MEMOIRS 



OP THE 



GEOLOGICAL SURVEY OF INDIA 



The Trans-Indus Salt Region in the Rohat District, by A. B. 

 Wynne, Geological Survey of India: With an Appendix on the 



KOHAT MINES OR QUARRIES, by H. WaRTH, Ph.D. 



INTRODUCTION. 



At the desire of Government, and under direct orders from the 

 Superintendent of the Geological Survey of India, the Trans-Indus Salt 

 Region was visited, and the country mapped during the working season 

 1873-74. 



It had been represented that the map available was hardly adequate 

 for the purpose of a detailed geological survey, but as no prospect 

 appeared of obtaining one more suitable, shift had to be made with a 

 MS. skeleton copy of part of the northern Trans-Indus Frontier Survey 

 (dated 1852-53) by Lieutenant (now Colonel) J. T. Walker, Bombay Royal 

 Engineers, published on the scale of two miles to an inch. A geologically 

 coloured copy of the part used is appended. 



Large portions of the original map are professedly unsurveyed, and 

 its precision was not found sufficient to enable points to be closely fixed 

 by prismatic compass bearings ; for general marching purposes it answered 

 admirably, and some of the larger stratigraphical features even were 

 recognisable upon it, but the hill ranges are roughly shown, and the scale 

 is far too small to admit of minute delineation of the geological boun- 

 daries, where these are complex. Indeed generally the structure of the 



( 105 ) 



Memoirs, Geologicnl Survey of India, Vol. XT, Art. 2. 



