The fort is depicted on this engraving:
(found on this page). The engraving was done by an actual witness of the events and the details are probably accurate. The defences would then consist in a wooden palisade, with two entrances. A modern rendering based on that engraving looks like this:
So no ditch, tower, stone or any other similar construction. Note, though, the way the palisade walls "overlap" on the entrances, making them narrow and preventing a marksman from shooting into the village from the outside.
Constructions meant to provide elevated places for sharpshooters were apparently not used before being introduced by Europeans (along with firearms), the archetypal example being the one built by Samuel de Champlain to help in the attack of an Iroquois village.