INDO-GANGETIC TRACT OF MOUNTAINS. 221 



10. In the first volume of the new series of the Geological Transac- 

 tions, a specimen of gypsum, as also of anhydrite, * is enumerated as 

 amongst those presented to the Society by Mr. Colebrooke, in the name 

 of Captain, then Lieut. Gerard. I have also heard of a specimen in 

 a Calcutta collection, which had been presented by Dr. Go van. I am not 

 aware of the locality of the latter ; the former was found somewhere in the 

 bed of the Sjnti river, on the confines of Laddky and at no great distance, 

 from a primary formation. No particulars are, however, given of the mode 

 )f its occurrence. These are the only instances of gypsum being found 

 in these mountains, that I know of, besides those detailed in the present 

 paper. Who was the first discoverer of the Dehra gypsum, I cannot say. 

 [ have been told that the substance had been familiar to the residents in 

 the Dun, who confounded it with white marble, and that Captain Grant, 

 of Sahdrunpiir, was the first to suggest its real nature. 



11. Gypsum is used as a material for statues, vases, columns, and 

 similar works of art. The purer and more crystalline varieties, are even 

 used for ornaments. When the water which it contains, and which 

 amounts to twenty-two per cent, is driven off by burning, it forms the 

 plaister of Paris, or material for stucco work, and for casts. It is also 

 used (unburned) as a dressing for land, extensively, I believe, in America. 

 The quality of the mountain gypsum is such as to fit it for all these 

 purposes, except the second ; but the quantity which has, as yet, been 

 discovered, is not, perhaps, sufficient to render it an object of much atten- 

 tion. A careful search might be successful in laying open greater stores, 



though, 



* I have in my possession a rolled piece of Anhydrite, presented to me by G. W. Traill, Esq^ 

 Commissioner; but I have mislaid the particulars of his note : it was, however, from the neighbour- 

 hood of the Snowy Peaks. 



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