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State, in South Australia as far north as Charlotte Waters, and in Tas¬ 
mania, and they were found to be plentiful in Central Australia by Pro¬ 
fessor Spencer, C.M.G., on his transcontinental trip, and Professor Gregory 
found them on his trip to Lake Eyre, and in Western Australia around 
Coolgardie they are numerous. 
These Obsidian buttons, &c., which are black by reflected light and 
light-grey and transparent in thin sections by transmitted light, occur 
laterally over a wide expanse ; vertically they also' have an extended range. 
They are found on] the surface on the top of the Grampians at 2,000 to 
3,000 feet above the general surface of the country. At Mt. William 
high up in the range they are found in the recent auriferous gravels from a 
few inches to 30 feet below 7 ' the surface. At Rokewood they are found in 
auriferous gravels below basalt. 
In shape these interesting objects may be arranged in a few classes. 
1st. Those that are much longer than broad, and that are contracted in the 
middle; 2nd. buttons or discoidal forms; 3rd. stopper-shaped examples, 
the sides somewhat tapering, and the discs much thicker than in the buttons. 
The long variety seldom exceeds 3 inches in length, and generally does 
not exceed 1 to 2 inches. The buttons are rarely 1 inch across, and more 
commonly are from J to } inch in diameter. The stopper-shaped ones 
are in some cases if inch across, and up to 1 inch thick. There is a 
very common feature about them, in that there are chips and flakes de¬ 
tached from them, especially in the case of the stopper-shaped examples ; 
but frequently also in the other varieties. This feature is often masked 
by sand wear, where they have lain on the surface, or by attrition, where 
they have been in gravel deposits. One very unusual form in the National 
Museum collection has been cut in two to show its structure. It consists 
of a hollow sphere about 2 inches in diameter, dull on the outside, but 
brilliantly polished on the inside. It is, in fact, a glass bubble with thick 
walls. Around the periphery is a peculiar rim, and this will be explained 
further on. A spherical example from near Charlotte Waters which Mr. 
H. Y. L. Brown, Government Geologist of South Australia, presented to 
me, on being cut through shows a highly polished interior divided by a 
diaphragm, an instance of a double bubble. The step-like character 
is exhibited in a modified form, on the outer edge of the buttons, and in 
some cases on the outer edge of the examples contracted in the middle. 
When these objects are found at the surface this edge, often quite sharp, 
is uppermost. Small rings perfect in form are also found; they are caused 
by the rim becoming detached frohi the central portion of the button. The 
stopper-like forms are the central portions of the buttons. 
To account for their wide lateral dispersion and for their presence on 
mountain tops, as well as deep in the valley gravels, many theories have 
been suggested, such as their transport by emus, by aborigines, &c. Again, 
others have endeavoured to explain their presence at such varying alti¬ 
tudes and over such wide areas by attributing them to a meteoric origin. 
The theory of dispersal by means of birds or human beings would 
scarcely account for their presence in some of the auriferous drifts, and 
there does not appear to be any need for invoking a meteoric origin. 
A simple explanation will account for their forms, their substance, and 
their remarkable dispersion, and it is this. 
These bodies represent the “ blebs ” of obsidian bubbles. From the 
Eocene period to recent times volcanoes were in active operation in Aus- 
■, tralasia. In Victoria there was remarkable activity. During these out¬ 
bursts bubbles of glass of varying size were formed in the vents, and were 
carried up by the ascending heated gases to great heights. The bubbles 
were dispersed according to the direction of the wind, and in a few hours 
may have been carried for hundreds of miles. As they cooled they would 
