The Occurrence and Distribution of Diamonds in India. 577 
describing the formations of the Central Provinces of India, 
merely say that the matrix of the diamonds is a lateritic grit the 
only rock in its vicinity being quartzose and metamorphic. 
Hence they argue that Malcolmson,* and after him Newbold were 
wrong in inferring the identity of the sandstones of Central, with 
that of Southern India from the supposed occurrence of the 
diamond in the former,and they enlarge upon the supposed fact that 
most of the diamond-bearing deposits though resting on rocks of 
various ages are merely superficial and recent, and that therefore 
the diamond does not afford a safe guide for correlating the older 
rocks. 
The whole discussion shows misconceptions on both sides 
which our present knowledge enables us perhaps to clear up. It 
is quite true that the sandstones of the Central Provinces which 
are referred to are not of the same age as the sandstones of 
Southern India which accompany the diamond-bearing strata, 
they are in fact very much younger, and Messrs. Hislop and 
Hunter were no doubt correct in asserting that the diamonds of 
the lateritic gravel had not been derived from them. But the 
mention of the quartzose metamorphic rock confirms what is 
independently probable, namely that the great basin of lower 
Vindhyan or Karnul rocks which occupies the upper portion of 
the Mahanadi valley stretches into the neighbourhood of 
Weiragurh, and it may therefore be suggested with a considerable 
degree of probability that the ultimate derivation of these 
diamonds is from a stratum occupying a horizon identical with 
that which constitutes the matrix of the Sambalpur diamonds, 
and as that in a general way has already been correlated with 
the diamond horizon in the Karnul rocks, the theories of both 
sets of observers contained hypotheses partly correct and partly 
erroneous the correct portions respectively supplementing one 
another. Malcolmson and Newbold were right in supposing that 
the diamonds of Weiragurh indicated the existence of rocks of 
the same age as those of Southern India (the Karnul formation), 
but were wrong in supposing that the fossiliferous sandstones 
which they referred to included the source of the gems. On the 
other hand Messrs. Hislop and Hunter while pointing out the 
* Bombay Branch Royal Asiatic Society’s Journal, Vol. i., p. 520. 
