482 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.40. 



In appearance and general physical properties these various bodies 

 from the widely separated sources possess certain points in common, 

 but are yet so different in appearance that examples from any one 

 locality are readily recognized. The Moravian and Bohemian forms, 

 as will be noted by reference to pi. 61 , figs. 4-6, are more or less rounded 

 pebbles or flattened slag-like masses, the surfaces of which are pitted 

 in a way which has been compared by some writers to the thumb-like 

 pittings on meteorites. In addition to this, they are dulled and 

 rendered opaque through abrasion from other stony particles very 

 much like ordinary pebbles from the bed of a stream. In some 

 instances they are deeply cut or notched as in fig. 5. The colors are 

 chrysolite green, and the refractive index so high that they have in 

 some instances been cut and utilized as gems. 



The examples from Billiton, shown in pi. 61, figs. 1-3, are much 

 more remarkable both on account of their shape and the extraordin- 

 ary groovings which traverse the surface in all directions. They are 

 of a deep, lustrous black color and translucent only on the thinnest 

 edges. 



The Australian and Tasmanian occurrences have more the appear- 

 ance of water-worn pebbles which have been abraded by wind-blown 

 sand (pi. 61, figs. 7-9). These are also black and opaque excepting 

 on the thinnest edges. In all, the glass is wholly amorphous without 

 trace of the trichites so characteristic of obsidian and other volcanic 

 glasses. A few characteristic forms only are shown on pi. 61 of this 

 paper; for a complete series the reader is referred to the work of 

 Franz Suess already noted. 



Chemically, as will be noted in the selected analyses referred to 

 later, these forms are all acid glasses approximating in composition 

 the glassy forms of terrestrial rhyolites but unusually rich in lime and 

 magnesia. They are also remarkable for their small water content as 

 indicated by loss on ignition, and their high fusing point. 



In none of the occurrences are the objects found in regions of vol- 

 canic rocks and under conditions which seem to render it at all likely 

 that they are of local derivation. It is seemingly impossible to con- 

 ceive of their having been ejected as volcanic bombs and drifted by 

 winds, and equally impossible, apparently, that they should belong 

 to either stream or glacial drift. An artificial origin is likewise con- 

 sidered impossible by the majority of those who have given the subject 

 consideration, and of late those who should be best qualified to judge 

 have been disposed to consider them as of a meteoric nature. It is 

 with especial reference to this view that the accompanying paper has 

 been prepared. 



Aside from the conditions under which these objects (which have 

 come to be known under the names of "Moldavites," "Billitonites," 

 "Australites," "Obsidianites," and " Obsidian bombs," and which 



