“…Specifically, the western margin of the Western Interior Seaway underwent significant shifts in coastal morphology and coupled with on-going tectonism resulted in numerous unconformities, lateral discontinuities, and cryptic or tenuous stratigraphic linkages ( Molenaar, 1983a ; Molenaar et al, 2002 ; Haq, 2014 ; Albright & Titus, 2016 ; D’Emic et al, 2019 ). Although a number of studies have sought to resolve these complexities by obtaining depositional ages via radiometric age dating, the “mid-Cretaceous” southwestern shoreline (New Mexico) of the Western Interior Seaway has largely gone underexplored ( Lawton & Bradford, 2011 ; Meyers et al, 2012 ; Roberts et al, 2013 ; Barclay et al, 2015 ; Juárez-Arriaga et al, 2019 ; Lawton, 2019 ; Laurin et al, 2019 ; Pană, Poulton & DuFrane, 2019 ; Rinke-Hardekopf, Dashtgard & MacEachern, 2019 ). Adjacent basins offer little aid as lithostratigraphic relationships become increasingly cryptic ( Albright & Titus, 2016 ; D’Emic et al, 2019 ; Tucker et al, 2020 ).…”