This was four miles in length, and two in breadth.

The town stood in its centre, the fort at the northern end.

The island was approached by two bridges, one close to the fort, the other at the south, both being defended by strong batteries.

There were also three fords, two of these being at the north end of the island, and also defended by batteries; the third was near the centre of the island, a mile below the fort, and leading to the native town.
The fort was separated from the rest of the island by a deep ditch cut across it.

It was defended by numerous batteries.