CHAPTER II. 



MEXICO. 



I. — General Considerations. 



jXCLUDINGr the Yucatan peninsula, tlie territory of tlie " United 

 States of Mexico " is a triangular mass which forms the southern 

 extremity of the North American continent properly so called. 

 These Hispano- American United States are bounded on the east 

 side by the long curve of the Gulf of Mexico, on the west bj^ the 

 shores of the Pacific, which describe a still more extensive arc of a circle. Both 

 curves gradually converge southwards in the direction of the Isthmus of Tehuan- 

 tepee, where Central America proper begins, if not in a political, at least in a geo- 

 graphical and historical sense. Both on the north and south sides, the frontiers 

 are purely conventional, corresponding in no way with the natural parting lines 

 of the fluvial basins. 



Doubtless, the north-east frontier, for a distance of about 750 miles, is traced 

 by the Ptio Bravo del Norte, which separates Mexico from Texas. But this 

 narrow stream is not a sufficiently salient geographical feature to constitute a 

 true dividino- line ; on both sides the plains and hills present the same general 

 aspect, and are subjec.*^ to the same climate. No material change is perceptible 

 for a long way beyond til? Texan border, where the population grows more dense, 

 and arable lands begin to replace li? unfertile savannas. 



West of the Rio Bravo the front iei^s, as laid down by the treaty between 

 Mexico and the United States, are a mere i^uccession of geometrical lines. At first 

 they coincide with 31° 47' north latitude /^or a distance of 100 miles ; then they 

 suddenly drop southwards to 31° 20' N., along which parallel they run westwards 

 to 111° W. of Greenwich. At this point, th^ line is drawn obliquely to the Rio 

 Colorado, 20 miles below the Rio Gila conflu ^^^^e, and then ascends this river to 

 the confluence at Yuma, whence it follow « a straight line across the neck of 

 the Californian peninsula to the Pacific coa st, 12 miles south of San Diego. 



Despite the fantastic character of th-'^s geometrical frontier, it coincides at 

 certain points with prominent physical traits in the general relief of the land. 

 Thus it connects the upper Bravo vallf 7 '^ith the head of the Gulf of California, 

 not far from the profound depression ■ between two distinct spurs of the Rocky 

 Mountains traversed by the Rio Gila. ■ 



At the other extremity of the M-^^ican territory, the political frontier is less 



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