318 
MANGANESE DEPOSITS OF INDIA : GEOLOGY. [PaET II : 
fewer number of ore-bands to the surface than the total number of lines of 
outcrop, especially in view of the fact that only one ore-horizon has been 
yet discovered in the true Chilpi area^ 
Admitting, then, that the outcrops of manganese-bearing rocks and 
ores correspond to only a small number of original beds of ore, the question 
again arises as to whether the deposition of ore over a particular horizon 
was continuous, i.e., whether the manganese oxides were laid down as a 
continuous sheet ; or whether they were deposited in a patchy fashion, 
such as would be the case were the deposition taking place in a series of 
basin-like areas, such as a series of lagoons or lakes. At first sight it would 
seem evident owing to the discontinuity of the ore-bodies situated along 
one line of outcrop that the latter theory is the correct one. But as ex- 
plained above, tliis interruption in the continuity of one particular outcrop 
may only be apparent and due to the obscuring of the intervening groimd. 
In some cases, however, it is real, namely those in wliich there can be no 
doubt that the ore deposit is of lenticular shape and definitely dies out in 
lenticular fashion in a comparatively short distance. This interruption 
might, of course, be explained as due to the squeezing out of a previously 
continuous bed into separate lenticidar portions under the influence of 
the severe tectonic disturbances to which these rocks were subjected. 
Fortunately, however, one of these cases of lenticular thinning out occurs 
at Balaghat, where the degree of metamorphism to which the ore-layer 
has been subjected could not be regarded as in any way adequate to 
account for such a squeezing out. It thus seems as if we can say with 
Dc})o.sition took ^^^^ degree of certainty that these manganiferous 
pliicc iu lagoou- or sediments were partly deposited in circumscribed 
lake-hke areas. ^^^^^ ^£ nature of lagoons or lakes and that they 
were partly deposited in areas of considerable extent such as a compara- 
tively large lake.^ 
One feature that is worth noting is that the ending of some of these 
areas is very sudden. Thus the south-east end of the ore-band in South 
Hill at Kandri, as seen in level No. 1, is about 70 feet across, and in the 
course of a few yards the band is rounded off and suddenly disappears 
Some ore-lcnticles beneath the surface. If this be a deposit that was 
due to squeeziug and originally laid down in a basin having this shape 
some to depo.sition m o . 
basin-shaped areas. before it was subjected to the tectonic movements 
characterizing the termination of the Dharwar period of sedimentation , 
1 Hub tlic accouilt of the Tliiroi i do|)().sil, page (iDU. 
2 1 am discussing in this placo the Ndgpur-Balighdt area only ; there is of course 
little doubt that the ores deposited in Dhdrwir times in other parts of India, such as 
Jh4bua and Narukot , were deposited in separate areas of deposition. 
