286 PROCEEDINGS OF SECTION C. 
Pyroxenifes : 
Diallagite — diallage. 
Bronzitite = bronzite. 
Websterite= diallage + bronzite. 
These rocks occur firstly over broad areas as serpentinised 
and partially serpentinised masses; secondly, as dykes 
traversing Silurian slates and even gabbro or serpentine. 
In the latter case they may be considered as belonging geo- 
logically to the gabbro. and bearing the same physical rela- 
tion to it as elvans do to granite. In some cases, too, they 
may be marginal differentiations of the gabbroid magma. 
Dykes of wehrlite and lherzolite occur on the Waratah- 
Corinna Road, the latter rock containing very little pyroxene, 
and approximating very closely to the olivine rock dunite. 
We have a very fresh harzburgite from the Upper Arthur 
River; unforunately, it is only known from a single speci- 
men, and the precise locality is not known. 
The pyroxenite rocks occur as diallagite at the bridge over 
the Heazlewood River, at the Upper Blythe River, Hamp- 
shire Hills, and as bronzitite near the Heazlewood Bridge, 
at the Bald Hill, Anderson’s Creek, New West Colebrook, im 
the North-East Dundas district. | Websterite is found at 
the Heazlewood in serpentine rock. 
The large dyke containing the Magnet galena lode is a 
dark-green rock containing porphyritic crystals of enstatite 
and augite. Professor H. Rosenbusch has examined this 
rock, and terms it a websterite-porphyry. He says:—“If 
we follow the rock back to its original and unaltered state, 
we shall find phenocrysts of bronzite, or enstatite (now 
bastite), in a ground-mass of rhombic and monoclinic 
pyroxenes (now a mixture of serpentine and a chlorite 
mineral). It is, therefore, a porphyritic form of websterite— 
a websterite-porphyry. Its nearest relations are certain 
bronzite-serpentines (without olivine). In the structure of 
the ground-mass it resembles the South African Kimberlite 
and the mica-peridotites of Kentucky, described by Diller. 
In this purity of form the type is quite new to me.” 
A very singular pyroxenite occurs to the W. of the 
Magnet lode, and half a mile north of the North Magnet 
Mine. It is a yellow-brown soft pyroxene rock, mostly 
weathered, and crowded with spheroids of the same mineral 
from the size of marbles to that of cannon-balls. The 
spheroids assume sometimes the shape of dumb-bells, and 
fall out of the matrix very readily upon handling. 
