20 THE VICTORIAN NATURALIST. 



hexagonal pyramids, sometimes in ordinary penetration twins, and 

 sometimes polysynthetically twinned ; tabular forms were also 

 procured, which on close examination proved to be complicately 

 polysynthetically twinned on a minute scale. 



g. Chabazite. — Typical forms of this mineral were obtained a 

 few miles further along the coast in a very vesicular layer of 

 basalt, nearly all the vesicles being nicely lined with Chabazite, 

 Aragonite or Calcite. It occurs in rhombohedra, commonly- 

 twinned, and it varies from colourless and opaque white to pink. 



TO. Calcite. — This mineral is to be found in many forms all 

 along this coast occasionally in the clear transparent form — 

 Iceland Spar — more frequently in white or yellowish translucent 

 forms, with the usual well-developed rhombohedral cleavage, also 

 as stalactites, stalagmites, and mammillary concretions. 



11. Aragonite. — So far as I am aware, some of the finest 

 crystallizations in our colony are to be obtained in this neighbour- 

 hood, consisting of right rhombic prism combined with brachy- 

 pinacoid and basal plane, about an inch to an inch and a half in 

 length, and from one-eighth to one-fourth of an inch in diameter ; 

 stellate twins of the same form are also worthy of mention, and 

 appear usually to consist of three or four individuals. There is 

 no apparent cleavage, and the fracture is uneven. 



12. Aragonite, var. ? — A fibro-crystalHne and crystalline form 

 of mineral containing carbonate of strontium in addition to 

 carbonate of lime. Hitherto I have not been able to find any 

 mineral description with which the present specimens quite 

 agree, the nearest relative being apparently Mossottite. Further 

 particulars on this mineral will be given later. 



13. Dolomite occurs in rhombohedra with curved faces and a 

 somewhat pearly lustre, also in compact complicately twinned 

 masses. 



14. Limonite. — Very good solid examples of this mineral can 

 be obtained along this coast, but especially as a casing to the 

 dykes already mentioned. 



15. Hematite. — Small specimens are occasionally met with 

 associated with the Limonite, and in the form of red ochre there 

 is a fair impregnation in some of the decomposed ash layers. — 

 G. B. Pritchard. 



In conclusion I may say that the weather from the start on 

 Good Friday was all that could be desired, while a better spot 

 for the marine zoologist would be difficult to find. Full 

 advantage was taken of these favourable circumstances, and 

 no time was wasted, but a fortnight might easily have been 

 spent in working among the reefs and along the shore in either 

 direction from our camp. Earlier in the season, too, the surround- 

 ing timbered country would, I feel sure, prove a good collecting 

 ground for the field zoologist and botanist, while some time might 

 be devoted to working the creeks. J. A. Kershaw. 



