BY W. F. PETTERD, C.M.Z.S. 19 



needles of strongly-absorptive tourmaline. The tourmaline- 

 bearing quartz is probably original, and the tourmaline 

 may be looked upon as resulting from the same boracic 

 acid emanations which were involved in the crystallisation 

 of the axinite. Where the quartz is secondary, replacing 

 axinite and augite, it contains long needles of actinolite. 

 The axinite is in veins and massive patches, and is inter- 

 grown with datolite, danburite, and the other minerals 

 of the rockmass. Professor A. Lacroix in his memoir on 

 the limurite of the Pyrenees, is of opinion that the rock 

 does not belong to a definite petrographical type, as it is 

 variable in structure, and its mineralogical composition 

 differs in different parts of the same mass. This remark 

 applies with unabated force to the Colebrook intrusion, 

 so far as the dyke as a unit is concerned. That there was 

 a granite reservoir not far off is shown by the tourmaline 

 quartz porphyry to the west at the South Renison Bell 

 Mine, between which and the Colebrook is another occur- 

 rence of axinite, in the form of axinite quartz veins, on 

 the West Coast P. A. sections, close to the granite. A 

 slide prepared from this veinrock shows axinite, quartz, 

 and an abundancy of leucoxene. It is noteworthy that 

 the axinite is confined to the veinstuff, as in Cornwall, but 

 there is no occurrence of limurite. On one of our slides 

 we notice in the clear substance of our axinite some pale- 

 green sub-spheroidal and polygonal translucent crystals, 

 generally made up of rods or fibres somewhat curved, pro- 

 ceeding from the periphery to the interior. These remind 

 one of the decomposition products of borocite called 

 " parasite " by Volger, a hydrous magnesian borate. The 

 wavy fibres are suggestive of some of the forms met with 

 in precipitations from a saturated solution, and the 

 phenomena seem to point to the existence of an excess of 

 boric acid in the rock magma." 



The crystals have been examined and described by Dr. 

 C. Anderson, M.A., B.Sc. (Records of the Australian 

 Museum, Vol. VI., Part 3), who states: — ''From hand 

 specimens in the museum collection it appears that the 

 macroscopic associates of axinite are calcite chiefly in veins, 

 chalcopyrite, pyrrhotite, actinolite in radiating aggregates, 

 and datolite in crystalline masses. To this list Petterd 

 and Twelvetrees, from microscopic examination, add 

 chlorite, tourmaline, danburite, and sphene, while they 

 find that the main mass of the rock is a pyroxene* which 



* Subsequent examination has shown the principal mineral to be 

 amphibole, generally actinolitic. 



