SANTA FE TO LAS VEGAS. 105 
SANTA FE TO LAS VEGAS. 
The altitude of Santa Fé is 6,846* feet; and for some miles after leaving the city we con- 
tinued to ascend, till we reached the summit of the pass over the first of the lines of elevation 
intervening between the valley of the Rio Grande and the ‘‘Plains.’’ The axis of this range 
is granitic, and from Santa Fé, to and beyond Rock Corral—our first camp—we had the red 
granite, already spoken of, constantly in sight. 
On the flank of this great granitic mass the stratified rocks of its western slope reappear, much 
disturbed, but very fully exposed. At the base of the series, as on the Sandia mountain, is 
the Carboniferous limestone, but here generally covered and concealed by the more recent 
strata. Above the limestone are the saliferous sandstones and variegated marls, of which 
splendid sections are exposed in Apache caiion. These strata are much disturbed, but other- 
wise unchanged. 
The base of the cliffs in the cafion is composed of the red and green foliated sandstones and 
shales, the upper portion of the Saliferous group. They here present precisely the same ap- 
pearance as at Camp 101, in the Navajo country, Sheep spring, &c. Above these are the 
white and red calcareous sandstones of the Marl series, of which a thickness of perhaps 500 feet 
is visible. 
These latter strata show marked differences from their equivalents in the country west of 
the Rio Grande. The variegated marls so conspicuous further west, and which, with bands of 
magnesian limestone, form the base of the series, are here entirely wanting, or so modified as 
not to be recognizable. The only representatives of the group of rocks are, in this vicinity, 
the red and white calcareous sandstones, or indurated marls, which in the Navajo country 
form its upper half. This change is a progressive one, as will be seen by reference to the pre- 
ceding pages; and even progressive, both east and west, from a centre on the meridian of the 
Moqui villages. In the valley of the Little Colorado, in that longitude, the greater part of 
the interval between the saliferous sandstones and the Cretaceous rocks is filled with thin beds 
of highly colored marls and bands of magnesian limestone; west of that point, in the Painted 
Desert, the same interval is filled with thicker and more indurated strata, though otherwise 
similar. In coming eastward toward the Rio Grande we observed the variegated marls with 
bands of dolomite and silicified wood, a locally well-marked subdivision of the series, becoming 
less and less conspicuous, until here in Apache cafion they are entjrely wanting. As the aggre- 
gate thickness of the Marl series is at the same time considerably lessened, it might be sup- 
posed that its lower division was simply thinning out, but a converse change was noticed in 
the more massive portions of the series running parallel with this. The indurated marls or 
calcareous sandstones of the Moqui sections (Camps 91 and 92) increase in thickness and 
solidity toward the east, until at Fort Defiance, Laguna, &c., they quite overshadow the dimin- 
ishing marls. We may therefore infer that this change is one of conversion as well as elimina- 
tion; and it presents another difficulty in the way of an attempt to draw, without more fossils, 
division lines between different portions of the Marl series. 
On the banks of the Pecos extensive erosions have laid bare all the strata from the Carbon- 
iferous to the Cretaceous formation. The section from the summit of the mesa near Pecos vil- 
lage to the bed of the stream is as follows: 
Cretaceous. 
1. Yellowish white sandstone. 
: *% Emory’s reconnaissance, 1848, p. 37. 
14———-L 
