GENEVA, Sept. 5 (Xinhua) -- Workers have uncovered a detailed Roman mosaic depicting two birds perched on a vessel during routine water pipe maintenance in the municipality of Avenches, the Swiss canton of Vaud said in a statement Wednesday.

The mosaic's design consists of a square extending 1.55 meters on each side, with rich decorations and a thick border of small yellow stones.

In the center of the newly discovered mosaic is a medallion that highlights a container on which two birds are perched.

The canton of Vaud, north of Geneva, said in a statement that the mosaic was part of the remains of a building on the outskirts of the Roman archaeological site in Avenches.

This is an area that has so far been little explored but is believed to contain ruins of especially high-quality buildings, the Swiss News Agency, SDA-ATS, reported.

A tribe of Helvetians, who later became today's Swiss had Avenches as their capital during the Roman era nearly 2,000 years ago, and the region is the subject of ongoing archaeological research.

"This Roman city was the capital of the Helvetii people, numbering 20,000 souls at the time; a settlement that rose to be a colony and was placed under the (Roman) emperor's protection.

"Its influence and outreach extended far and wide, from the north to the south of the Alps," says the website of Avenches.

The sanitation work, which involved digging a trench over 500 meters long, also uncovered remains of houses and graves.

After being cleaned, the mosaic will be transferred to the collections of the Roman Museum of Avenches.