ˈaɪs mˈɛlt fɹʌm ɹᵻsˈiːdɪŋ ɡlˈeɪʃɚz lˈɛft bˈoʊldɚz ðæt ðˈɛn, ɪn kˈɑːnsɚt wɪð ɹˈʌʃɪŋ wˈɔːɾɚz, kˈɑːɹvd "pˈɑːthoʊlz" ˌɪntʊ ðə sˈændstoʊn ʌvðə ɹˈɪvɚ vˈæli.
Ice melt from receding glaciers left boulders that then, in concert with rushing waters, carved "potholes" into the sandstone of the river valley.