Jemez — Albuquerque, N. Mex. — Reagan. 95 
up at present by the sediment carried down by its tributaries. 
Mountains. — The mountains of this section are the San 
Dia and the Jemez. 
The San Dia Mountains. — The San Dia mountains were 
caused by a drop of 11,000 feet along their western side, leav- 
ing an escarpment of 7,000 feet still remaining (Cope). The 
origin of these mountains dates back to a period later than the 
close of the Carboniferous usage, because their crest everywhere 
is Carboniferous rocks. These mountains are situated about 
8 miles east of Albuquerque and 25 miles to the southeast of 
Bernalillo. The dip of their strata is from 12 to 20° to the 
southeast. These mountains close in the Rio Grande embav- 
ment on the east of Albuquerque. 
The Jemez Mountains. — The Jemez mountains form a U- 
shaped plateau, the open space being toward the south in which 
most of the head streams of the Jemez river have their sources. 
The west portion of the U-shaped mountain area is called the 
Nacimiento mountains, and the east, the Cochite range. Its 
culminating point is Pelado whose crest is 11,200 feet in alti- 
tude. The core of these mountains is red feldspathic porphyry 
of the true Rocky mountain axis. The upper northwest part 
of these mountains terminates at the village of Nacimiento ; 
and the southern limit of each member terminates at the south 
in the latitude of the Indian village of Jemez. The}' are sit- 
uated 60 miles to the west and southwest of Santa Fe and 55 
miles north of Albuquerque. These mountains, judging from 
the youngest strata which flank their sides date back at least 
to Pre-Jurassic time. The oldest strata exposed are Carbon- 
iferous. They have been re-elevated at different times, as will 
be seen in the sequel. 
Villages and Cities. 
The villages and cities of this region are : — The Indian vil- 
lages of Santa Ana, Zia and Jemez, and the Mexican villages 
of San Y Sidro, Cafion de los Jemez, Perea (the Jemez Hot 
Springs) and the Sulphurs on the Jemez river; the Mexican 
villages of Cabizon, Lavantana and Nacimiento on the Rio 
Puerco ; and the Indian villages of San Felipe, San Dia and 
Ysleta, the Mexican villages of Thornton, Algodones, Bernal- 
illo and the city of Albuquerque, on the Rio Grande. Albu- 
querque is one of the leading cities of the southwest. Among 
