The origin of the stress that initiated the deformation of the salt anticlines of the Paradox basin has been attributed by previous investigators either to compressional folding or to deep-seated faulting. There is little independent evidence to indicate that either type of deformation was active at the right time and place.

In this paper evidence is presented to support the idea that the salt anticlines were initiated by the differential loading of the salt-bearing Pennsylvanian Hermosa formation by the Permian Cutler formation. The supporting evidence includes the following items: (1) the necessary stress was available; (2) many of the individual features of the anticlines are in agreement with theory and experiments based on a differential loading hypothesis; (3) the time of origin of the anticlines is as predicted by the differential loading hypothesis; and (4) the anticlines probably formed in sequence from northeast to southwest as required under a differential loading hypothesis.