402 



Transactions. — Geology. 



intersected by numerous small white veins. Beadily decomposed by H. 

 01. at a temperature of 212° Fall. ; lost 13 per cent, water, but as it is 

 very probable this is in greater part or altogether constitutional along with 

 that requiring a higher temperature for its expulsion, the whole of the 

 water present in the stone is entered in the appended analysis under one 

 head : — 



Silica . . 

 Alumina 





. 



38-82 

 .. 23-17 



Oxides of 



iron 





6-30 



Lime . . 







3-65 



Magnesia 







3-27 



Alkalies 







2-03 



Water . . 







22-76 



Carbonaceous 



matter 



traces 



10000 



Schrotterite, '.j£f Si + 8 H. — Professor Liver sidge (Trans. N.Z. lust., 

 vol. x., p. 500) mentions a mineral from the Malvern Hills, Canterbury, 

 which is probably schrotterite. His description is as follows : — " In rounded 

 wax-like masses, filling the cavities of an amygdaloidal trachyte (?) rock, and 

 has a mammillated incrustation upon its surface ; green, grey, and white ; 

 hardness about 3-5 ; streak, white ; rather tough ; breaks into more or 

 less conchoidal flakes ; translucent ; waxy lustre. Before the blowpipe it 

 becomes white and opaque and much harder, intumesces slightly and tinges 

 the flame green ; affords deep blue when ignited with cobalt nitrate ; does 

 not gelatinize with hydrochloric acid, but granular silica is thrown down ; 

 gives off much water when heated in a closed tube.' 



Pimelite, 2 .^y. Si + 3 Mg Si + 10 H. — The occurrence of this mineral 

 filling cavities in amygdaloidal rocks, at Malvern Hills, Clent Hills, etc., is 

 mentioned by Dr. v. Haast (Jurors' Bep. N.Z. Ex., 1865, p. 257). 



Idocrase (Yesiwianite), 3 (Ca, Mg) 3 Si + 2 J^\ Si 2 . — This mineral occurs 

 as dirty green, fluted, prismatic crystals, in quartz associated with the 

 crystalline rocks of Dusky Sound ; specimens having been forwarded by 

 Mr. W. Docherty. The larger crystals have a resinous lustre and the 

 smaller ones, which are of a brighter green, are more pellucid. 



Epidote, 2 (J^. jke) Si 3 + 3 Ca Si. — The occurrence of this mineral in 

 gneiss granite and granulite of the West Coast is mentioned by Dr. Hector 

 (Jurors' Bep. N.Z. Ex., 1865, p. 266) and by Dr. v. Haast in the diorites of 

 Mt. Torlesse range (Jurors' Bep. N.Z. Ex., 1865, p. 257) and in the 

 melaphyres of the Mt. Somers district (Geol. Bep., 1878-74, p. 9). A 

 massive form from Wairarapa, Wellington, of a greenish-grey colour, is 

 also in the collection of the Colonial Museum. Before the blowpipe it 



