This canyon was created by the old Lake Bonneville. The baby limestone found through out most of the canyon was formed from the lake receding and rising for a few thousand years. The rock looks like Spearfish Canyon in South Dakota, but its nowhere near as good, however there is good rock to be found here, and ALOT of choss too.
The best seasons are spring and fall but it is very possible to rock climb here in the middle of summer too.
A good but hard to find reference is Troy D. Anderson's semi-comprehensive guide, Metal In Your Head.
Getting There
From Cedar City find HWY 14, this goes through Cedar Canyon. From HWY 89 take HWY 14 to Cedar City.