28 THE BOOK CLIFFS COAL FIELD. 
About a quarter of a mile west of this place the following section is 
exposed at the same horizon: 
Section of lower coal bed near Book Cliff ' mine. 
Ft. in. 
Shale 6 
Coal * 7 
Bone h 
Coal 1 
Sandstone - 
Shale, carbonaceous 1 
Sandstone. 
Total coal 8| 
West of the Book Cliff mine less prospecting has been done than in 
the region to the east, but little variation in the thickness of the coal 
bed has been reported. At the Steele or Keystone mine (No. 11) 
there is 5 feet 3 inches of coal, including 4 inches of bone 1 foot 
from the top. The roof and floor are of shale, and the coal lies 3 feet 
above a bed of massive white sandstone. 
At the Black Diamond mine (No. 12) the following section was 
measured : 
Section of coal bed at Black Diamond mine. 
Shale. Ft. in. 
Coal 10 
Clay 2 
Coal 4 8 
Shale. 
Total coal 5 6 
Locally the coal bed is only 3 feet thick. At the Farmers mine the 
lower bed appears to be only 30 inches thick, but the upper coal is of 
greater value. 
Except in two important mines, the Book Cliff (No. 10) and the 
Cameo (No. 1), the upper coal is not worked on a commercial scale in 
this locality, partly because the lower coal in general is of better quality, 
but chiefly because the lower coal is more accessible, occurring several 
hundred feet nearer the base ot the cliffs. 
The upper bed, known as the Cameo coal, outcrops at river level at 
Cameo, on the Denver and Rio Grande Railroad. To the southwest 
it rises, and north of Palisades is 650 feet above the valley, lying at the 
base of the second tier of cliffs. (See PI. VII.) From Palisades the 
outcrop extends northwestward to the vicinity of the Book Cliff mine, 
at a distance of about a mile and a half from the crest of the lower 
escarpment. Thence westward the bench below the upper coal dis- 
appears and the two coal beds outcrop in the face of the cliffs, almost 
directly one above the other. The position of the upper coal is 
marked by a massive white sandstone almost immediately beneath it. 
This sandstone is locally 75 feet thick and can be traced for miles, but 
it is not constant and locally disappears. 
