302 HENRY G. SMITH. 
_ PRELIMINARY NOTE ON LIMESTONE OCCURRING 
NEAR SYDNEY. 
By Henry G. Situ, Laboratory Assistant, 
Technological Museum, Sydney. 
Communicated by J. H. Marpen, F.C.S., F.L.S. 
[Read before the Royal Society of N.S. Wales, November 2, 1892.) 
Tae Hawkesbury sandstones and the Wainamatta shales, being 
almost devoid of lime, it may be interesting to record the presence 
of an argillaceous Limestone occurring at Duck Creek, Auburn, 
and also near Homebush, both near Sydney. The exact locality 
where this limestone is opened out, is about a quarter of a mile 
south of the intersection of Cheswick Road and Duck Creek, 
Auburn. 
When I visited the locality, men were at work quarrying the 
limestone, this being used by a neighbouring municipality for 
road-making. When first broken, it is of a blue-grey colour, not 
much unlike basalt; it was spoken of as “blue metal” by the 
quarrymen, who no doubt consider it identical with the igneous 
rock bearing the same name. On weathering, the limestone 
becomes lighter grey in colour. 
The deposit is a sedimentary one, and is interspersed with small 
bands of carbonaceous shale, and thin bands of coal. It runs 
horizontal for some distance along the creek, this being nearly 
north and south, but where opened out, it is very irregularly 
deposited. There is about six feet of surface soil, under this 
about two feet of shale, very much carbonised, interspersed with 
small bands of good clay, nodules of ferruginous clay, and small 
bands of ironstone. The bed now being worked is six or seven’ 
feet thick. Under this, nodules of clay-ironstone are found; a | 
qualitative analysis of these nodules shows that lime is present in 
