One of the problems associated with massif-type anorthosite in high grade metamorphic terranes is the absence of anorthositic extrusives. However, if anorthosite formed by crystal segregation, volcanic equivalents of the final fluid differentiate might occur. Massive, stratiform hornblende-garnet granitic gneisses occur between two metasedimentary sequences in asynclinorium south of the main Adirondack anorthosite massif and north of the Thirteenth Lake anorthosite dome. The granitic gneisses are divided into three stratigraphic units on the basis of mineralogy. The entire stratigraphic configuration has been traced 70 kilometers laterally, and the interpretation of the literature indicates that it may extend for over 100 kilometers.