Millions of years ago, a huge baleen whale swam into what is now the Potomac River and died, sinking into the muck at the bottom. Just last month, the skull of that whale appeared at the base of cliffs on the river 150 feet below Virginia’s Stratford Hall, the birthplace of Confederate General Robert E. Lee.
Now, scientists from the Calvert Marine Museum in Solomons are digging up the rest of the whale’s skeleton, hoping it will help them understand life and climate change during the Miocene Epoch. It was Jon Bachman, an employee at Stratford Hall, who found the 15 million year old skull. He said he was walking along the beach with a group of scientists when he saw “something that looks like a gray hubcap sticking out about 3 ½ feet from where the cliffs meet the beach.”
The folks at Stratford Hall called the Calvert Marine Museum in Solomons, which dispatched a team of scientists led by paleontologist Stephen Godfrey. He removed the 6 ½ foot-long skull last month, put it in safe keeping at the museum and came back for the rest of the 25 foot skeleton. “These cliffs give us a portal into that 10 million year block of time that's represented by the depth of the sediments here from about 18 million years ago to about 8 million years ago,” Godfrey said one recent day. “So as close as to Washington we know what creatures were living here at that time.”
The cliffs at Stratford Hall line up with Calvert Cliffs, about 40 miles northeast in Maryland. The sites of the cliffs were once at sea level. Cycles in climate change formed glaciers taking sea levels down about 600 feet. The cycles peaked about 23,000 years ago. “And at that time all of the Chesapeake Bay, Potomac, the estuaries, all was just a river bottom,” said Robert Weems, a retired geologist who worked for the U.S. Geological Survey. “And the sea stuff was off the present coast”.
Weems, who spent his career studying the layer-cake-like cliffs along the Atlantic Coastal Plain, is trying to figure out when animals like the Stratford baleen whale disappeared. “So what we're trying to do is to get a very detailed correlation between the beds here and Calvert Cliffs,” he said. “If these are as it looks like, gonna work out to be 400,000 year cycles, we can work out a pretty detailed idea, within a half-million years probably, of the age of these things, and that will be just far beyond anything that I ever thought was going to happen in my lifetime.”
Geologists and paleontologists have been discovering bones and fossils at Stratford Hall for nearly 200 years. British geologist John Finch, who came to Stratford Hall in 1820, wrote of discovering “the fossil remains of some animals,” during a morning trek along the river, including “the first fossil bone of a manatus discovered in America.” Manatus is Latin for sea cow, or what we call manatee. “Some bones are washed out by the waves, and left on the shore by the tide,” Finch wrote. “Shark's teeth are found on the beach and in the cliffs.”
This discovery of the whale skull was kept quiet until it could be removed. Stratford Hall officials said they didn’t want visitors wandering near the unstable cliffs. And John Nance, another paleontologist with the Calvert Museum, worried about preserving the site. “We don't want to have a lot of people coming around and possibly disturbing it.” Nance said. “It holds a lot of scientific value, but on the market these bones wouldn't sell for very much at all.”
Big sharks teeth, from the ancient megaladon, are what really sell, he said. And while the occasional shark comes into the Potomac, the likes of the megaladon and this kind of baleen whale remain only as fossils and bones. “Whatever it is, this group that was once extremely happy here died out for reasons we can't explain yet,” said the geologist Weems. “It’s one of our many mysteries.”
You can see the skull and some of the bones in a display at the Calvert Marine Museum.