Carboniferous Foraminifera and Algae of the Amsden Formation (Mississippian and Pennsylvanian) of Wyoming

GEOLOGICAL SURVEY PROFESSIONAL PAPER 848-B Carboniferous Foraminifera and Algae of the Amsden Formation (Mississippian and Pennsylvanian) of Wyoming

By BERNARD L. MAMET

THE AMSDEN FORMATION (MISSISSIPPIAN AND PENNSYLVANIAN) OF WYOMING

GEOLOGICAL SURVEY PROFESSIONAL PAPER 848-B

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1975 UNITED STATES DEPARTMENT OF THE INTERIOR

ROGERS C. B. MORTON, Secretary

GEOLOGICAL SURVEY

V. E. McKelvey, Director

Library of Congress Cataloging in Publication Data Mamet, Bernard L. Carboniferous foraminifera and algae of the Amsden Formation (Mississippian and Pennsylvanian) of Wyoming. (The Amsden Formation (Mississippian and Pennsylvanian) of Wyoming) (Geological Survey professional paper; 848-B) Bibliography: p. Includes index. 1. Foraminifera, Fossil. 2. Algae, Fossil. 3. Paleontology-Carboniferous. 4. Paleontology-Wyoming. I. Title. II. Series. III. Series: United States. Geological Survey. Professional paper; 848-B. QE772.M294 557.3 r 08s [563'.1] 75-619056

For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, B.C. 20402 Stock Number 024-001-02631-7 CONTENTS

Page Abstract ______Bl Introduction _____-_ --- -- ____ _ 1 Taxonomic composition of the Amsden faunas ______2 Archaediscidae _-_ -______------2 Biseriamminidae _ _ 2 Bradyinidae ___ _-_ - ______3 Cornuspiridae (sensu lato) ______3 Earlandiidae ______-_-_____ -_-___-_--- 3 Endothyridae ______-____-______3 Eostaffellidae ______3 Fusulinidae _____ 3 Globoendothyridae ______3 Lasiodiscidae ______3 Ozawainellidae ______-______-____ 4 Palaeotextulariidae ______4 Pseudoendothyridae ______-_-____ 4 Tetrataxidae ______4 Zonation ______4 Zone 17 ______j___ 4 Zone 18 ______5 Zone 19 ______6 Zone 20 ______6 Zone 21 ______6 The Mississippian-Pennsylvanian boundary ______7 List of microfossils ______7 References cited ______14 Index ______17

ILLUSTRATIONS

[Plates follow index]

PLATES 1, 2. Representative thin sections of foraminifers and algae from the Amsden Formation.

Page FIGURE 1. Diagram showing stratigraphic ranges of Amsden foraminifers related to standard time-stratigraphic units ______B4

TABLE

Page TABLE 1. Checklist of Amsden foraminifer collections ______B3 m

THE AMSDEN FORMATION (MISSISSIPPIAN AND PENNSYLVANIAN) OF WYOMING

CARBONIFEROUS FORAMINIFERA AND ALGAE OF THE AMSDEN FORMATION (MISSISSIPPIAN AND PENNSYLVANIAN) OF WYOMING

By BERNARD L. MAMET

ABSTRACT Calcareous secreted Foraminifera are unevenly Calcareous microfossil assemblages from the Amsden For­ distributed in the Amsden Formation. The Darwin mation of Wyoming consist of at least 100 taxa, predomi­ Sandstone Member, for instance, yields no identifi­ nantly foraminifers but including some algae and forms of able fauna. Calcareous beds of the Horseshoe Shale, uncertain biologic affinity. Approximately 70 taxa are re­ Ranchester Limestone and Moffat Trail Limestone ported herein. No microfossils were found in the Darwin Members yield variable amounts of microfauna; the Sandstone Member, but significant microfossil assemblages were recovered from the Horseshoe Shale, Moffat Trail Lime­ richest assemblages are found in the pelmatozoan- stone, and Ranchester Limestone Members of the Amsden. lump-bearing grainstones and packstones; in con­ The reported assemblages permit recognition of Zones 17-21, trast, red silty mudstones and dolomites yield very an age range of earliest Namurian (middle Chesterian) into poor assemblages. However, despite the uneven dis­ early Westphalian (Atokan). tribution, the variable preservation, and the fact that the collections studied here were not made spe­ INTRODUCTION cifically for foraminifers, sufficient material was found to establish a biostratigraphic zonation. The presence of endothyrid foraminifers and At least 100 different foraminiferal taxa have primitive fusulinids in the Upper Mississippian and been observed in about 120 thin sections of samples Lower Pennsylvanian strata of Montana and Wyo­ collected from 40 localities. Most of these taxa are ming is well documented (Scott, 1945a, 1945b; very scarce or could not be identified to the specific Zellerfide Cooper, 1947; Zeller, 1950; Easton, 1962). level. Moreover, apterrinellids, serpulopsids, and cal- Little attempt has been made, however, to use them citornellids cannot be identified with confidence on as stratigraphic indices. This short contribution is random thin sections, and their role and value, if aimed at underlining the usefulness of these micro- any, in stratigraphy remain obscure. fossils for Carboniferous correlations. In particular, the fossils are of some interest for recognition of the The most important forms for biostratigraphic controversial Mississippian-Pennsylvanian bound­ correlations are reported here: ary. Archaediscus sp. Archaediscus of the group A. chernoussovensis Mamet Details of the stratigraphy and the occurrences of A. krestovnikovi Rauzer-Chernoussova these fossils are given by Sando, Gordon, and Dutro Archaediscus of the group A. krestovnikovi Rauzer- (1974). Representative thin sections of the Amsden Chernoussova microfossils are shown in plates 1 and 2. Lists of Asteroarchaediscus sp. microfossils are given in terms of the stratigraphic A. baschkiricus (Krestovnikov and Teodorovitch) units and localities described in Sando, Gordon, and Asteroarchaediscus of the group A. baschkiricus (Krestovnikov and Teodorovitch) Dutro (1974), and the localities are documented in Biseriella sp. table 1. B. moderata (Reitlinger) Bl B2 THE AMSDEN FORMATION (MISSISSIPPIAN AND PENNSYLVANIAN) OF WYOMING

B. parva (Chernysheva) "Tetrataxis" of the group "T." eominima Rauzer- Biseriella of the group B. parva (Chernysheva) Chernoussova Bradyinal sp. Trepeilopsis sp. Climacammina sp. Tuberitina sp. "Cornuspira" sp. Volvotextularia sp. Diplosphaerina sp. Zellerina sp. Earlandia sp. Z. discoidea (Girty) E. clavatula (Howchin) In addition to foraminifers, algae and incertae E. elegans (Eauzer-Chernoussova) sedis are also present. Among the alg;re, Spongi- E. vulgaris (Eauzer-Chernoussva and Eeitlinger) ostromata are the most widespread. Also noticeable cf. Endostaffellal sp. are the Rhodophycophyta (Stacheia, Stacheoides, Endothyra sp. etc.). Calcispheres are mostly represented by Calci- Endothyra of the group E. bowmani Phillips emend. Brady sphaera laevis Williamson. Asphaltina is present. E. excellens (Zeller) None of these forms has precise stratigraphic value. "Endothyra" of the group "E" prisca Eauzer- Chernoussova and Eeitlinger TAXONOMIC COMPOSITION OF THE Endothyra of the group E. similis Eauzer-Chernoussova and Eeitlinger AMSDEN FAUNAS E. tantala (Zeller) Endothyranella sp. ARCHAEDISCIDAE cf. Eolasiodiscus sp. Eoschubertella sp. The most useful index for stratigraphic zonation "Eosigmoilina" sp. of the latest Visean-early Namurian is the Archae- Eostaffella sp. discus - Neoarchaediscus - Planospirodiscus - Astero- Eostaffella of the group E. acutissima Kireeva archaediscus-Quasiarchaediscus-'Eosigmoilina" phy- E. circuit (Thompson) logeny. These genera have been found in abundance Eostaffella of the group £7. pseudostruvei (Eauzer- in most of the fossiliferous Amsden Formation thin Chernoussova) E. pinguis (Thompson) sections. As is generally the case in rocks of Na­ Eostaffellina sp. murian age, Archaediscus is represented only by E. paraprotvae (Rauzer-Chernoussova) relict Archaediscus of the group A. krestovnikovi, all Eotuberitina sp. other groups (A. moelleri, A. chernoussovensis) be­ Globivalvulina sp. ing rare or absent. The Archaediscidr.e with ob­ Globivalvulina of the group G. bulloides (Brady) Globoendothyra sp. structed lumen dominate, and Asteroc,rchaediscus Glomospira sp. and Neoarchaediscus are common in all clean wacke- Lipinella sp. (nom. nud.) stones and packstones. Millerella sp. The progressive elimination of the pseudofibrous M. pressa Thompson wall structure and its replacement by a "porcellane­ M. aff. M. pura Malakhova ous" wall, concomitant with the disappearance of Monotaxinoides sp. Neoarchaediscus sp. the inner tectum, lead to "Eosigmoilina" which is N. incertus (Grozdilova and Lebedeva) derived, for the first time, in Zone 19 from Quasi- Neoarchaediscus of the group N. incertus (Grozdilova archaediscus. This evolutionary change is well ob­ and Lebedeva) served in the middle part of the Amsden Formation Neoarchaediscus of the group N. parvus (Eauzer- at the Berry Creek section. Chernoussova) AT", parvus (Eauzer-Chernoussova) cf. Palaeonubecularial sp. BISERIAMMINIDAE Palaeotextularia sp. Biseriamminids are abundant in the / msden For­ Palaeotextularia of the group P. consobrina Lipina mation from Zone 18 upwards. Earliest forms are Palaeotextularia of the group P. longiseptata Lipina Biseriella of the group B. parva (Cternysheva), Planoendothyra sp. Planospirodiscus sp. whose outburst underlies Zone 18 (upper Chester P. minimus (Grozdilova and Lebedeva) time equivalent in the Midcontinent and the Cor­ Pseudoendothyra sp. dillera). Pseudoendothyra of the group P. kremenskensis Globivalvulina sensu stricto, with its characteris­ Eozovskaia tic diaphanotheca, appears for the first time in the Pseudoendothyra of the group P. ovata (Reitlinger) Pseudoendothyra of the group P. struvei (von Moller) basal Pennsylvanian beds. It is an important faunal Pseudoglomospira sp. element of Zone 21 (Globivalvulina of the group G. Tetrataxis sp. bulloides (Brady)). CARBONIFEROUS FORAMINIFERA AND ALGAE B3

TABLE 1. Checklist of Amsden foraminifer collections

Collec­ Permanent tion USGS Name of locality Mountain range County Location Member No. catalog No.

1 5441-PC _____ Probably SW*4 sec. 11, T. 21 N., R. 88 W. 8071-PC _ do ______do . ._ ____ do _ _ do ______Do. 3 3139-PC ______do ______do __ __ _ ._ __ do NW%SW% sec. 11, T. 21 N., R. 88 W Do. 4 3140 PC _ _ _ do __ __ _ do _ _ Do. 3085-PC __ _ __ do ______- __ do ______do __ _ _ SE^iNE^, sec. 10, T 21 N., R. 88 W _ _ Do. 6 3843 PC ____ Rawlins US 287 _ __ _ do ______do Probably NW&NW% see. 32, T. 22 N., R. 87 W. 13 21729-PC __ Meadow Ranch ______do ______do ______SWVtNEi/i sec. 25, T. 22 N., R. 88 W Do. 14 _ -do ______do - . NW% sec. 33, T. 23 N., R. 88 W Do. 45 21719-PC ____ Livingston Ranch ____ Washakie Range __ Fremont _ _ SWiiSW 1^ sec. 29, T 43 N., R. 106 W __ Horseshoe Shale. 50 Sec. 19, T. 41 N., R. 88 W ______19187-PC. 22206 PC __ _ do _ ___ _ SW% sec. 34, T. 57 N., R. 87 W ______Do. 64 22207-PC __ __do ______do ______do _ _ _do ______Do. 65 22208-PC ____ do ______- _ _do _ ___ _ do __ . Do. 67 16215-PC __ __ do __ ----- _do _._. __ _ _ do _ __ _ _do ______Do. 68 22204-PC _ _ _do ______do ______do _ - . SEii sec. 32, T. 57 N., R. 87 W Do. NW^NWVi sec. 19, T. 28 N., R. 113 W Do. 74 22985-PC ___ NW%NEi4 sec. 3, T. 33 N., R. 117 W _ 22986 PC __ _ __ do _ - ______do ______do ______do ______Do. 77 6960 A-PC __ _do ______-do _ _ _ do _ _ _ Do. 78 6960B-PC _ _ do __ . __ _ do ______do - - __do ______Do. 79 22981-PC . __ do ____ .._ _ _do ______. _ do _ _ do ______. _ Do. 82 22984-PC __ _ do ______-do ______. do _ 90 22995-PC __ Covey Cutoff Trail _ _ _do ______do _ __ . NW^NE^, sec. 27, T. 34 N., R. 117 W 92 S965-PC _____ -do ______do ______do _ rln Do. 93 6951-PC _ _ __ do ______do ______-do . __ _ do ______Do. 100 6965D-PC __ _ _do ______do __ .. __ _ __ do - __ _ do ______103 17905-PC __ __ do ______do _ Center sec. 19, T. 34 N., R. 117 W 104 17906-PC __ __ do ______do _ do _ _ __ do ______Do. 105 17907-PC __ _ do _ _ -do __ __ do _ _ . _ do ______. - _ -- Do. 109 23002-PC _ __ _ -do _ - - NE'/i sec. 14, T. 38 N., R. 118 W __ Do. 121 16208-PC _ __ Sec 2, T. 38 N., R. 115 W ___ Do. 122 16209-PC __ _ do ______-do __ - __ , do _ ___ do ______Do. 124 18799-PC __ _ -do _ _ _ _ _ do ______do - Sec. 3, T. 38 N., R. 115 W __ _ _ _ Do. 125 18785-PC __ -do _ _ _ -do _ _ - - _ do _ - Do. 126 22998-PC _ _ do ______do ______- do - _ -do ______. _ __ Do. 132 16211-PC _ _ _ ..do _ . __ _ _do ______do _ __ do ______145 23006-PC __ _ - do _ __ SWH sec. 16, T. 41 N., R. 117 W __ _ _ 153 24059-PC _ __ do __ __ ._ _ _ do _ NW% sec. 22, T. 47 N., R. 116 W __ - 154 24060-PC __ _do ______do __ - _ __ -do _ . _ __ do _ _ - ______Do. 160 24057-PC . Elk Ridge ______do ______do _ ._ SWVi sec. 26, T. 47 N., R. 116 W __

BRADYINIDAE EOSTAFFELLIDAE Bradyinaf has only been observed once, at the Tip Four genera of Eostaffellidae are known: Eostaf- Top Well locality. fella, Endostaffellaf, Eostaffellina, and Zellerina. Zellerina is abundant at all levels of the Chester and CORNUSPIRIDAE (sensu lato) has often been confused for Millerella. Eostaffellina, where it occurs in abundance (Ams­ "Cornuspira" is present but scarce. The absence den Creek section), is a good marker for the upper of Brunsia is puzzling. Chester and Morrow age equivalents.

EARLANDIIDAE FUSULINIDAE Common in most facies, the family is essentially Eoschubertella is restricted to the upper part of represented by Earlandia. No zonation can be de­ the Amsden Formation (Ranchester Limestone rived from this genus in Namurian time. Member).

ENDOTHYRIDAE GLOBOENDOTHYRIDAE Although this family is of great stratigraphic The family is poorly represented by scarce Glo- value in the Tournaisian-Visean, its usefulness dwin­ boendothyra. dles in the Late Visean and disappears in the Na­ murian. Only Endothyra and Pianoendothyra have been observed, the latter genus being scarce. Even LASIODISCIDAE at a specific level, little evolution can be detected, The most primitive member of this family, hence no zonation is feasible at the Mississippian- Eolasiodiscus, is abundant at the Covey Cutoff sec­ Pennsylvanian boundary. tion. B4 THE AMSDEN FORMATION (MISSISSIPPIAN AND PENNSYLVANIAN) OF WYOMING

OZAWAINELLIDAE

The unique representative of this family is Mil­ ZONAL ler ella sensu stricto; its first appearance is basal co RANGES Pennsylvanian (Zone 20). H OF CO Z rji O MEMPKRS OF AMSDEN PALAEOTEXTULARIIDAE NORTHAMERICANSYSTE AMERICANSERIINORTH WESTERNEUROPEAN MEGAFAUNALZONES FORMATION LOCALITY)(TYPE EUROPEANSTAGES FORAMINIFERALMAMETZ As in most of the American Midcontinent and in the Williston basin, the family is poorly developed in early Namurian with occasional Climacammina and Palaeotextularia. These genera become rather CHESTER abundant in the Pennsylvanian. ESTONE 4ESTONE H

TETRATAXIDAE *s 55 The family is unusually poorly represented by FPHALI 21 Tetrataxis and Monotaxinoides. i i is < d 7 55 <4 OT This composition of the families is typical of any > H North American Namurian carbonate platform w , microfauna. The only difference observed between *755 7 XH g ? « 5 20 the Amsden fauna and that of comparable carbonate PH assemblages of the Midcontinent and the Cordillera o R is the very poor development of the Tetrataxidae ' and Bradyinidae and the absence of Endothy- ? ranopsidae. I 1 ZONATION H 19 w1 Five Carboniferous foraminiferal zones can be 55 I identified in the Amsden Formation; they represent i i g 1 tf "? the time equivalents of the middle Chester to the !=» Atoka classical sequence of the Midcontinent (fig. S ^ E2 1). 18 55 _____ ZONE 17 PH co00 Definition. The base of the zone is defined at the oo 5 co i i outburst of Asteroarchaediscus and in particular at ^ the first proliferation of Asteroarchaediscus basch- H El 17 co kiricus (Krestovnikov and Teodorovitch). The zone W contains many elements inherited from the under­ o lying Visean Zone 16S, such as Neoarchaediscus and Planospirodiscus. The top of the zone yields the first biseriamminids referable to Biseriella. Examples of M V3c 16 Zone 17 assemblages are illustrated on plate 1, fig­ oo ^ ures 1-3. Comparison. In the Carboniferous Tethys, the base of Zone 17 is characterized by the disappear­ ance of numerous Visean elements such as Valvuli- FIGURE 1. Stratigraphic ranges of Amsden forrminifers re­ nella, Howchinia, and residual lituotubellids and lated to standard time-stratigraphic units. CARBONIFEROUS FORAMINIFERA AND ALGAE B5 forschiids. These taxa are unknown outside the ZONE 18 Tethyan realm. Zone 17 also normally yields Endo- Definition. This zone is characterized by the out­ thyranopsis sphaerica (Rauzer-Chernoussova and burst of Biseriella of the group B. parva (Cherny- Reitlinger) ; no Endothyranopsidae has been en­ sheva). Eostaffellina is also present. The top of the countered in the Amsden Formation. zone is marked by the first appearance of Quasi- Occurrence in Amsden Formation. The Zone 17 archaediscits. assemblage of the Amsden Formation is known only Comparison. In the Carboniferous Tethys, these from the Moffat Trail Limestone Member of ex­ characteristic elements are present, but Eostaffellina treme western Wyoming, where it has been posi­ is more abundant. Spherical "Pseudoendothyra" are tively identified in collections 103, 104, and 109 also encountered in the Tethys; in comparison, they from the Haystack Peak and South Indian Creek are unknown in North America. Loeblichia is also localities. These faunules contain the oldest forami- restricted to the Tethyan realm. nifers known from the Amsden. Other collections Occurrence in Amsden Formation. The principal (75, 79, 90, 92, 93, 126) from the Moffat Trail Lime­ occurrences of the Zone 18 assemblage are in the stone Member at Moffat Trail, Covey Cutoff Trail, Moffat Trail Limestone Member, where the assem­ and Hoback Canyon contain assemblages that repre­ blage has been identified in collections 74, 77, 78, sent Zone 17 or 18 but lack critical elements that 105, 122, 124, and 145 from the Moffat Trail, Hay­ permit differentiation of the two zones. stack Peak, Hoback Canyon, and Phillips Canyon Correlation. Zone 17 is of middle Chesterian age; localities of western Wyoming. The zone may be it includes a foraminiferal assemblage that occurs represented in collection 125 from the Moffat Trail in the Glen Dean and Menard Limestones of the Limestone Member at Hoback Canyon. Midcontinent region. The base of the Glen Dean is The Zone 18 assemblage also has been found in characterized by the first outburst of Asteroarchae- the Horseshoe Shale Member at Livingston Rar?,h discus baschkiricus (Krestovnikov and Teodoro- in the Washakie Range (colln. 45), where it indi­ vitch), while the underlying Golconda Formation cates partial time equivalence of the Horseshoe Shale yields only Neoarchaediscus and Planospirodiscus. and Moffat Trail Limestone Members. Possible rep­ Zone 17 is also known from the base of the Surrett resentation of Zone 18 in the Horseshoe Shale Mem­ Canyon Formation and from the upper part of the ber at Berry Creek (colln. 154) and in the Ranch-^s- White Knob Limestone of central Idaho (Mamet ter Limestone Member at Elk Ridge (colln. 160), and others, 1971; Skipp and Mamet, 1970). It has localities in the Teton Range, is doubtful because been observed in the Monroe Canyon Limestone of these occurrences are more in keeping with the dis­ southeastern Idaho (Sando and others, 1969). In tribution of the Zone 19 assemblage. Nevada, the upper part of the Battleship Wash Correlation. Zone 18 is of late Chesterian age; Formation is early Namurian (Mamet and Skipp, it includes a foraminiferal assemblage that occurs 1970). in the Clore and Kinkaid Limestones of the Mid- In Alaska, Zone 17 is observed in the Calico Bluff continent region. In Idaho, Zone 18 is known from Formation and in the middle part of the Alapah the middle part of the Surrett Canyon Formation, Limestone of the Lisburne Group in the Sadlerochit the top of the White Knob Limestone (Mamet r.nd Mountains, the Romanzoff Mountains, and the cen­ others, 1971) and the upper part of the Monroe tral part of the Brooks Range (Armstrong and Canyon Limestone (Sando and others, 1969). It is others, 1970). It is poorly developed in the Kogruk also observed in the Indian Spring Formation of Formation at Cape Lewis (Armstrong and others, Nevada (Mamet and Skipp, 1970). 1971). In Alaska, the zone is well displayed in the upper Zone 17 is also widespread in Canada, where it part of the Alapah Limestone in the Sadlerochit occurs in the upper part of the Windsor Group of Mountains, Romanzoff Mountains, and the central Nova Scotia (Mamet, 1970), in the middle part of part of the Brooks Range (Armstrong and others, the Etherington Formation in Alberta and British 1970). It is also known from the upper part of the Columbia (Mamet, 1968), in the middle part of the Kogruk Formation at Cape Lewis (Armstrong r.nd Nizi Formation in British Columbia (Mamet and others, 1971). Gabrielse, 1969), in the middle part of the Alapah In Canada, Zone 18 is unknown in the Maritime Limestone and at the top of the Hart River Forma­ Provinces, where nonmarine or brackish sediments tion in the Yukon Territory (Mamet and Mason, overlie early Namurian carbonates. It is present in 1970; Mamet and Ross in Bamber and Water- the upper part of the Etherington Formation of house, 1971). Alberta and British Columbia (Mamet, 1968) and B6 THE AMSDEN FORMATION (MISSISSIPPIAN AND PENNSYLVANIAN) OF WYOMING in the Nizi Formation of northern British Columbia pal occurrences of the Zone 20 assemblage are in the (Mamet and Gabrielse, 1969). It is also observed Ranchester Limestone Member, where it has been in the upper part of the Alapah Limestone and in found at two localities in western Wyoming (collns. the Ettrain Formation of the Yukon Territory 100, 132) and four localities in central Wyoming (Mamet and Mason, 1970; Mamet and Ross in (collns. 13, 14, 50?, 63, 64, 65, 67, 68). It also oc­ Bamber and Waterhouse, 1971). curs in the Horseshoe Shale Member of the Raw- lins hills (collns. 1-5). Con-elation. In the United States, the first true ZONE 19 fusulinids occur in the basal Pennsylvania and may Definition. This zone is characterized by the therefore be used to underline the sequence. Zone acme of Eosigmoilina-Quasiarchaediscus. In addi­ 20 corresponds to the Morrowan Series of the stand­ tion, it contains some elements inherited from early ard North American sequence. Namurian zones such as Biseriella and Astero- Zone 20 is well displayed at the base of the Penn- archaediscus. sylvanian sequence of central Idaho (Mamet and Comparison. The same faunal characteristics are others, 1971) and in the basal carbonates of the Bird known in the Tethys, where the zone is equivalent Spring Formation in Nevada (Mamet and Skipp, to most of the Homoceras Zone. 1970). In Alaska, Zone 20 is widespread at the base Occurrence in Amsden Formation. The Zone 19 of the Wahoo Limestone in the Sadlerochit Moun­ assemblage is known definitely only from collection tains (Armstrong and others, 1971). 153 in the Horseshoe Shale Member at Berry Creek in the Teton Range. It is probably also present in collection 154 at Berry Creek and may be repre­ ZONE 21 sented in the Ranchester Limestone Member at Elk Definition. This zone is recognized en the out­ Ridge (colln. 160). burst of Eoschubertella and Pseudostaffella. Dia­ Correlation. Zone 19 is considered to be of lat­ phanotheca-bearing Globivalvulina also become est Chesterian age although it is absent from the abundant at the base of the zone. Midcontinent region owing to post-Kinkaid, pre- Comparison. Direct comparison with the Car­ Pennsylvanian hiatus. This zone is known from the boniferous Tethys is difficult. Further studies are uppermost part of the Surrett Canyon Formation of necessary in order to relate Zone 21 with the stand­ central Idaho and is particularly well displayed in ard Baschkirian-Moscovian succession. If the Don­ the upper part of the Indian Spring Formation in bass sequence established by Brazhnikova and others Nevada (Mamet and Skipp, 1970). (1967) is correct, Zone 21 is still Baschkirian, a cor­ In Alaska, Zone 19 has been observed in the up­ relation which conflicts with the generally accepted permost part of the Alapah? Limestone in the West view that the base of the Atokan Series ie equivalent Sadlerochit Mountains. In Canada, the zone has been to the basal Moscovian (Thompson in Loeblich and identified in the Trail River-Trout Lake region in Tappan, 1964). the Yukon Territory (Mamet and Mason, 1970). It Occurrence in Amsden Formation. The Zone 21 is also present in the uppermost Alapah Limestone assemblage is known only from the Ranchester of the British and Buckland Mountains (Mamet and Limestone Member in the Rawlins hills (colln. 6) Ross in Bamber and Waterhouse, 1971). and at the Tip Top Well in the Green River Basin (colln. 71). ZONE 20 Correlation. In the United States, Zone 21 is well displayed in the Atoka age equivalent sequence Definition. The zone is identified on the first oc­ of central Idaho (Mamet and others, 1971). It is currence of true fusulinids (Millerella sensu stric- poorly displayed in the Bird Spring Formation of to). The first diaphanotheca-bearing Globivalvulina Nevada. also occur for the first time, but they are scarce. In Alaska, the zone is omnipresent in the oolitic Examples of Zone 20 assemblages are shown on facies of the middle part of the Wahoo Limestone plate 1, figures 6-8 and plate 2, figures 1-8. in the Sadlerochit Mountains. In Canada, it is pres­ Comparison. The same faunal characteristics are ent in the Lisburne Group of the Malcolm River known in the Tethys, where Semistaffella and primi­ section and in the Ettrain Formation in the Keele tive Pseudostaffella ? occur in addition. Range (Yukon Territory) (Mamet and Ross in Occurrence in Amsden Formation. The princi­ Bamber and Waterhouse, 1971). CARBONIFEROUS FORAMINIFERA AND ALGAE B7

THE MISSISSIPPIAN-PENNSYLVANIAN lidae. Pennsylvanian Millerella of Easton (19^2) BOUNDARY and of Moore (1964) correctly fit the Thompson (1942) diagnosis. As previously mentioned (Mamet and others, 1971), the formations exposed in the Midcontinent are unsuitable for definition of the Mississippian- LIST OF MICROFOSSILS Pennsylvanian boundary because the two sequences Collection 1. Horseshoe Shale Member, Cherokee Spring are separated by a hiatus. The exact biostrati- locality. graphic span of this hiatus is unknown, but the Age. Zone 20, late Namurian (Reticuloceras Zone), Fenn- latest Mississippian (Kinkaid Limestone, Grove sylvanian (Morrowan). Church Member) yields a good Zone 18 assemblage, Foraminifers present. while the first Pennsylvanian fauna is Zone 20. Thus Apterrinellidae Arcliaediscus sp. it is certain that Zone 19 is entirely missing and Asphaltina sp. plausible that Zones 18 and 20 are incomplete. Asteroarchaediscus sp. Zone 19 has been considered here as latest Ches­ Asteroarchaediscus of the group A, baschkiricus ter i an age equivalent, although it is missing in the (Krestovnikov and Teodorovitch) type Chester region. This age assignment is bio- Calcisphaera sp. stratigraphically consistent with the observation Earlandia sp. Endothyra sp. that Zone 19 is the acme of the evolution of the Endothyranella sp. Archaediscidae and is phylogenically linked with the Lipinella sp. (nom. nud.) underlying Zone 18. Moreover, Zone 20 marks the Millerella sp. appearance of the first true fusulinids, which become Neoarchaediscus of the group N. incertus (Grozdilovr the dominant assemblage of the Pennsylvanian mic- and Lebedeva) rofauna. This placement of the boundary respects Planospirodiseus sp. Pseudoglomospira sp. both lithostratigraphic and biostratigraphic conven­ Zellerina sp. tions. Collection 2. Horseshoe Shale Member, Cherokee Siting A somewhat similar position was adopted by locality. Lane, Sanderson, and Verville (1972), who consid­ Age. Zone 20, late Namurian (Reticuloceras Zone), Fenn- ered the Zone 19 Indian Springs Formation of sylvanian (Morrowan). Foraminifers present. Nevada to be entirely Chesterian. They defined the Apterrinellidae base of the Pennsylvanian on the first occurrence of Archaediscus sp. the conodonts Adetognatlius lautus and A. gigantus, Asteroarchaediscus sp. which occur for the first time slightly above the top A. baschkiricus (Krestovnikov and Teodorovitch) of the Indian Springs Formation. According to Biseriella sp. Brenckle, Zone 19 is still present in the lowermost B. moderata (Reitlinger) Calcisphaera sp. part of the Bird Spring Formation in the Arrow "Cornuspira" sp. Canyon composite section of Nevada (1973). Diplosphaerina sp. One must underline, however, the confusion ob­ Earlandia sp. served in the literature concerning the status of "Endothyra" sp. Millerella. When Thompson (1942) originally de­ Eostaffella sp. Eotuberitina sp. fined the genus, he correctly assumed that it was Girvanella sp. diagnostic of the Pennsylvanian. However, the Globivalvidina sp. Thompson concept of the genus subsequently varied Lipinella sp. (nom. nud.) greatly, and he incorporated in Millerella species Millerella sp. which would now be referred to Eostaffella or Zelle- Neoarchaediscus of the group N. incertus (Grozdilovr rina (Thompson, 1944, 1945). Scott (1945a, 1945b) and Lebedeva) N. parvus (Rauzer-Chernoussova) correctly identified Millerella, but references to Mil­ Pianospirodiscus sp. lerella in the upper Chester (Henbest, 1946, 1947; Pseudoendothyra sp. Cooper, 1946, 1947; Mellen, 1947; Thompson, 1948; Collection 3. Horseshoe Shale Member, Cherokee Spring E. J. Zeller, 1950; D. E. N. Zeller, 1953; Sage, 1954) locality. have to be re-evaluated. All published material of Age. Zone 20, late Namurian (Reticuloceras Zone), Penn­ sylvanian (Morrowan). such low Millerella occurrences (Cooper, 1947; E. J. Foraminifers abundant. Zeller, 1950; Sage, 1954) show taxa which should be Apterrinellidae referred to the Eostaffellidae, not to the Ozawainel- Asphaltina sp. B8 THE AMSDEN FORMATION (MISSISSIPPIAN AND PENNSYLVANIAN) OF WYOMING

Asteroarchaediscus sp. Neoarchaediscus sp. Asteroarchaediscus of the group A. baschkiricus N. incertus (Grozdilova and Lebedeva) (Krestovnikov and Teodorovitch) N. parvus (Rauzer-Chernoussova) Biseriella sp. Planospirodiscus sp. Calcisphaera sp. Pseudoglomospira sp. C. laevis Williamson Pseudoendothyra sp. Earlandia sp. Rhodophycophyta Endothyra sp. Zellerina sp. "Endothyra" of the group "E." pri-sca Rauzer- Collection 6. Ranchester Limestone Member, Rawlins US Chernoussova and Reitlinger 287 locality. Millerella sp. Age. Zone 21, early Westphalian, Pennsylvanian M. pressa Thompson (Atokan). Neoarchaediscus incertus (Grozdilova and Lebedeva) Foraminifers present. N. parvus (Rauzer-Chernoussova) Archaediscus sp. Planoendothyra sp. Asteroarchaediscus sp. Planospirodiscus sp. Calcisphaera sp. Pseudoglomospira sp. C. laevis Williamson Zellerina sp. Eoschubertella sp. Collection 4. Horseshoe Shale Member, Cherokee Peak lo­ Eostaffella sp. cality. Millerella sp. Age. Zone 20, late Namurian (Reticuloceras Zone), Penn­ Pseudoglomospira sp. sylvanian (Morrowan). Tetrataxis sp. Foraminifers present to abundant. Collection 13. Ranchester Limestone Member, Meadow Apterrinellidae Archaediscus sp. Ranch locality. Archaediscus of the group A. krestovnikovi Rauzer- Age. Zone 20, late Namurian (Reticuloceras Zone), Chernoussova Pennsylvanian (Morrowan). Asphaltina sp. Foraminifers scarce. Asteroarchaediscus sp. Asteroarchaediscus sp. Asteroarchaediscus of the group A. baschkiricus Asteroarchaediscus of the group A. baschkiricus (Krestovnikov and Teodorovitch) (Krestovnikov and Teodorovitch) Calcisphaera sp. Calcisphaera sp. Earlandia sp. C. laevis Williamson Endothyra sp. Earlandia sp. "Endothyra" of the group "E." prisca Rauzer- Endothyra of the group E. boivmani Phillips emend. Chernoussva and Reitlinger Brady Lipinella sp. (nom. nud.) Eostaffella sp. Millerella sp. EostaffeUina sp. M. pressa Thompson Globivalvulina sp. Neoarchaediscus incertus (Grozdilova and Lebedeva) Lipinella sp. (nom. nud.) N. parvus (Rauzer-Chernoussova) Millerella sp. Planospirodiscus sp. M. pressa Thompson Pseudoendothyra sp. M. aff. M. pura Malakhova Pseudoglomospira sp. Neoarchaediscus sp. Planoendothyra sp. Collection 5. Horseshoe Shale Member, Cherokee Peak lo­ Pseudoendothyra sp. cality. Tetrataxis sp. Age. Zone 20, late Namurian (Reticuloceras Zone), Penn­ Zellerina sp. sylvanian (Morrowan). Foraminifers abundant. Collection 14. Ranchester Limestone Member, Buck Spring Apterrinellidae locality. Archaediscus sp. Age. Zone 20, late Namurian (Reticuloceras Zone), Penn­ Archaediscus of the group A. krestovnikovi Rauzer- sylvanian (Morrowan). Chernoussova Foraminifers abundant. Asphaltina sp. Asteroarchaediscus sp. Asteroarchaediscus sp. A. baschkiricus (Krestovnikov and Teodorovitch) A. baschkiricus (Krestovnikov and Teodorovitch) Biseriella sp. Calcisphaera sp. B. moderata (Reitlinger) C. laevis Williamson Calcisphaera sp. "Cornuspira" sp. Endothyra sp. Diplosphaerina sp. Earlandia sp. Earlandia sp. Eostaffella sp. Endothyra sp. "Eotuberitina" sp. Eotuberitina sp. Globivalvulina of the group G. bulloides (Brady) CARBONIFEROUS FORAMINIFERA AND ALGAE B9

Lipinella sp. (nom. nud.) Planoendothyra sp. cf. Palaeonubeculariat sp. Pseudoendothyra sp. Pseudoglomospira sp. Stacheiinae Tuberitina sp. Tetrataxis sp. Collection 45. Horseshoe Shale Member, Livingston Ranch Collection 64. Ranchester Limestone Member, Amsden Creek locality. locality. Age. Zone 18, early Namurian (Eumorphoceras Zone), Age. Zone 20, late Namurian (Reticuloceras Zone), Penn­ Late Mississippian (late Chesterian). sylvanian (Morrowan). Foraminifers present. Foraminifers abundant. Asteroarchaediscus sp. Apterrinellidae Biseriella sp. Asteroarchaediscus sp. Biseriella of the group B. parva ( Chernysheva) Biseriella moderata (Reitlinger) Calcisphaera sp. Calcisphaera sp. Earlandia sp. Cornuspiridae Endothyra sp. Endothyra sp. Eostaffella sp. Eostaffella sp. Eostaffellina sp. E. circuli (Thompson) Neoarchaediscus sp. Eostaffellina sp. Palaeotextularia sp. Globivalvulina sp. Planospirodiscus sp. Lipinella sp. (nom. nud.) Pseudoendothyra sp. cf. Palaeonubeculariat sp. Zellerina discoidea (Girty) Pseudoendothyra sp. Collection 50. Ranchester Limestone Member, Trout Creek Zellerina discoidea (Girty) locality. Collection 65. Ranchester Limestone Member, Amsden C *eek Age. Zone 20?, late Namurian (Reticuloceras Zone) ?, locality. Pennsylvanian (Morrowan) ? Age. Zone 20, late Namurian (Reticuloceras Zone), Penn­ Foraminifers scarce and poorly preserved. sylvanian (Morrowan). Apterrinellidae Foraminifers abundant. Calcisphaera sp. Apterrinellidae Cornuspiridae Archaediscus sp. Earlandia sp. Archaediscus of the group A. krestovnikovi Rauzer- cf. Lipinella sp. (nom. nud.) Chernoussova Pseudoglomospira sp. Asteroarchaediscus sp. Collection 63. Ranchester Limestone Member, Amsden Creek A. baschkiricus (Krestovnikov and Teodorovitch) locality. Biseriella sp. Age. Zone 20, late Namurian (Reticuloceras Zone), Penn­ B. moderata (Reitlinger) sylvanian (Morrowan). Calcisphaera sp. Foraminifers abundant. Cornuspiridae Apterrinellidae Endothyra sp. Archaediscus sp. Eostaffella sp. Archaediscus of the group A. krestovnikovi Rauzer- E. circuli (Thompson) Chernoussova Eostaffella of the group E. pseudostruvei (Rauzer- Asteroarchaediscus sp. Chernoussova) A. baschkiricns (Krestovnikov and Teodorovitch) Eostaffellina sp. Biseriella sp. E. paraprotvae (Rauzer-Chernoussova) Biseriella of the group B. parva (Chernysheva) Globivalvulina sp. B. moderata (Reitlinger) Lipinella sp. (nom. nud.) Calcisphaera sp. Millerella sp. Climacammina sp. Neoarchaediscus sp. Cornuspiridae cf. Palaeonubeculariat sp. Diplosphaerina sp. Pseudoendothyra sp. Endothyra sp. Pseudoglomospira sp. Endothyra of the group E. bowmani Phillips emend. Volvotextiilaria sp. Brady Collection 67. Ranchester Limestone Member, Amsden Creek Eostaffella sp. locality. Eostaffellina sp. Age. Zone 20, late Namurian (Reticuloceras Zone), lenn- Eotuberitina sp. sylvanian (Morrowan). Globivalvulina sp. Foraminifers present. Millerella sp. Asteroarchaediscus sp. Neoarchaediscus of the group N. incertus (Grozdilova A. baschkiricus (Krestovnikov and Teodorovitch) and Lebedeva) Biseriella moderata (Reitlinger) Palaeotextularia sp. B. parva (Chernysheva) BIO THE AMSDEN FORMATION (MISSISSIPPIAN AND PENNSYLVANIAN) OF WYOMING

Diplosphaerina sp. Palaeotextularia of the group P. consobrina Lipina Earlandia sp. Palaeotextularia of the group P. longiseptatz Lipina Endothyra sp. Pseudoglomospiral sp. Eostaffella sp. Stacheia sp. Eotuberitina sp. Stacheoides sp. Globivalvulina sp. "Trepeilopsis" sp. Globoendothyra sp. Tuberitina sp. Lipinella sp. (nom. nud.) Collection 74. Moffat Trail Limestone Member, Moffat Trail Neoarchaediscus sp. locality. cf. Palaeonubeculariat sp. Age. Zone 18, late early Namurian (upper Eumorphoceras Palaeotextularia of the group P. consobrina Lipina Zone), Late Mississippian (Chesterian). Palaeotextularia of the group P. longiseptata Lipina Foraminifers present. Tuberitina sp. Archaediscus sp. Collection 68. Ranchester Limestone Member, Amsden Creek Archaediscus of the group A. krestovnikovi Rauzer- locality. Chernoussova Age. Zone 20, late Namurian (Reticuloceras Zone), Penn- Asteroarchaediscus sp. sylvanian (Morrowan). A. baschkiricus (Krestovnikov and Teodorovitch) Foraminifers abundant. Biseriella parva (Chernysheva) Apterrinellidae B. moderata (Reitlinger) Archaediscus sp. Caldsphaera sp. Asteroarchaediscus baschkiricus (Krestovnikov and C. laevis Williamson Teodorovitch) Earlandia clavatula (Howchin) Biseriella sp. E. elegans (Rauzer-Chernoussova) Biseriella of the group B. parva (Chernysheva) Endothyra sp. B. moderata (Reitlinger) Endothyra of the group E. boivmani Phillips emend. Caldsphaera sp. Brady Climacammina sp. Endothyra of the group E. similis Rauzer-Oernoussova Cornuspiridae and Reitlinger Endothyra sp. E. excellens (Zeller) Eostaffella sp. Eostaffella sp. Eostaffellina paraprotvae (Rauzer-Chernoussova) E. circuli (Thompson) Eotuberitina sp. Endothyranella sp. Globivalvulina sp. Eotuberitina sp. Lipinella sp. (nom. nud.) Neoarchaediscus incertus (Grozdilova and Lebedeva) cf. Millerellal sp. N. parvus (Rauzer-Chernoussova) Neoarchaediscus of the group N. incertus (Grozdilova Palaeotextularia sp. and Lebedeva) Planospirodiscus sp. Neoarchaediscus of the group N. parvus (Rauzer- Pseudoendothyra sp. Chernoussova) Pseudoendothyra of the group P. kremcnskvusis Palaeotextularia of the group P. consobrina Lipina Rozovskaia Palaeotextularia of the group P. longiseptata Lipina Zellerina discoidea (Girty) Planospirodiscus sp. Collection 75. Moffat Trail Limestone Member Moffat Trail Pseudoglomospira sp. locality. Stacheiinae Age. Zone 17 or 18, early Namurian (Eumorphoceras Tetrataxis sp. Zone), Late Mississippian (Chesterian). Zellerina sp. Foraminifers present. Collection 71. Ranchester Limestone Member, Tip Top Well Archaediscus sp. locality. Archaediscus of the group A. krestovnikovi Rauzer- Age. Zone 21, early Westphalian, Pennsylvanian Chernoussova (Atokan). Asteroarchaediscus sp. Foraminifers present. Caldsphaera sp. The following list was compiled by Betty Skipp (written Endothyra sp. commun., 1969). Endothyra of the group E. bowmani Phillip^ emend. Asteroarchaediscus sp. Brady Brady mat sp. Eostaffella circuli (Thompson) Climacammina sp. Neoarchaediscus sp. Endothyra sp. Pseudoendothyra sp. Eostaffella sp. Pseudoendothyra of the group P. kremenskinsis Eostaffella of the group E. acutissima Kireeva Rozovskaia Eostaffellmat sp. Collection 77. Moffat Trail Limestone Member, Moffat Trail Globoendothyra sp. locality. Lipinella sp. (nom. nud.) Age. Zone 18, early Namurian, Late Mississippian (late Millerella sp. Chesterian). CARBONIFEROUS FORAMINIFERA AND ALGAE

Foraminifers scarce. Endothyra of the group E. boivmani Phillips emend. Archaediscus sp. Brady Asteroarchaediscus sp. Endothyra of the group E. similis Rauzer-Chernoussova Earlandia sp. and Reitlinger Endothyra sp. Eostaffella sp. Endothyra of the group E. bowmani Phillips emend. E. circuli (Thompson) Brady Eotuberitina sp. Pseudoendothyra sp. Globoendothyra sp. Zellerina sp. Neoarchaediscus incertus (Grozdilova and Lebedeva) Collection 78. Moffat Trail Limestone Member, Moffat Trail N. parvus (Rauzer-Chernoussva) locality. Palaeotextularia of the group P. consobrina Lipina Age. Zone 18, early Namurian, Late Mississippian (late Palaeotextularia of the group P. longiseptata Lipina Chesterian). Pseudoendothyra sp. Foraminifers scarce. Pseudoendothyra of the group P. kremenskensis Archaediscus sp. Rozovskaia Asteroarchaediscus sp. Stacheoides sp. Calcisphaera sp. Tuberitina sp. "Cornuspira" sp. Zellerina discoidea (Girty) Endothyra of the group E. bowmani Phillips emend. Collection 92. Moffat Trail Limestone Member, Covey Cutoff Brady locality. Eostaffellina sp. Age. Zone 17 or 18, early Namurian (Eumorphoc°ras Pseudoendothyra sp. Zone). Late Mississippian (Chesterian). Zellerina sp. Foraminifers abundant. Collection 79. Moffat Trail Limestone Member, Moffat Trail Archaediscus sp. locality. Asteroarchaediscus sp. Age. Zone 17 or younger, early Namurian (Eumorpho- A. baschkiricus (Krestovnikov and Teodorovitch) ceras Zone) ?, Late Mississippian (Chesterian) ? Calcisphaera sp. Foraminifers present. C. laevis Williamson Archaediscus of the group A. krestovnikovi Rauzer- Climacammina sp. Chernoussova Diplosphaerina sp. Asteroarchaediscus sp. Earlandia sp. Calcisphaera sp. E. clavatula (Howchin) Endothyra sp. E. elegans (Rauzer-Chernoussova) Eostaffella sp. Endothyra sp. E. circuli (Thompson) Endothyra of the group E. bowmani Phillips emend. Neoarchaediscus sp. Brady Pseudoendothyra sp. E. excellent (Zeller) Pseudoendothyra of the group P. kremenskensis Endothyra of the group E. similis Rauzer-Chernousso-ra Rozovskaia and Reitlinger Pseudoendothyra of the group P. ovata (Reitlinger) E. tantala (Zeller) Pseudoendothyra of the group P. struvei (von Moller) Eostaffella sp. Collection 82. Ranchester Limestone Member, Moffat Trail E. circuli (Thompson) locality. Eotuberitina sp. Age. Undetermined. Neoarchaediscus sp. Foraminifers very scarce. N. incertus (Grozdilova and Lebedeva) Calcisphaera sp. N. parvus (Rauzer-Chernoussova) Endothyra sp. Palaeoteytularia of the group P. consobrina Lipina Collection 90. Moffat Trail Limestone Member, Covey Cutoff Palaeotextularia of the group P. longiseptata Lipina locality. Planospirodiscus sp. Age. Zone 17 or 18, early Namurian (Eumorphoceras P. minimus (Grozdilova and Lebedeva) Zone), Late Mississippian (Chesterian). Pseudoendothyra sp. Foraminifers abundant. Pseudoendothyra of the group P. kremenskensis Archaediscus sp. Rozovskaia A. krestovnikovi Rauzer-Chernoussova Pseudoglomospira sp. Asteroarchaediscus sp. Tetrataxis sp. A. baschkiricus (Krestovnikov and Teodorovitch) Tuberitina sp. Calcisphaera sp. Zellerina discoidea (Girty) Climacammina sp. Collection 93. Moffat Trail Limestone Member, Covey Cutoff "Cornuspira" sp. locality. Diplosphaerina sp. Age. Zone 17 or 18, early Namurian (Eumorphoceras Earlandia clavatula (Howchin) Zone), Late Mississippian (Chesterian). E. elegans (Rauzer-Chernoussova) Archaediscus sp. Endothyra sp. Asteroarchaediscus sp. B12 THE AMSDEN FORMATION (MISSISSIPPIAN AND PENNSYLVANIAN) OF WYOMING

cf. Biseriellal sp. Endothyra of the group E. bowmani Phillips emend. Calcisphaera sp. Brady Earlandia sp. Endothyra of the group E. similis Rauzer-Chernoussova Endothyra sp. and Reitlinger Eostaffella sp. Eostaffella sp. Neoarchaediscus sp. E. circuli (Thompson) Planospirodiscus sp. Neoarchaediscus sp. Pseudoendothyra sp. Palaeotextularia of the group P. consobrina Lipina Tetrataxis sp. Palaeotextularia of the group P. longiseptata Lipina Collection 100. Ranchester Limestone Member Covey Cutoff Pseiidoendothyra sp. locality. Pseudoendothyra of the group P. kremenskensis Age. Zone 20, late Namurian (Reticuloceras Zone), Penn- Rozovskaia sylvanian (Morrowan). Stacheia sp. Foraminifers abundant. Stacheoides sp. Archaediscus sp. Collection 105. Moffat Trail Limestone Member, Haystack Asteroarchaediscus sp. Peak locality. Biseriella of the group B, parva (Chernysheva) Age. Zone 18, late early Namurian (upp-jr Eumorpho­ B. moderata (Reitlinger) ceras Zone), Late Mississippian (Chesterian). Calcisphaera sp. Foraminifers present. Endothyra of the group E. bowmani Phillips emend. Archaediscus sp. Brady Asteroarchaediscus sp. E. excellens (Zeller) Calcisphaera laevis Williamson "Endothyra" of the group "E." prisca Rauzer- Climacammina sp. Chernoussova and Reitlinger Earlandia sp. Endothyra of the group E. similis Rauzer-Chernoussova E. elegans (Rauzer-Chernoussova) and Reitlinger Endothyra sp. cf. Eolasiodiscust sp. Endothyra of the group E. bowmani Phillips emend. Eostaffella sp. Brady Globivalvulina sp. Endothyra of the group E. similis Rauzer-Chernoussova Lipinella sp. (nom. nud.) and Reitlinger Millerella sp. Eostaffella sp. M. pressa Thompson E. pinguis (Thompson) Monotaxinoides sp. Eostaffellina sp. Neoarchaediscus sp. Neoarchaediscus sp. Planoendothyra sp. Palaeotextularia of the group P. consobrinc1 Lipina Planospirodiscus sp. Palaeotextularia of the group P. longiseptata Lipina Pseudoendothyra sp. Pseudoendothyra sp. Pseudoglomospira sp. Pseudoendothyra of the group P. kremenskensis Zeller in a sp. Rozovskaia Collection 103. Moffat Trail Limestone Member, Haystack Zellerina discoidea (Girty) Peak locality. Collection 109. Moffat Trail Limestone Member, South In­ Age. Zone 17, earliest Namurian (lower Eumorphoceras dian Creek locality. Zone), Late Mississippian (middle Chesterian). Age. Zone 17, earliest Namurian (lower Eumorphoceras Foraminifers scarce. Zones), Late Mississippian (Chesterian). Archaediscus sp. Foraminifers abundant. Asteroarchaediscus sp. Archaediscus sp. Calcisphaera sp. A. krestovnikovi Rauzer-Chernoussova C. laevis Williamson Asteroarchaediscus sp. Earlandia sp. A. baschkiricus (Krestovnikov and Teodorovitch) Endothyra sp. Earlandia sp. Neoarchaediscus sp. E. clavatula (Howchin) Planospirodiscus sp. E. vulgaris (Rauzer-Chernoussova and Reitlinger) Collection 104. Moffat Trail Limestone Member, Haystack Endothyra sp. Peak locality. Endothyra of the group E. bowmani Phillips emend. Age. Zone 17, earliest Namurian (lower Eumorphoceras Brady Zone), Late Mississippian (middle Chesterian). Endothyra of the group E. similis Rauzer-Chernoussova Foraminifers present. and Reitlinger Archaediscus sp. Eostaffella sp. Asteroarchaediscus sp. Globoendothyra sp. Calcisphaera laevis Williamson Neoarchaediscus sp. C, pachysphaerica (Pronina) N. incertus (Grozdilova and Lebedeva) Earlandia sp. N. parvus (Rauzer-Chernoussova) Endothyra sp. Planospirodiscus sp. CARBONIFEROUS FORAMINIFERA AND ALGAE P13

P. minimus (Grozdilova and Lebedeva) Asteroarchaediscus sp. Pseudoendothyra sp. Biseriella sp. Zellerina discoidea (Girty) B. moderata (Reitlinger) Collection 121. Moffat Trail Limestone Member, Hoback Neoarchaediscus sp. Canyon locality. Pseudoglomospira sp. Age. Undetermined. Collection 126. Moffat Trail Limestone Member, Hoi ack Foraminifers scarce, occur as ghosts. Canyon locality. Archaediscidae? Age. Zone 17 or 18, early Namurian (Eumorphocvras Endothyridae? Zone), Late Mississippian (Chesterian). Eostaffellidae? Foraminifers present. Collection 122. Moffat Trail Limestone Member, Hoback Archaediscus sp. Canyon locality . A. krestovnikovi Rauzer-Chernoussova Age. Zone 18, late early Namurian (upper Eumorpho- Asteroarchaediscus sp. ceras Zone), Late Mississippian (Chesterian). A. baschkiricns (Krestovnikov and Teodorovitch) Foraminifers scarce. Earlandia sp. Archaediscus sp. Endothyra sp. Archaediscus of the group A. chernoussovensis Mamel Endothyra of the group E. bowmani Phillips emend. Archaediscus of the group A. krestovnikovi Rauzer- Brady Chernoussova Eostaffella sp. Asteroarchaediscus sp. Glomospira sp. A. baschkiricus (Krestovnikov and Teodorovitch) Monotaxinoides sp. Biseriella sp. Neoarchaediscus sp. B. parva (Chemysheva) Planospirodiscus sp. B. moderata (Reitlinger) Pseudoglomospira sp. Calcisphaera sp. "Tetrataxis" of the group "T" eominima Rauzer- "Cornuspira" sp. Chernoussova Earlandia sp. Zellerina discoidea (Girty) Endothyra sp. Collection 132. Ranchester Limestone Member, Hoback Eostaffella sp. Canyon locality. Neoarchaediscus sp. Age. Zone 20, late Namurian (Reticuloceras Zones), N. incertus (Grozdilova and Lebedeva) Pennsylvanian (Morrowan). N. parvus (Rauzer-Chernoussova) Foraminifers scarce. Planospirodiscus sp. Biseriella sp. Zellerina discoidea (Girty) Calcisphaera sp. Collection 124. Moffat Trail Limestone Member, Hoback Earlandia sp. Canyon locality. Endothyra sp. Age. Zone 18, early Namurian (Eumorphoceras Zone), Globivalvulina of the group G. bulloides (Brady) Late Mississippian (late Chesterian). Pseudoglomospira sp. Foraminifers present. Collection 145. Moffat Trail Limestone Member, Phillips Archaediscus of the group A. krestovnikovi Rauzer- Canyon locality . Chernoussova Age. Zone 18, late early Namurian (upper Eumorphoceras Asteroarchaediscus sp. Zone), Late Mississippian (Chesterian). Asteroarchaediscus of the group A. baschkiricus Foraminifers scarce. (Krestovnikov and Teodorovitch) Archaediscus sp. Biseriella of the group B. parva (Chernysheva) Archaediscus of the group A. krestovnikovi Rauzer- B. moderata (Reitlinger) Chernoussova. Calcisphaera sp. Asteroarchaediscus sp. Cornuspiridae Biseriella sp. Endothyra sp. B. parva (Chernysheva) cf. EndostaffeUat sp. B. moderata (Reitlinger) Neoarchaediscus sp. Calcisphaera sp. Planospirodiscus sp. Earlandia sp. "Tetrataxis" of the group "T." eominima Rauzer- Endothyra sp. Chernoussova Neoarchaediscus sp. Trepeilopsis sp. Planospirodiscus sp. Zellerina discoidea (Girty) Pseudoglomospira sp. Collection 125. Moffat Trail Limestone Member, Hoback Tuberitina sp. Canyon locality. Collection 153. Horseshoe Shale Member, Berry Creek Age. Zone 18 (or younger?), early Namurian locality. (Eumorphoceras Zone), Late Mississippian (late Age. Zone 19, middle Namurian (Homoceras Zone), Late Chesterian). Mississippian (latest Chesterian). Foraminifers scarce. Foraminifers scarce. Apterrinellidae Apterrinellidae B14 THE AMSDEN FORMATION (MISSISSIPPIN AND PENNSYLVANIAN) OF WYOMING

Archaediscus sp. Easton, W. H., 1962, Carboniferous formation* and faunas Asteroarchaedisciis sp. of central Montana. U.S. Geol. Survey, Prof. Paper 348, Cornuspiridae p. 1-126, 14 pis. "Eosigmoilina" sp. Henbest, L. G., 1946, The Morrow Group, I ennsylvanian, Eostaffella sp. of Washington County, Arkansas [abs.]: Am. Assoc. Neoarchaediscus sp. Petroleum Geologists Joint Ann. Meeting Program, Collection 154. Horseshoe Shale Member, Berry Creek local­ April 2-4. ity. 1947, The Morrow Group of northwest Arkansas Age. Zone 18 or younger, early Namurian (Eumorpho- [abs.] : Washington Acad. Sci. Jour., v. 37, no. 10, p. 373. ceras Zone) ?, Late Mississippian (Chesterian) ? Lane, R. H., Sanderson, G. A. and Verville, G. J., 1972, Up­ Foraminifers scarce. permost Mississippian-basal Middle Pennsylvanian cono- Apterrinellidae donts and fusulinids from several exposurer in the south- Cornuspiridae central and southwestern United States. 24th Interna­ Biseriella of the group B. parva (Chernysheva) tional Geological Congress, section 7, Paleontology, p. Collection 160. Ranchester Limestone Member, Elk Ridge 549-555. locality. Loeblich, A. R., Jr., and Tappan, Helen, 1964, Treatise on Age. Zone 18 or younger, early Namurian (Eumorpho- invertebrate paleontology, Part C, Protista 2, Sarcodina, ceras Zone) ?, Late Mississippian (Chesterian) ? chiefly "Thecamoebians" and Foraminiferid": New York, Foraminifers scarce. Geol. Soc. America and Univ. Kansas P"ess, v. 1, p. Apterrinellidae Cl-C510a; v. 2, p. C511-C900. Aster oarchaediscus sp. Mamet, B. L., 1968, Foraminifera, Etherington Formation Biseriella of the group B. parva (Chernysheva) (Carboniferous), Alberta, Canada: Canadian Assoc. Climacammina sp. Petroleum Geologists Bull., v. 16, no. 2, p. 167-179. Cornuspiridae 1970, Carbonate microfacies of the Windsor Group Earlandia sp. (Carboniferous), Nova Scotia and New Brunswick: Endothyra sp. Canada, Geol. Survey Paper 70-21, p. 1-121, 19 pis. E. excellens (Zeller) Mamet, B. L., and Gabrielse, H., 1969, Foraminiferal zona­ Eostaffella sp. tion and stratigraphy of the type section of the Nizi Palaeotextularia sp. Formation (Carboniferous systems, Chesterian Stage), Planospirodiscus sp. British Columbia: Canada Geol. Survey Paper 69-16, p. 1-21. REFERENCES CITED Mamet, B. L., and Mason, D., 1970, Lisburne Group; litho- stratigraphy and f oraminiferal zonation, Trout Lake, Armstrong, A. K., Mamet, B. L., and Dutro, J. T., Jr., 1970, northwest Yukon Territory. Bull. Canadian Petroleum Foraminiferal zonation and carbonate facies of Carboni­ Geology, v. 18, no. 4, p. 556-565. ferous (Mississippian and Pennsylvanian) Lisburne Mamet B. L., and Skipp, B. A., 1970, Preliminary foramini- Group, central and eastern Brooks Range, Arctic Alaska: feral correlations of early Carboniferous strata in the Am. Assoc. Petroleum Geologists Bull., vol. 54, no. 5, North American Cordillera, in Cong. et Cclloques, Collo- p. 687-698. que sur la stratigraphie du Carbonifere: Liege Univ. 1971, Lisburne Group, Cape Lewis-Niak Creek, North­ v. 55, p. 327-348. western Alaska: U.S. Geol. Survey, Prof. Paper 750-B, Mamet, B. L., Skipp, Betty, Sando, W. J., ard Mapel, W., p. B23-34. 1971, Biostratigraphy of Upper Mississippan and asso­ Bamber. E. W., and Waterhouse, J. B., 1971, Carboniferous ciated Carboniferous rocks in south-centrrl Idaho: Am. and Permian stratigraphy and paleontology, northern Assoc. Petroleum Geologists Bull., v. 55, ni. 1, p. 20-33. Yukon Territory, Canada: Bull. Canadian Petroleum Mellen, F. F., 1947, Black Warrior Basin, Alabama and Geology, v. 19, no. 1, p. 29-250. Appendix I, by Mamet, Mississippi: Am. Assoc. Petroleum Geologists Bull., v. B., and Ross, C. A. Foraminiferal microfacies of the 31, no. 10, p. 1801-1816. Upper Paleozoic, northern Yukon Territory, p. 196-205. Moore, W. L., 1964, Notes on the morphology and taxonomic Brazhnikova, N. E., Vakarchuk, G. I., Vdovenko, M. V., position of the fusulinid MiUerella marbJensis Thomp­ Viniitchenko, L. V., Karpova, M. A., Polomietz, la, I, son: Jour. Paleontology, v. 38, no. 2, p. 294-305. Potievskaia, P. D., Rostovceva, L. F. and Chevtchentko, Sage, N. M., Jr., 1954, The stratigraphy of the Windsor G. D., 1967, Microfaunal reference horizons of the Car­ Group in the Antigonish quadrangles and the Mahone boniferous and Permian deposits of the Dnieper-Donets Bay-St. Margaret Bay area, Nova Scotia: Nova Scotia basin [in Russian.] Kiev, Izdat. "Naukova Dumka," 224p. Dept. Mines Mem., no. 3, 168 p. Brenckle, P. L., 1973, Smaller Mississippian and Lower Penn­ Sando, W. J., Gordon. Mackenzie, Jr., and Dutro, J. T., Jr., sylvanian calcareous f oraminif ers from Nevada: Cush- 1974, Stratigraphy and geologic history of the Amsden man Foundation Foraminiferal research, Special Publ. Formation (Mississippian and Pennsylvanian) of Wyom­ no. II, 82p. ing: U.S. Geol. Survey Prof. Paper 848-A (in press). Cooper, C. L., 1946, Upper Kinkaid (Mississippian) micro- Sando, W. J., Mamet, B. L. and Dutro, J. T., Jr., 1969, Car­ fauna [abs.]: Am. Assoc. Petroleum Geologists Joint boniferous megafaunal and microfaunal zonation in the Ann. Meeting Program, April 2-4. northern Cordillera of the United States: U.S. Geol. 1947, Upper Kinkaid (Mississippian) microfauna Survey Prof. Paper 613-E, 29p. from Johnson County, Illinois: Jour. Paleontology, v. Scott, H. W., 1945a, Age of the Amsden Formation [abs.]: 21, no. 2, p. 81-94. Geol. Soc. America Bull., v. 56, no. 12, pt. 2, p. 1195. CARBONIFEROUS FORAMINIFERA AND ALGAE P15

1945b, Pennsylvania!! stratigraphy in Montana and 1945, Pennsylvanian rocks and fusulinids of east and northern Wyoming [abs.]: Geol. Soc. America Bull., Utah and northwest Colorado correlated with Kansas v. 56, no. 12. pt. 2, p. 1196. section: Kansas Univ. Geol. Survey Bull. 60, pt. 2, p Skipp, B. A. and Mamet, B. L., 1970, Stratigraphic micro- 17-84. paleontology of the type locality of the White Knob 1948, Studies of American fusulinids: Kansas Univ. Limestone (Mississippian), Custer County, Idaho: U.S. Paleont. Contr., Protozoa, art, 1, p. 1-134. Geol. Survey, Prof. Paper 700-B, p. B118-B123. Zeller, D. E. N., 1953, Endothyroid Foraminifera and an­ Thompson, M. L., 1942, New genera of Pennsylvanian fusu- cestral fusulinids from the type Chesterian (Upper Mis­ linids: Am. Jour. Sci., v. 240, no. 6, p. 403-420. sissippian). Jour. Paleontology, v. 27, no. 2, p. 183-19r>. 1944, Pennsylvanian Morrowan rocks and fusulinids Zeller E. J., 1950, Stratigraphic significance of Mississippian of Kansas: Kansas Geol. Survey Bull. 52, pt. 7, p. 409- endothyroid Foraminifera: Kansas Univ., Paleont. 431. Protozoa, art. 4, 23 p.

INDEX

[Italic numbers indicate major references] Page Page Pige Cornuspiridae (sensu lato) .. 63,9,10,13,14 Ettrain Formation ------.. -- B6 Covey Cutoff locality, Moffat Trail Eumorphoceras Zone ___._-_ 9, 10, 11, 12, 13 Adetognathus gigantus -____--_-_--_-_ B7 Limestone Member, Zone 17 Evolutionary changes of wall structure 2, 6 lautus _ .-. .------7 or 18, Chesterian___ 6, 11; pi. 1, Alapah Limestone --. . .-- 6, 6 figs. 1, 2 Amsden Creek locality, Ranchester Ranchester Limestone Member, Zone Limestone Member, Zone 20, Morrowan______._ 6, 12; Fusulinidae 20, Morrowan ___ 6, 9, 10; pi. 2, pi. 1, figs. 6-8 figs. 4-6, 7, 8 Apterrinellidae ___.._ __ 7, 8, 9, 10, 13, 14 D Archaediscidae ______2, 7, 13 Archaediscus ... .. 2 Gvrvanella sp 7 chernotiaaovensis ______1, 2, 13 Darwin Sandstone Members, no fauna Glen Dean Limestone - --___------6 krestovnikovi ...... 1, 2, 8, 9, 10, 11, 12, 13 collections from .-____-- 1 Globivalvulina --_.__ __ 2, 6 moetteri .._ - . ___.__--_._ 2 Diplosphaerina sp _-_____ 2, 7, 8, 9, 10, 11 buttoides ... ______2,8,13 sp ______1,7,8,9,11,12,13,14 Donbass sequence __.______6 sp ______2, 7, 8, 9, 10, 12; pi. 2, figs. 2, 3 Asphaltina ... _ _ 2,7,8 Globoendothyra --.. _ 3 Aateroarchaediscus _-_.______2, 4, 6 E sp ______.______2,10,11,12 baschkiricus ...... 1, 4, 5, 7, 8, 9,10, 11, Globoendothyridae .-. 3 12, 13; pi. 2, fig. 1 Earlandia ...... ____..-. 3 Glomospira sp ----_ .-_-. 2, 13 sp ______1, 7, 8, 9, 10,11, 12, 13,14 clavatula ______2, 10, 11, 12 Golconda Formation - __. --- 6 elegans _ .______2,10,11,12 B vuloarte ...... 2,12 H sp ______2, 7, 8, 9, 10, 11, 12, 13, 14; Baschkirian-Moscovian succession. pi. 1, figs. 6-8 Hart River Formation ---_--- - 6 correlation problems ----- 6 Earlandiidae ___..____.._._ 3 Haystack Peak locality, Moffat Trail Battleship Wash Formation __.__._ B Elk Ridge locality, Ranchester Limestone Limestone Member, Zone 17 Berry Creek locality, Harseshoe Shale Member, Zone 18 or 19, and 18, Chesterian ____ 6, 12 Member, Zones 18 and 19, Chesterian ______5,6,14 Hoback Canyon locality, Moffat Trail Chesterian _ ----- 5, 6, 13, 14 EndostaffelM ...- ______3 Limestone Member, Zones 17 Biostfatigraphic indices, list of useful sp ______2,13 or 18 and 18 and unde­ forms __---__------.__-_ 1 Endothyra -_-__-.-._..__.-._____ 3 termined _ 6, 13 relict forms --. ---_.-----__ 3,4,6 bowmani ______2, 8, 9, 10, 11, 12, 13; Ranchester Limestone Member, Zone Biostratigraphic zonation .-_.-_ .. 4 pi. 1, figs. 1, 2, 3, 6-8 20, Morrowan --.- 6, 13 Bird Spring Formation .. _.__ 6, 7 excellens ______2,10,11,12,14; Homoceras Zone ____------6, 13 Biseriamminidae _-----___-_-_-____ 2 pi. 1, figs. 1, 2, 6-8 Horseshoe Shale Member ___ 1, 6, 6, 7, 8, 9, 14 Biseriella ...... ----- 4, 6, 6 prisca .... _ . 2, 8, 12; pi. 1, figs. 6-8 Howchinia __ -_.-_.-- .- 4 moderata ...... 1,7,8,9,10,12,13; similia ______2, 10, 11, 12 pi. 2, fig. 4-6 tantala ...______11 parva ...... 2, 5, 9, 10, 12, 13, 14 sp ______2, 7, 8, 9, 10, 11, 12, 13, 14; sp ______1,7,8,9,10,12,13; pi. 1, figs. 1, 2; pi. 2, figs. 4-6 Indian Spring Formation ------B, 6, 7 pi. 2, flgs.2, 4-6 Endothyranetta sp _---.-.__------2, 7, 10 Bradyinal ...... 3 Endothyranopsidae - .. __ -_ 4, 5 K sp ______2, 10 Endothyranopsis sphaerica ______6 Endothyridae ______3,13 Bradyinidae 3 Kinkaid Limestone ------5, 7 Eolasiodiscus ____-_--_____-_._____... 3 Brunsia ...... -__ 3 Kogruk Formation -_------B Buck Spring locality, Ranchester sp ______.______2,12 Limestone Member, Zone Eoschubertella ... -_____---_.____._ 3, 6 20, Morrowan-- 6, 8; pi. 2, figs. 2, 3 sp -._ _.__ ___-. 2, 8 EosigmoUina . __.-______2, 6 sp ______.______2, 14 Lasiodiscidae ------_--__. - __ 3 Eostaffetta ______._____ 3, 7 Lipinella sp ______-. 2,7,8,9,10,12 Ccdcisphaera laevis ...... 2,8,10,11,12; acutissima ______2, 10 Livingston Ranch locality, Horseshoe pi. 1, figs. 1, 2 circuli ...... 2,9,10,11,12; Shale Member, Zone 18, late pachyaphaerica ...... ______12 pi. 2, figs. 4-6, 8 Chesterian . ------___ 5, 9 sp ______7,8,9,110,11,12,13; pinguis ------..-._-- .-._ 2, 12 Loeblichia .--_----__-----_------B pi. 2, figs. 4-6 pseudostruvei ------2, 9; pi. 2, figs. 4-6 Calico Bluff Formation __------5 sp ______2, 7, 8, 9, 10, 11, 12, 13, 14; M Cherokee Spring and Peak localities, pi. 2, figs. 1, 4-6, 8 Horseshoe Shale Member, Eostaffellidae __..______.- 3,7,13 Meadow Ranch locality, Ranchester Zone 20, Morrowan __ 6, 7, 8 Eostaffellina ------3, 5 Limestone Member, Zone Climacammina ...... ------___ 4 paraprotvae ------2, 9, 10; pi. 2, figs. 4-6 20, Morrowan __ 6, 8; pi. 2, f «r. 1 sp ____ 2, 9, 10, 11, 12, 14; pi. 1, figs. 1, 2 sp ___.__.______2.8,9,10,11,12 Menard Limestone -_._------_--_------5 Clore Limestone -.___- -. .. 6 Eotuberitina sp __..____.. 2, 7, 8, 9, 10, 11; Microfauna distribution, lithologic Cornuspira ------3 pi. 2, figs. 2, 3 controls ------1, 2 sp ______2,7,8,11,13 Etherington Formation -..--_-----._-- 5 Microfossils, listed by collection number 7 PIT B18 INDEX

Page Page Page Millerella ...... B3, 4, 6, 7 Planospirodiacus ...... B2, 4, 5 generic concept problems _ . 7 minimus ...... 2, 11, 18 pressa ...... 2, 8, 12 sp ______2, 7, 8, 9, 10, 11, 12, 13, 14; Taxonomic composition of Amsden pura ...... _ 2, 8 pi. 2, fig. 7 faunules, by families ____ B2 sp ______2, 7, 8, 9, 10, 12; pi. 1, figs. 6-8 Paeudoendothyra ...... 4, 5 Tethyan realm indices .----____-_ 4,5,6 Mississippian-Pennsylvanian boundary kremenskensis ...... ___ 2, 10,11, 12 Tetrataxidae 4 problems _ _ 6, 7 ovata ...... 2, 11; pi. 1, fig. 4, 5 Tetrataxis ... _____-_.____-___-____ 4 Moffat Trail Limestone Member. _ 1, 5. 10, 11, struvei ...... 2, 11; pi. 1, figs. 4, 5 eominima ...... 2, 13 12,13; pi. 1, figs. 1-5 sp ______2,7,8,9,10,11,12,13; sp ______2,8,9,10,11,12 partial time equivalence(?) to pi. 1, figs. 1, 2, 3; pi. 2, figs. 4-6 Tip Top Well locality, Ranchest«r Lime­ Horseshoe Shale Member__ 5 Pseudoendothyridae ______4 stone Member, Zone 21, Moffat Trail locality, Moffat Trail Pseudoglomospira sp __ 2, 7, 8, 9, 10, 11, 12, 13 Atokan ______3,6,10 Limestone Member, Zones 17 Pseudostaffella ...... ____ 6 Trepettopais sp ______2, 10, 13 or 18 and 18, Chesterian 5, 10, 11; Trout Creek locality, Rancheste~ Lime­ pi. 1, figs. 4, 5 Q stone Member, Zore 20(7), Monotaxinoides .... ___-.._____ 4 Morrowan(?) ______6, 9 sp _.______2, 12, 13; pi. 1, figs. 6-8 ^uasiarchaediseus ...... ______2,5,6 Tuberitina sp _ -___ 2, 9, 10, 11, 13 Monroe Canyon Limestone ______5 Turrispiroides sp pi. 1, figs. 6-8 R N Banchester Limestone Member -- 1, 5, 6, 8, 9, Neoarchaediscus ...... 2,4,5 10, 11, 12, 13, 14; pi. 1, figs. 6-8; pi. 2, figs. 1-8 incertus ...... 2, 7, 8, 9, 10, 11, 12, 13 partial time equivalence(?) to Valvulinella ...... 4 parvus ...... 2,7,8,10,12,13 Horseshoe Shale Member__ 7, 8 Volvotextularia sp ______2, 9 sp ______2, 8, 9, 10, 11, 12, 13, 14 Rawlins US 287 locality, Ranchester Nizi Formation . _ 5, 6 Limestone Member, Zone 21, W Atokan -__._-_ . 6, 8 O References cited 14 Wahoo Limestone .___. Beticuloceras Zone ____.___ 7,8,9,12,13 White Knob Limestone Ozawainellidae 4, 7 Rhodophycophyta __ --- 2, 8 Williston basin ____. Windsor Group ..

PalaeonubecularM sp .. _. 2, 9, 10 Palaeotextularia ______4 Semistaffella ...... 6 consobrlna ...... 2,10,11,12 South Indian Creek locality, Moffat Trail Zellerina ...... 3, 7 longiaeptata ...... ______2, 10, 11, 12 Limestone Member, Zone 17, discoidea ...... 2, 9, 10, 11, 12, 13 sp ______2,9,10,14 Chesterian ___ 5, 12; pi. 1, fig. 3 sp ______-____ 2,7,8,10,11,12; Palaeotextulariidae ______4 Spongioatromata ...... -____. 2 El. 1, figs. 1, 2, 6-8 Phillips Canyon locality, Moffat Trail Stacheia ...... ____.. ___ 2,10,12 Zone 168 -__ -_._ _ ._.__.__ 4 Limestone Member, Zone 18, Stacheiinae ______-_-___ - _-_.. 9,10 Zone 17 -______4 Chesterian _-_--__ 5,13 Stacheoides ...... 2, I'D, 11, 12 Zoue 18 ____ -.______.__ 5 Phylogenetic lineages --- - 2 Stratigraphic position of fossil collections Zone 19 -______6 Planoendothyra -...... 3 in sections ______1 Zone 20 ______6 sp ______2,8,9,11,12 Surrett Canyon Formation ___ 5, 6 Zone 21 _- _ _ . -_ _. 6 PLATES 1 and 2 [Contact photographs of the plates in this report are available, at cost, from U.S. Geological Survey Library, Federal Center, Denver, Colorado 80225] PLATE 1 [All figures X 25, except fig. 8 X 17]

FIGURES 1,2. Collection 92, Covey Cutoff locality, Moffat Trail Limestone Member, Zone 17, earliest Namurian, mid­ dle Chester equivalent. Recrystallized foraminiferal-pelmatozoan-lump-bearing grainstone. Forg minif eral wall recrystallization is highly variable in figure 1, the diaphanotheca of the Pseudoendothyra sp. is reduced to a ghost, whereas the tectum of the nearby Endothyra is perfectly preserved. Biota is composed of Endothyra of the group E. bowmani Phillips emend. Brady (Endothyra esccellens of Zeller), Endothyra sp., Climacammina sp., Calcisphaera laevis Williamson and minute Zellerina sp. 3. Collection 109, South Indian Creek locality, Moffat Trail Limestone Member, Zone 17, earliest Namurian, middle Chester equivalent. Slighty recrystallized wackestone; diverse sections of Endothyra of the group E. bowmani Phillips emend. Brady, Earlandia sp., and Pseudoendothyra sp. are recognizable. 4,5. Collection 79, Moffat Trail locality, Moffat Trail Limestone Member, Zone 17 or 18, early Namurian, upper Chester equivalent. Slighty dolomitized, recrystallized packstone and grainstone. Foraminifers are almost exclusively pseudoendothyrids; Pseudoendothyra of the group P. ovata Eeitlinger, Pseudoendothyra of the group P. struvei (von Moller), etc. 6-8. Collection 10, Covey Cutoff locality, Eanchester Limestone Member, Zone 20, late Namurian, basal Pennsyl- vanian. Slightly recrystallized foraminiferal wackestone-packstone. Numerous equatorial sections of Mono- taxinoides sp. are visible. Other taxa are Endothyra of the group E. bowmani Phillips emend. Brady (Endothyra excellens of Zeller), Zellerina sp., cf. Millerellal sp., Earlandia sp., Turrispiroides sp., and "Endothyra" of the group "E." prisca Rauzer-Chernoussova and Reitlinger. GEOLOGICAL SURVEY PROFESSIONAL PAPER 848-B PLATE 1

..-.XV^^BK^bc* '- - .- v-n'.iLri'

REPRESENTATIVE THIN SECTIONS OF FORAMINIFERS AND ALGAE FROM THE AMSDEN FORMATION PLATE 2

[All sections from Ranchester Limestone Member, Zone 20, late Namurian, basal Pennsylvanian]

FIGURE 1. Collection 13, Meadow Ranch locality, X 30. Recrystallized wackestone. A small Asteroarchaediscus of the group A. baschkiricus (Krestovnikov and Teodorovitch) is barely visible, right of Eostaffella sp. 2, 3. Collection 14, Buck Spring locality X 30. Foraminiferal-pelmatozoan-spongiostromid pelletoid grainstone. Note the abundance of serpulopsids, apterrinellids, and biseriamminids (GloMvalvulina sp., Biseriella sp.). Small tuberitinids ("Eotuberitina" sp.) are also present. 4-6. Collection 65, Amsden Creek locality, figs. 4, 5, X 97, fig. 6, X 25. Foraminiferal packstone rich in apterrinellids, serpulopsids, and eostaffellids (Eostaffellina paraprotvae (Rauzer-Chernoussova), Eostaffella circuli (Thomp­ son), deeply umbilicated Eostaffella of the group E. pseudostruvei (Rauzer-Chernoussova), Eostaffella sp.). Some Endothyra sp., Pseudoendothyra sp., Biseriella moderata (Reitlinger), Biseriella sp., and Calcisphaera sp. are also present. The high magnification photographs show the wall structure of Biseriella sp. (a dark, dense tectum) and of Eostaffellina paraprotvae (Rauzer-Chernoussova). 7. Collection 68, Amsden Creek locality, X 30. Recrystallized packstone with a tiny Planospirodiscus sp. 8. Collection 64, Amsden Creek locality, X 25. Pelmatozoan packstone with Eostaffella sp. and Eostaffella circuli (Thompson). GEOLOGICAL SURVEY PROFESSIONAL PAPER 848-B PLATE 2

REPRESENTATIVE THIN SECTIONS OF FORAMINIFERS AND ALGAE FROM THE AMSDEN FORMATION

* U.S. GOVERNMENT PRINTING OFFICE: 1975 O S85 473/83