Wall Arch

It consisted of Entrada Sandstone, specifically the member known as Slick Rock.

Wall Arch was first reported and named in 1948 by Lewis T. McKinney.

Wall Arch collapsed some time between the night of August 4 and the morning of August 5, 2008, temporarily blocking Devils Garden Trail.

Officials from the National Park Service and Utah Geological Survey visited the site of the collapsed sandstone arch on August 7 and noted stress fractures in the remaining formation which may cause collapses in the future.

Media related to Wall Arch at Wikimedia Commons

Wall Arch in Arches National Park in 2003, before its 2008 collapse
Wall Arch within days after the collapse