This view, of the entrance to the escarpment through the tunnel, is what reminded me of similar spots at Fort Clinch at the Florida/Georgia border, and Fort Gaines at Mobile, Alabama...although there's probably only so much one can do with bricks in these situations, and as they were built at the same time, of course everything was as similar as they could make it. No points for originality in design on mid-19th-century American fortifications!