THE VICTORIAN NATURALIST. 95 



The Lepidoptera were scarce, and too active on the wing to 

 net amongst the rocks. Of Hymenoptera I did not notice any 

 species. Of the Orthoptera, the locusts were beginning to come 

 out. Of the wild flowers I did not see more than six varieties in 

 blossom. I had some specimens of the granite ; but, owing to 

 the sudden termination of my visit, I did not revisit the place 

 where I left them. 



I am indebted to the kindness of Professor M'Coy for the 

 names of the various specimens, and to Mr. J. A. Kershaw for 

 those of the beetles. 



ON A MINERAL OCCURRING IN IGNEOUS ROCK 

 AT YARRAVILLE. 

 By Thos. Steel, Yarraville. 

 ( Read before the Field Naturalists' Club of Victoria, i$t/i Oct., iSgo.) 



The mineral which I wish to bring under the notice of the Club 

 occurs in a rough trachitic dolerite, containing numerous scattered 

 olivine crystals, and more or less scoraceous in structure, which 

 overlies the dense dolerite rock of the district. It is found after 

 the manner common to zeolitic and other minerals, forming in- 

 crustrations and concretions in the rock cavities. 



The portions lining the cavities are in concretionary layers, 

 and are hard and crystalline, but nodular masses also occur, which, 

 when broken, disclose a thin crystalline crust or shell, surrounding 

 a hard porcellanous or amorphous white mass. 



The following are the figures yielded by analysis : — 

 Water @ 21 2° F. - - *20 



( Sulphate of lime - "24 

 \ Carbonate of lime - 62*96 



9878 



Essentially the mineral is, therefore, carbonate of lime, with 

 alumina and a little magnesia and other common bases. There 

 is sufficient carbonic acid present to satisfy the magnesia, which 

 probably exists as carbonate. 



Frequently, small nodular or lens-shaped masses are found 

 adhering to one corner of a cavity, and it is seldom that the 

 cavities are completely filled. More rarely, curious spongy- 

 looking masses are met with, composed of irregular masses of the 



