||Gray, green, black, and tan mafic and quartzofeldspathic to siliceous schist and gneiss interlayered with subordinate quartzite and marble. Unit consists mainly of metavolcanic rocks. Rock types include amphibolite, actinolite schist, garnet-plagioclase-hornblende semischist and gneiss, pelitic and semi-pelitic kyanite-garnet-biotite-feldspar-quartz schist, fine-grained quartz-feldspar-biotite schist, and marble; characterized by compositional layers a few cm to a meter in thickness. In the Juneau area, unit includes foliated and layered medium- to coarse-grained hornblende gneiss with lesser amounts of hornblende and biotite schist (Brew and Ford, 1985; Himmelberg and others, 1991). Protoliths are inferred to be basaltic, rhyolitic, and dacitic volcanic rocks, pelite, quartz-rich clastic strata, and limestone. Quartz-porphyritic metarhyolite with large blue quartz phenocrysts in a centimeter scale fragmental texture is a diagnostic rock type (Gehrels and others, 1992). Metarhyolite is commonly interlayered with metabasalt that sometimes displays relict fragmental and pillow structures. In Leconte and Thomas Bays, the unit includes amphibolite, muscovite-biotite pelitic schist, siliceous semischist, quartzite, and marble. Marble layers range from 10 cm to 20 m in thickness. Siliceous semischist has layers that contain up to 75 per cent quartz and alternate on a cm-scale with finer-grained biotite-rich layers, inferred to represent sandstone turbidites (McClelland others, 1991). Quartzite forms cm- to meter-scale layers, contains less than 20 per cent plagioclase, K-feldspar, biotite, muscovite, amphibole, epidote, and opaques, locally alternating with sub-millimeter laminae of biotite and white mica, and is inferred to represent both quartzose sandstone and felsic tuff (McClelland others, 1991). Felsic metatuff occurs as meter-scale layers and as 1-10 cm-thick layers in marble (McClelland others, 1991). Amphibolite layers up to 30 m in thickness are inferred to represent mafic extrusive rocks; massive and homogenous plagioclase-garnet-hornblende gneiss may represent mafic flows or intrusive rocks (McClelland others, 1991). In general the proportion of metavolcanic rocks increases southwestward. Metaclastic quartzite and quartz-cobble conglomerate are more common to the northeast (Gehrels and others, 1992). The rocks are strongly foliated and lineated, showing evidence for more than one deformation, and are locally proto mylonitic or phyllonitic. In the Ketchikan area, unit includes quartzofeldspathic biotite schist and gneiss, quartz-muscovite semischist, calc-schist, marble, and quartzofeldspathic biotite-amphibole gneiss. Metamorphic minerals include quartz, plagioclase, chlorite, epidote-clinozoisite, biotite, muscovite, actinolite, hornblende, garnet, kyanite, sillimanite, staurolite, calcite, and pyrite, indicating amphibolite grade regional metamorphism (Stowell, 1989; McClelland and others, 1991). These rocks are structurally interlayered with rocks of units Pzsg and PzZyp.