Ordnance Survey 1:50,000 first series [cartographic material].

Relief shown by contours, hachures, and spot heights.; Grid squares are 1 km. on a side.; Includes index map and index to adjoining sheets.; An interim issue of 153 sheets (out of 204 to cover Great Britain), based on photographically enlarged one-inch Seventh Series material prior to the appearance of the 1:50,000 Second Series. The 153 sheets produced were 5-7, 21, 26-30, 37, 38, 42, 45-63, 67-71, 74-78, 81-84, 89-92, 95-98, 102-114, 116-175, 178-204.; Some reprints after 1980 may bear additional title 'Landranger Series'.; All sheets also issued as military series M726.; Some sheets also issued as military series GSGS 5215 'Power line and obstruction overprint', GSGS 5235 'RAF topographic Decca chart' and GSGS 5256 'Topographic Dectrac chart'.; See R. Hellyer, 1999, 'Ordnance survey small-scale maps: indexes 1801-1998', Kerry : David Archer, entry 21A, p. 65.First serie