To the right of the gap in the cliff with a view of the Boston Skyline, O Wall rises out of the ground, culminating in a 15 foot arete with good holds. To the right of the O Wall, the cliff shortens abruptly to a few feet and forms the boundary between Granite Railroad Quarry and Swingle's Quarry.
1. O My, 5.6.
The approach is the same as M Wall in the Granite Rail Road Quarry,.