Map of tJie Durham Salt- District, 1888. 



2, Magnesian Limestone. /5. Eed and white Sandstone, with Red Marl, Eock-salt, and Gypsum; 

 /o. Eed and green marls with G-ypsum. gf. Black Shales (Ehaetic). ^1. Dark Shales and 

 Limestones (Lower Lias). O Salt-wells and trial-borings. 



J Alluyium. 



I'-'-'.S.-^-.vi^ Blown sand. Iliiii'/^: 



Tidal flats. 



