1856.] Proceedings of the Asiatic Society. 249 



Central India, sending a table of heights and distances along the 

 Railway line from Surat to Agra. 



From Col. Hannay through Mr. Grote, announcing the discovery 

 of a rich vein of iron ore at Dhubri. 



The Secretary read extracts from the letter. 



From Mr. Piddington, submitting a paper entitled, " A second 

 series of experiments to ascertain the mean quantity of silt held in 

 suspension by the water of Hooghly in various months of the year, 

 and also the quantity carried out to sea," as also "Notes of an 

 examination of three specimens of Bengal mineral waters." 

 The Librarian submitted his usual monthly report. 

 Mr. Oldham, at the request of the President, proceeded to give 

 some account of the results he had arrived at from the investigations 

 conducted by himself and his assistants in the Geological Survey in 

 Central India during the past season. 



Briefly referring to the many valuable papers which had been 

 contributed by previous observers illustrative of the Geology of 

 Central India, and to the fact that few parts of the immense empire 

 of India had excited more interest and attention than the districts 

 adjoining the Nerbudda river, Mr. Oldham pointed out that the 

 great thickness of sandstones and associated beds, which formed the 

 mass of the Vindhya range, was the most striking and remarkable 

 feature in that country. This had been spoken of as " the sand- 

 stone," "the great sandstone, &c." Capt. Franklin had referred it 

 to the age of the middle portion of the new red sandstone of Euro- 

 pean geologists. Jacquemont, for the greater part at least of the 

 area, assented to this view. Other observers had given it a different 

 position. Captain Sherwill for instance had mapped it as Old Eed 

 sandstone, although giving it the somewhat anomalous position of 

 resting upon " mountain limestone." In 1854, Dr. Carter of Bombay 

 had published a carefully compiled summary of the Geology of India, 

 in which the whole of this sandstone and associated beds was referred 

 to the same age as the coal bearing rocks of Bengal, all which he 

 classed with the Oolitic or Jurassic epoch of European geologists, 

 and he took his typical groups, and the names for his subdivisions 

 from localities in this district. He divided the whole into three 

 aub-groups, which he called — Tara, Kuttra and Punnah groups, in 



