46 GENERAL DESCRIPTION OF THE COUNTRY. 



Gold mines have "been worked at' the Calabasas^ onthe Santa Cruz river, and in the mowitaing 

 of New Mexico, on both sides of the KiS Bravo. ' - * ' 



It will not he extravagant to predict the discovery of many localities where silver mines can 



• ■ - 



he worked to advantage throughout the whole region where carboniferous limestone exists, ex- 



■m 



tending on the line of boundary from the^great bend.of the Eio Bravo, in Texas, to the meridian 

 of the San Luis range. Should this conjecture prove true, we shall have theri, in abundance, 

 the only commodity in which we are now deficient, and for w^hich we are at all dependent upon 

 any other country. 



5V.ilUXi^XV.l40 XV.5 



California. Vei 



ceeding richness, and, I think, one wholly disconnected 

 f the Santa Cruz river, between that river and the Gulf of 

 overed traversing a coarse sandstone, which. will be more 



particularly referred to in Chapter VI on that section of the boundary. . ' *" 



I have stated that the eastern portion of the continent, with which we are familiar, is entirely 

 different in its physical geography from the western, and arnong the distinguishing features of 



mountains 



that 



position until it reaches tide- water. 



* 



Between the two great chains, which I have attempted to describe, occupying the western 

 portion of the continent, there are other chains of mountains, so numerous that it is impossible 



by words ; some are continuous, some are detached ridges, others isolated 



em 



peaks, rising from the plateau almost with the uniformity and symmetrical proportions of arti- 

 ficial structures. Between them are found basins, which have no outlets to the ocean, but are 

 the receptacles of the drainage of the surrounding water-sheds. Of these, the most extensive is 

 the Great Salt Lake in Utah Territory, and the most remarkable for its historical associations 

 and present importance is the valley of the cify of Mexico. 



foTBl 



a prominent feature in the geography of North America, 

 extending two-thirds its length, and quite one-third its breadth. They belong to w^hat has been 



stem of North America 



Maria 



all -to the south of the 



limits 



Maria, which runs in a northern direction 

 of Casas Grandes. San Misruel, and Janos. 



The first is fed by the waters of the river Santa 



? 



bearin 



Santa 



of unusual freshets. 



meridian 



rise near the Santa Rita del Cobre, run towards that lake, but they disappear in the plain to 

 the north of the boundary, before reaching it. ... 



times 



'flphich last two-thirds of the vear, they become 



Their shores 



are covered with lacustrine deposites, and are usually unsuited to cultivation. The waters 



all locked up, however, by the mountains. Three great rivers 



these 



with their tributaries, have made their way in ditFerent directions to the ocean, cutting, in 



moun 



umbia. the Colo 



West 



Another river, the Gila, drains this plateau, cutting the 



mountains nearly at right Sngles, which, although a tributary of the Colorado, joins 



