which transits between two foothill areas, the Pyrenean and the Iberian, preambles of two mountain formations, the Pyrenees to the north and the Sistema Ibérico mountain range to the south; the Community has the highest peaks of both mountain ranges, the Aneto and the Moncayo respectively. Pyrenees The Aragonese Pyrenees are located in the north of the province of Huesca and are arranged longitudinally in three large units: High Pyrenees, Internal Depressions and Outer Ranges. The Aragonese High Pyrenees contains the maximum heights of all the Pyrenees mountainous chain. The High Pyrenees is formed in turn by the axial Pyrenees and the Inland Ranges. In the axial Pyrenees are the oldest materials: granites, quartzites, slates and limestones and the highest peaks like: the Aneto (), Maladeta () and the Perdiguero (). The inner Pre-Pyrenees, composed of more modern rocks (limestones) also has large mountains such as Monte Perdido (), Collarada () and Tendeñera (). The main Pyrenean valleys are formed by the rivers that are born there, which are: Ansó Valley: Veral river Hecho Valley: Aragón Subordán river Canfranc Valley: Aragón river Tena Valley: Gállego river Broto Valley: Ara river Aínsa Valley: Cinca river Pineta Valley: Cinca river Gistau Valley: Cinqueta river Benasque Valley: Ésera river The intrapirenaic depression is a broad perpendicular corridor. Its best represented section is the Canal de Berdún, which limits on the south with the reliefs of San Juan de la Peña () and Oroel Rock (), modeled on conglomerates of the Campodarbe Formation. The pre-Pyrenean outer ranges are in the Huescan foothills and constitute the southernmost unit of the Pyrenees; formed by predominantly calcareous materials, reach heights between and meters. The Sierra de Guara, one of the most important mountain ranges of the Spanish Pre-Pyrenees, stands out; its summit, the Guara Peak, reaches metres. The Mallos de Riglos, near the town of Ayerbe, stand out for their beauty. Depression of the Ebro The Aragonese central depression includes a wide lowland area, which is also the central part of the Depression of the Ebro. North of the river there is the Sierra de Alcubierre ranges () one of the typical limestone plateaus of the valley. The Ebro Valley is a tectonic pit filled with sedimentary materials, accumulated in the Tertiary age in horizontal series. In the center, fine materials such as clays, plasters and limestones were deposited. To the south of the Ebro there are