Auñamendi Eusko EntziklopediaFund Bernardo Estornés Lasa

Orography. The soil of Biscay is essentially mountainous. However, it has two beautiful fertile plains, that of Durango and that of Guernica. The former is more extensive, as it can be said to occupy the central part of the banks of the Ibaizabal. Guernica, formed by the alluvium of the river Mundaca, is growing as it is obstructed by river materials and maritime sands. The relief of Biscay is mainly shaped by the two mountain ranges that delimit the basins of the Ibaizabal. The southern one from Anboto and Alluitz, through Urkiola, Mugarra and Gorbea. The northern one, with the Arno, Kalamua, Oitz, Peñas de Lemona, Bizkargui and Berriaga mountains. A series of tributaries flow down from both mountain ranges, forming small valleys steep buttresses, hills and meadows until they flow into the Ibaizabal. The succession of lower elevation mountains in the northern area, or inland Biscay, gives rise to a series of independent rivers, Lea, Artibai, Mundaca, Butrón, etc. This gives rise to a series of small valleys, full of hills, small fertile plains, except for Guernica, which is quite important, oriented towards the coast. This has steep cliffs and small estuaries. On the other side of the Bilbao estuary, the Encartaciones area is also mountainous and has few meadows. The middle basin of the Nervión, from Areta to Basauri, has the same general appearance of Biscay, mountainous, green, dotted with farmhouses, villages and factories. The Bilbao estuary, with its also mountainous configuration and the occasional fertile plain that is being sacrificed for the sake of industry, deserves a separate chapter. The Biscayan mountain has two main chains running parallel to each other. The first of these, which we could call the Pyrenees, with a much more pronounced relief, stretches from Anboto to Gorbea. It is a continuation of the Pyrenean chain which, from the Mesa de los Tres Reyes in Navarre (2,430 m.) runs through Ori, Sayoa, Aralar, Aitzgorri, Artia, Elguea and Arlabán until it reaches Besaide, the border Guipúzcoa, Alava and Vizcaya. The main heights in Bizkaia in this range are from east to west: Anboto (1,246 m.), Alluitz (1,068 m.), Urkiola-Mendi (1,009 m.), Aramotz (1,009 m.) and Gorbea (1,475 m.). The Gorbea massif also has several important summits: Lekanda (1,302 m.), Gatzarrieta (1,183 m.), Gorosteta (1,255 m.), Aldamin (1,362 m.) and some others. On the border with Llodio (Alava), Ganekogorta (998 m.). In the mountains of Gordejuela, on the border with Alava, Beraskola (662 m.) and Espaldaseca (696 m.). The first foothills of the Ordunte mountain range begin with Mount Kolitza (874 m.), already on the border with Burgos. The Ordunte massif, a wall separating the lands of Bizkaia from those of Burgos, reaches important heights such as Burgüeno (1,032 m.), Maza de Pando (1,018 m.), Baiguerri (1,104 m.). The northern mountain range of Biscay, which forms the slope of small coastal rivers, begins at Kalamua (779 m.), Urko (791 m.), Mendibil (611 m.), Oiz (1,026 m.), Bizkargui (566 m.), Berriaga (366 m.), Muñarrikolanda (255 m.).