50 Proceedings of the Royal Society of Victoria. 



conij30sition, we see that it differs entirely from that of all known 

 aerolites, which are basic and represent the basalts, and more 

 especially the ultrabasic rocks of our earth. But it cannot be said, 

 on account of this, that acid meteorites do not exist, because it is 

 only natural that the more meteorites approach terrestrial rocks 

 in their lithological character and composition, the less likely 

 they are to attract attention. This is supported by the fact that 

 few aerolites are known that have not been seen to fall, whilst, on 

 the contrary, only about nine metallic meteorites or siderites have 

 authenticated origin, and their natui'e is only recognised by their 

 great difference from our ordinary terrestrial rocks. Now, nine 

 only represents a small proportion of the siderites found, and if 

 we assume that the aerolites which have fallen, but have not been 

 found, bear the same proportion to those found, they must exist 

 in very much greater numbers and have been passed by 

 unrecognised. 



It seems probable that obsidianites are not all of the same age, 

 for under similar conditions we find some perfectly fresh, with a 

 black, lustrous exterior, and others again more or less dulled 

 and showing signs of decomposition. Further, their presence in 

 post-pliocene drifts as well as on the surface and their variance 

 in composition tend to support this belief. And under a meteoric 

 hypothesis this is only what might be expected, as non-terrestrial 

 bodies are constantly falling on the earth, and have been doing so 

 in the distant past. The sti'ongest argument against this theory 

 certainly seems to me to be their regular form, which is so 

 completely opposed to all we know of meteorites. Why it should 

 be attained in these and not in others of a different composition, 

 although perhaps equally fusible, is indeed remarkable, but is it 

 not possible that these objects only represent a portion of this 

 interesting occurrence, and that their exceptional shapes are 

 really responsible for their discovery. If, on the basaltic areas 

 of the Western District, irregular fragments of obsidian were 

 seen, they would most likely, if at all, only attract passing notice, 

 and so probably elsewhere. Fragmentary rocks of any nature 

 would convey nothing to the majority of people, and only some 

 structural peculiarity would take their interest. A fact which 

 lends some strength to this theory is the occurrence under very 

 much the same condition of somewhat similar bodies elsewhere, 



