"We get an awful lot of college students," said Connie Smith, who has operated Matoaka Beach Cabins in St. Leonard with her husband for 47 years. The couple rents cottages for overnight stays and allows shoreline access to day-trippers.
Fossils embedded in the cliffs belong to the property's owner, but fossil hunters may keep anything near the water's edge, said James P. Reger, chief of environmental geology for the Maryland Geological Survey.
Visitors also should stay off the cliffs. "Its not safe to try to dig something out of the cliffs. They're fairly unstable," Reger said.
The right weather is important, too: Look for strong westerly winds and conditions that blow water out of the bay, lowering the water line near the cliffs.
"If I had to pick a time, it would be after a really big storm," Reger said.
A new moon and a full moon also help, because the tides pull more of the sea away from the shore, says Hazen. Then it's a matter of initiative.
"What you want is to be the first one out on the beach. If you're not, someone else is going to find whatever is there," he said.
Hazen didn't come to Calvert County to collect fossils. He and his wife, who live in Bethesda during the week, were attracted by the waterfront scenery when they bought their house in Port Republic about 15 years ago. But things changed one day during a walk on the beach.
"I saw people bending over and picking things up, and I asked them what they were doing and they said, `Looking for fossils from sharks' teeth.' I had been collecting fossils all over the world, so I figured, `Why not here?'" he said.
Hazen, whose 20th publication, a book about evolution, is due out in 2008, has hunted fossils since he was a teenager. His collection of 2,000 trilobites, a widely studied ancestor of the horseshoe crab, has taken him to Africa, Europe and Australia.
He's donating that collection - reputedly the world's largest - to the Smithsonian Institution, where dozens of specimens are expected to be displayed in a new Hall of Oceans exhibit in the Museum of Natural History in 2008.
"It's unbelievable stuff. It's just gorgeous material, I'm almost afraid to touch it," said Bohaska, the Smithsonian paleontologist.
But a highlight of Hazen's years of collecting came in January 2000 when he and his wife, Margee, each found fist-size teeth from an extinct variety of great white shark. They're displayed on a shelf in his house, along with corals, barnacles and two vertebra from a baleen whale that was probably 12 to 15 feet long.
"The idea that you can walk out of your house and find a 15 million-year-old whale bone is fascinating," he said.
His collection from Calvert Cliffs doesn't bear directly on most of his research at Carnegie. But it helps define his perspective on the complexities of evolution and life's origins.
Besides, it's a lot of fun.
On a recent fossil hunting walk near his house, Hazen used a half-broken rake to comb through the sand and debris at the water's edge. He quickly uncovered a tiny tooth from an extinct form of tiger shark - galeocerdo contortus. That was just the beginning.
"Here we go," he said, picking up what looked like a slab of petrified wood. He thinks it's a whale bone, about 15 million years old, but he'll ask Godfrey for his opinion later.
Another 10 minutes of walking led to the day's biggest prize: a tooth about 2 inches long from an ancient mako shark. He estimated the mako's size at 15 feet.
"This is big enough that this would have been eating dolphins," Hazen said.
During the rest of the hourlong walk, he seldom lifted his eyes from the sand. "There's a lot of things to look at, and you never know what you're going to see," he said.