7<> EXPLORING EXPEDITION FROM SANTA FE 



a great imaginary chain, which was assigned an inordinate extent and a trend 

 altogether hypothetical and abnormal. It is to be hoped that one result of our 

 expedition will be to bring 1 something- like order out of the confusion of ideas which 

 has prevailed in regard to the intricate mountain ranges of this region. As has been 

 before Intimated, thgse ranges, though numerous, exhibit no exceptional features, and 

 are comparatively simple and harmonious in structure and trend; while it is true that 

 the great mountain belt north of the San Juan River, with its higher chains, their thou- 

 sand interlocking' spurs and narrow valleys, form a labyrinth whose extent and intri- 

 cacy will at present defy all attempts at detailed topographical analysis. It is equally 

 true that a general topographical character has been given to all of this region by a 

 comparatively few lines of lofty summits, which have nearly a north and south trend, 

 and seem to form an integral portion of the, Rocky Mountain system. This great truth 

 may be learned at a glance by the drainage of this country; tin's all flows through 

 streams which have approximately a north and south direction. On the south, the 

 tributaries of the San Juan, the Navajo, the Blanco, the Upper San Juan, the Piedra, 

 the 1'inos, the Florido, theAnimas, the La Plata, and the Mancos, all flow southward- 

 and most of them issue from the north and south valleys, lying between the parallel 

 ranges to which I have so frequently referred. On the north side of this mountain-belt 

 similar topographical features present themselves. The tributaries of Grand River, 

 which sweep the bases of the northern extremities of these ranges, almost without 

 exception issue from valleys which have approximately a north and south direction; 

 hence, it is plainly apparent that one great fundamental idea pervades the topography 

 of all this region, and that one great force has given shape to all its principal topo- 

 graphical features. 



Most of the prominent ranges visible from our route have received from the Indians 

 and Mexicans distinct names, by which they are well known to those who know the 

 country; for example, the chain north of the Lagnna, of which the southern extremity 

 is drained by the Chama and Rio Navajo, is called the Sierra del Rio Navajo or the 

 Sierra del Navajo. From between the spurs of this sierra flows the Rito Blanco (Little 

 White River), so called from the milky color given to its waters by the Cretaceous 

 shales. From the valley separating the upper part of this sierra from the Sierra San 

 Juan, which does not extend so far south, issues that branch of the San Juan River 

 which retains its name. West of the San Juan Mountains, as we shall see as we pro- 

 gress with our geological narrative, the b'io de los Pinos issues from the. valley between 

 the Sierra San .Juan and the Sierra de los Pinos; beyond the Sierra de los Pinos 

 the great valley of the Animas; then the Sierra de la. Plata, west and north of which 

 lies the Sferra San Miguel; west and south of the latter chain, the broad expanse of the 

 Colorado Plateau. From this sketch, it will be seen that the great cast and west chains 

 of the Sierra San Juan and Sierra, de la Plata, which form so conspicuous features on 

 some of our maps, have really no existence, and need therefore no longer vex us as 

 incongruous elements in theorology of our country. 



Like the Santa Fc Mountains, the Sierra San Juan terminates abruptly south- 

 ward, standing out as a bold headland on the margin of the sea-like plateau. The 

 altitude of its highest summits must be nearly 1,"., 000 feet, as snow lies on them in 



