18 AiroiVEESABT ADDRESS. 



carnelians, rock crystals, and amethyst that cover the banks of 

 Uruguay downwards below the Eio Negro. This amygdaloid has 

 on its slopes a sandstone, considered tertiary, as young as the 

 brown coal formation of Europe ; but there is no mention by 

 any one of diamonds in that neighbourhood. 



All that can be said with certainty is, that agates, which hare 

 been dispersed by the destruction of amygdaloids in which they 

 were segregated, are found in Africa, where diamonds occur ; but 

 as yet no diamonds are found amidst the multitudes of agates in 

 the drift of Uruguay. The drift is evidently due to causes of 

 posterior date 1;o the age of the rocks to which the diamond has 

 been referred for its parentage ; and, therefore, in the present 

 state of the evidence no conclusion can be drawn as to the 

 positive indication of diamonds, because agates are present. 



I may add that, from Dr. Comrie, of H.M.S. " Dido," and one 

 of his brother ofS.cers, I have received a small collection of agates, 

 carnelians, and chalcedonies, from Du Toit's Pan; these are 

 mingled with beautifully clear crystals of quartz, opaque quartz, 

 rounded bits of jasper, spinelle-ruby, &c., all highly polished, 

 and in no respect differing from drifted mineral of the same kinds 

 in our New South Wales rivers, where no diamonds have been 

 found. 



I will conclude this subject by reference to what I consider an 

 interesting fact bearing on a question of human history, which 

 cannot be further alluded to. In a limestone cave at Cape 

 Point, Dr. Comrie found, with bones and rude pottery, several flat 

 stones of hard rocks, and amongst them some rounded perforated 

 stones, such as are represented in Sir John Lubbock's edition of 

 Sven Nilsson's Primitive Inhabitants of Scandinavia. These 

 latter appeared to me to have been used as sinkers for fishing . 

 others consider them as hammers. (Plate l,Jigs. 12, 34.) 



Now, in Mr. Dunn's report I find the following : — " There is a 

 tradition among the Booshmen that in former times their fore- 

 fathers made journeys to the banks of the Vaal Eiver to procure a 

 small white stone, with which they bored holes in those perforated 



