It is a large rocky wall with vines that are used to climb. Boulders are always falling out of the holes on the mountain, making it difficult to climb without getting hit.
At the top of the wall there is an entrance to Patch's home. He will repair any broken item Link has, but only after he has completed his Restoration Ceremony. Link must go here to fix the broken Tuni Nut and he can come back again during the quest for the Noble Sword.