THE SANTA FE ROUTE. 81 
cipal beds of coal, ranging from 3 to 5 feet thick m greater part. The 
field is about 12 miles long and 3 to 8 miles wide. The coal occurs 
in sandstone and shale of the Mesaverde formation. An interesting 
feature of this place is that a considerable part of the coal has been 
converted into anthracite and some of it into coke by the heat of 
two extensive sheets of igneous rock which have been forced in a 
molten condition between the beds. A large amount of this anthra- 
cite is mined, most of it from a bed which in other parts of the area 
yields bituminous coal. 
Four miles north of Los Cerrillos are the mines from which for 
many years our principal supply of turquoise was obtained. The 
mineral is found in small veins and other masses in an igneous rock 
(diorite porphyry), which cuts the Cretaceous shales and sandstones. 
It occurs very irregularly through the decomposed portions of the 
rock and also varies greatly in size, color, and suitability for use as a 
gem. It is believed that the turquoise has been deposited in cracks 
in the igneous rock by percolating waters which brought together, in 
solution, its constituents derived from the decomposing diorite por- 
phyry. Besides the principal mine there are several small openings 
in which small pockets of turquoise have been found from time to 
time. The value of the product has risen to $500,000 in some years; 
in 1895 one stone obtained was valued at $6,000. The locality has 
been known to the Indians for many centuries and was the source of 
the material used by them, in large amount, for beads and jewelry. 
Some of them regard it as a specific against contagion. When Pedro 
de Tovar, one of Coronado’s men, visited the Hopis in Arizona they 
presented him with specimens of turquoise which undoubtedly came 
from this place. Many of the early explorers visited the locality 
under the guidance of the Indians, for the place is referred to in the 
journals of all the expeditions which passed in this vicinity. On 
the slopes of Mount Chalchihuitl (tchal-tchi-wee’tl, the old Mexican 
name for turquoise), one of the minor peaks of the hills called Los 
Cerrillos, the earliest. observers discovered large pits that had been 
long abandoned, for the débris was overgrown with good-sized trees, 
1 The hills north of Los Cerrillos station | phenomena are visible at intervals in the 
are of similar origin to the Ortiz Moun- | next mile west. Nearly a mile west of 
tains, on the south—that is, they consist | Los Cerrillos a wall of the igneous rock 
of masses of igneous rock (diorite por- | rises 150 feet above the railway track and 
phyry) that has been forced up in molten | continues for nearly a quarter of a mile. 
condition through the Cretaceous shales.| At intervals westward past Waldo many 
along i ar vents of various sizes. | large dikes of the igneous rock cut the 
They constitute a group of six conical | shale, and most of them give rise to low 
peaks occupying an area of about 12 | but conspicuous ridges extending several 
square miles. The relations of one of | miles across the country. Some of these 
these masses is well exposed a short dis- | dikes are plainly visible a short distance 
t of the station, and other contact | north of the railway 
tan, 
