Strangford River from an accurate survey by George Johnson of Portaferry, pilot, 1755.

Single sheet, engraving, backed with contemporary wall-paper. Scale [circa 1:17,000 (bar)]. The bar scale is in English miles. This is an ungraduated chart marking rocks and soundings and contains a key to conventions and sailing directions. Prominent buildings are shown in view. The title cartouche is decorated with Neptune supporting a scallop shell.

The Samuel Johnson whose name appears prominently commending the chart is not the leading writer of the age (who died 1784) but the chart-maker's brother.