GEOLOGY OF THE COOMA DISTRICT, N.S.W. 193 
granite, the quartzite being mostly on the lower slopes 
nearest the igneous rock, while the slates appear on top of 
the ridge. Contact metamorphism has produced a very 
dense black slate, only imperfectly cleaved, and exceedingly 
rich in chiastolites. These vary very much in size, some 
being of microscopical dimensions, while others are upwards 
of 14 inches in length. In spite of the alteration which 
they have undergone, the slates contain a great abundance 
of fairly well preserved graptolites, Tetragraptus, Didy- 
mograptus and Diplograptus being recognized. The pres- 
ence of these fossils in such a good state of preservation 
here and elsewhere, denotes that the cleavage planes of the 
slates coincide with the bedding-planes of the original 
sediments. 
It is interesting to note that the presence of chiastolites | 
in the slates of Geygedzerick Hill was observed by Rev. 
W. B. Clarke in 1851,! though, curiously enough, he seems 
to have failed to notice the graptolites, in spite of the fact 
that, on his own testimony, he was ever on the lookout for 
them in the slates of New South Wales. 
A small patch of dark blue limestone is interbedded with 
the slates at Pearman’s Hill. The outcrop is not more than 
15 yards long by about 5 yards wide. The rock shows signs 
of great compression, and is crystalline; possibly this is 
due to the presence of the white gneiss a few yards away, 
that is of course, if the latter is really intrusive. A diligent 
search failed to reveal any fossils in the limestone. 
According to David, Helms and Pittman,’ the Ordovician 
rocks extend about 64 miles to the west of Berridale, where 
they are intruded by the Kosciusko granite. It is interest- 
ing to note that Mr. C. F. Laseron has recently’ found 
1 Southern Goldfields, p. 115. 
? Proc. Linn, Soc. N.S.Wales, xxv, 1901, p. 30, 
3 Personal communication from Mr. Laseron. 
M—July 1, 1914. 
