The Condrey Mountain Schist occupies a window through Late Triassic(?) amphibolite facies mélange of the Western Paleozoic and Triassic Belt in the north central Klamath Mountains. Along the western margin of the window, the schist comprises a sequence of multiply deformed, greenschist facies metavolcanic and fine-grained meta-sedimentary rocks, which are in thrust or high-angle fault contact with graphite-quartz-mica schist exposed in the window interior. Transitional blueschist-greenschist facies parageneses are developed in metabasites, metacherts, and metalliferous metasedimentary rocks in the graphitic schist in the central part of the window. All units record progressive, polyphase, deformational and metamorphic histories. The earliest stages of deformation in the blueschists generated isoclinal intrafolial folds (F 1 ), a layer-parallel transposition foliation, and a strong crossite lineation. The foliation is folded by two later sets of coaxial, isoclinal to tight folds (F 2 and F 3 ) that produce kilometer-scale, N-S trending, recumbent folds in the central part of the window. The same deformational sequence is recorded in the graphitic schist by continued regeneration of the transposition foliation through at least the second set of folds, and tight to isoclinal folding of the resulting surfaces. Both lithologies have been further deformed by extension parallel to F 3 axes (boudinage and fracturing) and a late folding (F 4 ) that produced kink bands, box folds, and chevron folds with E-W trending axes. Fold styles and asymmetries suggest that the early stages of progressive deformation (F 1 folding, transposition) resulted from noncoaxial deformation. Shear strains diminish during F 2 and F 3 folding and are replaced by irrotational flattening strains by the time of boudinage. The mineral assemblages formed prior to F 2 folding indicate greenschist-blueschist facies conditions during transposition. F 2 and F 3 folding were accompanied by the growth of deerite that lies in the axial planes of minor folds in meta-ironstones, indicating P-T conditions similar to those existent during transposition. Boudinage is concurrent with and followed by the static growth of chlorite, actinolite, albite, stilpnomelane, spessartine, and the Ba-silicate, cymrite. Ferroglaucophane rims on crossite may also have grown at this time. Pressure and temperature estimates, the relative time framework of deformational events, and the noncoaxial geometry of ductile strain are all consistent with, but not restricted to, a subduction zone environment. High shear strains may reflect descent and burial, whereas flattening and static mineral growth occur during uplift. Regional relationships favor an interpretation that relates metamorphism and ductile deformation to a Middle Jurassic subduction event, but do not preclude a Late Jurassic age for deformation and metamorphism.