56 GUIDEBOOK OF THE WESTERN UNITED STATES. 
is on the line of the Colorado & Southern Railroad from Denver to 
Texas. 
At Trinidad the plains give place to the high, rugged foothills of 
the Rocky Mountains. This change is due to the fact that here the 
Pierre shale is overlain by the Trinidad sandstone, which is sur- 
mounted by 2,000 feet of shales and sandstones that are resistant to 
erosion. The shales and sandstones above the Trinidad sandstone 
contain valuable deposits of coal. These coal-bearing rocks extend 
along the foot of the mountains for many miles in southern Colorado 
and southward for some distance in New Mexico. They are nearly 
horizontal in the vicinity of Trinidad. The prominent mountain 
mass southeast of Trinidad consists of coal measures and overlying 
strata capped by a thick sheet of black lava (basalt), constituting 
an extensive plateau with nearly flat top, known as Raton Mesa, 
One spur of this mesa projecting northward for some distance is 
named Fishers Peak after a German artillery officer who commanded 
a battery in the Army of the West that camped at its foot in 1846. 
Fishers Peak 
HTN 
Pierre shale 
Pierre shale SSS 
Figure 9.—Section threugh ee i tl t. a, Vermejo 
rmation ae coal bed; b, Trinidad sandstone, 
Its altitude is 9,586 feet, or more than 3,600 feet higher than Trinidad, 
so that it is a conspicuous object for many miles north and east. It 
is shown in Plate VIII. The mesa or plateau, which extends south 
from this peak, has a relatively level top about 20 square miles in 
area and is the remnant of a widespread lava flow that was poured 
out over the surface prior to the excavation of the valleys that are 
now so far below the mesa level. A portion of the same mesa, 
extending far to the southeastward at nearly the same altitude (8,511 — 
feet), is known as Bartlett Mesa. A section from Trinidad south- 
eastward to Fishers Peak and through Raton Mesa is given in figure 9. 
It is evident that many years have elapsed since the outflow of the 
lava sheet capping these mesas, because an enormous mass of material 
has been removed from the surrounding country, especially in the 
lower region to the north and east. However, the lava is geologic- 
ally of relatively recent age, being considerably later than the middle 
of Tertiary time. 
‘In the western part of Trinidad is a high ridge known as Simpsons 
Rest. Upon it stands an obelisk marking the grave of — 
Simpson, a noted mountaineer and trapper. 
