GLACIAL ACTION—SOUTH AUSTRALIA. 119 
protected, showed distinct evidences of glaciation. About 200 
yards still higher up the valley, where the main road almost 
touches the stream, near the tenth milepost, a few very large 
granite boulders occur in the bed of the river, some of which 
have been drilled and blasted and the pieces utilised to protect 
the banks from erosion. One of these,a pear-shaped mass, closely 
resembles the Port Victor granites, and measures 11 ft. by 7 ft. 
by 41 ft. The effect of weathering is seen in a partial exfoliation 
of this large boulder, but in places it still retains the glacial polish 
and grooving. A photograph of this erratic was taken by Pro- 
fessor David. (Plate 3.) 
From the tenth milepost the bed of the river continues to be 
strewn with large travelled stones, chiefly granite ; one measured 
8 ft. 6 in. by 5 ft. by 4 ft. 6 in. Another protruding from the 
glacial Drift on the north bank measured 10 ft. by 7 ft. by 6 ft. 
Another conspicuous example was of gneiss, giving a beautiful 
illustration of augen structure, whilst the largest transported 
stone seen in the bed of the river was observed a little west of 
the Inman Valley Bridge, near the post-office, and measured 
12 feet by 8 feet. 
Nearer the source of the Inman the larger erratics are less 
common, but at intervals the river flows over a_ bluish-black 
glacial clay, or argillaceous sandstone, which is very soft, and, 
apparently, destitute of stones, except some angular fragments of 
decomposed shale, similar in colour and composition to the bed in 
which they are included. 
The Bald Hills, situated 15 miles from Port Victor, and 7 
miles from Normanville, forms the watershed, as already stated, 
between either sea, and divides the valley into an eastern and 
western section. This transverse ridge is covered with a peculiar 
soil, which is very black and deep, such as might be looked for 
on low marshy ground, but very unusual on the crest of a range. 
This peculiarity attracted the attention of Selwyn, who says :— 
“‘T was unable to ascertain what rock it is that makes the rich 
black soil of the Bald Hills, but I imagine it to be due to the 
decomposition of the crystalline limestones, with the addition of 
some hornblendic and micaceous rocks.”* As there are no local 
limestones, and the bed-rock is a siliceous quartzite, it seems 
impossible that the dark soil is the product of the decomposition 
of the local rocks. It is more likely to have been derived from 
the dark-coloured glacial clay, which can be traced to the eastern 
flanks of the Bald Hills, and, doubtless, at one time covered their 
summits. This is made the more plausible as there are abundant 
evidences that the ice passed over the top of the Bald Hills at a 
height of 640 feet above sea-level. A good section of drift with 
* Op. cit. p. 4. 
