are horizontal, or merely lie at very low angles; that the highest beds thin out on the flanks of the mountains at elevations nowhere exceeding 1000 feet, and probably not averaging more than 600–700 feet above sea-level; and, further, that similar statements also apply to the Murray-River Tertiaries to the north of the Great Dividing Range.
A careful consideration of the interesting features presented by the deep leads of the Ovens District on the north side of the mountains, and of the Gippsland Marine Tertiaries on the south side, has led me to the belief that at the close of the Miocene or the commencement of the Pliocene period, the land-surface of Eastern Victoria probably did not differ essentially in its physical features from what is seen now, but that it stood at least some 300–400 feet lower, relatively to the sea-level, than it now does.
I perceive, further, that the upper margin of the Tertiary marine beds is now some 600–700 feet above the sea; and we have thus represented to us continuously, from the Miocene period inclusive, a high mountainous country falling in elevation to the westward, and having the sea on the south, and varying conditions of land and water to the west and north[1].
The fact that different genera of fish are found in the waters flowing from the north and south sides of the Australian Alps points to a high antiquity of the land-surface, and to a long continuance of the watershed.
Whatever may be the conclusions arrived at in respect to the continuity, duration, and elevation above the sea of the land-surface during Mesozoic times, it cannot, I think, be doubted that the Gippsland mountains have existed as dry land continuously since the earlier part of the Tertiary age.
A difficulty may be felt to arise from the fact that we have at Bacchus Marsh Miocene beds with plant-remains of "a totally different facies to the recent flora of the country, . . . an entirely extinct series of species, having generic and general resemblance to the foliage of Asiatic plants of tropical types of Dicotyledonous plants"[2]. It seems to me that such a difficulty may possibly be more apparent than real. In Eastern Gippsland we find at present, in the coast-lands and the river-valleys, a flora which has been described by Baron v. Müller as being of an Indian type, before which the Eucalyptus-vegetation recedes[3].
The inland mountains and plateaux show essentially the ordinary flora of Yictoria. If a subsidence of the land were to cause the present flora of the littoral country to become fossilized, and a re-elevation of the land were subsequently to take place, it might be that
- ↑ So far as I now remember, the Oligocene beds of Mount Martha at Port-Philip Bay, which are the oldest Tertiary deposits with which I am acquainted, also conform to the generally horizontal position of all the Tertiary groups.
- ↑ Professor M'Coy, Intercolonial-Exhibition Essays, 1866–67, "Recent Zoology and Palæontology of Victoria," p. 16; also Geological Survey of Victoria, Quarter-sheet, No. 12, N.E., notes 5 and 12.
- ↑ Catalogue of the "Victorian Exhibition, 1861. Essay by Ferd. Müller, M.D., Ph.D., F.R.S., &c.
