Page:Quarterly Journal of the Geological Society of London, vol. 35.djvu/30

4 basin at 2374 feet, which is the height of Lake Omeo above the sea. I have excluded in this estimation the deep river-valleys draining this plateau which, as at Eagle Vale or Tom Groggin, are under 1000 feet.

Prom the Great Dividing Range and approximately at right angles to its course successive spurs extend towards the coast; these spurs separate the rivers which drain the mountains. Some of these rivers empty themselves into the Gippsland lakes, and the remainder directly into the sea. The most easterly of these somewhat parallel ranges forms the western watershed of the Snowy River; this river rises in New South Wales on an extensive plateau, known as the Maneroo district, similar in character to that of Omeo, but of greater extent. The southern boundary of these highlands is well defined as the Coast Range, and, as is the ease with the Great Dividing Range, conforms to the coast-line. The slope northward, forming the Maneroo tableland, is very gentle, while it is sudden and abrupt towards the sea.

Commencing at Mount Phipps, the most southerly extension of the Great Dividing Range, near Omeo, a line of high land can be traced connecting it with the Coast Range. On this view the Omeo and Maneroo plateaux form one great tableland; these heights, commencing at Mount Phipps, are the Nunnyong Mountain, the Gelantipy tableland, Turnback Mountain, and the Bowen Mountain, where the Coast Range may be said to commence.

From this Coast Range spurs run towards the seas, separating the waters of the Goungrah, Bern, Tamboon, Wingan, and Genoa rivers; these spurs either end as promontory-like hills, or die away gradually in the marine Tertiaries.

All the rivers which I have enumerated present certain marked features in common. The character of the valleys varies with the geological formation in which they have been excavated, and the course of the rivers is sharply divided into a torrent portion and a river portion; the latter commences so soon as the streams leave the hills and enter the fringing Tertiary area. Here the valleys have been excavated in almost horizontal beds of sand, clay, and coarse shelly limestone, and are wide and flat.

The bottom of such a valley is usually occupied by a more or less wide stretch of alluvial soil, through which the river winds a slow and tortuous course. In other cases, such as the streams flowing into lake Tyers, the bottom of the valley is an estuary.

Where the rivers debouche into the Gippsland lakes, they do so usually between two banks, or natural levels, which have been formed in the manner of a delta. That at the mouth of the Mitchell River extends on each side from the termination of the higher ground into Lake King. The one on the north side of the river is about twelve miles, and the one on the south side of the river about six miles in length. The two levels end at the same point in Lake King. Each