
ABORIGINES OF THE SOUTH-EAST OF SOUTIL AUSTRALIA 475 
a anrface stain and the flint has been altered to a white or cream coloured material, 
similar apparently to that on the coastal sites. The chief difference seems to be 
the presence of ferric oxide, probably in a hydrated form both as a surface skin 
nud also dispersed to some extent through the white alteration product of the 
original fint. On some sites, notably the Long Gully Ridge, alteration of the 
flinta has gone so far that flints of the size of small houlders have been changed 
completely to a softer white material. That such boulders once consisted of flint 
is shown by the fact that until they are lifted or struck they are indistinguishable 
in colour, appearance, and shape from solid, unaltered flints, and also that some 
of them still contain a core of unaltered flint. 
These alterations are believed to be due to the loas of water which is cambined 
in veriable amounts with the silica in the original flint. The slow dehydration 
urider atmospheric conditions gradually produces the white alteration product 
which, however, is still silica and of similar hardness. The relative depths to 
which this alteration has progressed in this district may well be regarded a3 a 
line of research into the relative ages of these implements, The yellow iron stain- 
ing is believed to have been produced by the deposition of iron solutions on the 
Aint during burial beneath the soil or dune material for a period long enough to 
permit the fixation of the covering material by vegetation and the production in it 
of iron-bearing solutions resulting from the decay of vegetable matter, Con- 
versely, ihe notiveable absence of any colouring matter to relieve the whiteness 
of the alteration product characteristic of the eoastal and recent inland dunes 
is believed to be due to the almost total absence of iron solutious in ‘the soil and 
dunes, so that burisl under those conditions would not produce the appearance 
characteristic of burial on the more inland camp sites, Laboratory and field 
experiments are heing carried out and others are contemplated in an attempt 
towards a solution of these problems, the solution of which would assist materially 
in establishing the relative ages of some types of implements, 
Within the area examined, Tertiary limestones, approximately of Miocene 
Age, outcrop and form the basement on which the various dunes have been 
deposited. These Tertiary limestanes, however, appear to have a gentle dip in 
a northerly direction and disappear beneath séa level at about the latitude of Cape 
Banks, the most northerly outerop along the coast occurring about oné mile to 
the north of that cape. 
The presence in the Kongorong area, at or near the surface, of this limestone, 
probably was a contributing if not the main factor in the production of a better 
soil type as compared with the area immediately to the north-west, composed 
largely of wave or wind-sorted material, and in which soil deficiencies have been 
troublesome. 
It is. to these Tertiary limestones and their erosion and distintegration chiefly 
by wave action that the region owes its supplies of flint, which are practically 
the only material used by the aborigines in the production of stone} artefacts. 
Certain horizons in the limestone series contain fiint nodules and boulders in very 
large qnantities. Such ceeurrences are plentiful along the coastline between Cape 
Banks and Douglas Point and are particularly well exposed at Black Point. At 
Cape Buffon accumulations of flint pebbles appear to be derived from limestone 
reefs below sea leyel but probably not. far fromi the shore, 
The flints vary considerably in shape, colour, size and texture, and it is 
obvious that a. yery large proportion would have been unsuitable for implement 
manufacture by the natives, The successful selection of a flint pebble suitable 
for such a purpose would require a considerable degree of skill and knowledge 
and of intelligence. Flint pebbles sufficiently large and uniform in texture for 
the production of the large hand axe referred ta earher were found to be exceed- 
ingly scarce. 
