National Park Service LogoU.S. Department of the InteriorNational Park ServiceNational Park Service
National Park Service:  U.S. Department of the InteriorNational Park Service Arrowhead
Jefferson National Expansion MemorialGMP Logo
view map
text size:largestlargernormal
printer friendly
Jefferson National Expansion Memorial
Press Releases (GMP)
Dinosaur cartoon  

Did You Know?
On September 10, 1804 on Cedar Island, in South Dakota, William Clark discovered the fossilized remains of the ribs, backbone and teeth of a plesiosaur. Plesiosaurs were animals who lived at the same time as the dinosaurs, but swam rather than walking on land. Clark thought it was a giant fish bone!
more...

Last Updated: February 18, 2009 at 13:53 EST