292 Report S.A.A. Advancement of Science. 



With regard to the origin of the gems, the mere richness of the 

 deposit is sufficient to indicate a near source for the diamond, 

 although many of the constituents of the gravel itself have obviously 

 travelled far. Despite theories to the contrary, it seems evident from 

 the evidence obtained in New South Wales, as well as in this country, 

 that -what is commonly called " blue ground " is in all cases the 

 original source of the diamond, and the occurrence of enstatite, as 

 well as the presence of garnets, points to the same origin in the case 

 of the Somabula field. I am aware that Professor Gregory, without 

 making an inspection of the ground, has pronounced the opinion 

 that the diamond comes from pegmatite veins, but such an idea is fo 

 completely at variance with the local conditions, and with all that 

 we know of diamond occurrences, that it scarcely merits discussion. 

 I have little doubt that it will not be long before the pipe which 

 produced the diamonds is discovered, and that it will present, apart 

 from slight local peculiarities, all the usual features of the South 

 African mines already known. 



