The southern end of Auckland Island broadens to a width of 26 km (16 mi) where a narrow channel, known as Carnley Harbour or the Adams Straits, separates it from the roughly triangular Adams Island (area approximately 100 km² or 39 sq mi), which is even more mountainous, reaching a height of 705 m (2,313 ft) at Mount Dick.
The channel is the remnant of the crater of an extinct volcano, with Adams Island, and the southern part of Auckland Island forming the crater rim.

Two large indentations, Bolton's Bay and Fly Harbour, are the most prominent features of the island's south coast, both in the south east.
The southern end of Auckland Island broadens to a width of 26 km (16 mi) where a narrow channel, known as Carnley Harbour or the Adams Straits, separates it from the roughly triangular Adams Island (area approximately 100 km² or 39 sq mi), which is even more mountainous, reaching a height of 705 m (2,313 ft) at Mount Dick. The channel is the remnant of the crater of an extinct volcano, with Adams Island, and the southern part of Auckland Island forming the crater rim.
Two large indentations, Bolton's Bay and Fly Harbour, are the most prominent features of the island's south coast, both in the south east.
Adams Island, New Zealand