On the margin of one of them, bearing 55 1/2 degrees West of North from our camp, a green hill of rather singular shape rose to a considerable height above the surrounding country. I found the water in the lake beside it shallow and quite salt. The basin was nearly circular though partially filled with firm level earth which was water-worn at the brink, its surface being about three feet higher than the water. This was surrounded by a narrow beach of soft white mud or clay in which we found no change on digging to the depth of several feet. 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.