Page:Quarterly Journal of the Geological Society of London, vol. 35.djvu/61

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GEOLOGY OF NORTH GIPPSLAND, VICTORIA.
35

from the margins of the Gippsland lakes far up the river-valleys, extending round the margins of the lakes from river to river and up the rivers to the foot of the hills. The lowest terraces are in some places not more than a few feet above the river-level; the highest terraces may merge into the sandy ridges, and are edged in places by the high-level river-gravels. It seems to me not unreasonable to refer this Terrace Epoch of Gippsland to the Pleistocene period.

Succeeding these terraces, and but little elevated above sea-level, we find the alluvial flats of the rivers and the swamps and morasses bordering the lakes, and, as at Ewing's Marsh, lying in the hollows between an older coast-line and the sand dunes forming the present shore-line.

Nowhere in Gippsland have I been able to detect any appearances which I could in any way refer to a Glacial period analogous to that of the northern hemisphere. I have nowhere met with grooved or scratched rocks, erratic boulders, moraines, or any traces of ice-action; and I think that had such existed they would have been met with ere this. Mr. Selwyn has, I believe, already noted this.

The only features of the country which I think could in any way suggest glacial conditions are the apparently ancient lake-basins near Omeo. Most of these have now been drained and their beds deeply cut into by the streams. The sequence of the various gold-drifts has suggested to me that some of the workings were the beds of lakes during the Deep-Lead epoch. At Omeo one lake-basin still retains some water during and after wet seasons (Lake Omeo), and one other is a swamp. The bed of a third is now worked for gold, at the Dry Hill, Omeo. A slight alteration in the general level of the country would have sufficed to drain these lakes; and I think that the succession of several old stream-beds, the traces of which as auriferous leads are seen at increasing heights above Livingstone Creek, suggest an equal succession of periods of elevation of the land and of repose.

(k) Volcanic.—I believe that all the rocks to be classed under this head belong to the "Newer Volcanic." They consist of extensive flows of vesicular or compact dolerites and basalts. Three of the large outflows, known as the Wonangatta, the Dargo, and the Cobungra High Plains, are situated at about 5000 feet above the sea-level and immediately adjoining the Great Dividing Range. That of Nunnyong is only separated from it by the valley of the Tambo River; that of the Gelantipy and Black-Mountain tableland extends within fifteen miles of the Central Chain, and is situated on the line of high land connecting it with the Coast Range.

Smaller patches are found on the Buchan River to the west and on the Snowy River and near Tubbut to the east of Gelantipy.

Independently of the great outflows of the Bogong Mountains which I have spoken of (Cobungra High Plains &c.), there are some minor tracts on the Morass Creek, the Gibbo River, and Wambat Creek, all on the northern side of the watershed.

The larger areas named above are found capping the summits of the mountains, and also, in places, as flows, partially tilling the valleys.