BY GRAHAM OFFICER, B.SC. 157 
Mount Ida we noticed an old beach of conglomerate some 
feet above the surface of the lake. The addition of several 
feet of water would cause a considerable extension of the lake 
at both ends. 
From the top of Mount Olympus we counted about 30 
lakes and tarns on the opposite plateau, occupying undoubted 
rock basins in the greenstone. On Olympus itself, at the 
foot of the greenstone columns on the lake side, are two 
small basins of water, the “Olympian Tarns.” All these 
lakes are at different levels; Lake Laura, at the base of 
Mount Ida, though only separated from 8t. Clair by a ridge 
not more than 400 yards across, is 50 feet above the latter. 
It appears to be very shallow. Lake Petrarch is about 560 feet 
above St. Clair. It is also very shallow, and, I am inclined to 
think, there is a small area of subsidence, its bed being pro- 
bably sandstone. 
There has been an interesting discussion in the columns of 
Nature recently on the origin of rock-basin lakes, and the 
arguments for the glacial theory have been ably marshalled 
by Mr. A. R. Wallace. Mr. Wallace cites Tasmania, among 
others, as a country where these alpine lakes are associated 
with palpable signs of glaciation.* Now, though such signs 
of glaciation and associated rock-basin lakes occur on the 
West Coast, notably about the Pieman River, we do not find 
the slightest trace of glaciation either in the shape of striated 
rock surfaces, moraines, or erratic blocks in any part of the 
region traversed by us. Unfortunately we were unable to 
traverse the Traveller Plateau, but from its configuration, as 
observed from Olympus, I feel confident that signs of glacia- 
tion do not exist there. Yet, as we have seen, lakes and 
tarns are exceedingly numerous on the surface of this plateau. 
It is evident that the glacial theory is of no use here. Many 
of the button-grass swamps or flats really occupy rock-basins, 
and perhaps may be regarded as the equivalents of the peat- 
bogs of Europe. They seem to be directly connected with 
each other, that is to say, those in the same drainage area. 
The great rival to the glacial theory is the “ Harth-move- 
ment” theory. I think that if Mr. Gould’s basalt be really 
mythical, the latter theory will probably account for Lake 
St. Clair and for other lakes in the district, though the lakes 
on the Traveller plateau seem to be too numerous to be thus 
explained. Iam much inclined to the opinion that most of 
the basins of the Traveller Plateau lakes will be found to be 
satisfactorily explained by the ordinary processes of sub- 
aerial weathering and denudation. 
We found no fossils in situ in the sandstone of this region, 
but on the beach about the boat-house pieces of silicified 
Nature, Vol. 47, No. 1,219, 
