726 
NEW DIAMOND FIND IN THE TRANSVAAL. 
Tue latest Johannesburg papers (Stand- 
ard and Diggers’ News, Financial Record) 
bring news of a very interesting and prob- 
ably economically important discovery of 
diamonds in place, at a distance of no less 
than 300 miles from the mines of Kimberley 
and Jagersfontein. The locality is 20 miles 
east of Pretoria, the capital of the South 
African Republic, and one mile east of 
Merwe, a station on the railway leading to 
Delagoa Bay. The outcrop forms a knoll, 
or ‘kopje,’ in the Magaliesburg range. It 
is on the farm Rietfontein, No. 501. The 
first announcement of the discovery was 
made to the Johannesburg Geological So- 
ciety by Dr. David Draper, on September 
12th. 
The diamonds are found in a matrix, 
called by Mr. G. A. F. Molengraaff, State 
Geologist of the Transvaal, serpentine 
breccia, similar in nature to kimberlite. 
This rock extends over a small area not yet 
fully explored, but known to be at least 160 
feet by 250 feet, and believed to be a vol- 
canic neck. The kimberlite is much less 
decomposed than at Kimberley, the yellow 
ground being only 5 feet in depth, and the 
blue ground projecting above the general 
level, while at Kimberley the yellow or 
oxidized zone extended to more than 100 
feet below the surface. 
Only ten ‘loads’ (of 16 cubic feet) of 
rock had been washed up to September 20th. 
These, however, had yielded 23 stones. Dr. 
Draper reports one stone of 16 carats, 
another of 23, and the rest smaller. The 
16-carat stone is said in the News, of Sep- 
tember 25th, to bea fragment broken from a 
larger stone, the remainder of which has 
not been found. The yield per load would 
seem to be very high, but the amount 
washed is too small to justify predictions, 
while it certainly indicates a good ‘prospect.’ 
Dr. Draper reports garnet, carbonado, 
olivine and ‘ other minerals associated with 
SCIENCE. 
[N. S. Vou. VI. No. 150. 
the diamond’ as present in abundance. 
He very properly points out the likelihood 
that there are other diamond deposits in 
the neighborhood, and suggests the expedi- 
ency of a search for them. 
The new diamond deposit occurs in the 
quartzites of the Magaliesburg range, about 
35 miles due north of the Main Reef Se- 
ries of the Witwatersrand, at its farthest 
known eastern extension. The correlation 
of these quartzites and those along the Wit- 
watersrand is not altogether certain. Some 
authorities have maintained that the Maga- 
liesburg rocks are equivalent to the series 
underlying the Main Reef. Others, with bet- 
ter reason, as it seems to me, consider them 
equivalent to the Gatsrand Series which 
overlies the Black Reef, to the southward 
of the Witwatersrand. In either case they 
are Paleozoic, and much earlier than the 
coal measures of the Karoo, which are 
supposed to be Triassic, and which rest un- 
conformably on the Black Reef Series. The 
rocks of these earlier formations contain no 
coal and no bituminous shales so far as is 
known. In this new diamond occurrence 
there is no apparent reason to attribute the 
formation of the crystals to the local effect 
of lava on superficial deposits of amorphous 
carbon. It will be interesting to ascertain 
whether the lava of the new locality con- 
tains a soluble hydrocarbon like that which 
Sir Henry Roscoe found in kimberlite. 
Diamonds have not been found in the 
Transvaal in the original matrix until the 
discovery here reported. In 1893, how- 
ever, diamonds are said to have been found 
in auriferous ore close to Klerksdorp, in the 
southern part of the Transvaal. The gold- 
bearing ore at this point is reputed to be 
pudding stone of the Cape formation. The 
diamonds, of which somewhere about a 
score were found, were small and of a 
greenish tint.* I am not aware that any 
*C. §. Goldmann, South African Mining and 
Finance, Vol. 2, 1895-6, page 29. 
