It had been my object to ascertain the decline of the vast plain through which the Murray flows, that I might judge of the probable fall of the waters of the interior; but by the most attentive observation I could not satisfy myself upon the point. The course of the Darling now confirmed my previous impression that it was to the south, which direction it was evident the Murray also, in the subsequent stages of our journey down it, struggled to preserve; from which it was thrown by a range of minor elevations into a more westerly one. We were carried as far as 139 degrees 40 minutes of longitude, without descending below 34 degrees in point of latitude; in consequence of which I expected that the river would ultimately discharge itself, either into St. Vincent's Gulf or that of Spencer, more especially as lofty ranges were visible in the direction of them from the summit of the hills behind our camp, on the 2nd of February, which I laid down as the coast line bounding them.
A few days prior to the 2nd of February, we passed under some cliffs of partial volcanic origin, and had immediately afterwards entered a limestone country of the most singular formation. The river, although we had passed occasional rapids of the most dangerous kind, had maintained a sandy character from our first acquaintance with it to the limestone division. It now forced itself through a glen of that rock of half a mile in width, frequently striking precipices of more than two hundred feet perpendicular elevation, in which coral and fossil remains were plentifully embedded. On the 3rd February it made away to the eastward of south, in reaches of from two to four miles in length. It gradually lost its sandy bed, and became deep, still, and turbid; the glen expanded into a valley, and the alluvial flats, which had hitherto been of inconsiderable size, became proportionally extensive. The Murray increased in breadth to more than four hundred yards, with a depth of twenty feet of water close into the shore, and in fact formed itself into a safe and navigable stream for any vessels of the minor class. On the 6th the cliffs partially ceased, and on the 7th they gave place to undulating and picturesque hills, beneath which thousands of acres of the richest flats extended, covered, however, with reeds, and apparently subject to overflow at any unusual rise of the river.
It is remarkable that the view from the hills was always confined.—We were apparently running parallel to a continuation of the ranges we had seen on the 2nd, but they were seldom visible. The country generally seemed darkly wooded, and had occasional swells upon it, but it was one of no promise; the timber, chiefly box and pine, being of a poor growth, and its vegetation languid. On the 8th the hills upon the left wore a bleak appearance, and the few trees upon them were cut down as if by the prevailing winds. At noon we could not observe any land at the extremity of a reach we had just entered; some gentle hills still continued to form the left lank of the river, but the right was hid from us by high reeds. I consequently landed to survey the country from the nearest eminence, and found that we were just about to enter an extensive lake which stretched away to the S.W., the line of water meeting the horizon in that direction. Some tolerably lofty ranges were visible to the westward at the distance of forty miles, beneath which that shore was lost in haze. A hill, which I prejudged to be Mount Lofty, bearing by compass S. 141 degrees W. More to the northward, the country was low and unbacked by any elevations. A bold promontory, which projected into the lake at the distance of seven leagues, ended the view to the south along the eastern shore; between which and the river the land also declined. The prospect altogether was extremely gratifying, and the lake appeared to be a fitting reservoir for the whole stream which had led us to it.
In the evening we passed the entrance; but a strong southerly wind heading us, we did not gain more than nine miles. In the morning it shifted to the N.E. where we stood out for the promontory on a S.S.W. course. At noon we were abreast of it, when a line of sand hummocks was ahead, scarcely visible in consequence of the great refraction about them; but an open sea behind us from the N.N.W. to the N.N.E. points of the compass. A meridian altitude observed here, placed us in 35 degrees 25 minutes 15 seconds S. lat.—At 1, I changed our course a little to the westward, and at 4 p.m. entered an arm of the lake leading W.S.W. On the point, at the entrance, some natives had assembled, but I could not communicate with them. They were both painted and armed, and evidently intended to resist our landing. Wishing, however, to gain some information from them, I proceeded a short distance below their haunt, and landed for the night, in hopes that, seeing us peaceably disposed, they would have approached the tents; but as they kept aloof, we continued our journey in the morning. The water, which had risen ten inches during the night, had fallen again in the same proportion, and we were stopped by shoals shortly after starting. In hopes that the return of tide would have enabled us to float over them, we waited for it very patiently, but were ultimately obliged to drag the boat across a mud-flat of more than a quarter of a mile into deeper water; but, after a run of about twenty minutes, were again checked by sand banks. My endeavours to push beyond a certain point were unsuccessful, and I was at length under the necessity of landing upon the south shore for the night. Some small hummocks were behind us, on the other side of which I had seen the ocean from our morning's position; and whilst the men were pitching the tents, walked over them in company with Mr. M'Leay to the sea shore, having struck the coast at Encounter Bay, Cape Jervis, bearing by compass S. 81 degrees W. distant between three and four leagues, and Kangaroo Island S.E. extremity S. 60 degrees W. distant from nine to ten.
Thirty-two days had elapsed since we had left the depot, and I regretted in this stage of our journey, that I could not with prudence remain an hour longer on the coast than was necessary for me to determine the exit of the lake. From the angle of the channel on which we were, a bright sand-hill was visible at about nine miles distance to the E.S.E.; which, it struck me, was the eastern side of the passage communicating with the ocean. Having failed in our attempts to proceed further in the boat, and the appearance of the shoals at low water having convinced me of the impracticability of it, I determined on an excursion along the sea-shore to the southward and eastward, in anxious hopes that it would be a short one; for as we had had a series of winds from the S.W. which had now changed to the opposite quarter, I feared we should have to pull across the lake in our way homewards. I left the camp therefore at an early hour, in company with Mr. M'Leay and Fraser, and at day-break arrived opposite to the sand-bank I have mentioned. Between us and it the entrance into the back water ran. The passage is at all periods of the tide rather more than a quarter of a mile in width, and is of sufficient depth for a boat to enter, especially on the off side; but a line of dangerous breakers in the bay will always prevent an approach to it from the sea, except in the calmest weather, whilst the bay itself will always be a hazardous place for any vessels to enter under any circumstances.
Having, however, satisfactorily concluded our pursuit, we retraced our steps to the camp, and again took the following bearings as we left the beach, the strand trending E.S.E. 1/2 E.:—
Kangaroo Island, S.E. angle S. 60 degrees W.
Low rocky point of Cape Jervis S. 81 degrees W.
Round Hill in centre of Range S. 164 degrees W.
Camp, distant one mile S. 171 degrees W.
Mount Lofty, distant forty miles N. 9 degrees E.
Before setting sail, a bottle was deposited between four and five feet deep in a mound of soft earth and shells, close to the spot on which the tent had stood, which contained a paper of the names of the party, together with a simple detail of our arrival and departure.
It appeared that the good fortune, which had hitherto attended us was still to continue, for the wind which had been contrary, chopped round to the S.W., and ere sunset we were again in the mouth of the river, having run from fifty to sixty miles under as much canvass as the boat would bear, and with a heavy swell during the greater part of the day.
The lake which has thus terminated our journey, is from fifty to sixty miles in length, and from thirty to forty in width. With such an expanse of water, I am correct in stating its medium depth at four feet. There is a large bight in it to the S.E. and a beautiful and extensive bay to the N.W. At about seven miles from the mouth of the river, its waters are brackish, and at twenty-one miles they are quite salt, whilst seals frequent the lower parts. Considering this lake to be of sufficient importance, and in anticipation that its shores will, during her reign, if not at an earlier period, be peopled by some portion of her subjects, I have called it, in well-meant loyalty, "The Lake Alexandrina."