National Geographic : 1896 Sep
300 TOPOGRAPHIC TERMS OF SPANISH AMERICA are as follows, beginning at the north and east: The Montafia cordillera, the Colorado cordillera, the Guadalupe cordillera, and the cordillera of the eastern Sierra Madre. Each of these grades westward into a great mesa or plateau region. The Co lumbia plateau borders the Montafia cordillera. The Colorado plateau lies west, southwest, and southeast of the Colorado cor dillera. The Guadalupe cordillera is bordered on the west by a relatively smaller, but nevertheless extensive, plateau, known as the Sierra Diablo, which appears as a diminutive feature on the map. The eastern Sierra Madre of Mexico likewise flattens out westward into an extensive plateau region, which, for the want of a better name, I call the Parras plateau. The plateaus become tilted in places into cuestas, and, by faulting, the latter grade into sierras of the basin-range type, separated by bolsons. Each of the plateau regions is thus bordered on the west and south by great regions of bolsons and basin ranges. The Colorado plateau is bordered on the west and southwest by the Great Basin region of Powell and Gilbert, and' on the southeast by the Coahuilan bolson region. There are also internodal areas of mesa-like topography be tween the ends of the cordillera masses of the Rocky mountain systems, such as that lying between the southern end of the Colorado cordillera and the northern end of the Guadalupe cordillera. The great cordillera in western Mexico known as the Sierra Madre passes at its northern end into the Colorado plateau (not into the California sierras, as often supposed), and constitutes a partial barrier between the Coahuilan bolson region of Mexico, Trans-Pecos Texas, and New Mexico, and the great bolson (basin) region of Utah and .Nevada. The plateaus of the plains lying east of the Rocky mountain region south of Arkansas river are collectively a series of mesas overlooking broad plazas and separated from them by escarp ments. The conspicuous plaza regions are the Canadian and Pecos valleys of New Mexico. The great Central Denuded region of Texas, Oklahoma, and southern Kansas is also mostly a plaza region. On the east are Cretaceous prairies of Texas, which we have described as dip plains; these are incipient cuestas. The Central Denuded region lying between the westward-facing scarps of these prairies * on the east and the eastward-looking scarps of the plains on the west is collectively a great plaza country. *The old border of Appalachia forms the eastern boundary of this region, north of the Ouachita mountain system of Indian Territory.