Some Observations on the Archean Metamorphics of the Grand Canyon

Although the rocks exposed in the inner gorge of the Grand Canyon present one of the best Archean sections in the United States, and although their occurrence has been known since the time of Powell's classic exploration in 1869 and 1874, relatively little attention has been given to their study. This may be due in part to the complexity and inaccessibility of the rocks themselves, and in part to what may have seemed the superior attraction of the later formations, exposed at higher levels in the Canyon walls.