422 PROCEEDINGS OF SECTION C. 
noticed several peculiarities of structure which would repay 
further investigation and probably throw some light on the 
manner in which the crystals have been formed. Besides the 
felspar, there is a good deal of quartz and biotite, as well as 
hornblende. The mica and hornblende are generally very opaque, 
so that except in very thin sections it is difficult to study their 
optical characters. Scattered through the coarse-grained rocks 
are patches of much finer grain consisting largely of mica, and at 
first sight suggesting the idea that they are extremely altered 
inclusions of slate, but as they occur in the very heart of the 
granite they can hardly besuch. Besides the normal constituents, 
various accessory minerals are developed such as sphene, while, 
where the granite is slowly decomposing, I have detected calcite 
and prehnite filling cracks in the rock. 
It is probable, but not certain, that the rotten granite has re- 
sulted from the decay of the hard variety, and that the latter 
owes its preservation to some local difference of texture and com- 
position. 
As we travel out from Bathurst, and approach the metamorphic 
rocks, the granite seems to change its character. The hornblende 
disappears, the biotite is partly replaced by muscovite, and the 
felspar becomes distinctly red; so that, near the junction, the 
rock appears to be entirely different from the one we have studied 
at Bathurst. It may really be distinct and of different age, or, 
on the other hand, the change may be a gradual one ; but, owing 
to the surface rock being generally so much decomposed, it is 
difficult to decide the question. I hope to continue my study of 
the Bathurst granites, as I consider them a very interesting 
group of rocks; but for the present we must leave them. Before 
doing so, however, it may be of interest to mention that the area 
over which they form the surface rock is tolerably extensive, 
being something like 450 square miles. 
On proceeding outward from Bathurst in any direction, one 
finds, at a distance of about eight miles in some directions, ten or 
twelve in others, that one has passed off the granite and entered 
a metamorphic area. Even in travelling along roads the transi- 
tion is seen to be abrupt, but good exposures of the junction are 
not very easy to find. By examining railway cuttings and 
creeks, however, a good many very satisfactory sections may be 
obtained. In all of these that 1 have seen the granite finishes 
abruptly against a much darker rock, and there is no sign of a 
gradual passage from one to the other. The junction line, more- 
over, although so sharp, is not a straight line, but winds about in 
such a manner that there can be no possibility of a faulted 
junction, while small veins from the granite run into the 
contiguous rocks. These veins are very narrow, and often one 
about an inch in thickness can be traced for thirty or forty feet 
as straight as if the boundaries had been ruled. The rock 
