Warren lists a wooden baluarte or watchtower at Dumaran based on late 18th century reports by the diocese of Cebu on the defenses of the Visayas, which was under its ecclesiastical jurisdiction. If the fortification at Dumaran were made of stone and mortar conceivably the report would list it down as such. This might indicate that the ruined fort at Dumaran was built during the last decade of the 18th century or the early 19th.
The walls that remain at Dumaran consist of a bastion and short stretch of curtain wall, breached off center with an entrance. It is uncertain if the fortification was ever finished or that it had been ruined over time. Oral tradition claims that the fort was never finished and inspection of the evidence seem to corroborate the tradition.
The bastion is of an unusual shape consisting of a rounded projection at the center flanked by two short wall walls. The bastion does not conform to any typical shape. It is quite probable that the rounded projection is an older construction, possibly a circular tower of stone and mortar, which was then remodeled as a bastion.