Medium: Pen and ink on paper
This drawing covers the area surrounding the Blackwater River. Pencil lines radiate from trigonometrical stations: notable fixed locations from which angular measurements were taken. Rays emanating from Iltney near the centre of the map, on the south bank of the river, have been used to plot the relative position of the Chigborough Road on the opposite bank. The marshes around Tollesbury Fleet are indicated by irregular intersecting lines.