and
unsound hypotheses have been overturned by work of that kind, which,
especially in a country like India, can only be accomplished by
professionals, whose whole time can be devoted to the subject, and
whose operations are systematized under the leadership of one central
authority.
The
issue of the "Manual of the Geology of India" last year places the work
of the Survey and our present .knowledge of Indian geology in a more
accessible and condensed form than it possessed when scattered through
the now voluminous publications of the Survey. It is to be hoped that
writers of geological text books will in the future refer to it for
their facts rather than to the old sources of information, and that we
shall never again see the " diamond sandstone," so called, classed as
an Indian representative of the European Oolite.
Among
the authorities quoted by Dr. Carter in reference to the
diamond-bearing strata, the following are the principal:—Heyne,
Jacquemont, Franklin, Voysey, and Newbold.
Some
of these, especially Heyne, maintained that the diamond occurred only
in a superficial recent conglomerate, formed of a great variety of
fragments of the surrounding rocks, and resting indiscriminately on old rocks of different ages. Others recognized that in some
cases the matrix of the gem was a conglomerate, which was a member of
the clay slate formation, so called. This " clay slate formation,"
which included sandstones and limestones, and all their varieties now
embraced in the Vindhyan formation, were considered to be the altered
representatives of the Oolite, this being the age assigned to the
coal-measures and associated plant and reptillian fossil-bearing sand-
