The sand and gravel resources of the country around Welwyn Garden City, Hertfordshire description of 1:25000 resource sheet TL11 and TL21
Gozzard, J. R.
Institute of Geological Sciences (Great Britain)
London H.M.S.O.
1981
At head of title: Institute of Geological Sciences
Bibliography: p80
Map (1folded sheet) in pocket
Sand
Gravel