Polar-opposite interpretations have been proposed for why the Newark basin ends towards the NE in Rockland Co., NY. According to the isolated-basin (or "shelving-basin") viewpoint, the basin ends because the NE-striking strata lap out against a paleogeomorphologic bedrock high underlain by a pre-Newark basement complex. In this view, the curving Palisades ridge becomes a dike that cuts across most of the strata to connect with the nearly horizontal Ladentown extrusives high in the Newark succession.

According to the transverse-fold interpretation, the pre-Newark basement has been postdepositionally elevated along the Danbury anticline that is transverse to and ends on the NW against the basin-marginal Ramapo fault. In this view, the curving Palisades ridge is a folded sill; both it and the strata change strike from NE-SW to NW-SE and the regional dips change from NW to SW. The nearly horizontal Ladentown extrusives are inferred to occupy a block separated by a fault from the NW-striking, SW-dipping strata on the SW limb of the Danbury anticline.