AN ARCHAEOLOGIST has unearthed a colourful 3rd Century mosaic in Verulamium Park, St Albans, during building works on the ancient hypocaust and mosaic site.
The field archaeology unit at St Albans Museums was digging a trench for a new electricity cable when Jack Couch made the new find of a chequered mosaic.
Probably not seen for nearly 2,000 years, the mosaic is made up of red or brown tessera in a grid of grey Purbeck marble. It may be from the corridor of a town house built close to the hypocaust.
In Roman times hot air, stoked from a pit in a smaller adjoining room, was drawn underneath the floor of the hypocaust building, once part of a large house with up to 35 rooms.
Keeper of archaeology at St Albans Museums Dave Thorold said: "A new mosaic is always an interesting find. This type of mosaic would have been found in a high quality town house with between 20 to 30 rooms.
"The annoying thing is that because the park has English Heritage protection, we weren't allowed to dig out any more than necessary to put the cable down. We could only see part of the mosaic, which is probably about one metre wide and up to 10 metres long."
The UK's leading expert on Romano British mosaics, David Neal, was called in to record and photograph the mosaic. He said it was well made, laid and composed and was remarkable for the unusual width of the border.
The piece, which is developed from the popular chequer board pattern of the 1st Century, will feature in Mr Neal's multi-volume publication detailing all Roman mosaics. It has now been covered by a protective layer of sand and the trench has been filled in.