In the period 1742 to 1749, the British renewed their search for a northwest passage. Part of this involved exploring the « East Main » – the eastern shore of Hudson and James Bays. Four exploration routes are shown: Middleton (1742), Mitchell and Longland (1744), Moor and Smith (1747) and Coats (1749). The map also shows the extent of territory known to Europeans and the navigation of all exploration routes in the period 1651 to 1760. The historical names found on the map are derived from contemporaneous maps and written documents of the period.