GEOLEX

Summary of Citation: Park

Publication:
Weed, W.H., 1899, Description of the Fort Benton quadrangle
   [Montana]: U.S. Geological Survey Geologic Atlas of the United
   States, Fort Benton folio, no. 55, 7 p.

Usage in Publication:
Park shales, limestone conglomerates*

Modifications:	Geologic Province:	Dominant Lithology:
First used	Sweetgrass arch	Shale Conglomerate

Summary:
First published use of name. Intent to name and designation of type locality not given. Possibly named after Belt Park in southwest part of quad. Mapped (geologic map) in southwest part of quad in Little Belt Mountains, Cascade Co, MT, Sweetgrass arch, as one of seven units of Barker formation (first used). [Use of Barker was a mapping convenience as constituent units were not mappable at scale used; Barker probably not intended to be of group rank]. Consists of several hundred feet of shales and limestone conglomerates. Overlies Meagher limestones (first used) of Barker; underlies Pilgrim limestone (first used) of Barker. Barker contains middle Cambrian fossils.

Summary of Citation: Park

Publication:
Weed, W.H., 1900, Geology of the Little Belt Mountains, Montana:
   U.S. Geological Survey Annual Report, 20, pt. 3, p. 257-462

Usage in Publication:
Park shale*

Modifications:	Geologic Province:	Dominant Lithology:
Revised Overview	Sweetgrass arch

Summary:
Removed from Barker formation and raised to formation rank (though mapped as one of seven units of Barker). Composes greater part of Cambrian rocks in Little Belt Mountains, MT, Sweetgrass arch. Well exposed in road cuts at head of Sheep Creek, in valleys of Dry Wolf, Pilgrim, and Tenderfoot creeks, and near Barker. Lower part consists of gray or greenish micaceous shale; higher in section shales contain intercalated thin layers of impure limestone and flat limestone-pebble intraformational conglomerate. Thickness is 800 ft. Overlies Meagher limestone (revised); underlies Pilgrim limestone. Correlation of measured sections. Middle Cambrian trilobite HYOLITHES identified by Walcott.

Summary of Citation: Park

Publication:
Deiss, C.F., 1936, Revision of type Cambrian formations and
   sections of Montana and Yellowstone National Park: Geological
   Society of America Bulletin, v. 47, no. 8, p. 1257-1342

Usage in Publication:
Park shale

Modifications:	Geologic Province:	Dominant Lithology:
Revised Overview	Montana folded belt province Sweetgrass arch Central Montana uplift Yellowstone province	Shale Sandstone

Summary:
Exposure described by Weed (1900) at Dry Wolf Creek, Judith Basin Co, MT, is reexamined and remeasured as are other sections in Little Belt Mountains, Sweetgrass arch. Weed referred to Dry Wolf Creek section as north wall of Big Park (name unknown to inhabitants of Dry Wolf Creek Valley) which is probable source of name of Park and Weed described Big Park, among others, as a typical exposure. In this report, Dry Wolf Creek is designated as type section for Park and Pilgrim shales. At emended Dry Wolf Creek section, in sec 14, T14N, R9E, Park is 212 ft thick (base covered); Weed's original section is 115 ft thick. Thickness ranges from 330 ft on Keegan Butte, Cascade Co, in Little Belt Mountains to 120 ft on Crowfoot Ridge, Yellowstone National Park; average thickness is 200 ft, whereas Weed assigned 800 ft to Park. Overlies Meagher limestone (revised); underlies Pilgrim limestone (revised). Shale is uniformly very fissile, slightly micaceous, and dominantly green-gray color; thin-bedded, gray, crystalline, micaceous sandstones are irregularly intercalated with shales. Additional sections remeasured in central and southern MT within Montana folded belt province, Central Montana uplift and Yellowstone Park, Yellowstone province. Only LINGUELLA HELENA found. Plate 2 shows tentative correlation of revised Cambrian units at type sections. Park tentatively considered youngest Middle Cambrian formation in study area.

Summary of Citation: Park

Publication:
Dorf, E. and Lochman, Christina, 1940, Upper Cambrian formations
   in southern Montana: Geological Society of America Bulletin,
   v. 51, no. 4, p. 541-556

Usage in Publication:
Park shale

Modifications:	Geologic Province:	Dominant Lithology:
Revised	Bighorn basin

Summary:
Revised in that Park underlies, most likely conformably, newly named Upper Cambrian Maurice formation in southern Carbon Co, MT in Beartooth Mountains, Bighorn basin. Contact between Park and Maurice marks Middle-Upper Cambrian boundary.

Summary of Citation: Park

Publication:
Lochman, Christina and Duncan, D.C., 1944, Early Upper Cambrian
   faunas of central Montana: Geological Society of America
   Special Paper, 54, 181 p.

Usage in Publication:
Park formation

Modifications:	Geologic Province:	Dominant Lithology:
Revised	Montana folded belt province

Summary:
At Nixon Gulch, Three Forks quad, Gallatin Co, MT, Montana folded belt province, latest Middle Cambrian trilobite fauna found near base of Pilgrim formation of Deiss (1936). Park-Pilgrim contact raised so Pilgrim includes only Upper Cambrian rocks. Park-Pilgrim contact marks Middle-Upper Cambrian boundary.

Summary of Citation: Park

Publication:
Lochman, Christina, 1950, Upper Cambrian faunas of the Little
   Rocky Mountains, Montana: Journal of Paleontology, v. 24,
   no. 3, p. 322-349

Usage in Publication:
Park formation

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits Biostratigraphic dating	Williston basin

Summary:
Extends name to Little Rocky Mountains, Blaine and Phillips Cos, MT in Williston basin. Includes shale and gray limestone pebble conglomerate containing a fauna of Middle Cambrian age in a section measured along Lodgepole Creek, Phillips Co, MT. Thickness not given. Underlies Pilgrim formation below a covered interval 103 ft thick that is not assigned to either formation. Basal contact and underlying formations are not discussed.

Summary of Citation: Park

Publication:
Lochman, Christina, 1950, Status of Dry Creek shale of central
   Montana: American Association of Petroleum Geologists Bulletin,
   v. 34, no. 11, p. 2200-2222

Usage in Publication:
Park shale

Modifications:	Geologic Province:	Dominant Lithology:
Revised	Montana folded belt province

Summary:
Author re-examined key sections in Horseshoe Hills between Logan and Dry Creek, Gallatin Co, MT, Montana folded belt province. As lithology of Upper Cambrian is more like that in southern MT than in central MT, southern MT nomenclature used. Thus, Maurice formation is extended into Horseshoe Hills, replacing Pilgrim limestone of other workers. Park revised in that it now underlies Maurice. Chart showing comparison of published sections from Horseshoe Hills by various authors.

Summary of Citation: Park

Publication:
Sloss, L.L. and Moritz, C.A., 1951, Paleozoic stratigraphy of
   southwestern Montana: American Association of Petroleum
   Geologists Bulletin, v. 35, no. 10, p. 2135-2169

Usage in Publication:
Park shale

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits Overview	Montana folded belt province

Summary:
Extends into extreme southwest MT south of Boulder batholith and west of Yellowstone National Park within parts of Beaverhead, Madison, and Gallatin Cos, MT, Montana folded belt province. Conformably and transitionally overlies Meagher limestone. In places is in transitional contact with overlying Hasmark formation; where pre-Hasmark erosion has occurred is in disconformable contact with Hasmark. Where not eroded, thickness ranges from 100-150 ft. Correlates with upper part of Bloomington formation in southeast ID, upper part of Bayhorse dolomite in central ID, Switchback shale in northwest MT, and upper shale member of Gros Ventre formation in northern WY. Isopach map of Cambrian. Correlation chart. Cross section. Measured section. Middle Cambrian age.

Summary of Citation: Park

Publication:
Hanson, A.M., 1952, Cambrian stratigraphy in southwestern Montana:
   Montana Bureau of Mines and Geology Memoir, no. 33, 46 p.

Usage in Publication:
Park shale

Modifications:	Geologic Province:	Dominant Lithology:
Revised Age modified Overview Areal limits	Bighorn basin Central Montana uplift Sweetgrass arch Montana folded belt province

Summary:
Extends throughout southwest MT from Fergus and Carbon Cos on east to Mineral and Beaverhead Cos on west, which includes Bighorn basin, Central Montana uplift, Sweetgrass arch, and Montana folded belt province. Thickness ranges from less than 50 ft to about 500 ft; is thickest in southeast part of area. Conformably overlies Meagher formation; conformably underlies Pilgrim formation; both upper and lower contacts are gradational. Correlates in part with Steamboat limestone and Switchback formation of northwest MT; in part with Hasmark formation in Phillipsburg quad; upper part of Gros Ventre formation in northwest WY; and Bloomington formation in northeast UT. Retains use of Hasmark from Phillipsburg to Armstead in western part of study area. Many measured sections. Cross section. Correlation chart. Isopach map. Places Park-Pilgrim boundary to coincide with lithologic change from shale to limestone rather than to coincide with Middle-Upper [Late] Cambrian time boundary of Lochman and Duncan (1944). Late Middle Cambrian to early Upper [Late] Cambrian age. Age assignment based on fossils described by other workers in Three Forks, MT area (late Middle Cambrian) and by presence of ARAPAHOIA in upper part of Park equivalent (upper part of Gros Ventre) in western WY (early Upper [Late] Cambrian).

Summary of Citation: Park

Publication:
Shaw, A.B. and McGrew, P.O., 1954, Correlation of the pre-Quaternary
   formations of Wyoming; Chart II: Wyoming Geological Association
   Field Conference Guidebook, no. 9

Usage in Publication:
Park shale

Modifications:	Geologic Province:	Dominant Lithology:
Revised	Yellowstone province Greater Green River basin Bighorn basin Wind River basin

Summary:
Gros Ventre formation raised to group rank and its members raised to formation rank in a footnote on Chart II. Includes (ascending): Wolsey shale, Death Canyon limestone, and Park shale. The lower two formations are of Albertan age; the Park is mostly Albertan and at top early Dresbachian age. Gros Ventre overlies Flathead sandstone and underlies Dunoir limestone (rank raised) of Gallatin group (rank raised). This nomenclature is used from the Yellowstone province and Greater Green River basin of western WY east to the western Bighorn basin. The equivalent of the Gros Ventre in the Wind River basin is the newly named Buck Spring formation. In the eastern Bighorn and western Powder River basin, Gros Ventre is designated as an undivided formation. Gros Ventre apparently not divisible east of Death Canyon pinchout in the Bighorn basin.

Summary of Citation: Park

Publication:
McMannis, W.J., 1955, Geology of the Bridger Range, Montana:
   Geological Society of America Bulletin, v. 66, no. 11, p.
   1385-1430

Usage in Publication:
Park formation

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits	Montana folded belt province

Summary:
Extended to Bridger Range, Gallatin Co, MT, Montana folded belt province. Thickness is very consistent; 188 ft at Sacajawea Peak, 192 ft at Bridger Peak. Overlies Meagher formation with contact arbitrarily placed at top of uppermost Meagher-type limestone; underlies Maurice formation. Mapped undivided with Flathead, Wolsey and Meagher formations. Cross sections. Stratigraphic chart. Fossils including BRACHYASPIDON, EHMANIA? and OBULUS suggest late Middle Cambrian age.

Summary of Citation: Park

Publication:
Lochman-Balk, Christina, 1956, The Cambrian of the Rocky Mountains
   and southwest deserts of the United States and adjoining
   Sonora province, Mexico, IN Rodgers, John, ed., El Sistema
   Cambrico, su paleogeografia y el problema de su base; Symposium;
   Parte II, Australia, America: International Geological
   Congress, 20th, Report, Mexico City, 1956, p. 529-661

Usage in Publication:
Park member

Modifications:	Geologic Province:	Dominant Lithology:
Revised Biostratigraphic dating Overview	Williston basin

Summary:
Made a member of Emerson formation in the Little Rocky Mountains, Blaine and Phillips Cos, MT in Williston basin. Consists of dark-green, fissile, fossiliferous shale which becomes light-green and calcareous in upper portion. Thin beds of small limestone pebble conglomerates and layers of small white limestone nodules of a coquina of trilobite fragments become noticeable in top beds. Thickness 300-350 ft. Gradational through 75 ft of predominantly shale bed with overlying Zortman member (new). [The beds not assigned to either member.] Underlain by Meagher member. Middle Cambrian in age.

Summary of Citation: Park

Publication:
Klepper, M.R., Weeks, R.A. and Ruppel, E.T., 1957, Geology of
   the southern Elkhorn Mountains, Jefferson and Broadwater
   Counties, Montana: U.S. Geological Survey Professional Paper,
   292, 82 p.

Usage in Publication:
Park shale*

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Montana folded belt province

Summary:
Best exposed along flanks of north half of anticline in Devils Fence quad, Jefferson and Broadwater Cos, MT, Montana folded belt province. Conformably overlies Meagher limestone; conformably underlies Pilgrim dolomite. Though upper and lower contacts are almost always concealed, both must be either sharp or gradational over only a few feet. Thickness ranges from 200-290 ft. Geologic maps; measured section; generalized stratigraphic section. In places is intruded by sills of andesite or diorite. Middle Cambrian age.

Summary of Citation: Park

Publication:
Shaw, A.B., 1957, Cambrian of the southwestern Wind River basin,
   Wyoming: Wyoming Geological Association Field Conference
   Guidebook, no. 12, p. 8-16

Usage in Publication:
Park shale

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Wind River basin

Summary:
Recognition of Park shale in report area, Fremont and Natrona Cos, WY in the Wind River basin, is dependent on presence of underlying Death Canyon limestone. Is the upper formation of the Gros Ventre group. Where Death Canyon is missing, Park is not separable from the Wolsey shale. Averages about 400 ft thick in area. Underlies Dunoir (spelled Du Noir by Shaw in earlier reports). Cross sections. Upper part has CEDARIA zone fauna, a representative Upper Cambrian fauna. Lower Park representative of a deeper water deposit just beyond edge of coarse clastic deposition. Upper Park probably a very shallow water deposit that had restricted circulation.

Summary of Citation: Park

Publication:
Knopf, Adolph, 1963, Geology of the northern part of the Boulder
   batholith and adjacent area, Montana: U.S. Geological Survey
   Miscellaneous Investigations Series Map, I-381, 1 sheet,
   scale 1:48,000

Usage in Publication:
Park Argillite*

Modifications:	Geologic Province:	Dominant Lithology:
Redescribed Areal limits	Montana folded belt province	Argillite

Summary:
Maps unit in northern Boulder batholith area in Lewis and Clark and Jefferson Cos, MT in Montana folded belt province. Outcrop trends northwest-southeast from northwestern to central part of mapped area, then trends easterly to southwestern edge of map. Unit is 180-200 ft thick. Because of rock's high density (2.76) and lack of fissility, use of argillite rather than shale as part of unit's name is more appropriate. Conformably overlies Middle Cambrian Meagher Limestone; conformably underlies Upper Cambrian Hasmark Dolomite. Fossils include Middle Cambrian LINGUELLA. Geologic map.

Summary of Citation: Park

Publication:
Robinson, G.D. and Barnett, H.F., 1963, Geology of the Three
   Forks quadrangle, Montana, with sections on petrography of
   igneous rocks by H.F. Barnett: U.S. Geological Survey
   Professional Paper, 370, 143 p.

Usage in Publication:
Park shale*

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Montana folded belt province

Summary:
Good exposures east of Milligan Creek, west of Willow Creek, and on north bank of creek along the Madison-Gallatin Co line, MT, Montana folded belt province. Is generally described (partly covered) in two measured sections. The first section measured in sec 10, T1N, R1W where it is 150 ft thick and the other in NE1/4 NE1/4 sec 1, T2N, R1E where it is 100 ft thick. Lies between Meagher limestone beneath and Pilgrim limestone above. Is a marine shale; no fossils found in quad. Assigned to the Middle Cambrian. Geologic map. [Compare with Peale, 1893, 1896 and Berry, 1943.]

Summary of Citation: Park

Publication:
McMannis, W.J. and Chadwick, R.A., 1964, Geology of the Garnet
   Mountain quadrangle, Gallatin County, Montana: Montana Bureau
   of Mines and Geology Bulletin, no. 43, 47 p.

Usage in Publication:
Park Shale

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Montana folded belt province

Summary:
Within mapped area, thickness ranges from 175 ft in southwest to 241 ft in northwest; it is 217 ft thick in northeast part of area. Quad is in Montana folded belt province. Conformably overlies Meagher Limestone; conformably underlies Pilgrim Limestone. Mapped undivided with other Middle Cambrian units including Flathead Quartzite, Wolsey Shale and Meagher. Top of Park is approximate Middle-Upper Cambrian faunal boundary.

Summary of Citation: Park

Publication:
Lowell, W.R., 1965, Geologic map of the Bannack-Grayling area,
   Beaverhead County, Montana: U.S. Geological Survey Miscellaneous
   Investigations Series Map, I-433, 6 p., 1 sheet, scale

Usage in Publication:
Park Shale*

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits	Montana folded belt province

Summary:
Not present in mapped area in central Beaverhead Co, MT, Montana folded belt province. Park and Meagher Limestone probably eroded during local deformation. Wolsey Shale disconformably underlies Pilgrim? Dolomite.

Summary of Citation: Park

Publication:
Keefer, W.R. and Van Lieu, J.A., 1966, Paleozoic formations in
   the Wind River basin, Wyoming, IN Geology of the Wind River
   basin, central Wyoming: U.S. Geological Survey Professional
   Paper, 495-B, p. B1-B60

Usage in Publication:
Park Shale Member*

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits	Wind River basin

Summary:
Geographically extended into the northwestern part of the Wind River basin of WY as the upper member of the Gros Ventre Formation. Consists of 421 ft of gray micaceous shale with varying amounts of limestone that increases in abundance near top. The limestone commonly contains flat-pebble conglomerate of disk-shaped limestone oriented parallel to the bedding planes in a dense to granular limestone matrix. The flat pebbles are conspicuous on weathered surfaces. Overlies Death Canyon Limestone Member of Gros Ventre. Underlies Gallatin Limestone. Presence of Death Canyon makes division of Gros Ventre into members possible. The three members can be recognized as far as Bull Lake Canyon in sec 9, T2S, R3W. Cross sections. Age of Gros Ventre is middle and late Middle Cambrian.

Summary of Citation: Park

Publication:
Witkind, I.J., 1971, Geologic map of the Barker quadrangle,
   Judith Basin and Cascade Counties, Montana: U.S. Geological
   Survey Geologic Quadrangle Map, GQ-898, 1 sheet, scale
   1:62,500

Usage in Publication:
Park Shale*

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Sweetgrass arch

Summary:
Outcrops in south half of quad, Judith Basin and Cascade Cos, MT, Sweetgrass arch. About 170-250 ft thick. Conformably overlies Meagher Limestone; conformably underlies Pilgrim Limestone. Middle Cambrian age.

Summary of Citation: Park

Publication:
Witkind, I.J., Hoskins, P.A., Lindsey, V.L. and Mitchell, E.L.,
   1972, Geologic map of the Henrys Lake quadrangle, Idaho and
   Montana: U.S. Geological Survey Miscellaneous Investigations
   Series Map, I-781-A, 1 sheet, scale 1:62,500

Usage in Publication:
Park Shale*

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits	Montana folded belt province Snake River basin

Summary:
Occurs in Henrys Lake Mountains, Gallatin Co, MT, Montana folded belt province and Fremont Co, ID, Snake River basin where it forms broad saddles, grass-covered benches, and strike valleys. Thickness is 170 ft. Overlies Meagher Limestone; underlies undivided Bighorn? Dolomite, Snowy Range? Formation, and Pilgrim? Limestone. Middle Cambrian age.

Summary of Citation: Park

Publication:
GNU Staff, 1989, GNU Staff remark by T.W. Judkins.  Stratigraphic
   chart for Cambrian formations of western Montana (adapted
   from Tysdal, 1976, USGS Bull. 1405-I).: U.S. Geological
   Survey, unpublished geologic names committee note

Usage in Publication:
Park Shale

Modifications:	Geologic Province:	Dominant Lithology:
Figure	Montana folded belt province

Summary:
[We apologise. The figure for this synopsis is being reconstructed.]

Summary of Citation: Park

Publication:
GNU Staff, 1992, GNU Staff remark by T.W. Judkins.  Stratigraphic
   chart for Cambrian formations of Butte quadrangle, western
   Montana (modified from Wallace, 1987, USGS MF-1925).: U.S.
   Geological Survey, unpublished geologic names committee note

Usage in Publication:
Park Shale

Modifications:	Geologic Province:	Dominant Lithology:
Figure	Montana folded belt province

Summary:
Butte quadrangle, MT. (Compare with 1989 GNULEX Staff remark where Silver Hill Formation correlates with Flathead Sandstone and Wolsey Shale in sw MT and Bozeman, MT area.) [We apologise. The figure for this synopsis is being reconstructed.]