ABSTRACT
Mesozoic brachiopods from the Western Cordillera of North America are reviewed for the Late Triassic, Early Jurassic and Cretaceous. Analysis of the brachiopod faunas reveals endemic East Pacific forms, Boreal elements, widespread low-to mid-latitude forms, low-latitude Tethyan elements, and latitude-independent forms controlled by ecology (chemosynthetic environments). The Late Triassic brachiopod faunas provide the strongest evidence for origination in and movement from lower latitudes for some terranes, such as the Chulitna and Alexander terranes. Higher latitude cratonal rocks of the Triassic contain a Boreal component, the terebratellid Aulacothyroides. The Triassic (Spondylospira) and possibly Jurassic (Anarhynchia and Cooperrhynchia) contain East Pacific genera, although the possible chemosynthetic association of the Jurassic genera could mean there is no real palaeolatitudinal or palaeolongitudinal control on their occurrence. There are no discrete East Pacific North American genera in the Cretaceous, probably reflecting a high degree of connectivity with other faunas from elsewhere via the expanding Atlantic Ocean.
