Uluru (also Ayers Rock or The Rock) is a large rock formation in central Australia, in the Northern Territory. It is located in Uluru-Kata Tjuta National Park, 350 km southwest of Alice Springs at 25 degrees 20' 41" S 131 degrees 01' 57" E. It is the second-largest monolith in the world (after Mount Augustus, also in Australia), more than 318 m (986 ft) high and 8 km (5 miles) around. It also extends 2.5 km (1.5 miles) into the ground. It was described by explorer Ernest Giles in 1872 as "the remarkable pebble".'Uluru is an inselberg, literally "island mountain", an isolated remnant left after the slow erosion of an original mountain range. Uluru is also often referred to as a monolith, although this is a somewhat ambiguous term because of its multiple meanings, and thus a word generally avoided by geologists. The remarkable feature of Uluru is its homogeneity and lack of jointing and parting at bedding surfaces, leading to the lack of development of scree slopes and soil. These characteristics led to its survival, while the surrounding rocks were eroded. For the purpose of mapping and describing the geological history of the area, geologists refer to the rock strata making up Uluru as the Mutitjulu Arkose, and it is one of many sedimentary formations filling the Amadeus Basin.