STRABANE, NORTHERN IRELAND—Two cargo ferry boats thought to date to the medieval period have been discovered in the River Foyle, near the Lifford Bridge and the border between Northern Ireland and the Republic of Ireland, according to a BBC News report. Marine archaeologist Niall Gregory said that 15 such dugout log boats have been found in this section of the river, usually after seasonal high-water flows. “These boats were designed as work horses, to move and maneuver with some degree of agility within a moderate to strong current,” Gregory said. He estimated the age of these particular boats based upon the shape of their hulls, the use of medieval-style nails, the distorted wood grain, and the remains of sapwood on the exterior of the vessels. Samples of the timber will be analyzed and radiocarbon dated. The nails will also undergo analysis, he explained. Other boats found in this section of the river have been dated from A.D. 600 to 1520, Gregory added. For more on archaeology in Northern Ireland, go to "Saving Northern Ireland's Noble Bog."