The Boundary Ranges suite, and therefore the Stikine assemblage, are also tentatively correlated with parts of the Yukon-Tanana Terrane in Yukon (Aishihik Lake area), parts of the Taku terrane in southeast Alaska, and undivided metamorphic rocks in west-central British Columbia. Differences in the isotopic signatures of these rocks may reflect along-strike changes in the character of the basement rocks of the late Paleozoic Stikinia volcanic arc.