GENERAL DESCRIPTION OF THE COUNTRY. 47 



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moutli, and at an elevation so little above tlie sea^ that it may^ in a general description, be 

 considered a separate and independent drainage. 



Another feature of this basin system remains to be described, which is also common to all the 

 rest of the mountain regions occupying the plateau, and the region lying east of the Rocky 

 mountains. Between the ridges of mountains the traveller occasionally encounters vast plains, 

 which, %hen the sun is above the horizon, producing the phenomenon of the mirage, present 

 to him all the appearance of the sea. The plain bounds the view, and the line of the horizon 

 is broken into^waves, resembling, in appearance, the edge of the Grulf Stream, when seen from 

 the deck of a vessel ten or fifteen miles distant. The plains are clothed with vegetation of a 

 scrubby growth, incapable of aifording subsistence to any but a class of small animals, such as 

 antelope, prairie-dogs, and rabbits. Most generally, however, in the southern part of the 

 United States, these plains are clothed with a luxuriant growth of ^' grama," the most nutritious 

 of all the grasses. Sometimes they are destitute of all vegetation, except the larrea Mexicana, 

 the yucca, the cactus, and other spinous plants, and are paved with minute fragments of chalce- 

 dony, basaltj agate, and other hard rocks. Occasionally in these plains we encounter sand-dunes, 

 called by the Spaniards medanos, extending over a large area of country, and encircling what 

 might at first sight be supposed the shores of dried-up lakes. But an examination of the sand 

 with a microscope of sufficient power, dispels this idea. The grains seem to be angular, and 

 are not rounded by the attrition of water. An extensive formation of this kind occurs between 

 the Eio Colorado of the West and the base of the Sierra Madre, and extends many miles along 

 almost the whole extent of the western coast of the Gulf of California. Another very extensive 

 waste of sand lies to the south of the Arkansas river; a third is traversed by the Platte river ; 

 and a fourth which has come under my notice, less in extent, lies to the south of the Kio Bravo, 

 on the road from El Paso to the city of Chihuahua. 



The plains or basins which I have described as occurring in the mountain system, are not the 

 great plains of North America which are referred to so often in the newspaper literature of the 

 day in the expressions, ^^News from the plains,'' /'Indian depredations on the plains," &o. 



The term ^^ plains '' is applied to the extensive inclined surface reaching from the base of the 

 Rocky mountains to the shores of the Gulf of Mexico and the valley of the Mississippi, and form 

 a feature in the geography of the western country as notable as any other. Except on the bor- L 

 ders of the streams which traverse the plains in their cojiirse to the valley of the Mississippi, 

 scarcely anything exists deserving the name of vegetation. The soil is composed of disintegrated 

 rocks covered by a loam an inch or two in thickness, which is composed of the exuvise of animals 

 and decayed vegetable matter. The growth on them is principally a short but nutritious grass 

 called bufialo-grass, (Sysleria dyctaloides.) A narrow strip of alluvial soil, supporting a coarse 

 grass and a few cotton-wood trees, marks the line of the water-courses, which are themselves 

 sufficiently few and far between. 



Whatever may be said to the contrary, these plains west of the 100th meridian are wholly 

 unsusceptible of sustaining an agricultural population, until you reach sufficiently far south 

 to encounter the rains from the tropics. 



The precise limit of these rains I am not prepared to give, but think the Red river is, perhaps, 

 as far north as they extend. South of that river, the plains are covered with grass of larger 

 and more vigorous growth. That which is most widely spread over the face of the country is 

 the f^rama or mezquite grass, of which there are many varieties. This is incomparably the 

 most nutritious grass known. 



