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Lower Pennsylvanian (Morrowan) Ammonoids from the North American Midcontinent

Published online by Cambridge University Press:  22 December 2017

Walter L. Manger  and
W. Bruce Saunders
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Abstract

The Lower Pennsylvanian Hale Formation, which comprises the lower portion of the type Morrowan Series, in northwestern Arkansas, is subdivided into the Cane Hill and overlying Prairie Grove Members. The Cane Hill Member includes interbedded shale and sandstone with a basal conglomerate containing clasts reworked from underlying, truncated Mississippian formations. The Prairie Grove Member is highly variable, but includes sandy biosparite and calcareous sandstone. Highly fossiliferous pebble conglomerate and calcirudite lenses occur sporadically throughout the Hale Formation. Ammonoids and conodonts show that the Cane Hill-Prairie Grove boundary is unconformable.

Several thousand ammonoids collected from more than 100 localities in the Hale Formation show that four ammonoid zones and two subzones are recognizable in the Hale succession, and consequently in the redefined Halian Stage of the Morrowan Series. These are, in ascending order, the Retites semiretia, Quinnites henbesti, Arkanites relictus (including the Arkanites relictus relictus and overlying Cancelloceras huntsvillense Subzones) and Verneuilites pygmaeus Zones. Halian Stage ammonoids are known primarily from northern Arkansas, but an upper Arkanites relictus Zone (Cancelloceras huntsvillense Subzone) ammonoid assemblage occurs in the Primrose Member of the Golf Course Formation in south central Oklahoma.

Conodont-ammonoid associations in the Hale sequence provide a basis for integration of independently based zonal information. Rhachistognathus primus Zone conodonts occur in the Retites semiretia Zone; the Idiognathoides sinuatus Zone ranges through the Quinnites henbesti and Arkanites relictus relictus Subzone. The overlying Cancelloceras huntsvillense Subzone and Verneuilites pygmaeus Zone both contain conodonts of the Neognathodus symmetricus Zone.

The Hale ammonoid succession has few, if any, species in common with the type Namurian of Europe, but numerous genera are common to both sequences and the generic successions coincide and are equivalent in degree of development. The Retites semiretia Zone is equivalent to the Reticuloceras circumplicatile Zone (R1a); the Quinnites henbesti and lower Arkanites relictus Zones correspond to some portion of the R2b–R2c interval; and the upper Arkanites relictus Zone and the Verneuilites pygmaeus Zone correlate to Zone G1. The Retites semiretia Zone correlates to the lower Reticuloceras-Baschkortoceras Genozone (Nm2b1) of the upper Namurian in the south Urals; the Quinnites henbesti Zone is equivalent to some portion of the Nm2b2–3 intervals of this zone; the lower Arkanites relictus Zone is equivalent to the lower Bilinguites-Cancelloceras Genozone (Nm2c1) and the upper Arkanites relictus and Verneuilites pygmaeus Zones correspond to the uppermost interval (Nm2c2) in the south Urals sequence.

Systematic descriptions of biostratigraphically significant Halian taxa, including Reticuloceras tiro Gordon, R. wainwrighti Quinn, Retites semiretia McCaleb, Arkanites relictus relictus (Quinn, McCaleb, and Webb), A. relictus redivivus n.subsp., Quinnites n.gen. (type species Q. henbesti (Gordon)), Q. textum (Gordon), Bilinguites eliasi n.sp., Cancelloceras huntsvillense n.sp., and Verneuilites pygmaeus (Mather) are also presented.

Type
Research Article
Information
Journal of Paleontology , Volume 54 , Issue S10: The Paleontological Society Memoir 10: Lower Pennsylvanian (Morrowan) Ammonoids from the North American Midcontinent , May 1980 , pp. 1 - 56
Copyright
Copyright © 1980, The Society of Economic 

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References

Adams, G. I. 1904. Zinc and lead deposits of northern Arkansas. U.S. Geol. Survey, Prof. Paper 24, 89 p., 27 pls. Google Scholar
Adams, G. I. and Ulrich, E. O. 1905. Description of the Fayetteville Quadrangle (Arkansas-Missouri). U.S. Geol. Surv., Geol. Atlas, Folio 119.Google Scholar
Aisenverg, D. et al. 1978. Carboniferous sequence of the Donets Basin as a standard section of the Carboniferous System. Compte Rendu, 8th Congrès Int. Strat. Géol. Carb., Moscow, 1975, tom 1, p. 158–168.Google Scholar
Bisat, W. S. 1923. Gastrioceras cancellation (sp. nov.). Leeds Geol. Assoc. Trans. 19:3–6.Google Scholar
Bisat, W. S. 1924. The Carboniferous goniatites of the north of England and their zones. Yorkshire Geol. Soc. Proc. 20:40–124, pls. 1–8.Google Scholar
Bisat, W. S. and Hudson, R. G. S. 1943. The Lower Reticuloceras (R1) goniatite succession in the Namurian of the north of England. Yorkshire Geol. Soc. Proc. 24:383–446, pls. 23–30.Google Scholar
Bouckaert, J. 1961. Les goniatites du Carbonifère Beige. Soc. Beige de Géol., de Paléontol. et d'Hydrol.; Documents pour L'Etude de la Paléontologie du terrain Houiller, 9 p., 28 pls. Google Scholar
Bouckaert, J. and Higgins, A. C. 1970. The position of the Mississippian-Pennsylvanian boundary in the Namurian of Belgium. Colloque sur la Strat. du Carbon., Univ. Liege (1969), Proc. 55:197–204.Google Scholar
Bouroz, A., Einor, O. L., Gordon, M. Jr., Meyen, S. V. and Wagner, R. H. 1978. Proposals for an international chronostratigraphic classification of the Carboniferous. Compte Rendu, 8th Congrès Int. Strat. Géol. Carb., Moscow, 1975, tom 1, p. 36–52.Google Scholar
Brenckle, P. L. 1973. Smaller Mississippian and Lower Pennsylvanian calcareous foraminifers from Nevada. Cush. Found. Foram. Res. Spec. Pub. 11:1–82.Google Scholar
Brenckle, P. L., Lane, H. R., Manger, W. L. and Saunders, W. B. 1977. The Mississippian-Pennsylvanian boundary as an intercontinental biostratigraphic datum. Newsl. Stratigr. 6:106–116.Google Scholar
Chao, Kingkoo and Yuan, C. Y. 1974. A handbook of the Stratigraphy and Paleontology in southwest China. Science Press, Nanking Inst. Geol. Paleont., Acad. Sinica, 454 p., 202 pls. (in Chinese).Google Scholar
Cheney, M. G. 1940. Geology of north-central Texas. Amer. Assoc. Petrol. Geol. Bull. 24:65–118.Google Scholar
Cheney, M. G. et al. 1945. Classification of Mississippian and Pennsylvanian rocks of North America. Amer. Assoc. Petrol. Geol. Bull. 29:125–169.Google Scholar
Clardy, B. F. 1962. Goniatite cephalopod faunas from the Hale Formation. The Compass 39:103–109, pls. 1,2.Google Scholar
Croneis, Carey. 1930. Geology of the Arkansas Paleozoic area. Arkansas Geol. Surv. Bull. 3, 457 p., 45 pls. Google Scholar
Dunn, D. L. 1970a. Middle Carboniferous conodonts from western United States and phylogeny of the platform group. J. Paleontol. 44:312–342, pls. 61–64.Google Scholar
Dunn, D. L. 1970b. Conodont zonation near the Mississippian-Pennsylvanian boundary in western United States. Geol. Soc. America Bull. 81:2959–2974.Google Scholar
Eldredge, Niles and Gould, S. J. 1972. Punctuated equilibria: an alternative to phyletic gradualism. In, Schopf, T. J. M. (ed.), Models in Paleobiology, p. 82–115.Google Scholar
Elias, M. K. 1956. Upper Mississippian and Lower Pennsylvanian formations of south-central Oklahoma. In, Petroleum geology of southern Oklahoma, a symposium. Ardmore Geol. Soc., v. 1, p. 56–134, 6 pls.Google Scholar
Frezon, S. E. and Glick, E. E. 1959. Pre-Atoka rocks of Arkansas. U.S. Geol. Surv., Prof. Paper 314-H, p. 171–189, pls. 20–31.Google Scholar
Furnish, W. M. and Saunders, W. B. 1971. Faunal studies of the type Chesterian, Upper Mississippian of southwestern Illinois. Part I: Ammonoids from the middle Chester Beech Creek Limestone, St. Clair County. Paleontological Contributions, Univ. Kansas Paleontological Inst. Paper 51, 14 p., pls. 1, 2.Google Scholar
Glick, E. E., Frezon, S. E. and Gordon, M. Jr. 1964. Witts Springs Formation of Morrow age in the Snowball quadrangle, north-central Arkansas. U.S. Geol. Surv., Bull. 1194-D, 16 p.Google Scholar
Gordon, Mackenzie Jr. 1960. Some American Midcontinent Carboniferous cephalopods. J. Paleontol. 34:133–151, pls. 27, 28.Google Scholar
Gordon, Mackenzie Jr. 1965. Carboniferous cephalopods of Arkansas. U.S. Geol. Surv., Prof. Paper 460, 322 p., 30 pls.Google Scholar
Gordon, Mackenzie Jr. 1969. An early Reticuloceras Zone fauna from the Hale Formation in northwestern Arkansas. U.S. Geol. Surv., Prof. Paper 613, 19 p., 2 pls.CrossRefGoogle Scholar
Gordon, Mackenzie Jr. 1970. Carboniferous ammonoid zones of the south-central and western United States. Compte Rendu, 6e Congrès Int. Strat. Geol. Carb., Sheffield, 1967, tom 2, p. 817–826.Google Scholar
Gould, S. J. and Eldredge, Niles. 1977. Punctuated equilibria: the tempo and mode of evolution reconsidered. Paleobiol. 3:115–151.Google Scholar
Haley, B. R. et al. 1976. Geologic map of Arkansas. Arkansas Geological Commission and U.S. Geol. Survey, scale 1:500,000.Google Scholar
Harlton, B. H. 1938. Stratigraphy of the Bendian of the Oklahoma Salient of the Ouachita Mountains. Amer. Assoc. Petrol. Geol. Bull. 22:852–914.Google Scholar
Henbest, L. G. 1953. Morrow Group and lower Atoka Formation of Arkansas. Amer. Assoc. Petroleum Geologists Bull. 37:1935–1953.Google Scholar
Henbest, L. G. 1962. Type sections for the Morrow Series of Pennsylvanian age, and adjacent beds, Washington County, Arkansas. U.S. Geol. Surv., Prof. Paper 450-D, p. 38–41.Google Scholar
Henry, T. W. 1973. Brachiopod biostratigraphy of the Morrow Series (Lower Pennsylvanian) of northwestern Arkansas and northeastern Oklahoma. Unpublished Doctoral dissertation, University of Oklahoma, Norman, 515 p.Google Scholar
Henry, T. W. and Sutherland, P. K. 1977. Brachiopod biostratigraphy of Morrowan Series (Pennsylvanian) in northwestern Arkansas and northeastern Oklahoma. In, Sutherland, P. K. and Manger, W. L., Okla. Geol. Surv. Guidebook 18, p. 107–115.Google Scholar
Higgins, A. C. 1975. Conodont zonation of the late Visean-early Westphalian strata of the south and central Pennines of northern England. Geol. Surv. Great Britain, Bull. 53, 90 p.Google Scholar
Hudson, R. G. S. 1945. The goniatite zones of the Namurian. Geol. Mag. 82:1–9.Google Scholar
Knox, L. W. 1977. Morrowan (lower Pennsylvanian) ostracodes from Arkansas and Oklahoma. In, Sutherland, P. K. and Manger, W. L. (eds.) Okla. Geol. Surv. Guidebook 18, p. 139–148.Google Scholar
Korejwo, Krystyna. 1969. Stratigraphy and paleogeography of the Namurian in the Polish lowland. Acta Geologica Polonica, 19:609–709.Google Scholar
Lane, H. R. 1967. Uppermost Mississippian and Lower Pennsylvanian conodonts from the type Morrow region, Arkansas. J. Paleontol. 41:920–942, pls. 119–123.Google Scholar
Lane, H. R. 1977. Morrowan (Early Pennsylvanian) conodonts of northwestern Arkansas and northeastern Oklahoma. In, Sutherland, P. K. and Manger, W. L., Okla. Geol. Surv. Guidebook 18, p. 177–180.Google Scholar
Lane, H. R., Straka, J. J. II and Webster, G. D. 1970. North American Pennsylvanian conodont biostratigraphy. Geol. Soc. Amer. Mem. 127, p. 395–414.Google Scholar
Lane, H. R., and Straka, J. J. II. 1974. Late Mississippian and Early Pennsylvanian conodonts Arkansas and Oklahoma. Geol. Soc. America, Spec. Paper 152, 144 p.Google Scholar
Librovitch, L. S. 1946. Novaya skhema podrazdeleniya: korrelyatsii karbona Donetskogo basseina (na osnove rasprostraneniya tsefalopodovykh faun). Materialy Vsesoyuznogo nauchno-issledovatel'skogo Geologicheskogo Instituta, Obshchaya Seriya 7:77–90.Google Scholar
Librovitch, L. S. 1947. Goniatitovye fauny karbona SSSR i ikh znachenie dlya stratigrafii etikh otlozhenii. Moskovskoe obshchestva ispytatelei prirody Biulleten', Otdel geol. 22:51–68.Google Scholar
Mamet, B. L. 1975. Carboniferous foraminifera and algae of the Amsden Formation (Mississippian and Pennsylvanian) of Wyoming. U.S. Geol. Surv. Prof. Paper 848-B, p. 1–18.Google Scholar
Mamet, B. L. and Skipp, Betty. 1970. Preliminary foraminiferal correlations of Early Carboniferous strata in the North American Cordillera. Colloque sur la Strat. du Carbon., Univ. Liege, 1969, Proc. 55:327–348.Google Scholar
Manger, W. L. 1971. The stratigraphy of the Hale Formation (Morrowan) in its type region, northwestern Arkansas. Unpublished Doctoral dissertation, University of Iowa, Iowa City, 187 p.Google Scholar
Manger, W. L., Saunders, W. B. and Quinn, J. H. 1974. Lower Pennsylvanian ammonoids from the Primrose Member, Golf Course Formation, south-central Oklahoma (abs). Geol. Soc. America, Abstracts with programs, v. 6, 115–116.Google Scholar
Mather, K. F. 1915. The fauna of the Morrow Group of Arkansas and Oklahoma. Denison Univ. Sci. Lab. Bull. 18:59–284, 16 pls.Google Scholar
McCaleb, J. A. 1963. The goniatite fauna from the Pennsylvanian Winslow Formation of northwest Arkansas. J. Paleontol. 37:867–888, pls. 111–115.Google Scholar
McCaleb, J. A. 1964. Two new genera of Lower Pennsylvanian ammonoids from northern Arkansas. Oklahoma Geology Notes 24:233–237.Google Scholar
McCaleb, J. A. 1968. Lower Pennsylvanian ammonoids from the Bloyd Formation of Arkansas and Oklahoma. Geol. Soc. America, Spec. Paper 96, 123 p., 12 pls. Google Scholar
McCaleb, J. A., Quinn, J. A. and Furnish, W. M. 1964. The ammonoid family Girtyoceratidae in the southern Midcontinent. Oklahoma Geol. Surv. Circ. 67, 41 p., 4 pls. Google Scholar
Moore, R. C. et al. 1937. Upper Carboniferous rocks of the northern mid-continent region of North America (abs). Proc. Geol. Soc. Amer. 1936, p. 93.Google Scholar
Moore, R. C. et al. 1944. Correlation of Pennsylvanian formations of North America. Geol. Soc. America Bull. 55:657–706.Google Scholar
Nassichuk, W. W. 1975. Carboniferous ammonoids and stratigraphy in the Canadian Arctic Archipelago. Geol. Surv. Canada, Bull. 237, 240 p., 18 pls. Google Scholar
Nemirovskaya, T. I. 1974. The stratigraphic significance of platform conodonts of the upper suites of the Lower Carboniferous in the Donets Basin. Geol. Zhur. 34:128–132 (in Russian).Google Scholar
Patteisky, Karl. 1965. Die fauna des Westdeutschen Oberkarbons IV. Die goniatiten im Westfal des Niederrheinisch-Westfalischen Karbons. Paleontographica, Abt. A, 125:1–45, 9 pls.Google Scholar
Purdue, A. H. 1907. Description of the Winslow quadrangle (Arkansas-Indian Territory). U.S. Geol. Surv., Geol. Atlas, Folio 154.Google Scholar
Quinn, J. H. 1965. Reevaluation of Pygmaeoceras . Oklahoma Geology Notes 25:228–236.Google Scholar
Quinn, J. H. 1966a. Genus Reticuloceras in America. Oklahoma Geology Notes, 26:13–20.Google Scholar
Quinn, J. H. 1966b. The Pitkin and superjacent formations in northern Arkansas. Shale Shaker 17:2–12.Google Scholar
Quinn, J. H. 1970. Biostratigraphy of the Morrow Group of northern Arkansas. Arkansas Acad. Sci. Proc. 23:183–191.Google Scholar
Quinn, J. H. 1971. Correlation of Arkansas-European goniatite stages. Compte Rendu, 6e Congrès Int. Strat. Géol. Carb., Sheffield, 1967, tom 4, p. 1377–1386.Google Scholar
Quinn, J. H., McCaleb, J. A. and Webb, J. H. 1962. A Pennsylvanian Eumorphoceras from Arkansas. J. Paleontol. 36:112–114, pl. 21.Google Scholar
Quinn, J. H., and Saunders, W. B. 1968. The ammonoids Hudsonoceras and Baschkirites in the Morrowan Series of Arkansas. Jour. Paleont. 42:397–402.Google Scholar
Ramsbottom, W. H. C. 1969. Interim report of the Namurian working group. Compte Rendu, 6e Congrès Int. Strat. Géol. Carb., Sheffield, 1967, tom 1, p. 71–78.Google Scholar
Ramsbottom, W. H. C. 1977. Major cycles of transgression and regression (mesothems) in the Namurian. Yorkshire Geol. Soc. Proc. 41:261–291.CrossRefGoogle Scholar
Ramsbottom, W. H. C. and Calver, M. A. 1962. Some marine horizons containing Gastrioceras in north west Europe. Compte Rendu, 4e Congrès Int. Strat. Géol. Carb., Heerlen, 1958, tom 3, p. 571–576, pls. 14, 15.Google Scholar
Ramsbottom, W. H. C. et al. 1978. A correlation of Silesian rocks in the British Isles. Geol. Soc. London, Spec. Rep. 10, 81 p. 3 pls.Google Scholar
Rauser-Chernousova, D. M. 1928. O nekotorykh kammenougol'nykh ammonitakh Fergany. Moscow Univ., Fiziko-matematicheskii faculitet, Assotsiatsii nauchno-issledova-tellskikh institutor Izr. 1:164–178.Google Scholar
Ruzhencev, V. E. 1975. Carboniferous ammonoids and chronostratigraphy of eastern Siberia. Paleont. Zhur. 8:155–171 (in Russian).Google Scholar
Ruzhencev, V. E. and Bogoslovskaya, M. F. 1969. The Baskirian or Kayalian Stage? Doklady Akad. Nauk. SSSR 189:1332–1335 (in Russian).Google Scholar
Ruzhencev, V. E. and Bogoslovskaya, M. F. 1971a. The ammonoid family Homoceratidae. Paleont. Zhur. 4:17–34 (in Russian).Google Scholar
Ruzhencev, V. E. and Bogoslovskaya, M. F. 1971b. Namurian time in ammonoid evolution; early Namurian ammonoids. Trans. Paleont. Inst. Acad. Sci. USSR, v. 133, 382 p.Google Scholar
Ruzhencev, V. E. and Bogoslovskaya, M. F. 1975. The Family Reticuloceratidae and related taxa. Paleont. Zhur. 8:46–61 (in Russian).Google Scholar
Ruzhencev, V. E. and Bogoslovskaya, M. F. 1978. Namurian time in ammonoid evolution; late Namurian ammonoids. Trans. Paleont. Inst. Acad. Sci. USSR, v. 167, 336 p.Google Scholar
Sando, W. J., Mamet, B. L. and Dutro, J. T. 1969. Carboniferous megafaunal and microfaunal zonation in the northern Cordillera of the United States. U.S. Geol. Survey, Prof. Paper 613-E, 29 p.Google Scholar
Saunders, W. B. 1973. Upper Mississippian ammonoids from Arkansas and Oklahoma. Geol. Soc. America, Spec. Paper 145, 110 p. 8 pls. CrossRefGoogle Scholar
Saunders, W. B., Manger, W. L. and Gordon, M. Jr. 1977. Upper Mississippian and Lower and Middle Pennsylvanian ammonoid biostratigraphy of northern Arkansas. In, Sutherland, P. K. and Manger, W. L., Oklahoma Geo. Surv. Guidebook 18, p. 117–137.Google Scholar
Saunders, W. B., Ramsbottom, W. H. C. and Manger, W. L. 1979. Mesothemic cyclicity in the mid-Carboniferous of the Ozark shelf region? Geology 7:293–296.Google Scholar
Schmidt, Hermann. 1925. Die Carbonischen Goniatiten Deutschlands. Preuss Geol. Landesanstalt, Jahrb. 1924, v. 44, p. 489–609, pls. 19–26.Google Scholar
Simonds, F. W. 1891. The geology of Washington County. Arkansas Geol. Surv. Ann. Rept., 1888, v. 4, p. 1–148, 2 pls.Google Scholar
Smith, J. P. 1896. Marine fossils from the Coal Measures of Arkansas. Amer. Philos. Soc. Proc. 35:214–285, pls. 16–24.Google Scholar
Sohn, I. G. 1977. Late Mississippian and early Pennsylvanian ostracoda from northern Arkansas—a preliminary survey. In, Sutherland, P. K. and Manger, W. L. (eds.). Okla. Geol. Surv. Guidebook 18, p. 149–160.Google Scholar
Spivey, R. C. and Roberts, T. G. 1946. Lower Pennsylvanian terminology in central Texas. Amer. Assoc. Petrol. Geol. Bull. 30:181–186.Google Scholar
Straka, J. J. II. 1972. Conodont evidence of age of Goddard and Springer Formations, Ardmore Basin, Oklahoma. Amer. Assoc. Petroleum Geologists Bull. 56:1087–1099.Google Scholar
Strimple, H. L. 1977. Chesterian (upper Mississippian) and Morrowan (lower Pennsylvanian) crinoids of northeastern Oklahoma and northwestern Arkansas. In, Sutherland, P. K. and Manger, W. L. Okla. Geol. Surv. Guidebook 18, p. 171–176.Google Scholar
Sutherland, P. K. and Henry, T. W. 1977. Carbonate platform facies and new stratigraphic nomenclature of the Morrowan Series, northeastern Oklahoma. Geol. Soc. America Bull. 88:425–440.2.0.CO;2>CrossRefGoogle Scholar
Taff, J. A. 1905. Description of the Tahlequah quadrangle (Indian Territory-Arkansas). U.S. Geol. Surv., Geol. Atlas, Folio 122.Google Scholar
Tomlinson, C. W. 1959. Best exposures of various strata in Ardmore Basin, 1957. In, Petroleum Geology of southern Oklahoma. Amer. Assoc. Petrol. Geol. Spec. Pub. 2, p. 302–334.Google Scholar
Ulrich, E. O. 1904. Determination and correlation of formations. In, Adams, G. I., U.S. Geol. Survey, Prof. Paper 24, p. 90–113.Google Scholar
Wagner-Gentis, C. H. T. 1971. Description of goniatites. In, Wagner, R. H. (ed.), The Carboniferous of Northwest Spain, Trabajos de Geologia, Fac. Ci. Univ. Oviedo 1:344–353, pls. 2–6.Google Scholar
Webster, G. D. and Lane, N. G. 1967. Mississippian-Pennsylvanian boundary in southern Nevada. R. C. Moore Commemorative Volume, Kansas Univ. Press, Lawrence, Kansas, p. 503–522.Google Scholar
Wilmarth, M. G. 1938. Lexicon of geologic names of the United States. U.S. Geol. Surv. Bull. 896, 2396 p.Google Scholar
Zachry, D. L. and Haley, B. R. 1975. Stratigraphic relationships between the Bloyd and Atoka Formations (Pennsylvanian) of northern Arkansas. In, Headrick, K. N. and Wise, O. A. Contributions to the Geology of the Arkansas Ozarks. Ark. Geol. Comm., p. 96–106.Google Scholar
Zakharov, Ye. F. 1969. More information on the stratigraphy of the Namurian based on ammonoids of the Karachatyr Range. Doklady Akad. Nauk. SSSR 185:149–151 (in Russian).Google Scholar