Relief of the Precambrian surface in the Salt Valley-Cisco area, Utah and Colorado, is on the order of 19,000 feet between the crest of the Uncompahgre uplift in Colorado and the adjoining Paradox salt basin in Utah. Steep gravity and magnetic gradients just southwest of Cisco, Utah, indicate that the buried structural front of the ancestral Uncompahgre uplift has a relief of about 12,000 feet in a relatively narrow zone. Magnetic and gravity data further indicate that a buried ridge or salient of comparatively strongly magnetic Precambrian rocks extends southwesterly and westerly from the main structural front of the ancestral uplift, past Yellow Cat dome, nearly to Salt Valley. Northwest and west of the postulated salient the basement rocks are comparatively deeply buri d and weakly magnetized, according to drilling and to magnetic and gravity evidence.

Analysis of a 26-milligal gravity low over Salt Valley anticline indicates that the vertical extent of the salt core is about 8,000 feet. A gravity low of 10 milligals over Tenmile graben is related to a small, deeply buried salt anticline that is probably a northwestward extension of the Moab salt anticline.