BGS has drilled almost 600 boreholes to prove seismic interpretations of the marine Quaternary geology and bedrock from the UK Continental Shelf (UKCS). The collection also includes additional third party data and has assisted in the creation of BGS Marine Geology Maps. The boreholes penetrate beneath the sea bed to depths ranging from about 10m to over 300m depending on the target depth or technical problems associated with drilling the borehole. The data includes descriptive geological core logs and data which has been captured from these and in some cases natural gamma logs. A variety of analyses has been conducted on the core material such as Particle Size Analysis, micropalaeontological, geotechnical, palaeomagnetic and age dating. Core material are managed as part of the BGS Materials collection and are available for examination and subsampling. The data are stored as part of the National Geoscience Data Centre (NGDC) and the Marine Environmental Data and Information Network (MEDIN) Data Archive Centre (DAC) for Geology and Geophysics. Data are delivered via the BGS Offshore GeoIndex http://www.bgs.ac.uk/GeoIndex/offshore.htm. The activity and scan layers contains location information, metadata and links to scanned borehole logs, and the geological data layers contain observations and/or measurements as digital values. The data are applicable to a wide range of uses including environmental, geotechnical and geological studies. Reference: Fannin, NGT. (1989) Offshore Investigations 1966-87 British Geological Survey Technical Report WB/89/02, British Geological Survey.