NOTES AND EXHIBITS. 389 



rock crossing the Coal Cliff "Road and that to Bulli, at about eight 

 and a half miles from Appin, and appearing at the other side of 

 the Cataract River in a large patch on the Mount Keira Road, 

 and this may have been the real origin of the deposit here 

 illustrated. Most of the specimens consist of pure, dense, fibrous, 

 hydrated silica, but one much more open and cellular than the 

 rest contains also a good deal of carbonate of lime. 



Also specimens of the conglomerate and pebbles forming the 

 hills in the Narran District, known as the Murillas. They are 

 rounded masses of no great elevation rising out of the wide levels 

 between the Darling and Bokhara Rivers, which are recognised 

 as tertiary, and appear to rest upon the Cretaceous or Jurassic 

 beds which form the country on the right bank of the latter river. 

 It is evident that they are wrecks of an older formation (possibly 

 Daintree's desert sandstone), and it seems probable that they 

 represent in reality an upper member of the Cretaceous system. 

 But no information has been obtained as to the beds which 

 directly underlie them. The conglomerate is composed of pebbles 

 of milky quartz, imbedded in a mass of rounded pellets and grains 

 of rock crystal, firmly compacted by a siliceous cement into a hard, 

 coarse-grained quartzite. This, however, is more soluble than the 

 materials which it holds together, so that under atmospheric wear 

 and tear it is forced to release them once more, covering the 

 ground with sheets of white pebbles, which at a little distance 

 may be mistaken for snow. The specimens were brought to 

 Sydney by the Hon. P. G. King, M.L.C. 



