THE DIAMOND MINES OF INDIA 169
some
scientists believe is much more extensive than it is generally thought
to be. Many years ago it was worked near Wairagahr on the banks of the
Wainganga river, in the Chanda district southeast of Nagpur. These
mines were called Beiragahr by Tavernier. They are said to have been
rich, but have been abandoned for nearly a century.
Following
a direct line north from Wairagahr, at a distance about the same as
that between Wairagahr and Kollur, and from Kollur to Madras, the Panna
or Punna mines of the Bundelkhand are reached. These lie between the
tributaries of the Jumna and Sone rivers, which are tributaries of the
sacred Ganges river. This group of mines is about 250 miles due north
of Madras. The mines form two spurs from the neighborhood of Panna on
the Khan river; one extending due east to Rewah, and the other in a
northeasterly direction to the Jumna river a few miles west of
Allahabad.
The
diamonds occur in the Rewah strata of the upper Vindyan formation. The
diamondiferous stratum lies at varying depths down to twenty or
twenty-five feet. It is not thick, sometimes only a few inches, but
extends over a considerable area. In some parts of the district it is
found on the surface as a weathered or alluvial deposit. Near Panna it
is extremely difficult to work, as it is overlaid by a thick stratum of
clay containing fragments of sandstone and other pebbles, with a
quantity of broken, spongy, ferruginous rock called laterite, at the
base. This necessitates the digging of pits to reach the diamonds.
These excavations, fifty feet or more in diameter and thirty or forty
feet deep, make very wet and uncomfortable diggings, as the water
constantly seeps in
