Early Campanian ammonites and other molluscs from the Point Lookout Sandstone near Cabezon, Sandoval County, New Mexico

Abstract

P. syrtale also occurs in the Dalton Sandstone in the Cabezon area. It has also been reported from the upper part of the Mancos Shale in the upper Rio Grande Valley and along the western side of the Sierra Nacimiento, including the Satan Tongue of the Mancos Shale near La Ventana. P. syrtale has been reported to range from the lower Santonian to the lower Campanian. The Baculites specimens collected from the Point Lookout Sandstone near Cabezon are closest to variants of Baculites aquilaensis in their prominent arcuate nodes on the outer flanks. B. aquilaensis var. obesus was reported by Reeside from the basal part of the “Mesaverde Formation” east of Cuba, New Mexico. Scaphites leei III has also been reported from near the base of the “Mesaverde Formation” east of Cuba and from the Hagan coal field. This would correspond to the base of the Point Lookout Sandstone. S. leei III has also been reported from the upper part of the Mancos Shale on the eastern side of the San Juan Basin and from the Ortiz Mountains. S. leei III is the lowest Campanian Zone taxon. This indicates an earliest Campanian age for the Point Lookout Sandstone near Cabezon.