Diverging from its main southwest-to-northeast alignment, the range has a westward-trending branch known as the "Cuerda Larga", or Carpetanos Mountains (Montes Carpetanos). (This name is sometimes also applied to the northern part of the main axis of the Guadarramas between Peñalara and Somosierra.) The 15 km long Carpetanos sub-range is an imposing sight, starting in the Community of Madrid at Puerto de Navacerrada, and averaging more than 2,000 metres in elevation all the way to the Morcuera Pass ("Puerto de la Morcuera"). From there, the Carpetanos slope downward until they reach the confluence of the Lozoya and Jarama rivers. The highest peak of the Cuerda Larga is the Cabezas de Hierro at 2,383 metres.