This marine geophysical survey undertaken by Institute of Geological Sciences (BGS) took place in August 1972 in the Moray Firth and Sea of the Hebrides on board the M.V. Researcher. The survey was carried out as part of a regional mapping programme. Data were gathered for Project:72/5 using the following equipment Loch Ness: MS32 Echo-sounder, Fresh water sparker. Moray Firth: La Coste Gravimeter, 1000J Sparker, MS32 Echo-sounder. Sea of Hebrides: La Coste Gravimeter, Barringer Magnetometer, 2500J Sparker, MS47 Transit Sonar, Edo Western PDR. Blackstones Bank: Refraction, MS32 Echo-sounder. These data are archived by BGS. Technical details of the survey are contained in BGS Internal Report WB/ MG/72/35.