England and Wales: a palaeogeological map of the Lower Palaeozoic floor below the cover of Upper Devonian, Carboniferous and later formations ... /
Wills, Leonard Johnston.
London : Geological Society,
1975.
Accompanies: "A palaeogeological map of the Lower Palaeozoic floor below the cover of Upper Devonian, Carboniferous and later formations" (Memoir Geological Society of London, No. 8)