[LexBaird]

Vertical walls of Marble Canyon. No rubble lying at the low valley floor built up to a height one would expect from eons of erosion over time. Evidence of a large inland sea in southern Utah.

There is geological evidence that prehistoric Lake Bonneville drained north in a cataclysmic flood into the Snake River, via Cache Valley and the Portneuf Gap.

[carumba]

Yes, that is correct. There was another inland sea in south east Utah.