Distribution and Stratigraphic 

Significance of Foraminifera and 

Algae in Well Cores from 

Madison Group (Mississippian), 

Williston Basin, Montana

GEOLOGICAL SURVEY BULLETIN 1529-F

Distribution and Stratigraphic 

Significance of Foraminifera and 

Algae in Well Gores from 

Madison Group (Mississippian), 

Williston Basin, Montana

By WILLIAM J. SANDO and BERNARD L. MAMET 

CONTRIBUTIONS TO STRATIGRAPHY

GEOLOGICAL SURVEY BULLETIN 1529-F

Determination of age and correlation of the

Madison Group in the subsurface of the

Williston Basin on the basis of foramimfers and algae

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1981
UNITED STATES DEPARTMENT OF THE INTERIOR

JAMES G. WATT, Secretary

GEOLOGICAL SURVEY 

Dallas L. Peck, Director

Library of Congress catalog-card No. 81-607863

For sale by Distribution Branch, Text Products Section, 

U.S. Geological Survey, 604 South Pickett Street, Alexandria, Va 22304
CONTENTS

	Page

Abstract_........._......___...__.___..____.._______________________________________ Fl

Introduction_________________________________________ 1

Acknowledgments ___________________________________ 2

Distribution of microfossils___________________________ ____ 2

Biostratigraphy_______________________________________ 2

Lodgepole Limestone _________________________________ 2

Mission Canyon Limestone______________________________ 5

Charles Formation __________________________________ 7

Environmental interpretation _______________________________ 8

Regional correlation ____________________________________ 8

Conclusions _________________________________________ 11

References cited _____________________._________________ 11

ILLUSTRATIONS

Page

FIGURE 1. Isopach map of Madison Group in the Williston Basin, showing locations

of subsurface sections shown in figure 2 and discussed in text___ F3

2. Distribution of zonally identifiable microfossils in the Pine, Richey, 

Eggebrecht, and East Poplar cores____________________ 4

3. Correlation of Madison Group in Shell Pine Unit No. 1 well (4) with (1) 

Logan section, (2) composite of Monarch-US 89 and Dry Fork sections, 

and (3) composite of Little Chief Canyon and Mission Canyon sections 9

4. Paleogeologic map of Montana showing distribution of Big Snowy and 

Madison Groups and locations of stratigraphic sections shown in 

figure 3 ____________________________________________________________________ 10

m
CONVERSION FACTORS

Metric unit Inch-Pound equivalent

Length

millimeter (mm) 

meter (m) 

kilometer (km)

= 0.03037 inch (in) 

= 3.28 feet (ft) 

= .62 mile (mi)

Area

square meter (m2 ) 

square kilometer (km2 ) 

hectare (ha)

= 10.76 square feet (ft2 ) 

= .386 square mile (mi2 ) 

= 2.47 acres

Volume

cubic centimeter (cm3 ) 

liter (L) 

cubic meter (m3 ) 

cubic meter 

cubic hectometer (hm3 ) 

liter 

liter 

liter 

cubic meter

cubic meter

 0.061 cubic inch (in3 ) 

= 61.03 cubic inches 

= 35.31 cubic feet (ft3 ) 

= .00081 acre-foot (acre- ft) 

z=S10.7 acre-feet 

= 2.113 pints (pt) 

= 1.06 quarts (qt) 

= .26 gallon (gal) 

= .00026 million gallons (Mgal or 

10" gal) 

= 6.290 barrels (bbl) (1 bbl = 42 gal)

Weight

gram (g) 

gram 

metric tons (t) 

metric tons

= 0.035 ounce, avoirdupois (on avdp) 

==. .0022 pound, avoirdupois (Ib avdp) 

= 1.102 tons, short (2,000 Ib) 

= 0.9842 ton, long (2,240 Ib)

Specific combinations

kilogram per square 

centimeter (kg/cm2 ) 

kilogram per square 

centimeter 

cubic meter per second 

(mVs)

 0.96 atmosphere (atm)

= .98 bar (0.9869 atm) 

 35.3 cubic feet per second (ft3/s)

Metric unit

Spe

liter per second (L/s

cubic meter per seco

per square kilome

[(mVs)/km2 ] 

meter per day (m/d)

meter per kilometer 

(in/km) 

kilometer per hour 

(km/h) 

meter per second (m

meter squared per d

(m2/d) 

cubic meter per seco

(m«/s) 

cubic meter per min

(nV'/niin) 

liter per second (L

liter per second per 

meter [ (Ij/s)/m] 

kilometer per hour 

(km/h) 

meter per second (m

gram per cubic 

centimeter (g/cm

gram per square 

centimeter (g/cm

gram per square 

centimeter

degree Celsius (°C) 

degrees Celsius 

(temperature)
CONTRIBUTIONS TO STRATIGRAPHY

DISTRIBUTION AND STRATIGRAPHIC 

SIGNIFICANCE OF FORAMINIFERA AND

ALGAE IN WELL CORES FROM

MADISON GROUP (MISSISSIPPIAN),

WILLISTON BASIN, MONTANA

By WILLIAM J. SANDO and BERNARD L. MAMET'

ABSTRACT

Core samples of the Madison Group (Mississippian) from four wells in the Williston 

Basin, Montana, have yielded microfauna and microflora that are less abundant and 

diversified than those from outcrops of the Madison to the west because of less favorable environmental conditions in the Williston Basin area during Madison time. Mamet 

Zones 7, 8, 9, 10, and 11 (or possibly 12) are represented. Microfossil distribution supports the interpretation that the upper part of the Madison in the Williston Basin is no 

younger than early Meramecian (early Visean) and that the Madison is bounded above 

by the same regional disconformity that has been widely observed in surface sections.

INTRODUCTION

In a recent review of paleontologic evidence bearing on the age and 

geologic history of the Madison Group in the Williston Basin, Sando 

(1978) presented arguments, based on the distribution of corals, that 

the Madison Group in the subsurface is the same age as it is in outcrops west of the Williston Basin and that it is bounded above by the 

same regional disconformity observed in surface sections. These arguments run counter to most previously published interpretations of the 

age and nature of the upper boundary of the Madison in the Williston 

Basin (Perry and Sloss, 1943, p. 1301-1302; Hadley, 1950, p. 44; Sloss, 

1952, p. 65, 67; Nordquist, 1953, figs. 4 and 5; Gardner, 1959, p. 331-332; 

Sandberg, 1962, p. 64; Roberts, 1966, fig. 2; Maughan and Roberts, 1967, 

p. B5, fig. 1, pi. 2).

In order to test these conclusions, thin sections were made from core 

samples from the seven wells reported on by Sando (1978); Mamet 

searched the thin sections for foraminifers and algae and studied 

rewarding samples. The purpose of this report is to present data on the 

distribution and significance of these samples. No previous study of 

these microfossils from the Williston Basin has been published.

'Departement de Geologie, Universite de Montreal, Montreal H3C 3J7, Canada.

Fl
F2 CONTRIBUTIONS TO STRATIGRAPHY

ACKNOWLEDGMENTS

We are grateful to J. T. Dutro, Jr., and J. M. Berdan, U.S. Geological 

Survey, for their very helpful suggestions and their critical review of 

the manuscript. The excellent quality of the thin sections results from 

the work of K. R. Moore, U.S. Geological Survey.

DISTRIBUTION OF MICROFOSSILS

Although samples from all seven wells were examined, only the Pine, 

Richey, Eggebrecht, and East Poplar wells along the west flank of the 

Williston Basin in Montana provided adequate fauna and flora for zonal 

determinations (wells 1-4, fig. 1). Foraminifers and algae are rare in all 

cores; of 176 samples studied, only 28 samples contained zonally identifiable microfossil assemblages. Identifiable samples were zoned according to the North American scheme of Mamet and Skipp (1970a, b).

Figure 2 shows the distribution of zonally identifiable microfossils. 

Data on corals in these wells can be found in Sando (1978), and detailed 

lithic descriptions of the units in the wells can be obtained from American Stratigraphic Company logs. Coral zones recognized in the wells 

are those of Sando and others (1969). The correlation datum is the 

Coral Zone C2/D boundary.

BIOSTRATIGRAPHY

LODGEPOLE LIMESTONE

The Lodgepole Limestone, lowermost formation in the Madison 

Group, contains a few samples in the upper part that represent 

Zone 7, which ranges from uppermost Kinderhookian into lower 

Osagean (middle Tournaisian of Europe). The Zone 7 assemblage is 

widespread in the Woodhurst Member of the Lodgepole, where it coincides with Coral Zone Q. In the Williston Basin cores, the assemblage 

is very sparse and poorly diversified and consists mostly of Earlandiidae and accessory Endothyridae and Tournayellidae:

Bisphaera sp.

Brunsiina sp.

Calcisphaera laevis (Williamson)

Earlandia clavatula (Howchin)

E. elegans (Rauzer-Chernoussova)

E. minima (Birina)

Latiendothyra sp.

L of the group L. parakosvensis (Lipina)

Palaeospiroplectammina tchernyshinensis (Lipina)

Rectoseptaglomospiranella sp.

Septabrunsiina sp.

Septaglomospiranella primaeva (Chernysheva)
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F4 CONTRIBUTIONS TO STRATIGRAPHY

FIGURE 2. Distribution of zonally identifiable microfossils in the Pine, Richey, Eggebrecht, and East Poplar cores. Formation boundaries (solid 

lines), coral zones (dotted lines), and correlation from Sando, 1978, pi. 1. 

Positions of microfossil samples indicated by arrows followed by USGS 

locality numbers and by Mamet Zone numbers (in parentheses).
FORAMINIFERA AND ALGAE IN WELL CORES F5 

MISSION CANYON LIMESTONE

The overlying Mission Canyon Limestone contains good representatives of Zones 8,9, and 10. Zones 8 and 9 are characteristic of the lower 

part of the Mission Canyon elsewhere, and Zone 10 is widespread in the 

upper part of the formation. Zones 8 and 9 are of middle and late 

Osagean age (late Tournaisian of Europe) and coincide mostly with 

Coral Zone C2 . Zone 10 is of latest Osagean and early Meramecian age 

(early Visean of Europe) and coincides with the lower part of Coral 

Zone D.

In the Williston Basin cores, Zone 8 is represented by an abundant 

and diversified microfauna and microflora. Some levels contain algal 

bafflestones and algal mats. Columbiapora johnsoni is sporadic, sometimes very abundant and sometimes absent, and encrusting Asphaltinella shows the same erratic pattern. Foraminifers are mostly 

Tournayellidae, and endothyrids are poorly represented:

Asphaltinella sp. (sometimes very abundant)

Bevocastria sp. (common in algal nodules)

Bisphaera sp.

Calcisphaera sp.

C. laevis Williamson

Columbiapora johnsoni Mamet

Diplosphaerina sp.

Earlandia clavatula (Howchin)

E. moderata (Malakhova)

Issinella sp.

/. grandis Reitlinger

Kamaena sp.

Latiendothyra sp.

Nostodtes sp.

Palaeospiroplectammina tchernyshinensis (Lipina)

Parathurammina sp.

Ph aeophy cophy ta

Rectoseptaglomospiranella? sp.

Septabrunsiina parakrainica Skipp, Holcomb, and Gutschick

Septaglomospiranella sp.

Septatournayella sp.

cf. Spinoendothyra? sp. (very scarce)

Tuberendothyra sp.

Zone 9 is represented in the cores by an abundant and diversified 

microfauna and microflora. The microflora consists of Issinella bafflestones and Bevocastria nodular wackestones. Foraminifers are still 

dominated by Tournayellidae, along with minor Endothyridae (the 

Spinoendothyra fauna is quite sparse):
F6 CONTRIBUTIONS TO STRATIGRAPHY

Bevocastria sp. (very abundant in lagoonal facies)

Calcisphaera laevis Williamson

Earlandia clavatula (Howchin)

E. elegans (Rauzer-Chernoussova)

Endothyra sp.

Eoforschia sp.

Inflatoendothyra sp.

Issinella grandis Reitlinger (very abundant in bafflestones)

Kamaena sp.

K. pirleti Mamet and Roux

Latiendothyra sp.

Palaeoberesella sp.

P. lahuseni (von Moller)

Proninella sp.

Pseudoissinella sp.

Septabrunsiina sp.

S. parakrainica Skipp, Holcomb, and Gutschick

Septaglomospiranella sp.

Septatournayella pseudocamerata (Lipina in Lebedeva)

Spinoendothyra sp.

S. spinosa (Chernysheva)

Zone 10 is represented by an abundant and diversified microfauna 

and microflora. Tournayellidae are slowly eliminated and replaced by 

Endothyridae, Globoendothyridae, and Endothyranopsidae:

Calcisphaera laevis (Williamson)

C. pachysphaerica (Pronina)

Dainella sp.

Diplosphaerina sp.

Earlandia clavatula (Howchin)

E. vulgaris (Rauzer-Chernoussova and Reitlinger)

cf. Eblanaia? sp.

Endothyra sp.

Eoparastaffella sp.

Eotuberitina sp.

cf. Globoendothyra? sp. (or Eogloboendothyra? sp.)

Globoendothyra of the group G. baileyi (Hall)

Inflatoendothyra sp.

Issinella sp.

Parathurammina sp.

Priscella sp.

Quasipolyderma sp.

Radiosphaerina sp.

Septatournayellaf?) henbesti Skipp, Holcomb, and Gutschick
FORAMINIFERA AND ALGAE IN WELL CORES F7 

CHARLES FORMATION

The Charles Formation, uppermost formation in the Madison 

Group, is characterized by microfossil assemblages of Zones 10 and 11 

(possibly ranging into Zone 12). In the outcrop area of the Mississippian west of the Williston Basin, these zones are found in the upper 

part of the Mission Canyon Limestone (Sando and others, 1969). Zones 

10 and 11 are of early Meramecian age (early Visean of Europe) and are 

ordinarily the youngest zones found in the Madison Group beneath a 

regional disconformity overlain by the Big Snowy Group in Montana 

and the Amsden Formation in Wyoming (Sando and others, 1969). The 

only exception to this rule is in the Bighorn Mountains of Wyoming 

and Montana, where rare occurrences of Zone 12 are known (Sando and 

Mamet, 1974). The rest of Meramecian time (Zones 13 through 15) is 

represented by an hiatus wherever the Madison is directly overlain by 

the Chesterian (Big Snowy Group and lower part of the Amsden Formation) (Sando and others, 1975, fig. 13). The occurrence of Zone 11 

(possibly ranging into 12) microfossils near the top of the Charles 

Formation in the Pine and Eggebrecht wells corroborates the interpretation based on corals (Sando, 1978, p. 236) that the top of the 

Charles Formation in the subsurface is bounded by the same disconformity that is so well documented in outcrops of the Madison to the 

west.

Zone 11 (possibly ranging into 12) microflora is abundant and diversified in a lagoonal facies. Among the foraminifers, the endothyrids, 

globoendothyrids, and endothyranopsids dominate; the Eoendothyranopsis fauna is poorly represented:

Asphaltinella sp. (abundant in algal mats)

Brunsia sp.

Calcisphaera laevis (Williamson)

C. pachysphaerica (Pronina)

Dainella sp.

Erlandia of the group E. clavatula (Howchin)

E. vulgaris (Rauzer-Chernoussova and Reitlinger)

Eblanaia sp.

Endothyra sp.

cf. Eoendothyranopsis? sp.

Eoendothyranopsis of the group E. spiroides (Zeller)

E. spiroides (Zeller)

Eoforschia sp.

E. moelleri (Malakhova in Dain)

Eoparastaffella sp.

Globoendothyra bridgensis Skipp

cf. Inftatoendothyra? sp.

Issinella sp.
F8 CONTRIBUTIONS TO STRATIGRAPHY

Kamaena sp.

Nostocites sp.

Orthriosiphonoides sp.

Palaeoberesella sp.

Paracalligelloides sp.

Parathurammina sp.

Planoendothyra? sp.

Priscella sp.

Pseudoissinella sp.

Radiosphaerina sp.

cf. Septabrunsiina? sp.

Septatournayella(?) henbesti Skipp, Holcomb, and Gutschick

Skippella sp.

Stacheiinae

ENVIRONMENTAL INTERPRETATION

The Williston Basin foraminifers belong to the North America 

Realm (Mamet, 1977; Mamet and Skipp, 1979) but are far less abundant 

and diversified than in the Lodgepole and Mission Canyon Limestones 

of the outcrop area to the west (see microfossil lists in Sando and 

others, 1969). In the Williston Basin, most of the foraminiferal microfauna is observed in limestones that show signs of restricted circulation (sulfates are present in the Lodgepole and are widespread in the 

Mission Canyon and Charles). Pseudomorphs of sulfates are common in algal-rich lagoonal phases; this environment is basically unfavorable to foraminifers, which prefer open-marine conditions. On the 

other hand, the algal microflora is more abundant and diversified, 

including palaeoberesellids, issinellids, and bevocastriids. Dasyclads 

are usually restricted to Columbiapora. Asphaltinella is quite common 

and is accompanied by stacheiins in the upper part of the Charles 

Formation.

REGIONAL CORRELATION

Figure 3 shows correlation of the Madison Group in the Pine Well 

core with type sections of the Madison and its component stratigraphic 

units in the outcrop area to the west in Montana. Figure 4 shows 

locations of the sections.

The correlation diagram (fig. 3) was originally based on coral zones 

recognized by Sando (1978). Occurrences of zonally determined microfossil collections have been added to the diagram, and microfossil zone 

boundaries have been drawn. Three of the four microfossil-zone boundaries coincide with coral-zone boundaries. Thus, the microfossil correlations confirm the correlations made on coral zones and support the
1 2

Type section of Type section of Paine and

Madison Group Woodhurst Members of Lodgepole

o-> Limestone and reference section of

}±f Mission Canyon Limestone

Type sections of Lodgepole 

and Mission Canyon Limestones

1600- 

1400- 

1200-

800- 

600- 

400-

200- 

100- 

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-400

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FIGURE 3. Correlation of Madison Group in Shell Pine Unit No. 1 well (4) wit

posite of Monarch-US 89 and Dry Fork sections, and (3) composite of Litt

Canyon sections. Figure 4 shows locations of sections. Formation bounda

(wavy where disconformable), member boundaries indicated by dashed 

indicated by dots. Positions of microfossil collections indicated by zone n

(See Sando and Dutro (1974) for descriptions of the type sections and S

Pine well.)
F10 CONTRIBUTIONS TO STRATIGRAPHY
FORAMINIFERA AND ALGAE IN WELL CORES Fll

interpretation that the Madison Group in the subsurface of the Williston Basin is the same age as the Madison Group of outcrop.

CONCLUSIONS

Foraminifers and algae in the Madison Group of the Williston Basin 

are not as abundant or diversified as they are in other areas where the 

Madison microfossils have been studied, because of less favorable environmental conditions during Mississippian time in the Williston 

Basin. Despite these limitations, the presence of Zones 10 and 11 (possibly ranging into 12) assemblages near the top of the Charles Formation and the absence of assemblages from younger Meramecian 

zones indicates that the Charles is no younger than early Meramecian 

and that it is bounded above by the same regional disconformity that 

characterizes the top of the Madison Group in outcrop areas outside 

the Williston Basin.

REFERENCES CITED

Gardner, L. S., 1959, Revision of Big Snowy Group in central Montana: American Association of Petroleum Geologists Bulletin, v. 43, no. 2, p. 329-349.

Hadley, H. D., 1950, The Charles problem, in Billings Geological Society, 1st Annual 

Field Conference [Guidebook]: p. 44-46.

Mamet, B. L., 1977, Foraminiferal zonation of the lower Carboniferous; methods and 

stratigraphic implications, in Kauffman, E. G., and Hazel, J. E., eds., Concepts and 

methods of biostratigraphy: Stroudsburg, Pa., Dowden, Hutchinson, & Ross, 

p. 445-462.

Mamet, B. L., and Skipp, Betty, 1970a, Lower Carboniferous calcareous Foraminifera; 

preliminary zonation and stratigraphic implications for the Mississippian of North 

America: International Congress of Carboniferous Stratigraphy and Geology, 6th, 

Sheffield, 1967, Comptes Rendus, v. 3, p. 1129-1146.

 1970b, Preliminary foraminiferal correlations of early Carboniferous strata in the 

North American Cordillera, in Colloque sur la Stratigraphie du Carbonifere: Liege 

Universite, Congres et Colloques, v. 55, p. 327-348. 

-1979, Lower Carboniferous Foraminifera; paleogeographical implications: International Congress of Carboniferous Stratigraphy and Geology, 8th, Moscow, 1975, 

Comptes Rendus, v. 2, p. 48-66.

Maughan, E. K., and Roberts, A. E., 1967, Big Snowy and Amsden Groups and the 

Mississippian-Pennsylvanian boundary in Montana: U.S. Geological Survey Professional Paper 554-B, 27 p.

Nordquist, J. W., 1953, Mississippian stratigraphy of northern Montana, in Billings 

Geological Society, 4th Annual Field Conference, Little Rocky Mountains Montana, southwestern Saskatchewan, Sept. 1953, Guidebook: p. 68-82.

Perry, E. S., and Sloss, L. L., 1943, Big Snowy Group, lithology and correlation in the 

northern Great Plains: American Association of Petroleum Geologists Bulletin, 

v. 27, no. 10, p. 1287-1304.

Roberts, A. E., 1966, Stratigraphy of Madison Group near Livingston, Montana, and 

discussion of karst and solution-breccia features: U.S. Geological Survey Professional Paper 526-B, 23 p.

Sandberg, C. A., 1962, Geology of the Williston Basin, North Dakota, Montana, and 

South Dakota, with reference to subsurface disposal of radioactive wastes: U.S. 

Geological Survey open-file report, 148 p.
F12 CONTRIBUTIONS TO STRATIGRAPHY

Sando, W. J., 1960, Corals from well cores of Madison Group, Williston Basin: U.S. 

Geological Survey Bulletin 1071-F, p. 157-190 [1961].

 1978, Coral zones and problems of Mississippian stratigraphy in the Williston 

Basin, in Montana Geological Society, 24th Annual Conference [Sept. 24-27, 1978], 

1978 Williston Basin Symposium The economic geology of the Williston Basin: 

[Billings, Mont.], p. 231-237.

Sando, W. J., and Dutro, J. T., Jr., 1974, Type sections of the Madison Group (Mississippian) and its subdivisions in Montana: U.S. Geological Survey Professional Paper 

842, 22 p.

Sando, W. J., Gordon, Mackenzie, Jr., and Dutro, J. T., Jr., 1975, Stratigraphy and 

geologic history of the Amsden Formation (Mississippian and Pennsylvanian) of 

Wyoming: U.S. Geological Survey Professional Paper 848-A, 83 p.

Sando, W. J., and Mamet, B. L., 1974, New evidence on the age of the top of the Madison 

Limestone (Mississippian), Bighorn Mountains, Wyoming and Montana: U.S. Geological Survey Journal of Research, v. 2, no. 5, p. 619-624.

Sando, W. J., Mamet, B. L., and Dutro, J. T., Jr., 1969, Carboniferous megafaunal and 

microfaunal zonation in the northern Cordillera of the United States: U.S. Geological Survey Professional Paper 613-E, 29 p.

Sloss, L. L., 1952, Introduction to the Mississippian of the Williston Basin, in Billings 

Geological Society, 3d Annual Field Conference, Black Hills-Williston Basin, Sept. 

1952, Guidebook: p. 65-69.

irU.S. GOVERNMENT PRINTING OFFICE: 1981 361-614/267