ANNIVERSARY ADDRESS. 51 
‘ ghale from which Mr. H. G. Rienitz has collected a great number of 
fossil plants, many of which belong to forms as yet undescribed. 
Eastwards the sandstones thicken to their maximum, as proved 
at the Cremorne Bore, of over 1,020 feet. The sandstone is thick 
bedded, massive in places, but more frequently shewing diagonal 
bedding. The angle of dip of the diagonal bedding, if the plane of 
the true bedding be taken as the datum horizon, seldom exceeds 
26°. Mr. C. S. Wilkinson has stated that the prevalent dip of 
the diagonal bedding is towards the northeast, Beds of clay- 
shale are occasionally interstratified. One of the most persistent 
of these may be traced, at intervals, from near Blackheath to the 
monoclinal fold a distance of over twenty miles; it is one to 
eight feet thick and twenty feet below the top of the Hawkesbury 
Sandstone. A good section of it is exposed in the railway cutting 
at the eastern approach to the tunnel, at the top of Lapstone Hill. 
A short distance east of the Katoomba railway station a large 
isolated fragment of clay-shale, apparently on the same horizon as 
the bed just referred to, is seen in the railway cutting, embedded 
in the sandstone in such a way as to prove that it was contem- 
poraneously tilted out of its original horizontal position! The 
contemporaneous dislocation of this shale has been ascribed by 
Mr. C. 8. Wilkinson to some kind of ice action.? In places, 
especially towards the upper portion of the bed, the sandstone is 
loosely aggregated; in the middle and lower portions, however, it 
is more or less firmly compacted. It is composed of grains of 
quartz, decomposed fragments of felspar, minute crystals of iron 
pyrites, and, as recently shown by Mr. H. G. Smith, of red garnets.* 
Crystals and small veins of barytes may occasionally be noticed. 
Scales of graphite appear to be uniformly distributed in consider- 
able quantity throughout the whole mass of the sandstone; no 
satisfactory explanation of their presence has as yet been offered. 
1 Journ. Roy. Soc. N. S. Wales, Vol. x111., 1879, pp. 105 — 107. 
2 Contemporaneously contorted diagonal bedding, like that seen at 
Coogee, near Sydney, may be due to similar agency, as hey mae by me 
elsewhere.— Quart. J ourn. Geol. Soc., Vol. xi111., pp. 190 — 196, 
3 Journ Roy. Soc. N. 8S. Wales, Vol. xxvim., 1894, pp. 47 — 50. 
