Probably thousands of remains are buried under the New Haven Green, which was used as a cemetery until the early 19th century. The headstones were all relocated to New Haven's Grove Street Cemetery, but the bodies were not. Sandy's strong winds apparently caused an old oak tree to fall over on the green, revealing parts of a skeleton that the tree had been planted over.
You can read more about the finding (as well as see photos!) and the New Haven Green's history at the following sites: