2) contain introductory material regarding ge­ Historical Background ology and petroleum exploration techniques Only a few decades ago knowledge of the off­ which we trust will help the non-specialist, in shore geology west of Britain and Ireland was conjunction with some of the more general ref­ limited to a scattering of seabed samples. Dur­ follow the main erences cited in the text, to ing the last twenty five years, however, the parts of the chapters and the text figures. This tempo of geological investigation has gradu­ first chapter also contains a small amount of ally increased. The framework and outline ge­ introductory material concerning the opening ology of the western seaboard is now known, of the North Atlantic Ocean which should help although a great deal, some of it fundamental to lead into the more detailed account which in nature, still remains to be elucidated. Sev­ follows, and also help in the understanding of eral commercial and sub-commercial hydrocar­ some of the points made in later chapters. bon discoveries have been made and are being Credit must go to university departments, produced, . developed or investigated. A sus­ and later the Institute of Geological Sciences, tained phase of exploration drilling is antici­ for their parts in initially establishing the pated in the next five years in the Western existence of, and geological outlines for, the Approaches - Celtic Sea area and to the west offshore basins along the western seaboard of Britain and Ireland.