The majority of the nearly long up-thrust formation called the Waterpocket Folda rocky spine extending from Thousand Lake Mountain to Lake Powellis preserved within the park. Capitol Reef is an especially rugged and spectacular segment of the Waterpocket Fold by the Fremont River. The park was named for its whitish Navajo Sandstone cliffs with dome formationssimilar to the white domes often placed on capitol buildingsthat run from the Fremont River to Pleasant Creek on the Waterpocket Fold. Locally, "reef" refers to any rocky barrier to land travel, just as ocean reefs are barriers to sea travel.