The Cliff House Sandstone, the upper sandstone unit of the Mesaverde Group, was named for outcrops in the northwestern part of the San Juan basin near Mesaverde National Park, Colorado. Maps of the southeastern part of the basin reveal that the Cliff House fingers eastward into the marine Lewis Shale. There, a stratigraphically lower sandstone was named the La Ventana Sandstone Member of the Mesaverde Formation. The La Ventana was traced north to near the Colorado border where it merges with the underlying Point Lookout Sandstone. The nomenclature was revised to elevate the Mesaverde Formation to Mesaverde Group and the 3 members to formations. The La Ventana Member of the Mesaverde Formation was changed to the La Ventana Tongue of the Cliff House Sandstone. This change o the La Ventana from a member of the Mesaverde to a tongue of the Cliff House was based on the supposition that even though the sandstones did not merge on the outcrop, they would be found to merge in the subsurface. Preliminary subsurface studies suggest that the La Ventana Tongue and the Cliff House Sandstone do not merge.

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