In the Death Valley and Mojave Desert regions of southeastern California, the contact separating the lower and middle members of the Wood Canyon Formation (WCF) is currently interpreted as a regional-scale unconformity coincident with the base of the Sauk sequence. Regional mapping of this surface, however, reveals a nonconformable contact with underlying crystalline basement in cratonic settings and a relatively conformable contact atop a northwest-thickening wedge of off-craton strata that is capped by the lower member of the WCF. Consistent with an unconformity, the progressive loss of three carbonate units within the lower member of the WCF has been attributed to incision by the base of the middle-member WCF. However, fossil evidence and correlation based on carbon isotope compositions of each lower-member WCF dolostone unit reject top-down erosion to describe their loss and overall cratonward thinning. Results from multiple, detailed, measured stratigraphic sections of a conglomerate at the base of or low in the middle-member WCF also do not support a top-down erosion model because the conglomerate has variable stratigraphic position and is absent in some locations. Middle-member WCF conglomerate clasts also reveal variation in composition and grain size across the regions. Sequence-stratigraphic architecture indicates that filling of available accommodation space via a short-period normal regression coupled with high-order sea level fall generated the basal middle-member WCF unconformity. Consequently, the base of the Sauk sequence occurs lower in the stratigraphic section, most likely at the base of the underlying Stirling quartzite.