Only called a reef because travelers with horses and wagons found these formations rising like shark's new set of teeth out of the ground, had such a hard time navigating around them to get to some wetter place, I guess. 
Did they notice the paleo-man's art on the slick-rock sandstone? I did as I drove by after driving through this cut in the reef that had a dirt road built on it for off-road recreationists which took me by temple mountain (with old abadoned uranium mines in them). I had been watching out for the reddish cubular drawings anytime shiny vertical rocks whisked by my window. Oh lucky day, my 4th set of pictographs in 2 days (petroglyphs are made by carving into the rock). Red is my route driving through the reef just north of the Goblin Valley state park, not far from Capitol Reef National park. Blue is the pictograph discovery & amazement!Here is the art, painted a couple thousand years ago maybe? These are on the South Temple Wash and were painted with paint made from uranium laden carnotite ore! They used to mine uranium etc in Temple Mountain during the cold war, after WWII. See this cool Emery County Archive site about that.
