74  CONTRIBUTIONS   TO   ECONOMIC    GEOLOGY,  1907,  PART  II. 
CHEMICAL  CHARACTER. 
In  order  to  ascertain  the  quality  of  the  coals  of  the  Bull  Mountain 
field,  an  effort  was  made  to  collect  samples  for  chemical  analysis,  but 
owing  to  the  difficulty  of  getting  fresh  exposures  few  samples  of  much 
value  were  obtained.  The  samples  were  collected  in  a  uniform  man- 
ner and  in  compliance  with  specifications  used  by  the  fuel-testing 
plant  of  the  United  States  Geological  Survey,  as  given  on  pages  12-13. 
Analyses  of  these  samples  were  made  by  F.  M.  Stanton  in  the  chemical 
laboratory  at  Pittsburg,  and  the  results  are  given  in  the  following 
table : 
Analyses  of  coal  samples  from  the  Bull  Mountain  field,  Montana. 
[F.  M.  Stanton,  chemist  in  charge.] 
Name 
Mammoth. 
Wild- 
horse? 
Dor 
rity. 
Labor 
a  5797 
&5799 
5800 
a  5798 
a  5801 
Sampl 
e  as  received: 
24.59 
32.86 
27.94 
14.61 
.41 
4.83 
41.41 
38!  05 
3,449 
6,208 
17.45 
31.16 
45.05 
6.34 
.49 
5.45 
59.00 
.89 
27.83 
5,623 
10, 121 
12.69 
28.71 
50.90 
7.70 
.54 
5.44 
64.26 
.88 
21.18 
6,130 
11,034 
16.95 
30.78 
39.64 
12.63 
.49 
16.91 
„ 
33.05 
*' 
39.15 
H< 
/Ash 
10.89 
.34 
—  J 
P 
Ca 
Bt 
Loss  c 
Air-dr 
II 
* 
Ca 
Bi 
Thicla 
Thicki 
4,776 
8,597 
4,640 
8,352 
f  moisture  on  air  drying 
4.30 
3.00 
2.70 
3.20 
3.60 
ied  sample: 
21.20 
34.34 
29.19 
15.27 
.43 
4.54 
43.27 
.72 
35.77 
3,604 
6,487 
14.90 
32.12 
46.44 
6.54 
.50 
5.28 
60.82 
.92 
25.94 
5,797 
10,  434 
10.27 
29.51 
52.31 
7.91 
.56 
5.28 
66.04 
.91 
19.30 
6,300 
11,340 
14.20 
31.80 
40.95 
13.05 
.51 
13.81 
34.28 
Fixed  carbon 
40.61 
/Ash 
11.30 
iSulphur 
.35 
Hydrogen 
Carbon 
Nitrogen 
Oxygen 
lories 
4,934 
8,881 
4,813 
itish  thermal  units 
8,664 
less  of  bed 
Ft.  in. 
8    6 
1    6 
Ft.  in. 
8    6 
7    0 
Feet. 
4 
4 
Ft.  in. 
2    8 
2    8 
Feet. 
less  of  part  sampled 
2 
o  Badly  weathered. 
6Sli 
ghtly  w< 
athered 
5797.  Upper  18  inches  of  Mammoth  coal  bed  in  NE.  J  SW.  \  sec.  30,  T.  6  N.,  R.  27  E. 
5799.  Lower  7  feet  of  Mammoth  coal  bed  in  NE.  \  SW.  \  sec.  30,  T.  6  N.,  R.  27  E. 
5800.  Full  thickness  (4  feet)  of  Wildhorse  (?)  coal,  1  mile  northeast  of  Roundup. 
5798.  Full  thickness  (2  feet  8  inches)  of  Dorrity  coal  in  NE.  i  NW.  J  sec.  36,  T.  6  N.,  R.  26  E. 
5801.  Upper  2  feet  of  Dorrity  coal  in  NE.  \  NE.  i  sec.  27,  T.  6  N.,  R.  26  E 
These  analyses  differ  more  widely  in  British  thermal  units  than 
perhaps  should  be  expected  from  coals  of  the  same  field  having  very 
similar  physical  characters  and  occurring  under  the  same  conditions. 
The  differences  are  probably  due  to  the  fact  that  the  samples  repre- 
sent different  stages  in  the  deterioration  of  the  coals  consequent  upon 
their  exposure  to  the  deleterious  effects  of  the  elements.  Strictly 
fresh  samples  for  analysis  were  not  procurable  except  from  the  Wild- 
horse  coal.  A  sample  of  this  bed  was  taken  from  a  new  opening 
recently  made  by  the  Republic  Coal  Company,  at  a  point  1  mile  north- 
