20 
C. G. THORP, M.B., C.M. : 
The Cretaceous Fossils of the Gin-Gin Chalk and their 
Geological Relationships. By A. Gibb Maitland, F.G.S. 
(Read June ioth, 1913.) Printed as Geological Survey 
Bulletin No. 55. 
A Contribution to the Study of Australites. By C. G. 
Thorp, M.B., C.M., being the Anniversary Address of 
the President, Session 1912-1913. (Delivered July nth, 
I9I3-) 
As your retiring president, I must express my regret that 
I have been unable more efficiently to discharge my duties to 
the Society during my year of office, and that I was compelled 
by considerations of health to leave Perth during this, to me, 
most important period. Will you allow me to take this op- 
portunity to tender to you my most sincere thanks for the great 
honour that I feel that you have done me in electing me to the 
high office of president for the year which is distinguished above 
all other years, for Western Australia, by the foundation of our 
University, and which should mark the commencement of a 
flourishing and useful period for our Society — we hope, the 
commencement of a new era. 
For some years past I have interested myself in, and given 
much thought to, the problem of the origin of Obsiclianites, or, 
as they are more scientifically and better termed, Australites, 
Billitonites, or otherwise, according to the locality in which they 
are found. 
Australites, of which we know most, as they occur here- 
are small masses of a dark glass, found almost throughout Aus- 
tralia, south of the Tropic of Capricorn, and in Tasmania. A few 
have been found north of the Tropic of Capricorn, but very few. 
The map (Plate XVII) shows the localities where Australite s 
have been found, and is as up-to-date as has been found possible. 
It also shows the distribution of Billitonites, as far as recorded ; 
as in my opinion the two are identical and should be considered 
only together and as one whole. Without doubt, many localities 
of finds have not been recorded on account of the finder knowing 
neither what they are, nor the interest attached to them. 
The glass of which Australites, and apparently Billitonites, 
are composed is a singularly pure one, containing practically 
no small crystals, nor other inclusions, except bubbles., thus 
showing that it has been very quickly chilled from a perfectly 
fluid condition ; its brittleness, moreover, would support this. 
There have been several analyses of Australites made, some 
of which will be found in the table at the end of this paper, to- 
gether with analyses of Billitonites and Moldavites, for purposes 
’ 11 !| UK. MtLHUURIW ' 
