room
for doubt as to the source from whence they are derived. Coincident
with their occurrence is that of a group of rocks, which has been shown
to be referable to the Vindhyan series, certain members of which series
are found in the vicinity of all the known diamond-yielding localities
in India, and, in the cases of actual rock-working, are found to
include the matrix of the gems.
In
several of the previous accounts, the belief is either stated or
implied that the diamonds are brought into the Mahanadi by its large
tributary, the Ebe. It would not, of course, help the point I am
endeavouring to establish as to their origin, to say that the Ebe, at
least within our area, except indirectly,* is not fed by waters which
pass over Vindhyan rocks, but I have the positive assurance of the
natives that diamonds have not been found in that river, although gold
is and has been regularly washed for. On the other hand, diamonds have
been found in the bed of the Mahanadi as far west as Chanderpur, and at
other intermediate places well within the area which is exclusively
occupied by the quartzites, shales, and limestones of Vindhyan age.
The
fact that the place, Hira Khund, where the diamonds were washed, is on
metamorphic rocks, may be readily explained by the physical features of
the ground. The rocky nature of the bed there, and the double channel
caused by the island, afforded unusual facilities for, in the first
place, the retention of the diamonds brought down by the river, and
secondly, for the operations by which the bed could on one side
* By a few small streams which rise in an isolated outlying hill, called Gotwaki.
