In 1937 the City and County of Denver built Alameda Parkway as the main route to Red Rocks Park, exposing dinosaur tracks that geologists and the public observed for many years without detailed study. In 1983 the area now named Dinosaur Ridge was designated a National Natural Landmark to protect its fossil bones and tracks, then in 1991 it was placed on the State Register of Historic Places, and in 1994 the name Dinosaur Ridge was officially approved by the U.S. Board on Geographical Names. In 1987 the National Science Foundation funded research on the tracks by the University of Colorado at Denver Dinosaur Trackers Group, and in 1992 the Scientific and Cultural Facilities District funded excavations that uncovered many new tracks. This research showed that ornithopod dinosaurs not only walked on their hind legs, as formerly believed, but also often walked on all fours and often traveled in herds or social groups. Many similar tracks in the same rock layers to the north and several hundred miles to the south indicate large populations traveling or migrating along the shores of the Western Interior Seaway in Cretaceous time. Because Alameda means promenade, this well-traveled route has been called the Dinosaur Promenade or Dinosaur Freeway.