The archaeologists found traces of later occupation on top of the church, including early Islamic walls and Ottoman garbage pits. (Aluma is located near the Ottoman and later Palestinian village of Hatta.)
The excavations also revealed Byzantine glass vessels and a pottery workshop for making amphoras, cooking pots, kraters, bowls and oil lamps, IAA officials said.
To avoid building over ancient sites, archaeologists are often brought in for salvage digs ahead of construction projects like this one, sometimes yielding stunning discoveries. For instance, a "cultic" temple and traces of a 10,000-year-old house were discovered at Eshtaol west of Jerusalem in preparation for the widening of a road.
And during recent expansions of the main road connecting Jerusalem to Tel Aviv, called Highway 1, excavators found a carving of a phallus from the Stone Age, a ritual building from the First Temple era and animal figurines dating back 9,500 years.
Regarding the new discoveries, the IAA plans to remove the mosaic for display at a regional museum or visitors' center, and the rest of the site will be covered back up.
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