The final phase of Permian continental margin tectonism in east-central California produced a widespread unconformity that separates Lower Permian strata from Upper Permian to Lower and Middle(?) Triassic strata. This unconformity has a maximum angular discordance of about 25° and locally truncates at least 1 km of Lower Permian strata. Leonardian and (or) early Guadalupian deformation that resulted in development of this unconformity may have been coeval with early phases of the Sonoma orogeny in Nevada and with Permian tectonism in the western Mojave Desert of California, but the tectonic relations among these events are uncertain. Permian deformation in east-central California took place along a southeast-trending segment of the continental margin that may have been bounded by an active sinistral transform fault zone.