OCCURRENCE OF A CALCAREOUS SANDSTONE AT ROCK LILY. 407 
Narrabeen Series, as evidenced by the cores from the Holt Suther- 
land Diamond Drill Bore. 
At Rock Lily at the first headland to the north of the sandy 
beach there are several beds of a very calcareous sandstone, in 
which the calcite is crystallised out in the mass of the sandstone 
in isolated crystals. These crystals exhibit the characteristic 
cleavage of calcite, and in freshly fractured specimens the cleavage 
surfaces reflect the light uniformly over areas an inch or so in 
diameter, showing that the optical orientation of the calcite is 
not interrupted by the large number of enclosed sand grains. The 
origin of the calcite in this rock has not yet been determined. 
Possibly it has been derived from dissolving up of the valves of 
ostracods. 
NOTE ON THE OccURRENCE OF BARYTES ar FIVE-DOCK, anp 
ALSO AT THE PENNANT HILLS QUARRY near 
PARRAMATTA, WITH A SUGGESTION AS TO THE 
POSSIBLE ORIGIN OF BARYTES IN THE 
HAWKESBURY SANDSTONE. 
By Professor DaviD, B.A., F.G.8. 
[Read before the Royal Society of N. S. Wales, August 2, 1893.] 
THE first reference made to the occurrence of barytes in the 
Hawkesbury Sandstone is that made by Mr. H. G. Smith, F.cs., 
the Mineralogist to the Technological Museum, who recorded its 
occurrence at Cook’s River. 
At a recent excursion to Five Dock held by myself for my 
second year geological students, some of the quarrymen presented 
to us specimens taken from the quarry, showing small crystals of 
barytes associated with quartzite, and in close proximity to the 
