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into an estuary, for the quartz pebbles are very well rounded and many 
of them ground very small. They bear evidence of sea action, and 
not of river action. In the sea along the shore the pebbles would be 
subjected to constant wear by the waves and tides and by currents; 
the result has been the production of extremely well-rounded, generally 
small, and unusually white, quartz pebbles. In places they are bound 
together by clay or limonite into a conglomerate. There is a marked 
resemblance between these pebbles and conglomerates and such as are 
found at Studley Park, near Melbourne, where they are also probably of 
marine origin. The old auriferous leads have a definite course until they 
reach the shore-line, but along the old coast the gravels are dispersed 
irregularly. 
A peculiar feature in connexion with the auriferous alluvial workings 
over this area and as far back as Berringa, is the “ crevice mining,” which 
has been extensively carried on. The bedrock is decomposed Ordovician 
sandstones and slates, the latter altered and bleached and forming what 
is called a pipeclay bottom. Apparently through the action of currents or 
tides, crevices have been washed out of the bedrock, generally in the direc¬ 
tion of the strike of the beds, but not uncommonly also across the strike 
at varying angles. These crevices range from less than i inch in width to 
2 or 3 feet wide. In length they are sometimes more than ioo feet, and 
in depth they range from a few inches to 20 feet. Into these crevices 
sand and pebbles together with both fine and coarse gold have found their 
way and ultimately quite filled them up. It is commonly the case that in 
the gravel on the bedrock there is very little gold present, not enough to 
pay for working, but in the crevices rich returns were obtained. The 
method of mining for these crevices is to drive through the pipeclay and 
soft sandstone bedrock until the gritty seam of gravel filling the crevice is 
intersected ; it is then followed up, and the gravel from it washed to 
secure the gold present. 
A more distinct and direct proof that the sea beach at one time existed 
near Illibarook in Tertiary times is the presence of holes made by boring 
molluscs, such as Pholas, in the slaty bedrock. They are common in the 
vicinity. Sharks’ teeth are also reported to have been found in the wash- 
dirt in the neighbourhood. Near Pitfield the bores have proved that marine 
shells of Tertiary age are present beneath the basalt. 
It then appears that in Tertiary times sea beaches existed to the foot 
of the hills or as far as Berringa, and that these beaches have receded, 
no doubt through the rising of the land, until now the shore-line is 50 miles 
away and the old beaches are over 600 feet above present sea level. This 
indicates vast changes extending over a lengthened period of time. 
At Pitfield it has been found that the slimes from some of the alluvial 
workings are rich in gold, and they have been cyanided extensively; the 
slimes from the Union mine are reported exceptionally rich. As the ancient 
streams that brought down the auriferous gravels debouched into the sea a 
little further south, and as the fine gold of the slimes was no doubt carried 
on to the beach in great quantities by the streams and there probably con¬ 
centrated by the waves and tides, it is a matter for consideration whether 
there may not exist beach deposits of very fine gold similar to what 
occurred on the west coast of the South Island of New Zealand and 
yielded vast quantities of gold. 
It will probably be found when the gold won from the residues from the 
mines is added to the yields obtained in working them, that the leads 
actually contained enough gold to give splendid returns, but that a large 
proportion has been lost to the original workers through a wasteful and 
primitive method of gold saving. 
