New Vitrinite Reflectance Data 

itrinite Reflectance Data 

Bighorn Basin, North-Central WBighorn Basin, North-Central W

and South-Central Montana and South-Central Montana 

Open-File Report 2007-1246 Open-File Report 2007-1246 

U.S. Department of the Interior U.S. Department of the Interior 

U.S. Geological Survey U.S. Geological Survey 
New Vitrinite Reflectance Data for the Bighorn 

Basin, North-Central Wyoming and South-Central 

Montana 

By Thomas M. Finn, and Mark J. Pawlewicz 

Open-File Report 2007–1246 

U.S. Department of the Interior 

U.S. Geological Survey 
U.S. Department of the Interior 

DIRK KEMPTHORNE, Secretary 

U.S. Geological Survey 

Mark D. Myers, Director 

U.S. Geological Survey, Reston, Virginia 2007 

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Suggested citation: 

Finn, T.M., Pawlewicz, M.J., 2007, New vitrinite reflectance data for the Bighorn Basin, 

north-central Wyoming and south-central Montana: U.S. Geological Survey Open-File 

Report 2007-1246, 9 p.
Contents

Introduction.....................................................................................................................................................1

References Cited............................................................................................................................................3

Figures

1. Map showing general outline of the Bighorn Basin...............................................................5

2. Generalized stratigraphic chart of uppermost Jurassic, Cretaceous, and

lower Tertiary rocks in the Bighorn Basin ................................................................................6

Tables

1. Vitrinite reflectance (Ro) data and locations for cuttings samples from wells

drilled for oil and gas exploration and production in the Bighorn Basin.............................7

2. Vitrinite reflectance (Ro) data and locations for samples collected from

outcrops in the Bighorn Basin....................................................................................................9
New Vitrinite Reflectance Data for the Bighorn 

Basin, North-Central Wyoming and SouthCentral Montana 

By Thomas M. Finn, and Mark J. Pawlewicz 

Introduction 

The Bighorn Basin is a large Laramide (Late Cretaceous through Eocene) 

structural and sedimentary basin that encompasses about 10,400 mi2

 in north-central 

Wyoming and south-central Montana (fig. 1). Important conventional oil and gas 

resources have been discovered and produced from reservoirs ranging in age from 

Cambrian through Tertiary (Fox and Dolton, 1989, 1996a, b; De Bruin, 1993). In 

addition, a potential unconventional basin-centered gas accumulation may be present in 

Cretaceous reservoirs (Johnson and Finn, 1998; Johnson and others, 1999). The purpose 

of this report is to present new vitrinite reflectance data to be used in support of the U.S 

Geological Survey’s assessment of undiscovered oil and gas resources of the Bighorn 

Basin. These new data supplement previously published data by Nuccio and Finn 

(1998), and Yin (1997), and lead to a better understanding and characterization of the 

thermal maturation and burial history of potential source rocks. 

Eighty-nine samples of Cretaceous and Tertiary strata (fig. 2) were collected and 

analyzed—15 samples were from outcrops around the margins of the basin and 74 

samples were well cuttings (fig. 1). Forty-one of the samples were shale, two were 

carbonaceous shale, and the remainder from coal. 

1
All samples were analyzed by vitrinite reflectance to determine levels of thermal 

maturation. Preparation of samples for reflectance analysis required (1) crushing the 

larger pieces into 0.25-to 1-mm pieces, (2) casting the pieces with epoxy in pre-cut and 

drilled plugs, and (3) curing the samples overnight. Subsequently, a four-step grinding 

and polishing process was implemented that included sanding with progressively finer 

sandpaper (60 and 600 grit) followed with a two-step polishing process (0.3 and 0.05 

micron). Vitrinite reflectance measurements were determined at 500 X magnification 

using plane-polarized incident white light and a 546-nm monochromatic filter in 

immersion oil. For samples containing sufficiently high quality vitrinite, at least 25 

measurements were recorded. For samples of poorer quality, either due to a poor polish 

or to the presence of mineral or other inorganic material, fewer measurements were 

recorded. Analytical results are given in tables 1 and 2. 

2
References Cited 

De Bruin, R.H., 1993, Overview of oil and gas geology of Wyoming, in Snoke, A.W., 

Steidtmann, J.R., and Roberts, S.M., eds., Geology of Wyoming: Geological Survey of 

Wyoming Memoir No. 5, p. 836-873. 

Fox, J.E., and Dolton, G.L., 1989, Petroleum geology of the Wind River and Bighorn 

Basins, Wyoming and Montana: U.S. Geological Survey Open-File Report 87-450P, 

41p. 

Fox, J.E., and Dolton, G.L., 1996a, Bighorn Basin Province; in Gautier, D.L., Dolton, 

G.L., Takahashi, K.I., and Varnes, K.L., eds., National assessment of United States oil 

and gas resources—results, methodology, and supporting data: U.S. Geological Survey 

Digital Data Series DDS-30, Release 2, CD-ROM. 

Fox, J.E., and Dolton, G.L., 1996b, Petroleum geology of the Bighorn Basin, northcentral Wyoming and south-central Montana; in Bowen, C.E., Kirkwood, S.C., and 

Miller, T.S., eds., Resources of the Bighorn Basin: Wyoming Geological Association 

Guidebook, p. 19-39. 

Johnson, R.C., and Finn, T.M., 1998, Is there a basin-centered gas accumulation in Upper 

Cretaceous rocks in the Bighorn Basin?, in Keefer, W.R., and Goolsby, J.E., eds., 

Cretaceous and Lower Tertiary rocks of the Bighorn Basin, Wyoming and Montana: 

Wyoming Geological Association Guidebook, p. 257-273. 

Johnson, R.C., Crovelli, R.A., Lowell, B.G., and Finn, T.M., 1999, An assessment of inplace gas resources in the low-permeability basin-centered gas accumulation of the 

Bighorn Basin, Wyoming and Montana: U.S. Geological Survey Open-File Report 99-

315-A, 123 p. 

3
4

Nuccio, V.F., and Finn, T.M., 1998, Thermal maturity and petroleum generation history 

of Cretaceous and Tertiary source rocks, Bighorn Basin, Wyoming and Montana, in

Keefer, W.R., and Goolsby, J.E., eds., Cretaceous and Lower Tertiary rocks of the 

Bighorn Basin, Wyoming and Montana: Wyoming Geological Association Guidebook, 

p. 211-231. 

Yin, Peigui, 1997, Source rock maturation and diagenetic modeling in Badger Basin, in

Campen, E.R., ed., Bighorn Basin—50 Years on the Frontier, Part 2: Yellowstone 

Bighorn Research Association-Wyoming Geological Association-Montana Geological 

Association, 1997 Field Trip and Symposium, p. 41-44. 

 
T

50

N

T

55

N

T

9

S

T

45

N

T

40

N

R94W R90W R85W

R95W

R100W

R104W

T

50

N

T

55

N

T

57

N

T

9

S

T

5

S

R15E R20E R25E R30E R35E

R101W R95W

R90W R85W

R35E R40E

R105W

T

40

N

T

45

N

T

5

N

R5W R1W R1E R5E

T

8

N

R4W

T

8

N

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6

5 4

3

2

1

9

8

7

6

4 5

3

2

1

15

14

13

12

11

10

Montana

Wyoming

110° 109° 108° 107°

44°

45°

Figure 1. Map showing general outline of the Bighorn Basin, bordering mountain ranges, distribution of major rock units, and sample

localities. Numbers refer to column 1 (map no.) in tables 1 and 2.

0 10 20 30 40

Miles

Precambrian rocks

Tertiary volcanics

Bighorn Basin Province

Absaroka

volcanics

Beartooth

Mountains

Creek Mountains

Owl

Mountains

Bighorn 

Mesaverde outcrop

Outcrop locations

Well locations
PALEOCENE UPPER CRETACEOUS

CRETACEOUS TERTIARY (part)

EOCENE

(part)

JURASSIC

(part) LOWER

CRETACEOUS

Tatman Formation

Mowry Shale

Muddy Sandstone

Thermopolis Shale

Bearpaw Shale

Morrison Formation

Willwood Formation

Cloverly Formation

Lance Formation

Meeteetse Formation Lewis Shale

Fort Union

Formation

Mesaverde

Formation

Mesaverde Formation

Lower member

Claggett Member

Teapot Sandstone Member

Frontier Formation

Cody Shale

Figure 2. Generalized stratigraphic chart of uppermost Jurassic, Cretaceous and lower

Tertiary rocks in the Bighorn Basin.
Map no. API Operator Well name Tnsp. Rng. Sec. Sample type Lith. Top depth Bottom depth Formation %Ro n

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 16,500 16,550 Cody 1.40 4

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 17,000 17,050 Cody 1.73 5

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 17,500 17,550 Cody 1.00 7

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 18,000 18,050 Cody 1.17 8

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 18,500 18,550 Cody 1.53 15

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 19,000 19,050 Frontier 1.68 13

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 19,520 19,540 Mowry 1.72 9

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 19,740 19,770 Cloverly 1.24 15

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 20,000 20,040 Cloverly 1.60 10

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 12,800 12,850 Cody 1.43 3

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 13,000 13,050 Cody 1.31 9

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 13,500 13,550 Cody 1.38 2

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 14,000 14,050 Cody 1.60 7

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 14,500 14,550 Cody 1.68 15

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 14,710 14,760 Frontier 1.68 10

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 15,000 15,050 Frontier 1.75 7

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 15,500 15,550 Mowry 1.67 8

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 15,900 15,940 Cloverly 1.82 11

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 15,000 15,040 Cody 0.82 3

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 15,500 15,550 Cody 0.94 6

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 16,000 16,050 Cody 1.22 8

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 16,500 16,550 Cody 1.20 6

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 17,000 17,050 Frontier 1.51 8

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 17,450 17,480 Frontier 1.19 7

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 18,000 18,050 Mowry 1.53 13

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 18,270 18,320 Cloverly 1.69 16

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings coal 4,680 4,780 Willwood (?) 0.59 25

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings coal 5,540 5,600 Fort Union 0.56 25

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings coal 7,410 7,480 Fort Union 0.63 25

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings coal 9,120 9,220 Fort Union 0.56 25

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings coal 10,900 10,960 Fort Union 0.70 27

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings coal 11,380 11,430 Fort Union 0.74 25

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings coal 11,770 11,790 Fort Union 0.76 25

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings coal 11,940 12,000 Lance 0.79 25

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings coal 13,600 13,640 Lance 0.97 25

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings coal 13,800 13,840 Meeteetse 1.00 15

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings coal 14,890 14,960 Mesaverde 1.14 19

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings coal 15,480 15,520 Mesaverde 1.28 19

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings shale 15,960 16,060 Cody 1.48 4

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings shale 16,500 16,580 Cody 1.63 13

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings shale 17,000 17,080 Cody 1.69 21

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings shale 17,500 17,550 Cody 1.74 15

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings shale 17,810 17,870 Frontier 1.77 13

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings shale 18,000 18,040 Frontier 1.87 11

4 4902920532 Texas Pacific Red Point II Unit 1 53N 98W 30 cuttings shale 18,450 18,500 Mowry 1.60 15

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 4,830 4,980 Fort Union 0.59 25

Table 1. Vitrinite reflectance (Ro) data and locations for cuttings samples from wells drilled for oil and gas exploration and production in the Bighorn Basin, north-central Wyoming and south-central 

Montana. Map no. refers to numbers plotted in figure 1.

[API, well number assigned by American Petroleum Institute; Tsp., township; Rng., range; Sec., section; Lith., lithology; n, number of readings per sample. Queried (?) where uncertain. Depth is in feet.]
5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 5,430 5,550 Fort Union 0.52 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 6,870 6,960 Fort Union 0.62 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 7,350 7,470 Fort Union 0.61 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 8,070 8,110 Fort Union 0.63 27

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 8,150 8,190 Fort Union 0.64 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 8,510 8,550 Fort Union 0.59 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 8,830 8,910 Fort Union 0.72 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 9,360 9,430 Fort Union 0.70 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 9,760 9,840 Fort Union 0.62 29

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 10,000 10,070 Fort Union 0.69 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 10,720 10,780 Fort Union 0.81 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 11,060 11,140 Fort Union 0.74 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 11,580 11,620 Fort Union 0.74 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 12,120 12,170 Fort Union 0.82 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 12,600 12,630 Lance 0.79 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 12,880 12,950 Lance 0.65 17

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 13,470 13,560 Lance 0.64 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 13,730 13,780 Lance 0.99 25

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 14,000 14,050 Meeteetse 1.05 15

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 14,440 14,520 Meeteetse 0.75 15

5 4902920787 Husky Oil 14-25 Unit 53N 99W 25 cuttings coal 15,480 15,540 Mesaverde 1.12 25

6 4902920475 CIG Exploration 1McCulloch Peak 54N 101W 10 cuttings shale 11,660 11,690 Cody 0.75 7

6 4902920475 CIG Exploration 1McCulloch Peak 54N 101W 10 cuttings shale 12,000 12,050 Cody 1.10 12

6 4902920475 CIG Exploration 1McCulloch Peak 54N 101W 10 cuttings shale 12,500 12,550 Cody 0.99 9

6 4902920475 CIG Exploration 1McCulloch Peak 54N 101W 10 cuttings shale 13,000 13,050 Cody 1.12 8

6 4902920475 CIG Exploration 1McCulloch Peak 54N 101W 10 cuttings shale 13,500 13,550 Cody 1.07 18

6 4902920475 CIG Exploration 1McCulloch Peak 54N 101W 10 cuttings shale 14,170 14,190 Frontier 1.18 9

6 4902920475 CIG Exploration 1McCulloch Peak 54N 101W 10 cuttings shale 15,200 15,225 Cloverly 1.31 21

Map no. API Operator Well name Tnsp. Rng. Sec. Sample type Lith. Top depth Bottom depth Formation %Ro n

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 16,500 16,550 Cody 1.40 4

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 17,000 17,050 Cody 1.73 5

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 17,500 17,550 Cody 1.00 7

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 18,000 18,050 Cody 1.17 8

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 18,500 18,550 Cody 1.53 15

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 19,000 19,050 Frontier 1.68 13

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 19,520 19,540 Mowry 1.72 9

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 19,740 19,770 Cloverly 1.24 15

1 4902920489 American Quasar 1 Sellers Draw 48N 98W 21 cuttings shale 20,000 20,040 Cloverly 1.60 10

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 12,800 12,850 Cody 1.43 3

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 13,000 13,050 Cody 1.31 9

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 13,500 13,550 Cody 1.38 2

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 14,000 14,050 Cody 1.60 7

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 14,500 14,550 Cody 1.68 15

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 14,710 14,760 Frontier 1.68 10

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 15,000 15,050 Frontier 1.75 7

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 15,500 15,550 Mowry 1.67 8

2 4900320574 Santa Fe Energy 1-20 Tatman Mtn. 49N 96W 20 cuttings shale 15,900 15,940 Cloverly 1.82 11

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 15,000 15,040 Cody 0.82 3

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 15,500 15,550 Cody 0.94 6

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 16,000 16,050 Cody 1.22 8

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 16,500 16,550 Cody 1.20 6

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 17,000 17,050 Frontier 1.51 8

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 17,450 17,480 Frontier 1.19 7

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 18,000 18,050 Mowry 1.53 13

3 4902921064 Forest Oil 1 Emblem Bench 51N 98W 2 cuttings shale 18,270 18,320 Cloverly 1.69 16

Table 1. Vitrinite reflectance (Ro) data and locations for cuttings samples from wells drilled for oil and gas exploration and production in the Bighorn Basin, north-central Wyoming and south-central 

Montana. Map no. refers to numbers plotted in figure 1.—Continued

[API, well number assigned by American Petroleum Institute; Tsp., township; Rng., range; Sec., section; Lith., lithology; n, number of readings per sample. Queried (?) where uncertain. Depth is in feet.]
Table 2. Vitrinite reflectance (Ro) data and locations for samples collected from outcrops in the Bighorn Basin, northcentral Wyoming and south-central Montana.

[Map no. refers to numbers plotted in figure 1. Lith., lithology; n, number of readings per sample. Queried (?) where uncertain.] 

Map no. Latitude Longitude Sample type Lith. Formation %Ro n

1 43.84427 -107.53406 outcrop coal Fort Union 0.37 28

2 44.11637 -108.78875 outcrop coal Meeteetse 0.36 25

3 44.46481 -109.03073 outcrop shale Frontier(?) 0.56 5

4 44.30424 -108.92427 outcrop coal Meeteetse 0.36 26

5 44.27300 -108.87899 outcrop coal Fort Union 0.36 26

6 44.06968 -108.75522 outcrop carb shale Mesaverde 0.27 2

7 43.99319 -108.63836 outcrop carb shale Meeteetse(?) 0.69 8

8 43.91672 -108.52686 outcrop coal Meeteetse(?) 0.35 22

9 43.84570 -108.35965 outcrop coal Meeteetse(?) 0.38 26

10 43.79930 -108.29036 outcrop coal Mesaverde 0.42 22

11 44.27370 -107.87090 outcrop coal Meeteetse(?) 0.37 22

12 44.59260 -108.20030 outcrop coal Fort Union 0.96 18

13 44.78702 -108.64310 outcrop coal Lance 0.35 32

14 45.15844 -109.18591 outcrop coal Fort Union 0.42 26

15 44.72590 -109.21809 outcrop coal Mesaverde 0.34 26