82 



Bed No. 5. — Only the stalactitic concretions were avail- 

 able for examination from this geological horizon. The 

 particular example shown me by Capt. White is 8 inches in 

 length and numerously branched, reticulated and denticu- 

 lated. Its composition is that of a fine sand calcareously 

 cemented. Nodules and variously-shaped concretions of this 

 kind commonly occur in deposits of fine alluvial sand, and can 

 be found under such conditions in the banks of the River 

 Torrens near Adelaide. They were also present in the alluvial 

 bed, exposed under marine deposits, in the excavation made 

 for Fletcher's Graving Dock.W The bed containing these 

 nodules at the reedbeds is undoubtedly of freshwater origin, 

 probably laid down as river wash. 



Bed No. 6. — The white sand which formed the lowest 

 bed in the section, and was not bottomed, has all the appear- 

 ance of a wind-blown sand. It contains no organic remains, 

 is of uniform grain, and is practically free from any cementing 

 agent. In the excavation it had the character of a running 

 sand which flowed in as fast as it was shovelled out and 

 stopped all further sinking. It was probably formed as an 

 ancient sand dune, the base of which is below the present sea 

 level. 



The Stone Implements. 



.The stones showing aboriginal workmanship were of three 

 kinds : pounding-stones or cores, a hammer-stone, and a 

 fabricator. 



1. Pounding-stones. —There are five belonging to this 

 class, and these exhibit certain features in common, having 

 a flat base and are roughly chipped in a way that might make 

 them convenient for handling. The general form is very like 

 the cores that are left after flakes have been struck off for mak- 

 ing knives or scrapers, but the drippings have been too irregular 

 and ill-shaped for such a purpose. Capt. White's suggestion 

 that they may have been used for crushing, or pounding, is 

 therefore probable, although the flat faces give no sign of wear. 

 Lithologically these pounding-stones belong to two kinds 

 of siliceous rocks. Four of these have been obtained from 

 boulders of quartzite washed down from the hills in the vicinity 

 of Adelaide. The fifth is a siliceous rock, of coarser grain, 

 and the cement consists of colloid silica. The four first- 

 mentioned are of Cambrian age and are of metamorphic origin, 

 while the last-named is of Recent age and formed part of the 

 consolidated sands of the older drainage system of South 



(i) Howchin : "Remarks on a Geological Section at the new- 

 Graving Dock, Glanville, with special reference to a supposed 

 Old Land Surface now below Sea Level" (Trans. Rov. Soc. 

 S. Austr., vol. x. (1887), p. 31). 



