Perched near Mary's Bust, look for a small turnout on the northeast side of a vertical roadcut, 0.4 miles east of the handicap fishing access, or about 3 miles west of the Monastery/Cedar Park turnoff on highway 34. The crag is all but invisible from the road - you can barely see the road from the top. The faint access trail starts to the east and follows cairns up the steep hillside.
Most routes end atop the main face at about 120 feet, but a smaller rock above yeilds an additional 80 feet of 5.8 climbing.
Descent is accomplished from one of several fixed rap anchors on the main face, likewise for the upper Rasp. Rapping from the main face requires two ropes (60m) or two raps from the anchors atop Shag (or potentially other routes). Additionally, a descent route is said to exist to the east atop the main face, but I haven't explored it.
Pro: Bring plenty of quickdraws and maybe some webbing in case the tied slings on the rap anchors look tired.