This map was engraved and published by Thomas Jefferys. There are three states all published in rapid succession in the same year this being the second state with the imprint of John Chapman (fl.1770-77). Little is known of him beyond his known work. An Explanation upper right helps to identify the Market Towns, Parishes, Churches, Seats, Farms or Cottages, Parks, Turnpike Roads, ‘Inclosed’ partial and open roads and Roman points of interest. Also indicated are Coal Pits and Lead Mines along with natural features such as Hills, Woods and Parks etc. A fine plan of the town of Durham appears lower left accompanied by a compass rose and encapsulated by an ornate border. A nearby note records the fact that the latitude figures used were taken by Professor Hornsby in 1765. The longitude was deduced from the solar eclipse of 1766 and compared with those made at London, Sherborn and Oxford. The map is dedicated to Henry Earl of Darlington, the Lord Lieutenant of the county. The title appears in an ornate cartouche upper left with a mining scene. To its right is a model of the Bases and Triangles used to triangulate the county. All issues are rare. Provenance: acquired in The Netherlands 2006 for a private English collection. Harley, Brian ‘The Re-Mapping of England, 1750-1800’ in ‘Imago Mundi’ 19 pp. 56 & 63; Rodger (1972) 100; Worms & Baynton-Williams (2011).