Ammonoid faunas from the Cardium Formation (Turonian-Coniacian; Upper Cretaceous) and contiguous units, Alberta, Canada: II. Collignoniceratidae and Placenticeratidae

Ammonite species of the genera Prionocyclus, Subprionocyclus, and Collignon iceras described here from the Cardium Formation, in combination with scaph itid ammonoids and inoceramid bivalves, allow recognition of all biozones f or the Turonian Stage (Upper Cretaceous) established farther south in the U nited States Western Interior Basin. Although many of the species used in t his zonation were endemic to the Western Interior seaway, more cosmopolitan forms at some levels do allow correlation with western European sequences. The presence of Prionocyclus germari Reuss is firmly established in the lo wer parts of the Leyland Member, confirming the position of the Turonian-Co niacian boundary and earlier proposed constraints on the duration of the Ca rdinal-Leyland hiatus.