PLATE 32: PLAN OF HILLS BESIDE GREENHILL LAKE (INTERIOR OF AUSTRALIA, ENGRAVED FROM A MODEL).
Bate's Patent Anaglyptograph. Freebairn.
Published by T. and W. Boone.
GREEN HILL LAKE.
The green hill was the highest of several semicircular ridges whose forms may perhaps be better understood by the accompanying plan.* There was a remarkable analogy in the form and position of all these hills; the form being usually that of a curve, concentric with the lake, and the position invariably on the eastern or north-eastern shores, a peculiarity I had previously observed not only in the lakes near the banks of the Murray but also in others on the Murrumbidgee and Lachlan where the ridge consisted of red sand. The country on the western shore of these lakes is, on the contrary, low and wooded like the surrounding country. In such hills concretions of indurated marl frequently occur, but the earth they consist of is sometimes light-coloured, in other cases very dark, like the soil from trap-rock, and the ridges beside the lakes on the Murrumbidgee, consisted of red sand.
(*Footnote. Having modelled this feature I have the satisfaction of presenting to the reader the first specimen of a plan of ground worked from a model by the anaglyptograph, an important invention recently perfected in this country by Mr. Bates and likely to be of very considerable value in the representation of the earth's surface under the skilful management of Mr. Freebairn.)
MITRE LAKE.
The water of Mitre Lake was also salt,* but there were numbers of ducks and black swans upon it. The western shore was low, and the soil where it had been thrown up in the roots of fallen trees was nearly as white as chalk. A gray rather fine quartzose sand occurred in some places; and along the water's edge a very minute shell had been cast up in considerable quantities by the waves.** The hills to the eastward of this lake were arranged in a crescent around the basin, but this being composed of a number of hills almost separate from each other had a less regular or uncommon appearance, although they were apparently the remains of a curve equally as symmetrical as the others. The basin of this lake was very extensive but partly filled on the side next the low hills by a level tract of dry land covered with a brown bush (Salicornia arbuscula of Brown); and the concentric curves in which it grew, as if closing on the lake, seemed to record its progressive diminution. The breadth of this heathy-looking flat between the water and the crescent of low hills was nearly half a mile. A small rill of fresh water oozed into the lake from the sides of Mount Arapiles. The bed of this watercourse was soft and boggy near the lake, so that I could cross only by going up its channel much nearer to the hill and at a point where some rocks protruded and prevented our horses from sinking.
(*Footnote. For Professor Faraday's analysis of these waters see below.)
(**Footnote. This was a truncatella, a saltwater shell of which there are several species on the English and French coasts. The one found here has been named by Mr. J. De Carl Sowerby T. filosa.)