Samples and associated geological data are held at the British Geological Survey for Maritime Coastguard Agency (MCA), Civil Hydrography Programme (CHP), Bathymetric Survey HI1361; Barra Head to Castlebay, Area in SqKm: 135, (01/04/2012 to 01/08/2012), Standard: IHO S44ed5 Order 1a. Contract: Shallow. FY 2011/12. Contractor: EMU.