Ohyeahcomment: Went on a four day hike down Tanner and back again recently. We were originally going to try making it to the Confluence of the little Colorado and Colorado rivers, but it wound up being much too hot and too long of a hike. We cut it short and camped pretty close to here instead.
Sigma DC 10-20
I think the area you are interested in is mostly shale Supai formation. It's what causes the normally gray Redwall Limestone (thickest of the layers) to turn red. I think the Redwall Limestone has to be my favorite formation, because it is extremely prone to cave formation.
Hey, well at least you've got critiques on your mind. Really, you don't need to be a photographer to lend a critique. If you see something that doesn't look right or something that could look better, you shout it out. Regardless, thanks for always checking my stuff out.