A series of technical palaeontological and biostratigraphical reports produced in the London, Leeds, Edinburgh and Keyworth offices of BGS between 1953 and March 2000. The reports provide information on fossils collected during Geological Survey mapping or supplied by clients. Fossils are collected in order to date (relative age) the rocks in which they occur and/or to provide evidence for the conditions of deposition, so the information contained in each report usually includes determinations of the fossils present in a collection and an interpretation of their stratigraphical and/or their palaeoenvironmental/palaeogeographical significance.Individual reports vary enormously in scope, depending on the reasons for the investigation. Some reports may be site specific, documenting the fossil fauna/flora from a particular locality or borehole, whereas others may deal with material from a number of localities on a 1:10 000, 1:25 000 or 1:50 000 sheet, or from several boreholes. Other reports may be in the form of reviews. Geographical coverage is wide, covering the UK and Northern Ireland onshore, UK offshore and overseas localities.All reports are held as hardcopy only. Each report bears a unique identifying number in the form SS/YY/NN, where 'SS' identifies the series, 'YY' identifies the year in which it was written and 'NN' is a serial number. Reports were numbered sequentially, regardless of whether they dealt with material from the UK and Northern Ireland onshore, UK offshore, or overseas, and a sequential set is held by BGS. Reports are also filed by 1:50 000 sheet, (UK onshore), offshore quadrant and foreign country, as appropriate.