| The cliff face is part of the great El Capitan Reef of Permian age (See NPS, [2010b] for an overview about the Permian Period - 286 to 230 million years ago). The ancient reef forms the core of the Guadalupe Mountains that extends from west Texas to southeastern New Mexico. The shale and limestone beds exposed along the base of the mountain were deposited on the flanks (fore-reef) of the great barrier-style reef. The El Capitan Reef has been heavily studied because many major oil and gas reservoirs have accumulated in ancient reef tracts that occur buried below the surface in West Texas and elsewhere around the world. |
