Apparent offsets of various Paleozoic sedimentary facies belts and the frontal margins of two allochthons in northeastern Nevada and northwestern Utah have been explained by Stewart and Poole by 120 km of oroflexural bending, and by Thorman and Ketner as the result of displacement of about 65 km on a presumed Mesozoic, right-slip fault (Wells fault). Evaluation of stratigraphic data in this region, however, indicates large differences in the amount of offset of sedimentary facies of different ages, a pattern not easily explained by postdepositional tectonism. An alternative interpretation is that original depositional trends were influenced by a major, east-trending flaw in the crust, perhaps a bight in the continental margin, along which vertical movement occurred several times during Paleozoic time. The apparent offset of the frontal margins of allochthons composed of eugeoclinal rock is considered compatible with this interpretation.

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