Foundation and Superstructure
The foundation of the Cathedral is of Maine granite. Although the bed-rock of Morningside Heights (Manhattan schist) lies near the surface, it is so disintegrated near the top that it was necessary to go down 72 feet in some places in order that the Cathedral might rest securely on the “living rock.” The excavation and foundation alone cost a quarter of a million dollars. The main walls of the superstructure are also of granite, faced on the outside of the finished portion with Mohegan golden granite quarried near Peekskill, N. Y., and on the inside with a soft buff-colored limestone or dolomite called Frontenac stone from Pepin county, Wis. The great flying buttresses and massive piers of the Crossing, exposed in their rugged unfinished state, exhibit the dark Maine granite. Local materials are mentioned in their appropriate places.