Back to matchesWe found a matchYour institution may have access to this item. Find your institution then sign in to continue.TitleAn Apparent 20 Map-Unit Position Effect.AuthorsGIBSON, J. B.; THODAY, J. M.PublicationNature, 1962, Vol 196, Issue 4855, p661ISSN0028-0836Publication typeArticleDOI10.1038/196661a0