This volume covers Leg 41 of the cruises of the Drilling Vessel Glomar Challenger. The forty-first cruise of Glomar Challenger was devoted to the study of the eastern part of the central North Atlantic. The ship left Abidjan on 17 February 1975 and docked at Malaga on 10 April, after having drilled five sites off West Africa. The general objective of this cruise was to study the evolution of the eastern basins of the North Atlantic, off the continental margin of West Africa. Previous cruises did not provide material pertinent to the earliest evolution of the basins because most drill sites were located too far from the margin on relatively young crust, or failed to sample the lowermost part of the sedimentary section. A different approach was considered for Leg 41 because the available data already showed that most litho-stratigraphic units in the deep basins of the Atlantic had enough lateral extension so that drilling a limited number of sites in key areas would allow for large-scale regional interpretation. For this reason, only five first priority sites were selected by the JOIDES Atlantic Advisory Panel to be cored as continuously as possible. It was believed that with carefully chosen drill site locations and extensive sampling, Leg 41 results could be combined with those of previous cruises, both in the eastern and western basins in order to view the evolution of the eastern North Atlantic within the general evolution of the North Atlantic Ocean.