80 GUIDEBOOK OF THE WESTERN UNITED STATES. 
body of igneous rock intruding the coal-bearing Mesaverde sandstone. 
Considerable gold ore has been found here and there along the 
slopes of these mountains and also in placer form in the wash of many 
of the draws leading out of them. The mining is done mainly by 
Mexicans; none of it is on a large scale, but it has been in progress 
. for more than two centuries and at intervals still yields a small profit. 
Gold was taken from the Dolores mine in this district as early as 1830. 
At milepost 849 the sandstones of later Cretaceous age rise from 
beneath the Tertiary beds and appear in ledges of considerable promi- 
nence just north of the railway, the ridge of breecia dropping back 
to the north. Halfway between mileposts 849 and 850, this sand- 
stone contains numerous petrified logs,! some of them 50 to 60 feet 
long, exposed in a small area a short distance north of the railway. 
From this place westward the sandstones are conspicuous in promi- 
nent ledges, in which most of the beds dip steeply to the southeast. 
Buff is the prevailing color, but some of.them are red. 
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Figure 15,—Section through ei 3 miles rig of Los se N. Mex., showing relations of coal 
the sheets o us rock 
Just north of the railway, halfway between mileposts 851 and 852, 
a large mass of igneous rock cuts across the beds of sandstone and 
shale. It was forced up in molten condition through cracks in the 
strata. A short distance farther west, where the igneous rock is 
quarried extensively, it is exposed cutting across vertical shales. 
This is in the eastern part of the village of Los Cerrillos. 
Los Cerrillos (sair-reel’yos, locally sair-ree’ yos; Spanish for little 
hills) is an old Ms rere mostly by mining in the adjoining 
Madrid, a few miles south of it, are large 
Los Cerrillos. aa mines whose product is taken by a branch rail- 
Population ara feet. way to Waldo, the next station beyond Los Cerrillos. 
Kansas City 868 miles, Lhe total amount of coal so far mined is more than 
" 2,500,000 tons, and the output in 1913 was approxi- 
mately 68,000 tons. Coal was discovered here in 1835. Before the 
railway was constructed the output of the mines was small, but 
in 1882 the deposits here became a very important source of supply, 
and a large area has since been worked out. There are three prin- 
These appear to be the remains write structure shows that they were conifers. 
a forest of Cretaceous age. | (See also the description of the Petrified 
= —— chalcedonized, but te aan Forest, pp. 107-109.) 
