[Probably named for exposures on Pelly River whose headwaters are in Canada]. Name was suggested by Brooks and accepted by McConnell. Comprises oldest rocks of gneissoid character in Yukon River region, eastern AK and Yukon Territory, Canada. These gneisses are intricate series of crystalline rocks whose genesis is doubtful. Everywhere unit shows profound metamorphism. Unconformably underlies quartz schist and quartzites of Birch Creek series [name later abandoned]. Age is undetermined.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
Pelly gneisses of Collier (1903) redescribed as Pelly gneiss. Consists mainly of granitic rocks but locally includes darker varieties of monzonitic, dioritic, and even gabbroic character. Is typically light-colored rock having secondary structure that ranges from laminated gneissoid to contorted schistose fabric, thus grading from massive gneiss to feldspathic quartz-mica schist. Intrudes older rocks of Birch Creek schist [name later abandoned]. Is considered to be of Precambrian age.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
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