56 
LAEAMIE BASIN, WYOMING. 
of this anticline, a heavy white sandstone, probably the same as that 
which constitutes Pine Ridge, outcrops, dipping to the east at an 
angle of 40°. No coal, however, has been reported in the vicinity of 
this sandstone. 
Three miles farther southwest, on the west side of this anticline, in 
the NE. \ sec. 6, T. 17 N., R. 77 W., coal outcrops along the road. It 
dips westward beneath the ridge and may be either one of the coals 
that lie above the sandstone of Pine Ridge. It is reported that coal 
croppings continue on this line to Centennial Valley, but none of them 
were definitely located. 
In digging a deep well on Mill Brook, coal was encountered at 300 
feet in two beds, one 6 feet and another 3 feet thick. 
The following are analyses of coal from the Laramie Basin: 
Analyses of coal from the Laramie Basin a 
Water. 
Volatile 
matter. 
Fixed 
carbon. 
Ash. 
Sulphur. 
Total. 
1 
Brown mine, Dutton Creek 
11.25 
11.85 
14.50 
14.40 
11.50 
36.85 
34.05 
34.50 
34.90 
32.40 
45.00 
47.30 
44.75 
39.70 
49.70 
6.90 
6.20 
6.25 
11.00 
6.40 
1.13 
1.25 
1.03 
81.85 
?, 
do 
81.95 
3 
Chase mine, Mill Creek 
75.25 
4 
74.60 
5 
do 
82.10 
a Bull. Univ. Wyoming No. 7, 1905. Analyses 1 to 4 by School of Mines, University of Wyoming; 
5 by American Smelting and Refining Co. 
GYPSUM. 
Two varieties of gypsum occur in the Laramie Basin — earthy 
gypsum, or gypsite, and rock gypsum. The rock gypsum is used 
together with a very small amount of gypsite in the mill of the Con- 
solidated Plaster Company at Red Buttes; the gypsite is used by the 
Acme Cement Plaster Company near Laramie. 
ROCK GYPSUM. 
The thickest deposits of gypsum rock in the Laramie Basin lie along 
the foot of the north slope of Red Mountain in T. 12 N„ R. 76 W., a 
short distance north of the Wyoming-Colorado line. The gypsum 
outcrop first appears from beneath the Tertiary deposits near the 
middle of the west side of sec. 7, winds in and out around the foothills 
of Red Mountain through sees. 8, 9, and 10, passes out through the 
northeast corner of sec. 10, bends to the north, swings sharply west- 
ward through the middle of sec. 3, and turns northward again near 
the middle of sec. 4, where the gypsum becomes too thin to be of 
importance. The base of the gypsum beds throughout this region 
is marked by a bed of limestone a foot or more thick, crowded with 
fossils of upper Carboniferous age. A section of the gypsum measured 
at its maximum development in this vicinity, from the top of the 
beds on the northern foot of Red Mountain, in sec. 9, down to the 
fossil bed, is as follows: 
