1 : 21120 This fair plan describes the north bank of the River Thames from Purfleet and West Thurrock, at the bottom, to Upminster, at the top. The manuscript is covered with pencil rays. Radiating from trigonometrical stations, these were used for measuring and plotting topographical features. Field boundaries infilled with stripes depict cultivated land. Marshes and untilled agricultural land are identified by 'open dotting' at the bottom of the map.