The Lower Cretaceous Gulf Coast (Tethyan)--Western Interior transition--Microfossil evidence from northeastern New Mexico and adjacent states
— Kenneth K. Kietzke

The Glenciam Formation of northeastern New Mexico, southeastern Colorado and the Oklahoma Panhandle contains a Lower Cretaceous (Albian) foraminiferal fauna transitional between the Tethyan faunas of the Gulf Coast region and the Western Interior faunas of Wyoming and southern Canada. The fauna consists of 28 species of Foraminifera and three species of Ostracoda. The foraminiferal fauna is dominated by arenaceous species with distinct affinities with those of the Kiowa Shale of Kansas. Comparison of the Glencaim and Kiowa foraminiferal faunas indicates a greater Western Interior influence on the Glencairn fauna and a greater Tethyan influence on the Kiowa fauna. This suggests greater southern penetration of the Western Interior foraminiferal fauna along the western margin of the Interior basin and a greater northern penetration of the Tethyan fauna along the eastern Interior-basin margin, possibly a result of deflection of currents by the Mesa Rica delta and the associated Bravo dome. This study further suggests the southern Western Interior foraminiferal  fauna was populated by opportunistic ("facies") species found in the Tethys region during earlier, Walnut and
Kiamichi time.