The New International Encyclopædia/Sierra Morena
SIERRA MORENA, mṓ-rā'nȧ. A mountain range of Spain running along the southern edge of the great central plateau, and forming the boundary between the provinces of Ciudad Real on the north and Jaén and Cordova on the south (Map: Spain, D 3). It rises but slightly above the plateau, its average elevation being about 3500 feet, but on the south it falls in a steep and imposing escarpment toward the low valley of the Guadalquivir. The railroad from Madrid to Cordova crosses it through several tunnels in the romantic pass called the Puerto de Despeñaperros.