Harpers Corner Road Closed for Winter
The Harpers Corner Road is closed for the winter at Plug Hat Picnic Area which is approximately five miles from US Highway 40. The road is tentatively scheduled to open on March 31. More »
Ely Creek Backcountry Campsites Closed
The Ely Creek backcountry campsites located along the Jones Hole Trail have been closed until further notice due to bear activity in the area. More »
About unionid clams:
Unionid clams live in freshwater rivers and are related to bivalves such as clams, oysters, and scallops. They are filter feeders and sessile, which means they stayed in place their whole lives. They do not have internal skeletons that could be fossilized. However, their hard shells are either fossilized or sediment fills the empty shell cavity to make a mold of the shell.
Why are unionid clams superstars?
Unionid clams give us valuable information about the past environment. Since they need water, we know there was a permanent river as opposed to flooding from rain. The water must have been clear, since they were filter feeders that would not want sediments interfering with feeding. All unionid clam larvae are parasitic on fish and use them to travel around river drainages. Their abundance in the Carnegie Quarry indicates that fish were abundant, even though their remains are unknown from that layer.
Jurassic Fact: Unionoid clams, in their thousands, are by far the most abundant organism preserved in the Carnegie Quarry.
For more information: Visit the Quarry Exhibit Hall to see an extremely well-preserved clam on exhibit.You can also hike the Fossil Discovery Trail to see unionid clams still in the rock.
Did You Know?
A population of peregrine falcons has been established at Dinosaur National Monument. The park's rugged canyons make ideal habitat for the once endangered raptor. Fossils show that dinosaurs evolved into birds--and so still live in modified form at Dinosaur.