LATE EARLY SINEMURIAN (EARLY JURASSIC) AMMONITES FROM THE TASEKO LAKES MAP AREA, BRITISH COLUMBIA

Abstract:  Abundant and well-preserved Early Jurassic ammonite assemblages occur in the Taseko Lakes map area on the Cadwallader Terrane in the southern Coast Mountains of British Columbia. The ammonite assemblage described herein includes nine genera and 14 species, most of them already known from classical localities of northern and southern Europe. The presence in particular of Caenisites brooki (Sowerby) and C. turneri (Sowerby) permits high-resolution correlation with the Turneri Zone of the north-west European Sinemurian zonation. The specimens were collected at four localities but most come from an olistolith where the ammonite assemblage is dominated by Coroniceras ( Paracoroniceras ) mutabile Macchioni, Smith and Tipper, associated with Lytotropites fucinii (Bonarelli) and Hypasteroceras montii (De Stefani). The latter two species, whose exact age is here established for the first time, have a Mediterranean distribution.