Chapter VIII.— Economic Geology. 



It is not in an accumulation of sandstones^ shales^ and limestone 

 like the Vindhyans that one would expect to find much metallic wealth, 

 and as yet none such has been discovered. Their mineral resources, with 

 one remarkable exception, — the diamond mines of Punna, — are chiefly 

 -confined to building stones and limestones. 



Wlien describing the Rewah group, the characters and position of 



the diamond-bearing layer were pointed out. Mr. 

 Diamonds. . 



H. B. Medlicott also, m his report on the Vindhy- 



ans of Bundelkund, had previously discussed the geological aspect of 



the question.* The economic geology of the diamond deposits has been 



already so fully treated of by Franklinf and Jaquemont,J who give 



ample details of the mode of working and extraction of the gems, the 



various kinds of diamonds found, the value of the mines, &c., that it 



would be useless to enter into the subject again. Giving, therefore, 



references to where the above information may be found, we shall pass 



on to the humbler, but far more important, resources of the formation. 



The Hmestones consist of the lower Vindhyan and the Bundair. Of 



the former, it is chiefly the Rotasgurh limestone 

 Limestones. . 



that IS worked, not from any superiority over those 



lower in the series, but from the circumstances of its topographical posi- 

 tion. It is largely quarried and burned in the neighbourhood of Eotas- 

 gurh itself, and supplies the surrounding districts extensively, being 

 brought down the Sone in boats, and thence up and down the Ganges. 

 The most northerly outcrops are at present (1869) quarried under Euro- 

 pean superintendence for the Sone canal works at Dehree. 



Attempts have been made to utilize this limestone for litho- 

 graphy, specimens having been sent to Calcutta by Lieutenant Sherwill 



* Memoirs, Vol. II, p. 65. 



t Asiatic Researclies, Vol. XVIII, p. 100. 



J Voyage dans I'lnde, Tome I, p. 399. The mines have also been described by 

 Dr. Adam, Jour. Asiatic Society, Bengal, Vol. XI, p. 399, and by Dr. Hamilton, Edinburgh 

 Philosophical Joiu'nal, Vol. I, p. 49. 



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