420 PROCEEDINGS OF SECTION C. 
The island of Ugi presents yet another variety of geological 
structure, a low-lying island ; it is composed of bedded foramini- 
ferous limestone, once incrusted with coral-rock, which is 
now toa great extent removed by denudation; flints occur in 
the surface soil, though I have not yet found them zz situ. I 
intend, however, to continue my observations on this island.” 
—Jour Roy. Soc. N.S. W., 1883. 
3—THE PLUTONIC AND METAMORPHIC ROCKS 
OF BATHURST, NEW SOUTH WALES. 
By W. J. Cuiunies Ross, B.Sc., F.G.8. 
Av the last meeting of the association I contributed a short 
paper on “Metamorphism and the Rocks of the Bathurst 
District.” I should hardly have brought forward another paper 
on a similar subject but that Mr. Stirling informed me that it 
was proposed to make the study of the metamorphic rocks of 
Australia a special feature at the present meeting, while at the 
same time he courteously invited me to contribute something on 
that branch of geology. 
During the past year I have had the opportunity of studying 
some of our rocks in more detail than I had previously done, and 
I therefore propose to give a short account of some of them, both 
as to their description and mode of occurrence, and to exhibit 
specimens and sections in illustration of my remarks. On 
reading Mr. Howitt’s interesting paper on the metamorphic rocks 
of Gippsland, which was published in the last volume of 
Proceedings, I was struck with the similarity of the geology of 
that area to that of the Bathurst district, although there appear 
also to be considerable differences. I am not personally 
acquainted with the Gippsland rocks, with the exception of a few 
small specimens lent me by Rey. J. M. Curran, F.G.S8., but shall 
be glad to learn from those familiar with them whether they at 
all resemble our Bathurst rocks. I do not propose to deal with 
the geology of the Bathurst district, but to confine myself to 
recording my own observations on the two groups of plutonic and 
metamorphic rocks. I use the term plutonic advisedly, to indicate 
the holocrystalline intrusive rocks of the granitic type, as being 
tolerably well understood, and not committing one to any 
particular theory as to their origin. 
Before proceeding to deal with the rocks themselves, I may 
say, for the benefit of those not acquainted with our district, that 
Bathurst is built on granite, which extends for a considerable 
distance round the town and that outside the granitic area we 
