CiiAP. XXXVI.] 
NAGPTJR : GTJGTJLDOHO. 
949 
of the deposit consists of ordinary mica-schists, while the south wall in 
one place is of mica-schist and in another of interlaminated mica-schist 
and quartzite. In the absence of cross-cuts it is not possible to say what 
is the thickness of the mica-schists in which the ore-body is apparently 
immediately enclosed. But it cannot be very thick, because outcrops 
of quartzites are seen quite close in on both sides. 
This, as noted on page 948, is situated on the very top of Guguldoho 
Tiio workable part Hill, the summit of which is some 350 to 400 feet 
of the ore-hand. above the level of Sonegaon village. Messrs. Jessop 
and Company had made a large number of irregular, shallow excavations 
along this part of the ore-body at the time of my visit in February 1904. 
They showed that here also a considerable part of the ore-bodj^ consists 
of unaltered or only partially altered rhodonite-spessartite-quartz-rock 
or rhodonite-rock (often pale greenish in colour). The thickness of the 
ore-body varies from 15 to 40 feet measured horizontally, the solid man- 
ganese-ore being in one place as much as 16 feet wide. The dip is very 
steep, 50° to vertical to the south side, and the strike somewhat variable 
— between W. 22° N. and W. 30° S., and averaging about east and west. 
Towards the west end of this portion of the deposit (350 yards long) the 
back of the ore-band dives below the surface for about 100 yards, then 
reappearing from beneath the schists. 
The manganese-ores consist largely of sooty varieties, especially corn- 
Nature and quality "^on being an ore composed of fairly large granules of 
of the ore. a bright very magnetic mineral set in a sooty matrix 
containing a certain proportion of psilomelane. This is the ore to which 
I have often referred as ' speckled ore '. There is also a certain amount of 
the hard grey ore composed of tiny braunite grains set in a fairly hard 
matrix of psilomelane. This ore shows fairly numerous cavities con- 
taining ochreous matter. The speciality of this deposit is, however, the 
large amount of concretionary ore showing every variety of stalactitic, 
botryoidal, mammillated, and concentric, structure. Plate 6, fig. 2, shows 
specimen of a botryoidal variety. This ore occurs especially near the 
surface, and also in geodic cavities in the varieties of ore first men- 
tioned, at intervals right to the bottom of even the deepest excavation 
(21 feet). It is probable that it was formed by the secondary solution 
and re-deposition at the surface of the ordinary braunite-psilo- 
melane ores. If such be the case then this concretionary psilomelane 
will probably become much scarcer deeper down, where the man- 
ganese-ore, if it still persist, may be expected to consist of the various 
varieties of the braunite- psilomelane mixtures. 
IV z 2 
