CHAPTER XXIII. 
OF THE MOUNTAIN SYSTEMS. 
Remarks upon.—Pinalneo mountains, parallel ranges.—Geographical extent.—Classification of the strata.—Igneous 
rocks.—Age of the range.—Mogollon mountains.—Interval between it and the former range.—Geology of.—Igneous 
axis, importance of.—Of the lesser ranges and isolated hills between THE SAN PEDRO RIVER AND THE COLORADO DESERT.- 
Organ mountains, extent, direction, axis.—Stratified rocks of.—Carboniferous limestone.—Minerals of.—East side of 
THE RANGE.—JORNADA DEL MUEBTO.—KeLATIVE AGES OF THE IGNEOUS ROCKS OF THE SYSTEM.— Of THE SANDSTONES WEST OF THE 
ORGAN MOUNTAINS. 
Since observation in Europe bas 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 ; hut 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 Ballous 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 he 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 canons 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 Rio Grande lie 
the long chain of the Organ mountains. These will he 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 
