This paper takes up the whole problem of the structure, relations, and origin of the great body of anorthosite in the Adirondack region. References are made to anorthosites of other well known regions, and it is hoped that some important light may be thrown on the problem of the anorthosites in general. Particular attention is given to Bowen’s recent paper,1 “The problem of the anorthosites,” in which he elaborates an hypothesis regarding the structure and origin of anorthosite with special reference to that of the Adirondacks. I regard this paper as a very important contribution to the subject, because he has called attention to many important features hitherto either overlooked or not sufficiently emphasized. But, as a result of more than six months of field-work within and close to the Adirondack anorthosite area and much laboratory work, I find Bowen’s hypothesis untenable.
Still more recently, by way of discussion of