( vi ) 



obviated by the adoption^ in this country^ of the plan which has for 

 years been in use on the Ordnance Survey of Great Britain^ of dividing 

 the larger sheets into four ' quarter-sheets/ Such a plan would render 

 it practicable to give to the public, at reasonable intervals, geological 

 maps of the country represented on each quarter-sheet, without the neces- 

 sity of waiting for the completion of the whole sheet. Each of these 

 quarter-sheets would embrace an area of more than three thousand six 

 hundred square miles ! A reference to the annual reports of the Geolo- 

 gical Survey of India will show, for instance, with regard to the country 

 now referred to, that three ' quarter-sheets ' of this map might have been 

 issued years since. 



No map is given with the present report, as it is supposed to refer 

 to the sheet 79 of the Indian Atlas, geologically coloured, which is now 

 in the engraver^s hands awaiting publication. 



Thomas Oldham. 

 Geological Survey Office, 



April 1864. 



