ALBITE-oligoclase feldspar concentrations occur abundantly in the Eocambrian to Lower Ordovician metasediments, along the entire metamorphic Caledonian–Appalachian mountain chain. In Spitsbergen (refs. 1 and 2 and personal communication from W. Horsfield); Stavanger, Norway; SE Scotland; Antrim, N. Ireland; Co. Mayo, Ireland3; Burlington Peninsula, Newfoundland; Pennsylvania; Dutchess County, New York4; and Maryland, particular attention has been given to the albite schist association.