BY W. F. PETTERD, C.M.Z.S. 69 



abundant, occurring in connection with a dense white 

 quartz (W. H. Twelvetrees). It has also been recorded 

 from the Mt. Lyell district. 



118. Epsomite (Sulyhate of Magnesium). 



Found as sub-crystallised, aggregated, and delicately 

 fibrous masses, but also commonly as a more or less compact 

 incrustation. It occurs in caverns and rock-fissures, and is 

 derived from saliferous rocks. Abundant in the neighbour- 

 hood of the Dromedary Mountain ; about the Upper Lake 

 River ; near the Western Tier ; at Exton ; Alum Clif! 

 caverns, near Chudleigh : Kangaroo River, near Campania, 

 in a considerable deposit (Montgomery). 



119. Erythrite (Arsenate of Cobalt J. 



This mineral may be at once known by its characteristic 

 peach-blossom colour. An extremely small quantity has 

 been obtained, int-ermixed with earthy ferruginous gossan, 

 at the Penguin Silver-lead Mine, Penguin River ; and in 

 small patches of distinct colouration as a coating on lode 

 gangue, probably derived from the transmutation of an 

 arsenide, at the Hampshire Silver Mine, Hampshire Hills 

 (W. R. Bell). Also occurs coating schist, Lake Dora. 



120. EuDiALiTE (MetasUicate of Sodium, Calcium, Iron, 



and Zirconium Oxy chloride). 



Described by Dr. F. P. Paul as an essential in the nephe- 

 line-eudialite basalt of the Shannon Tier. The rock is 

 greenish-grey coloured, and close-grained, and is con- 

 sidered by Dr. Paul as a distinct type of basic effusive, 

 which is of extremely unusual occurrence, if not unique. 

 It is a phase of the interesting rocks of the locality to 

 which it is apparently confined. It occurs in the conical 

 outcrop locally known as the " Beehive." The eudialite is 

 colourless, and as accessories sodalite and apatite occur. 

 The Zr Oo = 0-21 of the mass, or 2 per cent, of the rock 

 consists of" the mineral in question. It is also found as an 

 occasional accessory in the melelite-nepheline-basalt of the 

 same locality. In the lastmentioned rock an apparently 

 new mineral also occurs, which Dr. Paul states is related 

 to olivine. According to that petrologist the analysis 

 is Ca.Si^Og, but he regards Ca^ Si O4 as highly probable. 

 In thin section it is colourless to^light-grey in large irregu- 

 lar individuals. Refraction and double refraction rather 

 strong, and differ little from those of the ferruginous 



