GLACIAL ACTION—SOUTH AUSTRALIA. 127 
subject to revision. The highly indurated and jointed features of 
the deposits at Government quarry, Yankalilla, differ in these 
respects from any known Tertiary rocks in South Australia, and 
are suggestive of a higher geological age. 
3. With regard to the stratigraphical characteristics,” much 
remains to be done. The glacial drift, as developed in the Inman 
and associated valleys, does not agree very closely with the typical 
boulder clay of the Northern Hemisphere. It is more character- 
istically arenaceous than argillaceous, varying from loose sand, to 
sand-rock, sandstones, grits, and conglomerates. Even the so- 
called “shales” in the Government Geologists Report, and the 
borings of the Victor Harbour Coal Company, would seem to be 
an arenaceous rock of a dark mud-stone character. The nearest 
approach to a true clay deposit is got at Hallet’s Cove, and the 
best example of Till—unstratified clay with glaciated stones 
irregularly distributed through the mass—is found at Cape Jervis. 
THE GLACIAL AGENT. 
4. It is not attempted, at the present stage of observations, to 
say positively whether the glacial phenomena were effected by 
glacier, iceberg, or shore ice. The powerful ground glaciation in 
the Inman, on the Bald Hills, and over a great extent of surface 
at Hallett’s Cove, the roches moutounées (at the latter place 
particularly), as well as the persistency and regularity of the 
striz, would seem to demand land ice of considerable extent for 
their production. If icebergs are assumed to be the cause of the 
glacial phenomena, they must have been of local origin, as the 
morainic material has evidently been gathered from our own 
shores, whilst local icebergs would also require local glaciers to 
give birth to them. Shore ice would certainly explain some of 
the features, as, for example, the number of water-worn pebbles 
which are found in the drift, both at the Cape and Inland. These 
pebbles have certainly first been subjected to river or coastal attri- 
tion, and have been subsequently faceted by ice movements. The 
glacial beds in the Inman Valley have at present an elevation of 
over 600 feet above sea-level. If, therefore, we admit the agency 
of shore ice as the means of distribution, we must assume that 
there has been since the days of glaciation an elevation of the 
land in the neighbourhood at least equal to that mentioned above. 
The facts are perhaps best explained by reference to a combination 
of agencies rather than to a single form of ice action. 
