This small dome forms the summit of the Ribcage crags. If you've come this far, and climbed Out of Darkness and Winter Solstice slabs, you might as well finish off your multipitch cactus-climbing adventure by ascending the south face of Upper Dome as well. The excellent online guide lists three short routes up this rock.

If you decide to climb to the summit of the Solstice slab and then want to climb Upper Dome, drop eastwardly (skier's left, climber's right) down an inobvious, dubious looking gully. The left side the gully is formed by the base of the Upper Dome, so keep hugging the left side of the gully and you'll eventually pass by the base of the climbs. Alternately, you could get there by going up from the base of Right Tower, but there's a boulder move to surmount, and then very nasty brush to climb through (including rasberries, with big, bad thorns).

Bill Lawry suggests:
After mostly climbing Winter Solstice, one can nicely get to Last Chance on Upper Dome: On the route Winter Solstice, one passes a knee-high grass-y-ish plant in the crack. At that point, head right and up to then drop climber's right into a kind of gully. Once in the gully, scramble up ~20 feet to a huge ledge at the start of Last Chance. Two to four inch cams work at left end of huge ledge for belaying up your partner and for leading Last Chance.