BOSTON — An archaeological dig in Boston’s historic Chinatown has been cut short after it turned up a 1980s music cassette, a toy dinosaur and other bric-a-brac.

The city’s Archaeology Program tweeted Tuesday that it was wrapping up its three-week excavation at a vacant lot near the neighborhood’s distinctive gateway because researchers have reached the water table, and it is unsafe to dig further. The dig had been expected to last until the fall.

Researchers have been humorously tweeting some of their recent “finds,” including a cassette by Boston R&B group New Edition, a dinosaur toy , linoleum flooring and other items from the 1970s and 1980s.

City archaeologist Joe Bagley had hoped to turn up artifacts shedding new light on immigrants from China, Europe and the Middle East who came to the city from 1840 to 1980.