This geophysical survey has been carried out by British Geological Survey (BGS) for BGS, the survey took place in June 1974 in Plymouth Bay area, western English Channel on board the MV Briarthorn. The purpose was to collect data as part of UK regional mapping programme. The main objectives were the completion of gravity coverage between MOD surveys to the south and the coast of Plymouth Bay. Acquisition of sparker data along deep seismic lines. Completion of routine sparker coverage over the IGS 1:250000 Lands End sheet, and the eastern part of the IGS 1:250000 Lizard sheet. Sub-bottom profiling data were collected using Sparker. Seabed data were collected using Transit sonar. Gravity and Magnetometer data were recorded. Navigation: Decca Main Chain. These data are archived by BGS. Technical details of the survey are contained in BGS report WB/MG/81/114.