176 TG BONNEY [SEPTEMBER 
rock was a true breccia. That opinion was not altered by the study of 
Professor Lewis’s manuscripts, but I thought it possible that his 
Kimberlite might be represented in certain very compact fragments of 
serpentinous aspect, the nature of which I had been unable to deter- 
mine, owing to the want of definite characters and to my own ignorance 
of what a serpentine formed from a glassy or very compact peridotite 
would be like. Apart from this possibility, my views on the main 
question differed from those put forward by my friend. It was, 
however, my obvious duty to keep the difference of opinion as far as 
possible in the background, and to endeavour to act as a simple channel 
for the publication of the views of one who was no longer able to speak for 
himself. Not long after the book had been published, Sir W. Crookes 
allowed me to examine a piece of breccia which had been obtained at a 
depth of 1320 feet, and was in even better preservation than any 
which I had hitherto seen. About the same time Sir J. B. Stone 
forwarded to me another set of specimens which he had received 
from Kimberley. Among these were two or three blocks, in almost as 
good a condition as that just named, and from an even greater depth, 
viz. 1400 feet. After study of these’ I was more than ever convinced 
that the Kimberlite was a true breccia, formed by the explosive de- 
struction of some coarsely crystalline rocks, such as eclogites and peri- 
dotites (including representatives of the sedimentary rocks of the region). 
I was also able to ascertain the true nature of those fragments which 
hitherto I had thought might possibly be serpentine of an exceptional 
character ; they proved to be in reality nearer to argillites, but to have 
undergone certain alterations, in all probability partly from contact 
action, and partly from water, perhaps at a rather high temperature, 
and no doubt at a later time. Thus I arrived at the conclusion, that 
the so-called Kimberlite was not an altered peridotite, but a breccia, in 
which the diamond, like the olivine, pyroxenes, garnet, etc., was not 
authigenous, but a derivative from some older rock. ‘This I thought 
very probably was a peridotite, for an a@ priori argument, as we may 
call it, which Professor Lewis had used seemed valid, even though 
he might have misunderstood the nature of the Kimberlite, and 
his idea that a very basic rock would be the birthplace of 
diamonds was confirmed by their occurrence in meteoric iron (Canon 
Diablo”) and their manufacture by Moissan through the intervention 
of that metal. 
Two suggestive discoveries must next be mentioned, of which, 
however, I was ignorant till within the last few months. A diamond 
had been obtained in 1892 embedded in a garnet (pyrope); and in 
another specimen no less than six diamonds occurred closely associated 
1 See Geol. Mag. 1897, p. 448. 
2 Another occurrence of diamond (not very pure) in a meteorite which fell at Novo 
Urei, Russia, Sept. 22, 1886, is mentioned by Professor Kuntz, Lighteenth Ann. Report 
of the U.S. Geol. Survey, Part V. p. 1195. 
2 Tees 
