Five hundred feet. Now observe the tilted condition
of the remnants. To get the original height of the depositions begin with
No. 1, the stratum nearest the Archaean and measure that. Suppose it gives
us five hundred feet. No. 2 gives two hundred feet; No. 3, five hundred
feet; No. 4, one hundred and seventy-five; and so on up to No. 14. As these
strata were deposited horizontally, all we have to do is to mentally
replace them in their horizontal position. Throw the tilted strata back
again into their original condition, and by this method of measurement it
is seen that the twelve thousand feet can be made up. Figure 2, facing page
98.
Another interesting question here arises: "What became of the vast quantity
of sand and silt and pebbles that formed and were carried away during such
a gigantic process? For, think of it, eleven thousand five hundred feet of
strata, or rock, two miles high, almost three times as high a mass as the
present distance in vertical height from El Tovar to the river! Where has
it all gone?"
Naturally an answer to these questions is mere conjecture, as only from a
study of the facts revealed underneath the present strata, can any
comparative knowledge be gained of the conditions existent at that
prehistoric age. There may have been one river, or a score, or any number
between, and it is probable one or more rivers carried the Algonkian debris
westward and deposited it, as the Colorado River (not brought into
existence until centuries later) is now doing with the debris of the
existent strata.
