On the sandy banks of the Loire, near Ancenis (Loire-Atlantique), 17th-century shipwrecks and 12th-century fisheries have been unearthed in an “exemplary” state of preservation, a sign according to archaeologists of intense activity around the river . “It is extraordinary and exceptional to discover remains of such quality in such a small space,” enthuses Anne Hoyau-Berry, an archaeologist at the National Institute for Preventive Archaeological Research (INRAP).
With skin tanned by the sun and beige construction pants, this archaeologist has been working since August 16 at one of the three excavation sites deployed on the banks of the Loire. Submerged by water for most of the year, Île Coton, Île Poulas and Île aux Moines have become the scene of new discoveries.
Near Coton Island, a dozen shipwrecks from the 17th and 18th centuries have just been unearthed, in an exemplary state of preservation. A rare and remarkable fact, these ships, which show signs of wear, were deliberately filled with stones and installed on the side, to create two breakwaters over 40 meters long.
“The first hypothesis is that they were dikes to protect the tip of Coton Island,” explains Ms. Hoyau-Berry. “But the discovery of a third perpendicular breakwater makes us lean towards the development of a port or the desire to transport water to this precise place.”
These flat-bottomed barges are characteristic of freighters of the time that transported raw materials (wood, stones, slate, sand), salt or wine.
About 14 meters long, they are cleaned stone by stone by the archaeologists on site, who must pump the water that rises from the ground and irrigate the wood to prevent it from deteriorating when it dries.
“It is a physically difficult meticulous work, acknowledges the archaeologist. But the summer drought allowed us to work in good conditions.”
And now it is a “race against time before the return of the water” that is committed for scientists, says Denis Fillon, delegate of INRAP management in Pays de la Loire and scientific director of the sites. The work will end in October with the arrival of the floods.
“Like a Highway”
Several samples of wood (probably oak) were taken to define the species used, the forests from which they come and even the shipyard of origin of the boats.
“They are so well preserved that you can still see the traces of the modeling tools,” continues Anne Hoyau-Berry. In the coming days, archaeologists will carry out underwater excavations to take a closer look at the foundations of the reefs.
Upstream, on Poulas Island, three 12th-century fixed fisheries were discovered, made of stones and wooden pilings. Arranged in a “W” shape, they were used to catch both the fish that went up the current (salmon) and those that went down it (eel).
Belonging to local and ecclesiastical lords, they made it possible to respect the approximately 150 “scarcity days” a year imposed by the Church of the time. Traces of millers have also been brought to light, a sign of the density of river activities.
“You have to imagine the Loire at that time as a road, where we fished and transported goods”, describes Denis Fillon. “We are far from the image of the wild river!”
These archaeological sites, which mobilize 33 scientists, with a budget of 1.6 million euros, are part of a broad program to rebalance the Loire bed led by Voies navigable de France (VNF), between Les Ponts-de-Ce and Nantes. The work planned by VNF should start next year.
“The goal is to restore a more natural dynamic to the river, which developed extensively in the 19th and 20th centuries,” explains Séverine Gagnol, head of the Loire unit at VNF.