The wonderful stone shapes of Goblin Valley result from millions of years of geologic history. The goblins are made of Entrada sandstone, which consist of debris eroded from former highlands and redeposited here on a tidal flat (alternating layers of sandstone, siltstone and shale). The goblins show evidence of being near an ancient sea with 1) the ebb and flow of tides, 2) tidal channels that directed currents back to the sea and 3) coastal sand dunes.