GYPSUM. 57 
Section of gypsum-bearing beds at the base of Red Mountain on the north side. 
Feet. 
Red gypsum rock, nearly pure 6 
Red shale 35 
Gypsum 3 
Red shale 10 
Gypsum 4 
Reddish shale 55 
Banded gypsiferous rock 5 
Red sandy shale 88 
Gypsum, massive 67 
Fossiliferous limestone 1 
274 
The main gypsum bed, ranging in thickness from 30 to 60 feet, 
extends nearly the whole length of the outcrop outlined above. The 
distance to Red Buttes, the nearest point on the railway, is about 
25 miles. 
Gypsum outcrops near the middle of the north side of sec. 7, T. 13 N., 
R. 73 W., a mile east of Sportsman Lake, where a small pit shows 
4 or 5 feet of pure rock gypsum. Whether this is the full thickness of 
the bed is not known. A curly, laminated gypsiferous limestone 
(Forelle) outcrops a quarter of a mile farther east and dips beneath the 
gypsum. This limestone extends east of north in a low ridge to Forelle 
and beyond, passing a quarter of a mile east of Red Buttes station. 
A mile south of Red Buttes station and a quarter of a mile east of 
the limestone ridge just described is the deposit of gypsum which has 
been worked since 1890 by the Consolidated Plaster Company. The 
beds dip beneath the limestone and are therefore lower than the 
gypsum at Sportsman Lake. The quarry at present worked is just 
east of the mill and shows a face of 15 feet of solid gypsum rock, which 
will probably be increased to 20 feet with further progress into the 
hill. A quarry formerly worked lies northwest of the mill and shows 
a face of 8 or 10 feet. The dip of this bed would carry it 25 or 30 feet 
above the quarry now worked, showing the existence of two beds at 
this point. The upper bed was struck again near the point where the 
siding to the mill leaves the main line of the Union Pacific Railroad, 
but north and south of these points the gypsum appears to thin 
out and disappear. An analysis of the gypsum from this bed, by 
D. O'Brine, of the Colorado Agricultural College, is as follows: 
Analysis of gypsum from Red Buttes. 
CaO 32. 5 
A1 2 3 3 
Fe 2 3 Trace. 
Si0 2 2 
S0 3 46. 3 
H 2 20. 8 
100.1 
