The remains of an early Liffey quay wall, some 70 metres north of the present one, have been unearthed by archaeologists in O'Connell Street on the site of an electricity sub-station for the Tallaght Luas line.
Ms Christine Baker, the archaeologist who made the discovery, told The Irish Times yesterday the provenance of the wall could not be fixed precisely, but it probably dates from around 1700.
Standing about one metre high, the double wall of mortared stone with rubble infill is 1.5 metres wide and spans the entire site of the sub-station. It is three metres below the present ground level.
Ms Baker said the wall post-dates Dublin Corporation's 1675 grant of a 299-year lease to Jonathan Amory for land reclamation between Liffey Street and Marlborough Street - the famous "Amory Grant".
Mr Franc Myles, who had earlier excavated the remains of late 17th century houses on the site, said this was part of a plan to channel the river so that ships could reach the old Custom House on Wellington Quay.
The line of the old quay wall is not shown on DeGomme's 1673 map of Dublin, but it does appear on Brookings's 1728 map, by which time much of the land had been developed, so it must have been built between those years.
The remains of another structure have been uncovered just north of the wall as well as a piece of glass inscribed "David Haoerd 1711". Ms Baker said it is believed that Haoerd was an early 18th century wine merchant.
Since both structures are standing on the site of the Luas sub-station, they are to be "preserved by record" through plans and photographs. This means that they will be removed to make way for its construction.
The excavation is due to end on Friday, when the site is handed back to the contractors. "They've been very patient with us," said Ms Baker, who works for consultant archaeologists Margaret Gowen and Co.
Mr Eamonn Brady, the Luas information officer, said the excavation had only delayed the project for two weeks. "While providing Dublin with a modern transport system, we are very conscious of the city's history."
Dúchas, the Heritage Service, favours providing some indication at street level of where the old quay wall stood, after the underground sub-station is finished.
