44 A FURTHER NOTE ON OBSIDIAN BUTTONS. 



eve. The ollipsoidal sliajx^, which is not iiiiconiinoii 

 ii) Anstralijni s|)(;('ini(!iis of tlic buttons, is inconsistent 

 Avith the tlu'orv of a long rotatory fliglit tlirongh the air, 

 for any snc^li \ <,)lcanic ejectanienta nnist have cooh'd too 

 quickly to alhnv of any change of form on reaching the 

 ground. A sinuiar elongation of originally sj)heroidal 

 cavities in vesicular basaltic lavas is a familiar instance 

 in this coimection. 



The general probabilities seem to be in favour of the 

 origin of the obsidian in or near the country in wliich 

 the " buttons " are found, even if volcanic rocks of the 

 necessary acidic type are not now in evidence : that they 

 have been largely distributed by human agency cannot 

 be doubted. Their reported occurrence in drift gravels 

 in certain localities is still a mystery for the elucidation 

 of which no satisfactory explanation Iras yet been ottered. 



