This rugged peak is The Sentinel, an unnamed peak so called by the local Las Vegas hiking contingent. All mountains have their unique character, although some ooze more character than others. The Sentinel is such a peak. The route followed the ridge in the foreground to the left, then ascended the steep left slope up rock solid limestone to the ridge top, and the further off toward the summit (not visible here).

Ascent of The Sentinel, Lake Mead Recreation Area, March 13, 2009.
Photo by Ellen Johnson