Limerock Professional Review and Guide
"This difficult trail leads down from the rim into the remote recesses of Blackwater Canyon. Most of the trail follows an old, barely distinguishable railgrade. The ties are gone but their impressions are not (read: bumpy).
The scenery is gorgeous. Avoid this run after heavy rains (you'll never cross the creeks) and after midsummer, when the nettles (unless cut back) get pretty bad. Highlights: Cliffs, rocks, roots, boulders, canyon views, waterfalls, stream crossings, stinging nettles"