The country immediately behind Cape Jervis may, strictly speaking, be termed a promontory, bounded to the west by St. Vincent's Gulf, and to the east by the lake Alexandrina, and the sandy track separating that basin from the sea. Supposing a line to be drawn from the parallel of 34 degrees 40 minutes to the eastward, it will strike the Murray river about 25 miles above the head of the lake, and will clear the ranges, of which Mount Lofty and Mount Barker are the respective terminations. This line will cut off a space whose greatest breadth will be 55 miles, whose length from north to south will be 75, and whose surface exceeds 7 millions of acres; from which if we deduct 2 millions for the unavailable hills, we shall have 5 millions of acres of land, of rich soil, upon which no scrub exists, and whose most distant points are accessible, through a level country on the one hand, and by water on the other. The southern extremity of the ranges can be turned by that valley through which Mr. Kent returned to the schooner, after Captain Barker's death. It is certain, therefore, that this valley not only secures so grand a point, but also presents a level line of communication from the small bay immediately to the north of the cape, to the rocky point of Encounter Bay, at both of which places there is safe anchorage at different periods of the year. HINTS FOR FUTURE EXPEDITIONS. The only objection that can be raised to the occupation of this spot, is the want of an available harbour. Yet it admits of great doubt whether the contiguity of Kangaroo Island to Cape Jervis, (serving as it does to break the force of the prevailing winds, as also of the heavy swell that would otherwise roll direct into the bay,) and the fact of its possessing a safe and commodious harbour, certainly at an available distance, does not in a great measure remove the objection. Certain it is that no port, with the exception of that on the shores of which the capital of Australia is situated, offers half the convenience of this, although it be detached between three and four leagues from the main.