Ever since people had begun to catalog the strata in particular outcrops, there had been the hope that these could somehow be used to calculate geological time.

Earthquakes and tsunamis that resulted from the collision could have wrought havoc on the sedimentary record, causing discrete strata to swirl together and completely scrambling time lines.

Layer upon layer of different rocks recede down into the Grand Canyon and back through time, until the strata, at the river, revealed some of the oldest exposed rocks on earth.