XXxiv. ABSTRACT OF PROCEEDINGS. 



polished pebble in the neighbourhood of Branxton near Greta. 

 Absolutely conclusive evidence, however, of ice-action in this 

 neighbourhood was not forthcoming until the beginning of this 

 year, when Mr. W. G. Woolnough, b.Sc. Demonstrator in Geology 

 at Sydney University, discovered a beautifully striated, polished, 

 and facetted pebble in the Upper Marine Beds of the Permo- 

 Carboniferous system in a railway cutting near Branxton Railway 

 Station. A few days later a number of glaciated pebbles were 

 discovered by myself in company with Mr. O. Trickett and Mr. 

 E. C. Andrews, b.a., of the Geological Survey of N.S. Wales, and 

 Mr. W. G. Woolnough. 



These glaciated pebbles occur on a geological horizon over 1000 

 feet below the level of the Greta Coal Seams, whereas the horizons, 

 where Mr. Woolnough and Mr. Oldham discovered their glacial 

 pebbles, are from 1,500 to about 2,000 feet above the level of the 

 Greta Coal Seams. These glacial beds at Lochinvar are at the 

 very base of the Permo-Carboniferous System, and in general 

 appearance closely resemble the Bacchus Marsh Glacial beds of 

 Victoria, a locality where there is evidence of ice action on a 

 grand scale over a wide area. These last belong probably to about 

 the same geological age as the beds near Lochinvar. The height 

 of the glacial beds at Lochinvar is about 200 feet above the sea, 

 and the thickness of the beds probably not less than 200 feet. 

 The pebbles were probably transported by floating ice. Those at 

 Lochinvar were carried to their present resting place before the 

 Greta Coal-seams were formed, and those at Branxton some time 

 subsequent to the formation of the Greta Coal, in either case at 

 times when this part of the Hunter Coal-field was submerged under 

 the sea, as marine shells of Permo-Carboniferous age occur 

 immediately above the glacial beds. 



EXHIBITS. 



(a) Models of ruled surfaces, and of solids whose bounding 

 surfaces are ruled, by G. H. Knibbs, f.r.a.s., Lecturer in Survey- 

 ing, University of Sydney. 



