elevations of the Cordillera, as it passes upward from Durango, lean towards the west until they pass the centre of Chihuahua, and then bending once more, nearly north, pursue their way through New Mexico into the remote wilderness of our Union. Towards the east these steeps become gradually depressed until they are lost in the vast and uncultivated regions of the Bolson de Mapimi, whose elevation above the sea is still 3,800 feet, according to the measurement of Dr. Wislizenius.
Seventeen rivers and streams flow through the territory of this State. The Rio Bravo, or Rio Grande del Norte; the Rio Conchas; Florida; Chihuahua; Tonachi; Llanos; Casas Grandes; San Buenaventura; Carmen; Santa Isabel; Pasesiochi; Mulatos; Chiñapas; Parral; San Pedro; Batopilas; and Rio Grande de Bavispe. The lakes or lagunes are those of San Martin; Guzman; Patos, or Candelaria; Encinillas; and Castilla. The river Nasas, which rises in Durango debouches in the Lake of Cayman, in the Bolson de Mapimi. The climate resembles that of the adjoining State of Durango. In the year 1834, the population, according to official statistics was 145,182; at present, it is estimated