Professor Bonney — Parent-roch of the Diamond. 247 



views in regard to the original home of the diamond. The more 

 important part, however, runs as follows : — " He assumes that 

 they (the garnet diopside boulders) are fractures from a much 

 older rock, which, having been subjected to the same action as 

 river boulders, were brought to the surface, together with the 

 kimherlite, from a fluviatile deposit,^ at a great depth. Quite 

 naturally he now deduces the hypothesis that all the diamonds 

 found in the kimherlite have their origin in such diamanti/erous 

 soapstone formation (diamantseifen) deposited in the depth of the 

 Karoo formation and brought to the surface by the same eruptive 

 agencies as produced the kimherlite necks (stocks)." Professor 

 Beck then proceeds to argue against the probability of these 

 " diamantiferous soapstones " underlying the whole of the Karoo 

 formation. But I never even mentioned a soapstone, and do not 

 know what Professor Beck means by it, unless it be the matrix 

 of the so-called kimherlite ; neither have I ever asserted anything 

 like the sentences which I have placed in italics. I agree with 

 him that the existence of a bed of " diamantiferous soapstone " at 

 the base of the Karoo (i.e. in the Dwyka conglomerate) is most 

 improbable, but of that he is the sole inventor, and 1 strongly 

 object to having such nonsense fathered upon me. I have read 

 my paper again, and think, speaking from some experience as 

 a writer, that it ought to be intelligible to anyone who really 

 understands English. I did not, indeed, elaborate every minute 

 detail of the argument." For this I had two reasons — one, that as 

 I was addressing scientific experts, they did not require elementary 

 instruction ; the other, that, as I personally object to elaborate 

 demonstrations of the obvious, or to being told with much detail 

 that Queen Anne is dead, I abstain, as far as possible, from 

 inflicting this penance on others. What I said amounted to this, — 

 that the diamond had now been found as a constituent of a coarse- 

 grained eclogite ; that this eclogite no doubt formed part of an 

 old crystalline floor, underlying the Permo-Triassic deposits, from 

 which fragments must have been broken off and rolled by water 

 action into boulders ; that these probably had been inmates of the 

 Dwyka conglomerate ; that after the Karoo Beds were deposited, 

 volcanic explosions had shattered much of the crystalline floor 

 (eclogites, peridotites, etc., some of them diamantiferous), and sent 

 its fragments flying up together with the overlying Dwyka con- 

 glomerate ^ and Karoo Beds ; and that the pipe was ultimately 

 tilled up with this broken material, which was subsequently exposed 

 to solfataric, perhaps also very locally to contact action. 



Thus Professor Beck is criticizing an hypothesis which is none of 

 mine, but of his own imagining. From this I turn to the one 

 which he proposes as a substitute. " We take the garnet diopside 

 lumps, notwithstanding their form, not as actual boulders, but of 



' The italics are mine. 

 ^ My views will be found on pp. 235, 236. 



3 The boulders, pebbles, and mineral grits in this would be scattered like shot 

 from a gun. 



