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DENVER & RIO GRANDE WESTERN ROUTE. 14] 
tion, also of Upper Cretaceous age. The first shale to be seen is 
exposed in a cut in the side of a hill, but it is so close to the moving 
train that its character can not easily be determined. It is, however, 
very limy, and many of its layers consist of soft, white, impure lime- 
stone. This formation is the Niobrara limestone, and it is charac- 
terized by shells (Jnoceramus) from 8 to 10 inches in diameter, 
which occur in great abundance. These shells are of peculiar con- 
struction, for the grain of the shell runs directly through it instead 
of along or around it as in most shells, both fossil and living, and 
this structure makes the shell very weak and easily broken. At the 
time this shale and limestone were deposited there were, so far as is 
now known, no mountains in this region, and the sea had an un- 
broken sweep from the site of Missouri River on the east to the 
site of the Wasatch Mountains on the west. Many persons may find 
it hard to believe that changes so great have taken place in the face 
of the earth, but one who diligently studies the rocks is impressed 
more with its instability and change than with its stability. He 
soon learns that change has been the rule rather than the exception— 
that the rocky crust of the earth, which is so frequently referred to 
as “everlasting,” is not everlasting in the sense of unchangeable. 
The earth’s crust has been and doubtless is to-day like thin ice that 
bends under the skater’s weight but seldom breaks, and a depression 
in one place gives rise to an elevation in another. Depressions in 
the crust of the earth, if they were at all profound, have led to the 
invasion of the sea, and elevation has caused the formation of dry 
land and possibly mountains. 
The shale over which the traveler is passing is known in most of 
western Coloradd and Utah as the Mancos shale, but toward the east 
the middle part of the shale changes to limy shale and then to lime- 
stone (Niobrara), and where this limestone is found the shale under- 
lying it is generally called the Benton shale. That the rocks which 
form the large ridge on the left are coal-bearing is shown by old pros- 
pects and mine dumps that at many places scar the slopes. The first 
old mine to attract attention may be seen on the left just before 
the train passes milepost 370. This mine was near the top of the 
ridge, and the coal was lowered to the valley by a long inclined 
tramway, but Nature is fast removing the scars made by man, and 
they will soon not be noticeable. The first active operation to be seen 
is the Garfield (Vulcan) mine, opposite milepost 371, which is on a 
coal bed 14 feet thick. Coal from this mine also is lowered to track 
level over an inclined tramway, but this tramway is comparatively 
short. Farther along the mountain side the traveler may see moe 
escaping from an opening nearly on the same level as the mouth o 
the Garfield mine. This smoke comes from a fire in the mine that 
