45 



they had cooled. They are solid to the centre, and this 

 points to their rotation having been comparatively slowf 

 The inference that the volcano was a lunar one is, in our 

 opinion, unnecessary, and is moreover open to more than one 

 objection. Admitting that the energy of a large volcano on 

 the moon's surface may be sufficient to discharge a piece of 

 lava from our satellite, tbis projectile would then revolve 

 round the earth in an orbit of its own, and as has been pointed 

 out by Sir R. S. BallJ if it once completed that orbit it 

 would never fall on the earth. On the theory of probabilities 

 the chances of the orbital path coinciding with the position of 

 the earth in space are infinitesimal ; but it must absolutely 

 coincide on the first revolution, if the projected lava disc is 

 ever to find a resting place on our globe. And yet we are 

 asked to believe, not in one such coincidence, but in thousands. 

 It is highly improbable that small bodies like these buttons 

 would survive the friction and heat of their descent through 

 the air. This friction reduces countless meteorites to meteoric 

 dust, or to the small fragments which occasionally succeed in 

 reaching us. Further, it is difficult to believe that objects of 

 such a symmetrical figure had ever begun to revolve in a 

 planetary orbit. To our mind the elliptical form of one of 

 the bombs is decisive against the theory of a lunar origin, 

 showing as it does that it was still in a viscous state when it 

 fell upon the soil. 



There seems therefore no other source to resort to than 

 terrestrial volcanoes of an acid or sub- acid type. This 

 hypothesis only requires that the molten spray should have 

 been carried by winds as far as Tasmania and Australia. 

 Having regard to the Krakatoa ash being transported in the 

 air to enormous distances from its point of ejection*, we 

 cannot make distance a reason for denying to these singular 

 buttons of obsidian a source in some pliocene or quarternary 

 volcano of the southern hemisphere. The nearest known 

 source of tertiary obsidian is New Zealand, but whether 

 these objects have been brought from that island, or from 

 the Antarctic continent or elswhere, it is as yet impossible to 

 say. 



Note. — Since the above paper was read, additional information 

 has been received from various sources respecting further localities 

 in Tasmania. These are the Norfolk Range, in stanniferous 

 drift ; Camden Plain, Mount Barrow, in auriferous wash ; at 

 Lisle, in auriferous wash. 



t The Ancient Volcanoes of Great Britain. Sir A. Geikie, 1897, vol. i., p. 60. 



J The Story of the Heavens. Sir R. S. Ball, 1892, p. 355. 



* "The speed and distance attained by the pumice ejected from the volcano 

 may be conceived from the fact stated in Mr. Douglas Archibald's contribution to 

 the report, that dust fell on Sept. 8th, more than 3,700 English miles from the seat 

 of its eruption." Dr. W. Marcet's address, " Nature," March 20, 1890, p. 477. 



