198 THE GENESIS OF THE DIAMOND. 



not the same as at present, bnt that it has been denuded or washed 

 away, or has been removed by glacial action. There is, however, not 

 the least possible evidence to bear out such a contention. If the 

 country rock and diamond-bearing ground had become decomposed 

 and been washed away, then diamonds w^oidd have been found in the 

 " wash " or in ravines and water courses in the vicinity of the mines. 

 Such is not the case, and no diamonds have been found in alluvial 

 soil nearer than the Vaal River, about 20 miles distant, and these 

 diamonds are totally different in character from the " mine " stones. 



The Kimberley mines lie in basins from which no water flows into 

 any stream, but runs into pans or vleis, where it evaporates or is used 

 for mining purposes. 



In this connection it may be stated that Dutoitspan mine is situate 

 within a few hundred feet of Du Toifs pan, a pond, which is fed by 

 small Avater courses during the rainy season. The bottom of the pan 

 was probably 30 feet lower than the edge of the mine, where the 

 yellow diamond-bearing ground joined the basalt, yet it is a signifi- 

 cant fact that no diamonds have been found in the pan. 



Bultfontein mine is also quite as near this pan and lies at a con- 

 siderable elevation above it. 



At Kimberley and De Beers mines the same conditions exist, but 

 the drainage from these mines is to the north into Diebel's vlei, which 

 is 100 or more feet below the mines and nearly 4 miles distant there- 

 from. No diamonds have been found between the mines and the 

 vlei nor in the vlei itself, and I repeat that this is a significant fact. 

 By what laws of nature would it be possible to obliterate a large 

 section of these mines and leave no diamonds behind in these depres- 

 sions? In case the depressions have been made since the formation 

 of the pipes, would it not be reasonable to expect that the forces that 

 made them would have washed a portion of the diamond pipes into 

 them ? 



I have given these facts at considerable length because my conten- 

 tion that these are the craters and not simply the necks of mud 

 volcanoes has been questioned. It is contended that the craters have 

 been washed away, but this is hardly borne out by local observations. 

 The tops of these craters are bell-shaped, as is the case of ordinary 

 volcanoes. I can not conceive how these craters could have been just 

 filled to the level of the surface of the surrounding country, except 

 that the material which filled them came up as mud highly charged 

 with gases which escaped in the air on nearing the surface and 

 allowed the mass of mud to subside.- There must have been some 

 process to incorporate the shales, which lie near the surface, so thor- 

 oughly with the eruptive mass. 



Any denudation of the tops of these craters would have left behind 

 some trace, even more than a trace, some concentration of diamonds 



