Oz is the small upper left quadrant of the Cheeks beginning at "Lions, Tigers, and Bears" and ending at "Jesters of Chaos"; and encompassing a wide range of corners, splitters, & arete's that distinguish it from the Black Sea---which is mostly homogenous geology on a sweeping knob studded shield. Home of the immaculate Quad Crack. 

Take the left branch when headed from the UTW to the cheeks. If you are going way down hill, then head back up. On approach, marvel at the Incisor, Wilman's Walkabout, and the lurking tsunami of Quads lurking above a beautiful submarine like feature.