Did you find anything?
If I had seen this earlier, I would have suggested rapping the "Bottomless Pit" in the Haleakala crater. Don't let the ranger see you though, cuz I'm sure its not legal.
Otherwise, like Spicoli says, its a choss pile. I'm going there on the 16th, but plan to snorkel and lay in the sand. My wife would kill me if I even suggested bringing climbing gear.