THE SANTA FER ROUTE. 85 
the Santa Fe marl, at a point 6 miles northeast of Algodones, consist 
_ of the Dakota and associated sandstones and the red beds, while 
farther south the underlying rocks appear in a ridge of limestone 
(the Magdalena) which rises gradually to a high range known as the 
Sandia Mountains. (sahn-dee’ah, Spanish for watermelon). This 
range is a very prominent feature that extends along the east side 
of the Rio Grande valley for 7 miles. Its higher summits rise some- 
what above an altitude of 10,000 feet—that is, 5,000 feet above the 
river. 
Ruiz (rwees) is a contraction of the name of the Franciscan friar 
Rodriguez, who organized a small expedition from Mexico in 1581. 
On an exploring trip through the pueblos, he and 
— two other Franciscans remained after the departure 
Sia sos mites, Of their soldiers. The three friars were murdered 
by the Indians, Rodriguez being the last of the three. 
He was killed in this neighborhood, and his body was thrown into 
the Rio Grande, which was then in flood. 
On the west side of the river opposite Ruiz, a small body of black 
volcanic rock (basalt) is exposed, cutting across the marls and forming 
asmall peak. Probably this represents a feeder for the lava flow on 
the mesa, which here trends off to the northwest. 
Near Bernalillo the steep western front of the Sandia Mountains is 
plainly in view (PI. XIII, A, p.75). The greater part of the slope is 
_ granite and schist, but at the top there is a capping of several hun- 
dred feet of limestone, which also dips continuously down the more 
moderate eastern slope of the range. This limestone presents to the 
west a light-colored, almost unbroken cliff of considerable height, 
which is readily recognized above the darker, rugged, haget slopes. 
A cross section of the Sandia Mountains ! is given in 
evidence afforded by small exposures of 
' This range is the ‘sebtivabn imag of a 
limestone along the west foot of the moun- 
series of nearly similar ranges which 
stretch from north to south east of the 
Rio Grande, extending as far south as El 
been supposed that the beds on the west 
front of these mountains are cut off by 
ie & great fault, or in other words that 
_ they are due to an uplifted block of the 
earth’s di broken off along its west 
side. ere is, however, considerable 
tains to show that they are due mainly to 
an upward arch of the strata, effected 
mostly pon but doubtless with 
reaks. Most “ _—s 
slawk the west foot of the mountains are 
covered by a thick sheet of the Santa Fe 
Rio Grande valley. 
out at many places in the slopes on both 
sidesoftheriver. They are sands and fine 
loams, with some layers of reddish tint, all 
lying nearly horizontal. The broad basin 
or old valley which they occupy is exca- 
vated in of Cretaceous age. 
