Traverses, large mounds of earth built throughout the interior of the fort, were originally 14 feet high and 20 feet wide at their base. They were designed to protect the defenders from incoming artillery fired from British batteries across the river and east of the fort. The Grasd Traverse runs the length of the fort and is one of the few remaining original earthworks. The garrison also dug small underground shelters into the southern bases of the traverses for further protection from the British bombardment. In early May 1813, an English officer who had been taken prisoner and returned on parole told his general, "It is powder and shot throuwn away to fire at that fort! I can compare the Americans to nothing but an army of ground hogs."