I didn't determine anything; geologists (a.k.a. 'objective science') did. I only mentioned that fact as a structural means of displaying the passage of time. I didn't mention the first half-billion years because I was so very young at the time --just a little nipper, really-- so I don't remember it terribly well. Except that then, where I happen to be standing --or sitting, actually (in present day Ootah)-- was located roughly on the Earth's equator at the time. As regards the last thousand years, there have been three (3) periods of drought, but rest assured, this land has not been under water --other than the occasional

Stepping back in time:

Mat Warner rode with the Wild Bunch (of Butch Cassidy & the Sundance Kid train and bank robbing fame). He wrote inscriptions on the rocks in a handful of places, and this is but one.

People of the Archaic lived in and passed through these regions several thousands of years ago. They left their inscriptions on the rocks in a handful of places, and this is but one.

Twenty-six times in the last half-billion years, this land was under water. Between those times, the waters receded and sands blew in and sands blew out, adding to and subtracting from the layers of rock that ultimately formed, and are now exposed in the vast anticline we call the San Rafael Swell. Washes, intermittent and perennial streams, and even a few rivers erode the rock, and in places great canyons form. And this is but one.