Obsidian Bombs in Australia. 25 



trappean, porphyritic, and trachytic rocks which occurs about 

 four miles further south, because the detritus is all local and 

 there is no easily assignable crater. 



" Whether this explanation is sufficient or not, the facts them- 

 selves are interesting, for these singular bodies have been found 

 in three localities in Australia, at intervals of 455 and 205 miles 

 apart — the distances from the Murray and Darling Plain to the 

 Turon, and from the Turon to the Uralla. That they could have 

 had only one point of origin is scarcely to be supposed, if they 

 are really of sub-aerial volcanic origin. In two of the three 

 localities, at least, there is presumption of such action ; and in 

 both of these localities the bombs are embedded in gold deposits." 



In the Melbourne Intercolonial Exhibition Catalogue,^ 1866, 

 mere mention of their occurrence is made as being abundantly 

 distributed over the surface of the basaltic plains round Mount 

 Elephant and Mount Eeles^ ( ? Eccles), and on the tertiary mud 

 plains of the Wimmera, far removed from any known basaltic 

 craters or points of eruption. Some analyses are also given, but 

 will not be referred to now. In the descriptive catalogue of the 

 rock specimens and minerals in the National Museum, 1868, 

 mention is made of a remarkable obsidian ball found in the 

 Upper Regions Station, Horsham. On account of its low 

 s^aecific gravity, 1-06, it was deemed advisable to have it cut, but 

 unfortunately no ineans were taken to collect the enclosed gas. 

 It now shows a cavity having a beautiful polish, and may be 

 seen in the collection of Victorian minerals in that ^Museum. 

 Tliis specimen will be fully dealt with subsequently. 



Professor Tate'^ inclines to the opinion that their distriljution 

 has been effected by human agency, and mentions that they are 

 held in high estimation by the aborigines, but considers that the 



1 Notes on the Physical Geoofi-aphy, Geolojfy and Mineralogy of Victoria, by -Alfred 

 R. C. Sehvyn and George H Ulrich, p. 65. 



2 No such mountain is known in Victoria, and it is presumed that Mount Eccles is 

 meant. Prof. Ulrich, who was at that time engaged on the geological sur\ey of the 

 colony, says that the name was given to him by Mr Selwyn, who collected a number of 

 obsidian buttons there, but that if a basaltic point named Mount Eccles is given on the 

 maps situated on the western jDlaiii towards Warrnambool and in the neighbourhood of 

 Mount Elephant, we would be justified ia concluding it to be the cori-ect one. There is no 

 doubt that the names apply to the same mount, as in Selwyn's map Mount Eele.s is in the 

 position given to Mount Eccles in other maps. 



3 Trans. Philosoph. Soc. Adelaide, S. Aust., vol. ii. (1S79), pp. 70, 71. 



