In 2005 and in 2006, a series of archeological test-trenching was executed in Courrendlin in the lieu-dit "Vers la Vieille Eglise", on the last section to be investigated of the laying-out of the A16 motorway. The discovery of structures and of rather important remains led to plan an excavating campaign which took place from March to December 2008. These works allowed the finding of a roman road and of artisanal structures.

The oldest one is a pit, dating from the first century, where charcoal was made. The output of charcoal being deeply linked to the story of metallurgy, the presence of this pit is an indirect evidence of metal work on the site during the first decades of roman times.

A few meters away lay an oblong hearth dating from the second century. Some similar examples and the presence of hammer scales allow to interpret it as a smith's hearth. It was entirely covered during the building of the road.

The most numerous structures, of an original type, are eleven hearths in pits of various dimensions in which bone was burnt at high temperatures (from 550° up to 800°C). This bone material is very specific. It belongs to ox in over 95 % cases, with an evident selection : the only observed remains are those of articular ends (long bones and small bones such as tarsals and carpals) and vertebras, but only their centrum. These elements have been split with a chopper before being burnt, in order to ease the releasing of grease. The use of bone as a combustible is excluded. As all these operations have been made deliberately and repeatedly from the second century to the second half of the fourth century, we can consider that the output of burnt bones was the selected purpose. This material, once brought to ashes might have been used in metallurgy for a thermochemical treatment of steel. The use of burnt bones in metallurgy has already been advanced for several sites but has never been clearly proved.

Moreover several elements refer to metallurgy. A ditch containing many damaged iron objets intended for melting is explained as a smith's depot. A few dross seem to give evidence for ore melting. We can notice among the finds, beyond some forge scraps, the presence of two half-products i-e a transitory shape given to metal after melting for a better commercialization. At last most of the bones are stained with rust : this might be explained by their long stay in a soil on which ironwork has been intense.

Another original structure was discovered nearby. It is a keyhole- shaped oven long 3,30 m installed in the bank of an old channel of the Birse river, with the evident will to take advantage of the natural substratum to get an inclined structure : between the mouth and the bottom of the chamber the variation of level reaches 18 %. Organic substances have been burnt there at temperatures not exceeding 700°.

Natural sciences allow us to reconstitute the evolution of local environment. Towards 7000 BC, before the arrival of the first cultivators into Delemont valley, the regnant conditions near streams were of a semi-aquatic type. The vegetal landscape of the plain where the site is located was rather open, with deciduous trees under which grew high weeds and bushes. The former meander, where the remains are kept, is left by the Birse river at the first Iron Age, time when the anthropic impact is weak: the vegetal cover around the site is rather open, constituted of meadows which are sometimes wet and of cultivated areas : forests seem distant. At La Tene, generally speaking, a rather thin alluvial deposit spreads over the site. There is an extension of open surfaces and of cultivated areas, even if the forests remain important. In roman times, the old meander of the Birse river only reappears during exceptional floods. Such a milieu, often soaked, certainly prevented the creation of permanent rural settlement but not the building of a road. As for the landscape around the site, it seems deeply influenced by agricultural practices. Then, and particularly from the Low Middle Ages, the evolution of the local landscape is especially marked by the sinking process of the river and the agricultural exploitation of the soil.

Translation: Jean-Pierre Mazimann