Built more than 300 years ago, one of the oldest protective walls built by European settlers has been uncovered in Quebec City.

Construction workers on a condominium project stumbled across the base of a palisade that was built in 1693 during the Nine Years' War.

The Beaucours Rampart was the last of a series of walls, redoubts, and batteries built over several years, all of which were hastily constructed after British troops overran the capital of Acadia, Port Royal in what is now Nova Scotia, in 1690.

Named after the engineer who oversaw the construction, the Beaucours Rampart included the first versions of the Saint Louis and St. Jean gates, and two stone forts to increase firing points on the western side of Quebec.

It's believed that 500 people worked on the wall, which protected the 800 settlers living in Quebec City.

Jean-Yves Pintal, the lead archaeologist for the project, said it was a considerable investment.

"They decided to invest a lot of money to protect Quebec as a European city. So almost 15 percent of the budget of the New Front pass on the building of this Rampart, which was the first real Rampart to protect the west flank of Quebec City at this time.

Construction on stone walls began about ten years later, and as a result the location of the original wooden wall was forgotten about for centuries until a 20-metre-long beam was uncovered at the end of October.

The crews on Ste. Ursule St. immediately realized they had found something old, but did not know exactly what they were dealing with.

Pintal said he was surprised to to find the wood was so well-preserved under layers of clay.

Careful excavation has revealed thick wooden beams, braced with cross planks going back about two metres, and another thinner wall. The spaces between would have been filled with earth in order to absorb the impact of bullets and cannonballs.

The challenge Pintal and his team now face is to remove the water-saturated wood from the clay before it freezes and is damaged.

Temperatures are expected to drop below freezing in the next few days, so crews are racing against time to remove the exposed wood.

If necessary they will install heaters and temporary shelters at the site to remove the fortifications.

Once the wood is dried -- a process that make take two years -- the wall will be rebuilt and put on display.