564 MANGANESE DEPOSITS OF INDIA : MINING. [PaRT III 1 
of deposits that crop out on low ground there is usually a covering of 
Fig. 36. — A detrital or talus-ore deposit. 
detrital ore a few feet thick. In many cases these detrital deposits have 
to be worked in the course of opening up the ore-body in situ. But this 
is not always the case. Thus, in the case shown in figure 30 on 
page 555, there would in all probability be a considerable quantity of 
detrital ore on the scarp slope OF'. Before throwing down this slope the 
waste from uncovering the ore-body in situ, all the detrital ore should be 
worked over. This is not a counsel of perfection ; for it often happens 
that considerable quantities of good merchantable ore may be quickly 
won at a small cost from the detrital deposits ; and the income derived 
from such may be a great help to the hard-pressed manager by allowing 
him to give his company an immediate output of ore, and leaving him 
some time to open up the deposit in situ in a rational way. It is also 
worth noticing that some in situ deposits, namely those formed at the 
surface, show a progressive deterioration with depth, the best ore being 
that immediately at the surface. From this it follows that in many cases 
the ore found in the detrital deposits, having been formed by the denu- 
dation of the uppermost portions of the ore-body in situ, must be of a 
better quality than that found in the latter. Even in working over 
detrital deposits, in which the ore fragments occur in variable abundance, 
and usually in a matrix of clayey, loamy or gritty soil, it is well to employ 
some system. I had the difference well illustrated at the deposits 
situated near Shiddarhalli, in the Shimoga district. In both cases I am 
referring to detrital deposits consisting of loose fragments of ore scattered 
through a clayey or loamy soil to depths up to 10 feet or a little more, 
and lying on comparatively level ground at the base of hills from which 
the ore had probably been derived. In the one case the deposits — those 
situated in the Kadur district, Hadikere village limits, just over the 
Shimoga boundary, and east of Shiddarhalli — had been worked anyhow. 
Pits had been dug here and there and the waste from the extraction 
