Miocene snapshots
These are some of the ancient shark teeth that the Hazens have collected in the Calvert Cliffs area in Southern Maryland during the past 25 years.
Calvert Cliffs, which rise more than 100 feet along 30 miles of the Calvert County coastline, are eroding at a pace of nearly 3 feet a year, spilling secrets from their clay-rich soil of the world as it was 15 million years ago in the Miocene epoch.
Robert Hazen, a senior staff scientist at the Carnegie Institution, and his wife, Margaret Hazen, a writer and historian, have been studying fossils from the cliffs for the past 25 years. The fossiles include shells, shark teeth, and whale, shark and crocodile bones. According to the Maryland Department of Natural Resources, over 600 species of fossils have been found. Robert Hazen is also researching mineral evolution in the cliffs: how minerals (in this case, manganese) are forming because of microbes and vice versa.
Although beautiful and majestic, the cliffs can be dangerous. Sections can fall without warning, dropping boulders along the Chesapeake Bay shoreline. Sometimes, conditions are created at high tide where the soil underfoot has the consistency of quicksand.
The public can gain safe access to the beaches at the cliffs through Calvert Cliffs State Park, where shark teeth wash up with seashells along the shore.
Says Hazen, “What you’re seeing is a snapshot of history.” Hazen says the fossils show an entire ecosystem: “You had clams ... and then you have these predatory snails [top] that ate the clams. ... There’s even a little fish vertebra [dark circle below the snail shell].”