My first acquaintance with the Adirondack Grenville was through the kindness of Prof. James F. Kemp, under whose guidance in the field, a most delightful experience, I saw the problem of the stratigraphy of this Precambrian series of sediments. It is a problem fraught with many obstacles because of the complex folding2 of the Grenville, its patchy distribution, injections, and metamorphism. Later I became interested in the Adirondack graphite deposits and studied the Grenville sediments stratigraphically above and below the graphitic quartz schists,3 which constitute the ore.
In this work I have received valuable assistance from George H. Chadwick, David H. Newland, Wilbur G. Valentine, and Robert J. Howard. In 1917 sufficient field data was at hand to suggest some stratigraphic correlations involving a thousand feet of rocks on the eastern Adirondacks. Since then further field studies and a restudy of several hundred pétrographic slides justify, I believe, a . . .