One may approximately estimate the various strata of the wall of the Kaibab as follows:

Colorado River, say. . . 2400 feet above sea level Archaean . . . . . . . . 1000 " thick Algonkian . . . . . . . 1100 " " Cambrian . . . . . . . . 1000 " " Carboniferous . . . . . 2750 " " --------- Total level above sea. . 8250

Bass Tomb or Holy Grail Temple. The great north wall is not featureless. There are a number of architectural forms, of wonderfully varied shape, resting upon bases of massive solidity. The most striking of these is a squarebased monumental mass,--Holy Grail Temple, formerly Bass Tomb,--on which rests a well-shaped pyramid, crowned with a red and white circular shaft. The whole butte is well proportioned, having a base of sixteen square miles, and rising to a height of six thousand seven hundred and ten feet.

King Arthur Castle. Slightly to the east of it is another majestic butte, inferior only in size. The crowning shaft is missing here, but a castellated structure of red rock suitably dominates it. It bears the name King Arthur Castle, and is seven thousand three hundred and fifteen feet elevation.