sconce

No sconce or fortress of his raising was ever known either to have been forced, or yielded up, or quitted.

one that […] must raise a sconce by the highway and sell switches

Just then, a broad sconce-piece or low water-washed berg came driving up from the southward. The thought flashed upon me of one of our escapes in Melville Bay; and as the sconce moved rapidly close alongside us, McGary managed to plant an anchor on its slope and hold on to it by a whale-line.