Original sentence: Handbook of Texas Online:  Palo Duro Canyon.Ogallala Formation:  This late Miocene to early Pliocene unit forms the cliffs and ledges at the very top of the Canyon.Quartermaster Formation:  Permian in age, this comprises the red, lower slopes of the Canyon.Tecovas Formation:  Part of the Dockum Group with the Trujillo Formation, this multicolored Triassic unit consists of shale, siltstone, and sandstone.Texas Parks and Wildlife:  Palo Duro Canyon.There are special effects, music and dance againt the canyon walls.Trujillo Formation:  This Triassic formation is harder than the underlying Tecovas, and forms many of the Canyon's ledges
Edited sentence: Handbook of Texas Online: Palo Duro Canyon.Ogallala Formation: This late Miocene to early Pliocene unit forms the cliffs and ledges at the very top of the Canyon.Quartermaster Formation: Permian in age, this comprises the red, lower slopes of the Canyon.Tecovas Formation: Part of the Dockum Group with the Trujillo Formation, this multicolored Triassic unit consists of shale, siltstone, and sandstone.Texas Parks and Wildlife: Palo Duro Canyon.There are special effects, music and dance against the canyon walls.Trujillo Formation: This Triassic formation is harder than the underlying Tecovas, and forms many of the Canyon's ledges