Side-scan sonar surveys, augmented with echo-sounding, have revealed a series of columnar bodies, broken into segments, lying on the bed of the Tay Estuary at the southern end of the first Tay Railway Bridge. These are, with the aid of archive material, interpreted as the remains of 11 twin, brick uprights (Pier Nos. 4–14) that survived the infamous Tay Bridge Disaster of 1879, but were demolished after the opening of the new railway bridge. The piers in question, along with three farther to the south (Nos. 1–3), supported the southernmost 1550 feet (ca. 470 m) of the 2-mile structure, the only part of that ill-fated bridge which was built to the original plans of its designer, Thomas Bouch. They have lain forgotten on the bed of the Tay Estuary for over 100 years.