Fortey, Richard A. Lower Ordovician trilobites of the Kirtonryggen Formation, Spitsbergen / by Richard A. Fortey, David L. Bruton. - 1 online resource (120 pages) : illustrations. - Fossils and Strata ; Number 59 . - Fossils and strata ; no. 59. . Includes bibliographical references. ISBN: 9781118850633 Subjects--Topical Terms: Paleontology--Ordovician. Index Terms--Genre/Form: Electronic books. LC Class. No.: QE726.2 / .F678 2013 Dewey Class. No.: 560.1731