TOPOGRAPHICAL NOTES. 233 



road, from which point they change into a more hilly country, which, at the 

 Paisano Pass, rises to an altitude of over 5000 feet in the lowest gap between 

 the mountains. 



The mountains through which Paisano Pass is cut continue northwest into 

 the Limpia and Boracho mountains, which again seem to extend into and 

 connect with the Guadaloupe range, which reach in the Guadaloupe Peak a 

 height of 9000 feet above the sea level, while the surrounding country rises to 

 only about 7000 feet. 



Southeast we find the Cathedral Mountains, the Mount Ord range, and 

 farther on the St. Jago Mountains, with the Rosillas, Corazones, and Chisos 

 mountains, and across the river the Sierra Carmen, the highest point of which 

 is said to reach an altitude of 10,000 feet above the sea level. 



From this mountain chain the country descends in about 50 miles from 

 Boracho (altitude 4450 feet above sea level) to the Pecos River. (Altitude at 

 Pecos City 3900 feet). Southeast of Fort Davis and north of Marathon 

 Station rises an isolated and steep granitic upheaval to an altitude of 800 feet 

 above the surrounding flats, covering about three square miles. This granite 

 mountain is surrounded by the stratified heights (Carboniferous) of the Com- 

 anche Mountains on the west and north, and by the strongly ferruginous 

 quartz and quartzitic mountains of the Pena Colorado range on the east, 

 which range extends east of the St. Jago Mountains in a southeasterly direc- 

 tion about 25 miles below Marathon, and can be traced over 12 miles in its 

 northwest course alongside of the Comanche Mountains. Farther north and 

 east the Cretaceous limestone begins, forming long-stretched hills with flat 

 tops. 



RIVERS. 



The Rio Grande, from El Paso to Presidio, runs southeast between moun- 

 tain chains which are nearly parallel to each other and to the more east- 

 ern mountain chains of West Texas. Below Presidio this river turns more 

 to the east (about north 60 degrees east), following this course to the south 

 slope of the Chisos Mountains, about 10 miles west of the 103d meridian, 

 near the 29th degree of northern latitude; there it turns nearly at right 

 angles to the northeast, and after traversing the canyons, follows this 

 same course, flowing between the Sierra St. Jago on the Texas side, and the 

 Sierra Carmen on the Mexican to a point about midway between the 103d 

 and 10 2d meridians, from whence it takes an eastern course, with a slight 

 southern deflection. 



The Pecos River flows in a southeastern direction, and in its lower course 

 cuts its way mostly through the limestone strata of West Texas. With the 

 exception of Toyah and Howard creeks, this river has no tributaries from 



