One of the outstanding problems of regional metamorphism concerns the amount of material introduced from external sources. If material is added, it is necessary to determine the stage in the metamorphism when such introduction takes place and to discover the source of the added substances. Goldschmidt (1921) has shown, for example, that alkalis and silica have been added to argillaceous sediments in the Stavanger region of Norway, and Barth (1936) has made similar observations in Dutchess County, New York. In both areas the introduced elements were derived from nearby intrusives.
In the Littleton and Moosilauke quadrangles of westernmost New Hampshire (Fig. 1) high-grade metamorphic rocks were developed without any notable introduction of material from external sources (Billings, 1937, p. 544–545). Farther east, however, after high-grade metamorphic rocks were formed by recrystallization, potash was locally introduced in large quantities. It is the purpose of this paper to present the . . .