diamonds
are sometimes found in these pebbles when broken up, it would seem that
the latter must include an earlier if not the original matrix of the
gem. This point is of great interest, since it brings us to a horizon,
the base of the formation, which is strictly comparable with that of
the Banaganpilly group, which includes the lowest known matrix in
Southern India. The order of succession of the rocks in the
Mahanadi-Godaveri tract has not yet been ascertained; but from the fact
of the only known localities where the diamond occurs being situated on
the margin of the area, it may with a considerable degree of
probability be assumed (notwithstanding possibly faulted boundaries)
that the matrix is in a bed close to the base of the formation.
With
regard to the minor areas, the Bhadrachelum diamonds may perhaps have
been derived from some of the Karnul or Vindhyan rocks in the
neighbourhood of the Godaveri.
The
geology of the Chutia Nagpur localities is not yet known, but it is
probable that in their vicinity an outlier of the Mahanadi-Godaveri
rocks may exist
The Simla diamonds, if the find be authentic, are of considerable interest, for although, as has been shown, diamonds per se do
not afford evidence sufÂficient for exact correlation, still when it is
remembered that according to some authorities the older Palaeozoic
rocks of the Himalayas present many points of resemÂblance with those
of the Peninsula, the possibility of the matrix containing these
diamonds being on a horizon comparable to that in the Banaganpilly
group of the Karnul (L. Silurian ?) formation cannot fail to suggest
itself.
As particulars regarding the exact locale whence the
