly direction, escaped through the Great Australian Bight. From what I could judge, the desert I traversed is about the breadth of that remarkable line of coast, and I am inclined to think that it (the desert) retains its breadth the whole way, as it comes gradually round to the south, thus forming a double curve, from the Gulf of Carpentaria, on the N.E. angle of the continent, to the Great Bight on its south-west coast; but my readers will, as they advance into my narrative, see the grounds upon which I have rested these ideas. If such an hypothesis is correct, it necessarily follows, that the north and north-west coasts of the Continent were once separated from the south and east coasts by water; and as I have stated my impression that the current from the north, passed through vast openings, both to the eastward and westward of the province of South Australia, it as necessarily follows, that that province must also have been an island. I hope it will be understood that I started with the supposition that the continent of Australia was formerly an archipelago of islands, but that some convulsion, by which the central land has been raised, has caused the changes I have suggested. It was still a matter of conjecture what the real character of Central Australia really was, for its depths had been but superficially explored before my recent attempt. My own opinion, when I commenced my last expedition, inclined me to the belief, and perhaps this opinion was fostered by the hope that such would prove to be the case, as well as by the reports of the distant natives, which invariably went to confirm it, that the interior was occupied by a sea of greater or less extent, and very probably by large tracts of desert country.

      With such a conviction I commenced my recent labours, although I was not prepared for the extent of desert I encountered--with such a conviction I returned to the abodes of civilized man. I am still of opinion that there is more than one sea in the interior of the Australian continent, but such may not be the case. All I can say is, Would that I had discovered such a feature, for I could then have done more upon its waters tenfold, than I was enabled to accomplish in the gloomy and burning deserts over which I wandered during more than thirteen months. My readers, however, will judge for themselves as to the probable correctness of my views, and also as to the probable character of the yet unexplored interior, from the data the following pages will supply. I have recorded my own impressions with great diffidence, claiming no more credit than may attach to an earnest desire to make myself useful, and to further geographical research. My desire is faithfully to record my own feelings and impulses under peculiar embarrassments, and as faithfully to describe the country over which I wandered.

      My career as an explorer has probably terminated for ever, and only in the cause of humanity, had any untoward event called for my exertions, would I again have left my home. I wish not to hide from my readers the disappointment, if such a word can express СКАЧАТЬ