Chap. XLT. ] 
TUMKUU DISTRICT. 
1151 
In the first place I should not describe as laterite the brecciate rock 
noticed above, and in the second place I see no need for any theory of 
igneous origin to explain occurrences that are probably the rosult of the 
superficial replacement of rocks by means of aqueous solutions. This 
occurrence of manganese-ore is also held by Messieurs Jambon & Cie. 
22. Ragikalvadikinakeri Bhaui Nagalagutti. 
This deposit, also held by Jambon and Cie., is situated about ^ mile 
S. E. of the Kanjiganagutti deposit, on nearly level ground at the east 
base of Urumanjanmatti Hill. It is a detrital deposit formed of pebbles 
and boulders of manganese-ore in a matrix o' soil, and probably derived 
from the top of Urumanjanmatti by denudation. The existence of this 
detrital deposit indicates that formerly there must have been a con. 
siderable amount of marketable ore on the summit of Urumanjanmatti. 
Some 125 tons of ore had been extracted from a comparatively small area 
of this ground in the course of 2 weeks previous to my visit. The ore 
consisted largely of good hard grey psilomelane. with a certain propor- 
tion of lead -like psilomelane. Some of the ore contained minute crystal- 
line specks, and some contained patches of the light grey crystalline 
mineral. The ore was being won in a systematic way by means of a 
series of parallel trenches (see page 565). I give the deposit the above 
lengthy name — the meaning of which would in English fill up about two 
lines of print — because there seems to be no other ; it might be shortened 
to Nagalagutti. 
Tumkur District. 
The occurrence of manganese-ore in this district seems to have been 
known as far back as 1857, for ' good samples ' of ore, similar to the 
' silicated sequioxide' {i.e., the braun^te) of the Vizagapatam district, 
were sent from Tumkur to the Madras Exhibition of this year.l 
The exact locality, however, was not stated, and it was not till 1906, 
when the boom in the manganese industry lead to active prospecting 
for this mineral all over Mysore, that the actual position of any depo- 
sits seems to have been ascertained. In this year the Peninsular 
Minerals Company of Mysore, Limited, started work, and extracted 
4,827 tons of ore during the year, 4,128 tons of which were railed. 
In 1907 the same company extracted 13,091 tons of ore. 
1 Reports by the Juries;, p. 2. 
