162         CONTRIBUTIONS   TO    ECONOMIC   GEOLOGY,   1907,   PART   II. 
tunately,  there  are  only  a  few  places  in  the  area  where  fresh  samples 
could  be  obtained.  On  account  of  the  weathered  condition  of  the 
coal  many  of  the  samples  are  low  in  heating  value,  yielding  only  a 
little  over  5,000  British  thermal  units.  The  two  samples  from  the 
Glenrock-Big  Muddy  zone  which  run  over  9,300  British  thermal 
units  were  quite  fresh. 
Analyses  of  coal  samples  from  the  Glenrock  coal  field,  Wyoming. 
[F.  M.  Stanton,  chemist  in  charge.] 
Geologic  formation 
Fort  Union  (?). 
Montana. 
Name  of  coal  zone 
Douglas-Inez. 
Glenrock-Big  Muddy. 
Resistant 
sandstone. 
Low- 
est. 
Laboratory  No 
a  5318 
a  5317 
a  5321 
a  5422 
5325 
5326 
5330 
5322 
a  5320 
a  5323 
a  5319 
Sam 
pie  as  received : 
22.92 
42.62 
22.25 
12.21 
.58 
20.44 
30.49 
18.68 
30.39 
.43 
37.86 
29.08 
22.37 
10.69 
35.01 
28.46 
28.82 
7.71 
22.87 
48.03 
20.54 
8.56 
.52 
22.87 
33.89 
36.71 
6.53 
.97 
21.90 
34.05 
37.38 
6.67 
.86 
19.92 
49.25 
20.25 
10.58 
.68 
5.39 
51.96 
.60 
30.79 
4,851 
8,732 
15.58 
23.28 
22.68 
38.46 
1.17 
'2,'94i' 
5,294 
19.17 
26.17 
17.54 
37.12 
.52 
3.85 
30.68 
.56 
27.27 
2,718 
4,892 
19.83 
Volatile  matter. . . 
Fixed  carbon 
/Ash 
41.39 
26.21 
12.57 
\Sulphur 
.35         .28 
.72 
Hydrogen 
43 
Carbon 
£> 
Nitrogen 
Oxygen 
Ca 
4,071 
7,328 
3,136 
5,645 
2,861 
5,150 
3,295 
5,931 
4,679   •  4.956 
5,040 
9,072 
4,581 
8,246 
Bi 
Loss 
dr 
Air- 
itish  thermal  units 
of  moisture  on  air 
ping 
8,422 
8,921 
4.30 
5.30 
21.40 
23.30 
4.40 
4.20 
3.30 
1.50 
2.40 
5.30 
2.00 
iried  sample: 
19.46 
44.53 
23.25 
12.76 
.61 
15.99 
32.19 
19.72 
32.10 
.45 
20.94 
37.00 
28.46 
13.60 
.45 
15.27 
37.11 
37.57 
10.05 
.37 
19.32 
50.24 
21.49 
8.95 
.54 
19.49 
35.37 
38.32 
6.82 
1.01 
19.23 
35. 21 
38.66 
6.90 
.89 
18.70 
50.00 
20.56 
10.74 
.69 
5.30 
52.75 
.61 
29.91 
4,925 
8,865 
13. 50 
23.85 
23.24 
39.41 
1.20 
"3,013" 
5,424 
14.65 
27.63 
18.52 
39.20 
.55 
3.44 
32.40 
.59 
23.82 
2,870 
5,166 
18.19 
il 
Volatile  matter 
Fixed  carbon 
fAsh 
42.23 
26.75 
12.83 
[Sulphur 
.73 
Hydrogen 
p, 
Carbon 
0 
Nitrogen 
Oxygen 
Ca 
Br 
Thic 
lories 
4,254 
7,657 
3,312 
5,961 
3,640 
6,552 
4,296 
7,733 
4,894  1  5,173 
8,810     9,312 
5,212 
9,382 
4,675 
8,414 
itish  thermal  units 
kness  of  coal  bed . . 
Ft.  in. 
1    10 
Ft. in. 
4    2 
Ft.  in. 
1    8 
Ft.  in. 
2    6 
Ft.in. 
3    6 
Ft.  in. 
4    8 
Ft.in. 
5    6 
Feet. 
6 
Feet. 
3 
Ft.in. 
1     10 
Feet. 
3 
a  Weathered  sample. 
There  is  much  less  variation  in  quality  than  the  above  analyses 
would  indicate,  but  it  seems  probable  that  coals  of  the  Fort  Union  (?) 
formation  are  slightly  inferior  to  those  of  the  Montana.  The  latter 
are  blacker,  more  brittle,  lustrous,  and  clean.  Of  the  Fort  Union  (?) 
coals,  those  at  the  base,  in  the  Glenrock-Big  Muddy  zone,  seem  to  be 
the  best. 
METHOD   OF  WORKING. 
So  far  mining  has  been  carried  on  by  beginning  at  the  outcrop  and 
following  the  coal  down  the  dip  to  the  north  or  northeast.  It  may 
be  that  in  the  future,  when  coal  is  more  valuable  and  the  parts  near 
the  outcrop  are  worked  out,  shafts  will  be  sunk  back  from  the  out- 
crop and  the  coal  worked  up  the  rise. 
