Paul Smiths, NY, Sep 17, 2009 — Anorthosite, the signature grey rock familiar to climbers and hikers in the Adirondacks is an ancient form of granite formed 15 miles below the surface more than a billion years ago. Pushed to the surface by recent mountain building activity, its deep cracks form the valleys and deep lakes of the region. Martha Foley and Curt Stager talk about the area's "ancient bones."