America's Majestic Canyons Author:National Geographic Society Wrinkled and scarred, the face of North America bears the marks of more than a billion years of geological activity. Uplifting, erosion, glaciation, folding and faulting, heating and cooling, river carving, and weathering by wind and rain have all collaborated to create a continent seamed with cracks and fissures. Geologists list more than a t... more »housand canyons in North America and Hawaii, ranging from gentle wooded slopes of the Midwest and East, to astonishing rock-walled chasms of the West. For inclusion in this book, geologists and National Geographic staff members selected a representative sampling of canyons, gorges, and valleys, basing their choices on geological interest, scenery, uniqueness, and geographic distribution. In each region, one canyon receives major attention; those remaining combine in smalled but dazzling portfolios of America's majestic canyons.« less