CHAPTER XXIII. 



OF THE MOUNTAIN SYSTEMS. 



Remarks upon. — Pinalneo mountains, parallbl ranges. — Geogbaphical extent. — Classification of the strata. — Igneous 

 BOCKS. — Age of the range. — Mogollon mountains. — Interval between it and the former range. — Geology of. — ^^Igneous 

 axis, importance of. — Of the LrssER ranges and isolated hills between the san pedbo river and the Colorado desert. — 

 Organ mountains, extent, direction, axis. — Stratified rocks of. — Carboniferous limestone. — Minerals op. — East side op 

 THE range. — Jornada del mderto. — Relative ages of the igneous rocks of the system. — Of the sandstones west of the 

 organ mountains. 



Since observation in Europe lias shown that the direction of the upheaval of mountain 

 systems is a key to ascertain the epoch of their elevation, it becomes a duty in explorations upon 

 this continent to try how far observations upon American mountain chains may afford the clue 

 to their relative antiquity ; but little, as yet, has been done here in this field. M. E. De Beau- 

 mont, who has applied the observations so successfully to France and Mediterranean Europe, 

 having developed by his observations over 30 systems of elevation of different antiquity, has 

 himself classed the Alleghany mountains in the systems of the Bullous of France, his second 

 oldest system ; and the ranges at Keewenau and Cape Blomidon are classed with that of Morban, 

 in France, the fifth series of elevations. Other analogies are not yet admitted. Without 

 endeavoring to ally the ranges of this country with those of Europe, and strive to form parallels 

 where the resemblance is but remote, it may be useful, notwithstanding, to place by themselves 

 the observations and generalizations made upon mountain ranges, and from the material form a 

 system of continental elevations. 



Throughout New Mexico the direction of the ranges are north and south. Those to the east, 

 on the elevated plateau, running only a few degrees west of north, and those to the west 

 diverging N. 45° W. to N. 60° W. 



Those which are more conformable to the meridian are generally longer chains, while those 

 running N.W. and W.N.W. become isolated ranges, or a chain of unconnected hills, which, 

 however persistent in their linear direction, may yet be travelled round, owing to their isolated 

 position. The Mogollon mountains are the only known exception to this rule. There are no 

 ranges in the territory running east and west. 



The hills crossed on the route were the ranges at the cailons of the Gila and at the mouth of 

 the San Pedro river ; these have been called here the Pinaleno mountains. East of these 

 are the foot hills and outliers of the Mogollon mountains, and west of the Pimas villages are 

 the Estrella hills and some isolated ranges of small importance. East of the Eio Grande lie 

 the long chain of the Organ mountains. These will be considered in the order enumerated. 



PINALENO SYSTEM. 



The Santa Catarina mountain, the Sierra Calitro and the Pinaleno hills may all be classed 

 together as one mountain system, as well from their proximity as their geological constitution. 

 These ranges occupy a large portion of southern New Mexico and of the newly acquired territory 



