All sorts of debris, both natural and man-made, has washed up on the banks of the famed Potomac River over the years. However, one finding late last month is particularly notable: a 15 million-year-old whale skull. According to The Washington Post, the baleen whale skull emerged from a cliff face in the eroding bank of the Potomac, in an area particularly well-known for unearthing marine fossils. But the complete and intact 1,000 pound skull is the biggest area scientists have seen so far, and the fact that it was unearthed whole is particularly rare.

The first sign of the skull was spotted in June in cliffs on the edge of Stratford Hall, the birthplace of Robert E. Lee; scientists from the Calvert Marine Museum were working nearby and brought to the site to examine the finding. "The more they dug," said Jim Schepmoes, spokesperson for Stratford Hall, "the bigger this thing got." While it's not fully clear yet what species this specimen is, further tests will be run to confirm the suspicions that the skull is that of a baleen whale. Judging from the size of the skull, scientists estimate the whale may have been as long as 25 feet, and the rest of the skeleton is believed to be embedded in the cliff still — excavations will continue to retrieve the rest of the creature's remains. For now, those who want to see the skull can check it out at the Calvert Museum.