Reports, images, GIS and gridded products describing the Palaeozoic geology and conventional petroleum systems of parts of the UK offshore from the greater Irish Sea area. Carboniferous rocks were the focus in areas from the Firth of Clyde, Solway Basin, Manx-Peel Basin to the East Irish Sea Basin and surrounding areas (Quadrants 110-126). The peer-reviewed products were produced for the 21CXRM Palaeozoic Project by BGS for DECC/OGA, Oil and Gas UK and oil company sponsors between November 2014 and May 2016, to improve regional digital datasets and knowledge of the underexplored Palaeozoic petroleum systems, and to stimulate exploration. The petroleum systems analysis was based on new interpretations of well, seismic, gravity-magnetic and source rock datasets, integrated with petrophysical studies, basin modelling and UK onshore knowledge. Released data were collated and interpreted, and interpretations of unreleased data were included with agreement of the data owners. Unreleased raw data is excluded. The datasets are applicable for use at scales between 1: 750,000 to 1: 3,000,000.