In 2009, the Maryland-National Capital Park and Planning Commission dedicated 41 acres in South Laurel to Dinosaur Park — a working fossil site that opens to visitors of all ages the first and third Saturdays each month.
The drop-in program invites the public to learn hands-on about fossils that formed on the site of an ancient river from the Cretaceous period, some 115 million years ago.
Amateur paleontologist and park volunteer, Dave Hacker, of Bowie, said anyone finding what they think could be an animal fossil is instructed to notify one of the guides.
"Fossils aren't found by digging, but by looking," Hacker said. "We don't dig any holes until we know there's a fossil."
According to Hacker, keeping the fossils at the park is important not just so that everyone can learn from them, but also because it's not unusual to find completing pieces later.
He said volunteer paleontologists searched in vain all summer for the top half of a dinosaur tooth discovered last June. In September, an elementary school student found the missing piece when it finally surfaced.
Peter Kranz — a paleontologist that the county contracts with to do programs at the Dinosaur Park — said that 5-year-old Grace Johnson found a partial tibia of a flesh-eating dinosaur on a field trip he conducted last summer for the Dinosaur Fund, a separate educational organization that offers spring break and summer dinosaur camps.
Kranz said the tibia fossil is significant and will be turned over to the Smithsonian Museum on National Fossil Day, Oct. 15, where the Dinosaur Park will have a table and display.
Dinosaur Park Program Coordinator Ben Miller said about 5 percent of the fossils found at Dinosaur Park end up on display at the Smithsonian. Others are stored at Prince George's County Parks and Recreation's repository at Mount Calvert Historical and Archaeological Park, in Upper Marlboro.
A femur fossil of Maryland's State Dinosaur, discovered prior to the dedication of Dinosaur Park, is currently on display at the Maryland Science Center in Baltimore.
Miller said pieces of dinosaur bones are more structured than ordinary rocks and have patterns, and that the best way to find teeth is to look for shiny, smooth surfaces.
"And any time you see that black stuff that crumples up, it's going to be fossilized wood," he said.
According to Miller, a small piece of the prolific petrified wood or a single plant impression are the only fossils park visitors are permitted to take home.
Saturday in the park
Dinosaur Park is located at the end of Mid-Atlantic Boulevard, an industrial area where 30-foot buildings provide visual perspective for the height of the plant-eating Astrodon johnstoni that lived in Maryland. A small prehistoric garden is open from dawn until dusk featuring living plant fossils like the ancient Equisetum, more commonly known as horsetail.
Wayside panels provide information about prehistoric life here as well as some history of the African American ironworkers who first discovered dinosaur bones in a nearby open pit mine during the 19th century.
Park visitors walk the same ground where dinosaurs and prehistoric turtles and crocodiles thrived.
Midway through the open house program Oct. 4, more than 100 visitors had come through Dinosaur Park, including two Scout groups. Prince George's County Parks and Recreation staff and volunteers lead the park tours, which begin with a brief orientation.
The excitement of volunteers like Susan Cahill, of Greenbelt, who presented the orientation on Saturday, appears to be caught by the young children present.
"Today you are deputy dinosaur hunters and scientists," she said.
Cahill compared the area to the bottom of a lake where bones and plants sink and embed in the mud. When a young boy asked if there could have been Loch Ness monsters there, she smiled.
"Maybe there could have been a relative," she answered.
After orientation and a review of rules, small groups were guided to the fenced-in fossil area where they were shown fossils that had already been discovered at the park, some that day.
Rylan Jenkins, 9, of Columbia, said he found a plant imprint and a piece of ironstone. His mom, Jessica Jenkins, said she and Rylan and his brothers, Ramsey, 11, and Finn, 6, had seen a femur fossil from the area on display at the Smithsonian and decided to visit.
Ivy Antunes, 16, lives in the neighborhood and drove her brother, Max, 13 — who said he discovered a possible pine cone fossil — and their dad, Sandy Antunes.
Antunes said that they'd driven by and wondered what the signs meant on more than one occasion. After reading about the Dinosaur Park's first and third Saturday program in the Laurel Leader, he said they decided to stop by.
North Laurel residents Tyler Ostrowski, 8, his brother, Cole, 7, and their dad, Scott Ostrowski, returned to Dinosaur Park for a second visit during Saturday's open house.
"The boys asked to come back," Ostrowski said. "It's a nice family activity on a Saturday."
Fossil discoveries at Dinosaur Park
1991: Arnold Norden and his children, John and Heather, discover a nearly intact 4-foot femur of Astrodon johnstoni.
1998: The Maryland General Assembly names the plant-eating Astrodon johnstoni as the official Maryland State Dinosaur.
2002: Thomas Lipka discovers the skull of an ancient pond turtle and the jaw of a prehistoric shrew-like mammal.
2006: A 2-foot-long tibia of an ostrich-sized dinosaur with a lizard tail (part of the Smithsonian collection) is discovered.
2009: The Maryland-National Capital Park and Planning Commission designate 41 acres in Muirkirk as Dinosaur Park.
2011: Park volunteer David Hacker discovers a large bone (or possibly a claw) that Smithsonian experts judge belonged to an astrodon.
June 2014: Park visitor Henry Wilson discovers half of the bottom tooth of a large flesh-eating dinosaur.
August 2014: Grace Johnson discovers the partial tibia of a large flesh-eating dinosaur.
September 2014: Park visitor Gavin Johnston discovers the top half of the tooth discovered by Wilson in June.
September 2014: Park volunteer Max Bovis discovers a shoulder blade (or possibly a rib bone) of an astrodon.