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jig ee eee a E a i cei each hl aA i lS di : EN Ge Ea Saati a sama 
ANNIVERSARY ADDRESS. 53 
period. Reference is given below to a description by R. Etheridge 
Junr., of this interesting fossil. A fossil fish, Cleithrolepis, has 
been found in the Hawkesbury Sandstone at an altitude of 3,450 
feet near Katoomba (?).? 
3. Wianamatta Shale. Of this formation, which probably at 
one time covered a considerable area on the Blue Mountains, only 
a small portion is left undenuded. The westernmost extension of 
these shales is probably at a point about halfway between 
Linden and Faulconbridge. At Springwood the shales attain a 
thickness of about eighty feet, and, further eastwards are com- 
pletely denuded away at intervals, until the monocline at the 
top of Lapstone Hill is reached. They form a thin capping near 
the top of the monocline and thicken out rapidly at its base in the 
valley of the Nepean. They occupy almost the whole of the 
surface area between Penrith and Sydney, and extend northwards 
at least as far as the Kurrajong Heights, and southwards beyond 
Sutton Forest. The Rev. W. B. Clarke estimated their maximum 
thickness at eight hundred feet; he called them Wianamatta 
Shales, from Wianamatta the native name for South Creek. The 
junction of these shales with the underlying Hawkesbury Sand- 
stone is frequently marked by contemporaneous erosion. The 
shales are dark grey to bluish-grey at a depth, owing to the 
presence of iron, probably as protoxide, and carbonaceous material. 
Near the surface where they have been weathered, they have 
become bleached through the aggregation of the iron into segre- 
gation-veins and nodules of hematite and limonite, and the removal 
of some of the carbonaceous material. Bands and nodules of clay 
ironstone occur on certain horizons, especially near the base of the 
series, and thin seams of coal have been described in the upper 
beds of these shales. Mr. Clarke states that one of these seams 
with its clay bands, at South Creek, has an aggregate thickness 
of four feet. 
1 Annual Rep. Dep. Mines, 1886, pp. 174-176, pl. appendix N., f.1-—3. 
2 Remarks on the Sedimentary Formations of New South Wales. By 
Rev. W. B. Clarke, Fourth Edition, 1878, p. 70. 
