In 1937, Wordie organised an expedition to North West Greenland to investigate cosmic radiation at high latitudes and great altitudes. He assembled a team of ten men, nine of whom were from Cambridge University, among them Lethbridge and two other archaeologists. Setting sail in June 1937, Lethbridge undertook excavations of Eskimo sites at Rhyder Island, Cary Island, North West Island, and Isbjörn Island. On returning home in October 1937, it was decided that various geographical features encountered would be named after team members, and thus two lakes on Baffin Island were named the Lethbridge Lakes. During the trip, Lethbridge became particularly interested in the design of Eskimo boats, resulting in the self-publication of his 11-page booklet, "Umiak – the European Ancestry of the 'Women's Boat'", in 1937. He followed this with a second book, "The Fishermen of Durness" (1938), in which he argued that a study of contemporary traditional fishing communities could inform archaeologists more about ancient boat-making and fishing.