Original sentence: Island in the Sky is a broad and level mesa to the north of the park between Colorado and Green river with many overlooks over the White Rim, a sandstone bench 1200 feet (365 m) below the Island, and the rivers which are another 1000 feet (304 m) below the White Rim.The detached unit to the north, the Horseshoe Canyon unit, contains panels of rock art made by hunter-gatherers of the Late Archaic Period who predated the Ancestral Puebloans.This area was once home of the Ancestral Puebloan Indians of which many traces can be found
Edited sentence: Island in the Sky is a broad and level mesa to the north of the park between Colorado and Green river with many spectacular overlooks over the White Rim, a sandstone bench 1200 feet (365 m) below the Island, and the rivers which are another 1000 feet (304 m) below the White Rim.The detached unit to the north, the Horseshoe Canyon unit, contains large panels of rock art made by hunter-gatherers of the Late Archaic Period who predated the Ancestral Puebloans.The most notable panel in the canyon is named the Great Gallery.This area was once home of the Ancestral Puebloan Indians of which many.traces can be found