GLACIAL ACTION—SOUTH AUSTRALIA. 117 
erratics became conspicuously evident, both by the roadside and 
partly exposed in the cultivated ground on either side of the 
valley. The lower reaches of the Inman River are much silted, 
its waters flowing over a sandy bed, except where the stream has 
cut its way by a narrow gorge through a spur of the hills and 
flows between high per pendicular cliffs. 
A little past the seventh milepost from Port Victor, the party 
made for the river where a low exposure of the older rocks could 
be seen in outcrop, distant about 248 yards from the public road. 
This proved to be a very fine glaciated pavement, which we 
immediately concluded must be “Selw yn’s Rock.” The bed-rock 
is a very dense, dark-coloured siliceous quartzite, which at this 
point occupies the entire bed of the stream. It dips in a direction 
S. 55° E. at 26°. The principal polished face is on its northern, 
or left bank, gently sloping to the bed of the river, and in a 
position which must involve its submergence whenever the river 
is in flood. The exposed portions of the polished pavement 
measures over 20 feet in length and 6 feet in breadth. On the 
water side it has been broken and eroded by the river action, and 
to landward it has a cover of river silt several feet in height. By 
clearing away the silty bank, the polished surface was seen to 
underlie this cover for an unknown distance. 
The glaciated pavement is not only highly polished, but deeply 
grooved and striated. The strisw apparently belong to one system 
and follow a uniform direction, with a bearing of W. 93° N., 
which agrees with the general trend of the main valley. The 
grooves are broad rather. than deep, some of them measuring fully 
2 inches in breadth (see pl. 2). A few yards higher up the 
stream a smaller polished surface is seen on the southern bank, 
where a washaway has exposed the bed-rock free from cover a few 
yards away from the stream. The strize here have the same 
general direction as on the larger polished face, which is diagonal 
to the course of the stream, their trend being W. 12° N. Within 
the limits of the current (as might be expected), the river-bed 
has been eroded to an extent that has destroyed all evidences of 
glacial action—the glaciated pavements, on either side of the 
stream, being above all but abnormal floods. It is also evident 
that at one time the polished rock has been covered by glacial 
drift as the inequalities in the floor have been filled with a par- 
ticularly compact sandstone, corresponding to the local arenaceous 
drift, only of harder texture. Samples 6 inches thick were taken 
from some of these depressions, and they are very suggestive of 
having been formed as a moraine profonde. The aneroid reading 
at this spot indicated a height of 200 feet above sea-level. 
If this be the particular glaciated rock discovered by Selwyn, 
it is evident that the bed of the stream has undergone some 
changes in the interval. His description of the superficial deposits 
