304 W. J. CLUNIES ROSS. 
specimens were chosen for examination. The rock is a good deal 
weathered, but presents the usual so i of a porphyritic 
basalt under the microscope. 
C. This is one of the quarries in the columnar basalt, at a 
height of five hundred and twenty feet. It is much fresher and 
rather coarser grained, otherwise it resembles the rock from B. 
D. This is the site of the Corporation quarry. The specimens 
were taken from near the floor of the quarry, height about five 
hundred feet. Most of the rock is much weathered and it is 
difficult to obtain good pieces for section cutting. General 
character as before. 
E. At the north-west end of the hills, at the part nearest 
to Mount Apsley. Specimens were obtained at a height of 
about 600 feet. While generally resembling the other sections, 
the felspar crystals in the ground mass are larger and the rock 
bears more resemblance to that found at Apsley. All these 
specimens are remarkably similar and approximate very closely 
in appearance to those figured by Mr. Curran.’ 
Passing now to Mount Apsley, we find a distinct change in the 
microscopic characters of the rock, Mr. Curran does not seem 
to have examined sections from this locality. He mentions 
- obtaining them from the Bald Hills, near Perth, from the 
Pinnacle Hill (G), and from Mount Pleasant. As one notices 
the various outliers it appears so obvious that the basalt must 
have flowed from the Bald Hills, vid Pinnacle to Apsley, and 
thence to Mount Pleasant, that it would hardly appear necessary 
to specially examine the Apsley rock. I was therefore astonished 
when, having had a section cut, I found it to be very different 
from those from the Bald Hills. Instead of a porphyritic rock, 
with a ground mass of small felspars and granules of other 
minerals, one finds a comparatively coarse-grained basalt of 
arta uniform texture, the felspars in particular forming 42 
oe Geology of Bathurst,” pl. 14. “* Microscopic Structure of Aus- 
tralian Rocks,’ Journal of Royal Society of N.S.W., Vol. xxv., pl. 21. 
