632 
MANGANfiSE DEPOSITS OF INDIA : DESCEIPTIVE. [pART IV : 
mark for some hundred yards along the beach. The pisolites have prob- 
ably been washed up to their present position by the tide, for they also 
occur in situ in the blue clay of which the shore is here composed and can 
be seen projecting in bimches from the clay all the way between the 
high. and low-water marks. In this blue clay there are bits of the roots 
and twigs of plants, as well as small concretionary tubes. The way in 
which the concretions of manganese-ore have been formed is not known, 
but is a point of great interest and worth determination. The pisolites 
from this locality are all very much of one size, namely about 0 2 
inch in diameter. Mr. Munro tells me that such small bodies also occur 
in great num1>ers scattered on the surface of the ground near the 
Mudpoint telegraph station. Here, however, they are much smaller than 
at the Silver Tree G.T.S., averaging about s ^^^^ diameter. 
