I’ve been reading about the geomorphology of southern Utah. Present understanding of the Pleistocene Epoch does not have glaciers extending into southern Utah. In particular, the “glacial etching” caption on a photo from Zion NP is in error. Mountain tops in southern Utah may have had glaciers form on top. The etching shown in the Zion photo is from facial horizontal deposition fragmentation and horizontal fragmentation. It does form a striking checkerboard pattern, but it has nothing to do with glaciation!