Sheet 42, Old Series 1". c1850. 1st edition. Brecknockshire / Monmouthshire: Brecknock, Abergavenny, Hay. Hand-coloured
Sheet 42, Old Series 1". c1850. 1st edition. Brecknockshire / Monmouthshire: Brecknock, Abergavenny, Hay, Blaen Afon, Dowlais. Hand-coloured engraving, 73 x 99cm, four quarter sheets dissected, mounted on linen, and folded to 24 x 16.5cm with index map pasted on top outside fold. Topographic date1832 for SW and SE quadrants. Issue date 1865 for NW. No geological dates on SW and SE quadrants. Some dates and legends lost in the joining of the four quarters. Legends for NW and SW sheets. Clear plate marks. Spill stains in left margin extending just into top left corner and more extensive in backing linen. Otherwise, clean, bright colours. In good to very good to condition.
About the England & Wales One Inch Old Series
The Geological Survey of England and Wales used the Old Series of the Ordnance Survey topographic map at a scale of one inch to the mile as its basemap, initially. These engraved basemaps were published and revised between 1805 and 1885; the sheet sizes varied and the layout and numbering system were eccentric. The Old Series geological maps were hand-coloured and without geological sections, which were published separately. The GS of E&W published the Old Series from 1850 to 1900, when it switched to the colour printing and the New Series one inch maps. However, old stock of the Old Series continued to be issued, hand-coloured, until the 1930s.