196 PROCEEDINGS OF SECTION C. 



of the Australites the first great difl&culty to be faced by those who 

 believe in a volcanic origin is to find the source of these bodies. 



At the end of Mr. Dunn's paper is given a map of Australia, showing 

 the distribution of Australites. An examination of this map will show 

 that the known occurrences of these bodies are confined to a broad 

 belt running approximately W.N.W. through Tasmania and Southern 

 Australia. 



The Australites are known to be of late Kainozoic age, and during 

 that period, as far as known, the only active volcanoes throughout this 

 belt were those of South-western Victoria. The lavas from these 

 volcanoes have not been at all thoroughly examined, but there seems 

 little doubt that only basaltic types were extruded during this period. 

 The upholders of the volcanic origin of the Australites have therefore 

 looked for a source beyond the shores of Australia, and the volcanoes 

 of New Zealand and the Malay Archipelago have been suggested. 



Even if the Victorian volcanoes had produced a lava of the com- 

 position of the Australites the problem of distribution has to be faced. 

 Australites have been found nearly 2,000 miles from the nearest possible 

 Victorian source, and it is inconceivable that they were transported 

 tliis distance by projection from a volcano. 



Mr. Dunn has evidently recognised this difficulty of transport, 

 and in order to overcome it has suggested his hypothetical bubbles. 

 These bubbles are purely imaginary, as nothing of a similar nature 

 has ever been observed during volcanic eruptions. As neither the form 

 nor the structure of the Australites supports the hypothesis, we must 

 look elsewhere for the explanation of the origin and distribution of 

 these objects. 



The only remaining hypothesis worth considering is that they are 

 of meteoritic origin. Supporters of this hypothesis depejid jiiore on a 

 process of elimination than on direct proof. 



Each of the other hypotheses has been weighed in the balance and 

 found wanting, as in every case the arguments for have been easily 

 outbalanced by the arguments against. So far, no valid reasons have 

 been advanced against the meteoritic origin of the tektites, and there 

 are numerous points in favour of this being the correct explanation. 

 No hypothesis can be accepted as giving the correct explanation of 

 the origin of Australites unless it is capable of accounting for their 

 source, form, composition, and distribution. Professor Merrill's 

 suggestion that they are rolled pebbles of Obsidian may be dismissed, 

 as it fails to account for their composition, distribution, or source, and 

 is absolutely negatived by their form. The hypothesis that they have 

 been formed by lightning discharge is so far pure imagination, and no 

 rguments have been adduced in its favour. This hypothesis has the 



