http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Rev. from survey made by B.K.S. Air Survey Ltd. 1963.
Printed and published by the Director General of the Ordnance Survey.
Relief shown by contours, gradient tints, hachures, spot heights, and land form drawings. Depths shown by contours.
Scale 1:21,120. Or 3 in. to 1 statute mile ;