Ancient rivers carved the tops and exposed edges of these blocks, removing some layers and sculpting intricate formations in others. The Paria Valley was created and later widened between the plateaus. The Paria River and its many tributaries continue to carve the plateau edges. Rushing waters carrying dirt and gravel gully the edges and steep slopes of the Paunsaugunt Plateau on which Bryce Canyon National Park lies. With time, tall thin ridges called fins emerge.
Fins further erode into pinnacles and spires called hoodoos .
These in turn weaken and fall, adding their bright colors to the hills below. Early Native Americans left little to tell us of their use of the plateaus. We know that people have been in the Colorado Plateau region for about 12,000 years, but only random fragments of worked stone tell of their presence near Bryce Canyon. Artifacts tell a more detailed story of use at lower elevations beyond the park's boundary. Both Anasazi and Fremont influences are found near the park.