Early in September of 1911 my brother Emery and I landed in Green River City, Wyoming, ready for the launching of our boats on our long-planned trip down the Green and Colorado rivers. For ten years previous to this time we had lived at the Grand Canyon of Arizona, following the work of scenic photography. In a general way we had covered much of the country adjacent to our home, following our pack animals over ancient and little-used trails, climbing the walls of tributary canyons, dropping over the ledges with ropes when necessary, always in search of the interesting and unusual.