Auatralites from. Wo^tern Victoria. 365 



Examitiafion of interior of Ausiralite. 



The australite Avas immersed in water in a watch glass, and 

 examined under the microscope. 



The specimen is completely glassy, showing neither crystallites 

 or microlites, and is completely isotropic, except for slight strain 

 polarization effects at the thin ends of the australite. 



Disc-shaped Australite presented by Mr. Charles D' Alton to 

 Geological Museum of the U niversity. 



Measurements. — The weight determined by the chemical balance 

 is .3184 grams. 



The specific gravity determined by Joly's spring balance is 2.41. 



Length of australite is 13 mm. or |^ inch. 



Breadth of australite is 11.8 mm. or ?,# inch. 



Maximum thickness is 1.2 mm. or ^^ inch. 



Length of australite, excluding the flange, is 5.2 mm. or ^f inch. 



Breadth of australite, excluding the flange, is 45 mm. or ^-^ 

 inch. 



Appearance of Australite. 



The specimen is approximately disc-shaped, and almost circu- 

 lar in outline. It is dark bottle-green in colour, and quite trans- 

 lucent, owing to its thinness. The flange is much broader, and 

 slighter thicker than the central portion. The edge of the flange is 

 perfect, except for a small chip. It is smooth, except for small 

 pits and quite clearly could never have formed a portion de- 

 tached from a glass bubble. 



Upper Surface. — The whole surface is crowded with minute pits, 

 some hemispherical in shape, some shallower, and many are con- 

 fluent at their edges. In addition shallow grooves are seen form- 

 ing a closed, roughly elliptical curve tangent at one point to the 

 central portion, and passing out to neai- the margin of one part 

 of the flange. The junction of the flange with the central portion 

 is depressed, and the flange as a whole is thicker than the central 

 portion. 



Lower Surface. — The lower surface is almost flat. It is covered 

 with minute pits, and in the central portion with sub-parallel 

 grooves trending in the direction of the longer axis of the speci- 

 men. These grooves, however, fail to reach the margin of the 

 flange. 



