SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES • NUMBER 32

The Guadalupian Symposium

Bruce R. Wardlaw, Richard E. Grant,

and David M. Rohr

EDITORS

ISSUED

AUG 2 I 2000

mm INSTITUTION

SMITHSONIAN INSTITUTION PRESS

Washington, D.C.

2000
ABSTRAC T

Wardlaw, Bruce R., Richard E. Grant, and David M. Rohr, editors. The Guadalupian

Symposium. Smithsonian Contributions to the Earth Sciences, number 32, 415 pages,

frontispiece, 191 figures, 43 plates, 45 tables, 2000.—The internal stratigraphy of the Cutoff

Formation in the Guadalupe Mountains is clarified, and the unit is divided into three members:

the Shumard Canyon, the El Centro, and the Williams Ranch members. The Shumard Canyon

Member of the Cutoff Formation in the Guadalupe Mountains correlates to the upper part of the

Cathedral Mountain Formation in the Glass Mountains. The El Centro and Williams Ranch

members of the Cutoff Formation and the lower part of the Brushy Canyon Formation, including

the Pipeline Shale in the Guadalupe Mountains, correlate to the Road Canyon Formation. The

changeover in conodonts from transitional forms to Mesogondolella nankingensis (=M

serratd) provides a basal definition for the Guadalupian and occurs within correlation unit 3 in

the El Centro Member of the Cutoff Formation and cycle 2 of the Road Canyon Formation.

The geology, stratigraphy, and depositional setting of the Permian in the Del Norte Mountains

and of the Word Formation in the Glass Mountains are discussed in detail, and this data suggest

deposition in a foreland basin or backbay between the Marathon Fold Belt and the Delaware

basin. The internal stratigraphy of the Road Canyon, Word, Vidrio, Altuda, Capitan, and Tessey

formations reveal the following: (1) the Road Canyon was deposited in four cycles and the Word

in six cycles; (2) the Altuda can be divided into five informal members and the Tessey into three

members; (3) the Vidrio is an unconformity-bounded unit; and (4) the Capitan displays

characteristic platform margin to slope foresets.

Biozonation of the Guadalupian is discussed, and details are provided on the fusulinid and

conodont zonations. Changes in conodont fauna, based on the succession of Mesogondolella

species from M. nankingensis to M. altudaensis, divide the Guadalupian into five zones.

Five new species of conodonts (Sweetina crofti Wardlaw, Mesogondolella shannoni

Wardlaw, Hindeodus wordensis Wardlaw, Iranognathus punctatus Wardlaw, and Sweetognathus bicarinum Wardlaw) and two new species of fusulinids {Codonofusiella {Lantschichites) altudaensis Wilde and Rudine and Rauserella bengeensis Wilde and Rudine) are

described.

OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is

recorded in the Institution's annual report, Annals of the Smithsonian Institution. SERIES COVER

DESIGN: Volcanic eruption at the island of Krakatau in 1883.

Library of Congress Cataloging-in-Publication Data

The Guadalupian symposium / Bruce R. Wardlaw, Richard E. Grant, and David M. Rohr, editors,

p. cm. — (Smithsonian contributions to the earth sciences ; no. 32)

Includes bibliographic references.

1. Geology—Guadalupe Mountains (N.M. and Tex.)—Congresses. 2. Geology, Stratigraphic—Congresses. 3. Paleontology—Guadalupe Mountains (N.M. and Tex.)—Congresses. 4. Guadalupe Mountains (N.M.

and Tex.)—Congresses. I. Wardlaw, Bruce R. II. Grant, Richard E., 1927-1994. III. Rohr, David Malcolm,

1947- . IV. Series.

QE1.S227 no. 32 [QE79] 550s-dc21 [557.64'9] 99-12440

® The paper used in this publication meets the minimum requirements of the American

National Standard for Permanence of Paper for Printed Library Materials Z39.48—1984.
Contents

Page

Preface v

Memorial to Richard Evans Grant vii

1. GUADALUPIAN STUDIES IN WEST TEXAS, by Richard E. Grant, Bruce R. Wardlaw,

and David M. Rohr 1

2. GUIDEBOOK TO THE GUADALUPIAN SYMPOSIUM, by David M. Rohr, Bruce R.

Wardlaw, Shannon F. Rudine, Mohammad Haneef, A. John Hall, and Richard E.

Grant 5

3. GUADALUPIAN CONODONT BIOSTRATIGRAPHY OF THE GLASS AND DEL

NORTE MOUNTAINS, by Bruce R. Wardlaw 37

4. FORMAL MIDDLE PERMIAN (GUADALUPIAN) SERIES: A FUSULINACEAN

PERSPECTIVE, by Garner L. Wilde 89

5. MEMBERS FOR THE CUTOFF FORMATION, WESTERN ESCARPMENT OF THE

GUADALUPE MOUNTAINS, WEST TEXAS, by Mark T. Harris 101

6. CYCLIC DEPOSITION OF THE PERMIAN ROAD CANYON FORMATION, GLASS

MOUNTAINS, WEST TEXAS, by Bruce R. Wardlaw, Charles A. Ross, and Richard

E. Grant 121

7. COMPARISON OF THE DEPOSITIONAL ENVIRONMENTS AND PHYSICAL STRATIGRAPHY OF THE CUTOFF FORMATION (GUADALUPE MOUNTAINS) AND THE ROAD

CANYON FORMATION (GLASS MOUNTAINS): LOWERMOST GUADALUPIAN

(PERMIAN) OF WEST TEXAS, by Mark T. Harris, Daniel J. Lehrmann, and Lance

L. Lambert 127

8. CORRELATION OF THE ROAD CANYON AND CUTOFF FORMATIONS,

WEST TEXAS, AND ITS RELEVANCE TO ESTABLISHING AN INTERNATIONAL

MIDDLE PERMIAN (GUADALUPIAN) SERIES, by Lance L. Lambert, Daniel J.

Lehrmann, and Mark T. Harris 153

9. FUSULINID BIOSTRATIGRAPHY AND PALEONTOLOGY OF THE MIDDLE

PERMIAN (GUADALUPIAN) STRATA OF THE GLASS MOUNTAINS AND DEL

NORTE MOUNTAINS, WEST TEXAS, by Zhendong Yang and Thomas E.

Yancey 185

10. CARBONATE DEPOSITION OF THE PERMIAN WORD FORMATION,

GLASS MOUNTAINS, WEST TEXAS, by James D. Rathjen, Bruce R. Wardlaw,

David M. Rohr, and Richard E. Grant 261

11. GEOLOGY AND DEPOSITIONAL ENVIRONMENTS OF THE GUADALUPIAN

ROCKS OF THE NORTHERN DEL NORTE MOUNTAINS, WEST TEXAS, by

Shannon F. Rudine, Bruce R. Wardlaw, David M. Rohr, and Richard E.

Grant 291

12. THE ALTUDA FORMATION OF THE GLASS AND DEL NORTE MOUNTAINS,

by Bruce R. Wardlaw and Shannon F. Rudine 313

13. A DEEP WATER TURBIDITY ORIGIN FOR THE ALTUDA FORMATION (CAPITANIAN,

PERMIAN), NORTHWESTERN GLASS MOUNTAINS, TEXAS, by Mohammad

Haneef, David M. Rohr, and Bruce R. Wardlaw 319

14. ANATOMY AND ORIGIN OF CAPITAN LIMESTONE FORESET BEDS IN THE

GLASS MOUNTAINS, WEST TEXAS, by Mohammad Haneef. 333

15. LATE GUADALUPIAN BIOSTRATIGRAPHY AND FUSULINID FAUNAS, ALTUDA

FORMATION, BREWSTER COUNTY, TEXAS, by Garner L. Wilde and Shannon F.

Rudine 343

in
iv SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

16. LlTHOFACIES AND DEPOSITIONAL HISTORY OF THE TESSEY FORMATION,

FRENCHMAN HILLS, WEST TEXAS, by Mohammad Haneef and Bruce R.

Wardlaw 373

17. CONODONT BlOSTRATIGRAPHY OF THE PERMIAN BEDS AT LAS DELICIAS,

COAHUILA, MEXICO, by Bruce R. Wardlaw, Shannon F. Rudine, and

Merlynd K. Nestell 381

18. ANCESTRAL ARAXOCERATINAE (UPPER PERMIAN AMMONOIDEA) FROM MEXICO

AND IRAN, by Claude Spinosa and Brian F. Glenister 397

19. DEPOSITIONAL CONTROLS ON SELECTIVE SILICIFICATION OF PERMIAN

FOSSILS, SOUTHWESTERN UNITED STATES, by Douglas H. Erwin and David L.

Kidder 407
Preface

The Guadalupian Symposium was held from 13 to 15 March 1991. It consisted of a one

day meeting of oral presentations, which were given at the campus of Sul Ross State

University, Alpine, Texas, and a two day field trip to outcrops in the Glass and Del Norte

mountains. The meeting at Sul Ross was highlighted by anecdotal presentations by

Norman D. Newell and Lloyd Pray. Most of the presentations are represented as papers

herein. The field trip was highlighted by Heinz Kozur finding several rattlesnakes, Dick

Grant being attacked by a dog, and stirring discussions on the breccia outcrops that form

the base of the type section of the Road Canyon Formation.

The term Guadalupian was first proposed as a subdivision of the Permian by Girty in

1902. Glenister and Furnish (1961) concluded that the Permian could be divided into five

world-wide stages, including the Guadalupian, which was further divided into the Wordian

and Capitanian substages. One of the three primary objectives resulting from the 1989

meeting of the International Subcommission on Permian Stratigraphy was the designation

of the Guadalupian in the United States. Guadalupian strata in the Guadalupe Mountains

are well known. They have served as the primary example for the development of sequence

stratigraphy. The original concepts of the divisions for the regional stratotype for the

Guadalupian, however, included both the Guadalupe Mountains and the Glass Mountains.

In order to better document the Guadalupian rocks and faunas for worldwide correlation,

the Guadalupian Symposim was organized by the editors. The presentations highlighted

new and significant work in the Glass and Del Norte mountains and the correlation

between these strata and the Guadalupe Mountains.

The symposium provided the impetus for Glenister et al. (1992) to formally propose the

Guadalupian as the international standard reference for the Middle Permian Series. Four

Titular Members and three Corresponding Members of the Subcommission on Permian

Stratigraphy attended the symposium and were unanimous in their support of the

Guadalupian as the international standard. This volume, along with the previous

monographs by Girty (1909), P.B. King (1931, 1948), R.E. King (1931), Miller and

Furnish (1940), and Cooper and Grant (1972, 1974, 1975, 1976a,b, 1977), serve as the

primary documentation for the Middle Permian Guadalupian Series.

It should be noted that the Guadalupian Symposium and the articles that comprise this

volume predate the use of the conodont genus "Jinogondolella" and the abandonment of

stage names, such as "Leonardian" or "Dzhulfian." The use, or lack of use, of some of

these antiquated terms does not indicate acceptance or disapproval.

Literature Cited

Cooper, G.A., and R.E. Grant

1972. Permian Brachiopods of West Texas, I. Smithsonian Contributions to Paleobiology, 14:1-231, plates

1-23.

1974. Permian Brachiopods of West Texas, II. Smithsonian Contributions to Paleobiology, 15:233-793,

plates 24-191.

1975. Permian Brachiopods of West Texas, III. Smithsonian Contributions to Paleobiology, 19:795-1921,

plates 192-502.

1976a. Permian Brachiopods of West Texas, IV. Smithsonian Contributions to Paleobiology, 21:1923-2607,

plates 503-662.

1976b. Permian Brachiopods of West Texas, V. Smithsonian Contributions to Paleobiology, 24:2609-3159,

plates 663-780.

1977. Permian Brachiopods of West Texas, VI. Smithsonian Contributions to Paleobiology, 32:3161-3370.
vi SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Girty, G.H.

1902. The Upper Permian in Western Texas. American Journal of Science, fourth series, 14:363-368.

1909 ("1908"). The Guadalupian Fauna. United States Geological Survey Professional Paper, 58: 651 pages,

31 plates. [Date on title page is 1908; actually published in 1909.]

Glenister, B.F., and W.M. Furnish

1961. The Permian Ammonoids of Australia. Journal of Paleontology, 35:673-736.

Glenister, B.F., D.W. Boyd, W.M. Furnish, R.E. Grant, M.T. Harris, H. Kozur, L.L. Lambert, WW. Nassichuk,

N.D. Newell, L.C. Pray, C. Spinosa, B.R. Wardlaw, G.L. Wilde, and T.E. Yancey

1992. The Guadalupian: Proposed International Standard for a Middle Permian Series. International Geology

Review, 34(9):857-888.

King, P.B.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part 1: Descriptive Geology. University of Texas

Bulletin, 3038: 167 pages, 15 plates. [Date on title page is 1930; actually published in 1931.]

1948. Geology of the Southern Guadalupe Mountains, Texas. United States Geological Survey Professional

Paper, 215: 183 pages, 23 plates.

King, R.E.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part 2: Faunal Summary and Correlation of the

Permian Formations with Description of Brachiopoda. University of Texas Bulletin, 3042: 245 pages,

44 plates. [Date on title page is 1930; actually published in 1931.]

Miller, A.K., and W.M. Furnish

1940. Permian Ammonoids of the Guadalupe Mountain Region and Adjacent Areas. Geological Society of

America, Special Paper, 26: 242 pages, 44 plates.
Memorial to Richard Evans Grant

J. Thomas Dutro, Jr., and Bruce R. Wardlaw

Washington, D.C., and Reston, Virginia

Our esteemed colleague Dick Grant passed away while assembling this collection of

manuscripts for the sound establishment of the Guadalupian as a Middle Permian standard.

His loss delayed the final editing of this volume and severely threatened our ability to

accomplish it. We dedicate "The Guadalupian Symposium" to the memory of Dick and his

undying love of the Permian.

Richard Evans Grant, curator of invertebrate paleontology at the National Museum of

Natural History, Smithsonian Institution, for more than 35 years, died of a heart attack on

December 7, 1994. He was 67 years old. Grant was a world-renowned brachiopod

specialist who was best known for his work on Permian brachiopod systematics and

biostratigraphy. For more than 20 years he worked with G. Arthur Cooper on the Permian

of West Texas; their collaboration resulted in a magnificent series of monographs

published by the Smithsonian Institution Press between 1972 and 1977. Dick was

particularly interested in the functional morphology and paleoecology of brachiopods, and

he contributed many basic ideas about the living habits and evolution of two major groups:

the productids and the rhynchonellids.

Born on June 18, 1927, in St. Paul, Minnesota, Dick was the son of Dr. Charles L. Grant,

a Lutheran minister, and Gladys N.E. Grant. He spent his first 20 years in Minnesota,

except for two years in the U.S. Navy (1945-1946). His choice to serve in the Navy was

a reflection of his passion for boats, which he built as a child. Dick majored in philosophy

and received his B.A. degree from the University of Minnesota in 1949. He switched to

geology for his M.S., which he received from the same university in 1953. A student of W.

Charles Bell, he moved with Charlie to the University of Texas, in Austin, Texas, where

he was awarded a Ph.D. in 1957 for his study of the Cambrian of southwestern Montana.

His thesis was published as Geological Society of America Memoir 96 in 1965. While in

Austin working on his thesis, Dick spent two years as an instructor in the geology

department as Bell's assistant.

Dick came to the Smithsonian in 1957 as an assistant to G.A. Cooper, whereupon he

permanently switched paleontologic allegiances from trilobites to brachiopods. The

appointment, which was on Cooper's NSF grant, was for four years. He next worked as a

paleontologist for the U.S. Geological Survey (U.S.G.S.) from 1961 to 1972, expanding

his experiences and knowledge of the Permian from West Texas to the entire world.

During his U.S.G.S. career, he performed field work in such far off places as Tunisia,

Sicily, Greece, Yugoslavia, Iran, Pakistan, Thailand, Alaska, and the northern Rocky

Mountains. Much of his work on productoid living habits, functional morphology, and

general ecology was completed during this period.

Dick returned to the National Museum of Natural History in 1972 to replace Cooper as

brachiopod curator after Cooper's retirement. He spent the rest of his career working in the

Department of Paleobiology, and he served as its chairman from 1972 to 1977. It was

during that time that he and Cooper published their impressive six-volume monograph on

the Permian brachiopods of West Texas.

Grant received many honors, including the Director's Award for Outstanding

Achievement in 1977 and the National Academy of Science's Daniel Giraud Elliot Medal

in 1979. He was president of the Paleontological Society from 1978 to 1979 and treasurer

of the International Palaeontological Association from 1980 to 1989. He was a Fellow of

the Geological Society of America and the American Association for the Advancement of

Sciences and was a member of the Society of Economic Paleontologists and Mineralogists,

vn
viii SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

the American Association of Petroleum Geologists, the Geological Society of Washington,

and the Paleontological Society of Washington.

For the past 20 years, Dick had been active in the affairs of the Subcommission on

Permian Stratigraphy, in particular the Permian-Triassic boundary working group. He had

nearly completed editing this volume (with Wardlaw and Rohr), which records the

proceedings of the Guadalupian Symposium in Alpine, Texas, in 1991; this work

establishes a Middle Permian Series for the Permian System. Dick also was concluding his

major contributions to the revision of the Brachiopod volumes of the Treatise on

Invertebrate Paleontology; these included revision of the superfamilies Productoidea (with

C.H.C. Brunton and S. Lazerev), Stenoscismatoidea, Oldhaminoidea, and Richthofenioidea, and the family Gemmelaroiidae.

During the 1980s, Dick published a wide variety of important contributions, including

monographs on the stenocismids, the cardiarinids, and the gemmellaroids. He also

described the faunas of several of the regions with which he had been involved as far back

as the 1960s: Hydra, Greece; Axel Heiberg Island, Arctic Canada; Guatemala; and

elsewhere.

Dick worked with a wide variety of specialists and foreign visitors during his career. In

particular, he helped several Chinese paleontologists, including Jin Yugan, Xu Guirong,

and Shi Xiaoying, with getting their brachiopod systematic papers published. In addition

to Cooper, Brunton, and Lazerev, Dick collaborated with E.E. Brabb, B.F. Glenister, P.M.

Kier, M.K. Nestell, D.M. Rohr, AJ. Rowell, F.G. Stehli, C.K. Stropoli, and B.R. Wardlaw.

He is survived by his wife, Lucy Grant of Alexandria, Virginia, sons Charles Lewis

Grant and Evan Richard Grant of Richmond, Virginia, and Lauren Philip Grant of

Morgantown, North Carolina, and sister Ruth Grant-Rugh of Cornwall-on-Hudson, New

York.

Dick Grant was a vibrant and forceful presence in the world of brachiopod and Permian

studies for more than three decades, and he was an energetic, imaginative, and resourceful

member of the paleontological community in the National Museum for most of his long

and productive career.

Selected Bibliography

1962. Trilobite Distribution, Upper Franconia Formation (Upper Cambrian), Southeastern Minnesota. Journal

of Paleontology, 36:965-998.

1962. [with G.A. Cooper] Torynechus, New Name for Permian Brachiopod Uncinuloides King. Journal of

Paleontology, 36:1128-1129.

1963. Unusual Attachment of a Permian Linoproductid Brachiopod. Journal of Paleontology, 37:134-140.

1964. [with G.A. Cooper] New Permian Stratigraphic Units in Glass Mountains, West Texas. Bulletin of the

American Association of Petroleum Geologists, 48:1581-1588.

1965a. The Brachiopod Superfamily Stenoscismatacea. Smithsonian Miscellaneous Collections, 148(2): 1-192.

1965b. Faunas and Stratigraphy of the Snowy Range Formation (Upper Cambrian) in Southwestern Montana and

Northwestern Wyoming. Geological Society of America, Memoir, 96:1-171.

1965. [with D.V. Ager, D.J. McLaren, and H. Schmidt] Rhynchonellida. In Raymond C. Moore, editor,

Treatise on Invertebrate Paleontology, Part H, Brachiopoda: 552-632. Lawrence, Kansas: University of

Kansas Press for the Geological Society of America.

1965. [with P.M. Kier] Echinoid Distribution and Habits, Key Largo Coral Preserve, Florida. Smithsonian

Miscellaneous Collections, 149(6): 1-68.

1966a. Late Permian Trilobites from the Salt Range, West Pakistan. Palaeontology, 9:64-73.

1966b. A Permian Productoid Brachiopod, Life History. Science, 152:660-662.

1966c. Spine Arrangement and Life Habits of the Productoid Brachiopod Waacenoconcha. Journal of

Paleontology, 40:1063-1069.

1966. [with G.A. Cooper] Permian Rock Units in the Glass Mountains, West Texas. United States Geological

Survey Bulletin, 1244-E:E1-E9.

1968. Structural Adaptation in Two Permian Brachiopod Genera, Salt Range, West Pakistan. Journal of

Paleontology, 42:1-32.

1969. [with G.A. Cooper] New Permian Brachiopods from West Texas. Smithsonian Contributions to

Paleobiology, 1: 20 pages.
NUMBER 32 ix

1970a. Brachiopods from Permian-Triassic Boundary Beds and Age of Chhidru Formation, West Pakistan. In

B. Kummel and C. Teichert, editors, Stratigraphic Boundary Problems: Permian and Triassic of West

Pakistan. University of Kansas, Department of Geology Special Publication, 4:117-151.

1970b. Brachiopods in the Permian Reef Environment of West Texas. Proceedings of the First North American

Paleontological Convention, Sept. 5-7, 1969, Part J: 1444-1481.

1970. [with F.G. Stehli] Permian Brachiopods from Huehuetenango, Guatemala. Journal of Paleontology,

44:23-36.

1971. Taxonomy and Autecology of Two Arctic Permian Rhynchonellid Brachiopods. In J. Thomas Dutro, Jr.,

editor, Paleozoic Perspectives: A Paleontological Tribute to G. Arthur Cooper. Smithsonian

Contributions to Paleobiology, 3:313-335.

1971. [with E.E. Brabb] Stratigraphy and Paleontology of the Revised Type Section for the Tahkandit

Limestone (Permian) in East-Central Alaska. United States Geological Survey Professional Paper,

703:1-26.

1971. [with F.G. Stehli] Permian Brachiopods from Axel Heiberg Island, Canada, and an Index of Sampling

Efficiency. Journal of Paleontology, 45:502-521.

1972. The Lophophore and Feeding Mechanism of the Productidina (Brachiopoda). Journal of Paleontology,

46:213-248.

1972. [with G.A. Cooper] Permian Brachiopods of West Texas, I. Smithsonian Contributions to

Paleobiology, 14:1-231.

1973. [with G.A. Cooper] Dating and Correlating the Permian of the Glass Mountains in Texas. In A. Logan

and L.V. Hills, editors, The Permian and Triassic Systems and Their Mutual Boundary. Canadian Society

of Petroleum Geologists, Memoir, 2:363-377.

1973. [and G.A. Cooper] Brachiopods and Permian Correlations. In A. Logan and L.V. Hills, editors, The

Permian and Triassic Systems and Their Mutual Boundary. Canadian Society of Petroleum Geologists,

Memoir, 2:572-595.

1974. [with G.A. Cooper] Permian Brachiopods of West Texas, II. Smithsonian Contributions to

Paleobiology, 15:233-793.

1975. [with G.A. Cooper] Permian Brachiopods of West Texas, III. Smithsonian Contributions to

Paleobiology, 19:795-1921.

1976. Permian Brachiopods from Southern Thailand. Journal of Paleontology, 50(3)supplement: 269 pages.

[Paleontological Society Memoir, 9.]

1976a. [with G.A. Cooper] Permian Brachiopods of West Texas, IV. Smithsonian Contributions to

Paleobiology, 21:1923-2607.

1976b. [with G.A. Cooper] Permian Brachiopods of West Texas, V. Smithsonian Contributions to

Paleontology, 24:2609-3159.

1977. [with G.A. Cooper] Permian Brachiopods of West Texas, VI. Smithsonian Contributions to

Paleontology, 32:3161-3370.

1980a. The Human Face of the Brachiopod. Journal of Paleontology, 54:499-507.

1980b. Koskinoid Perforations in Brachiopod Shells: Function and Mode of Formation. Lethaia, 13:313-319.

1981. Living Habits of Ancient Articulate Brachiopods. In J.T. Dutro, Jr., and R.S. Boardman, organizers,

Lophophorates, Notes for a Short Course. University of Tennessee, Department of Geological Sciences,

Studies in Geology, 5:127-140.

1987. Brachiopods of Enewetak Atoll. In D.M. Delaney and others, editors, The Natural History of Enewetak

Atoll, Volume 2, Biogeography and Systematics, pages 77-84. U.S. Department of Energy.

1987. [with A.J. Rowell] Phylum Brachiopoda. In R.S. Boardman, A.H. Cheetham, and AJ. Rowell, editors,

Fossil Invertebrates, pages 445-496. Palo Alto, California: Blackwell Scientific Publications.

1988. The Family Cardiarinidae (Late Paleozoic Rhynchonellid Brachiopoda). Senckenbergiana Lethaea,

69:121-135.

1990. [with B.R. Wardlaw] Conodont Biostratigraphy of the Permian Road Canyon Formation, Glass

Mountains, Texas. United States Geological Survey Bulletin, 1895-A:A1-A18.

1990. [with B.R. Wardlaw, R.A. Davis, and D.M. Rohr] Leonardian-Wordian (Permian) Deposition in the

Northern Del Norte Mountains, West Texas. United States Geological Survey Bulletin, 1881-A:A1-A14.

1991. [with C.K. Stropoli and B.R. Wardlaw] Wordian (Permian) Brachiopod Assemblages, Western USA.

In D.I. MacKinnon, D.E. Lee, and J.D. Campbell, editors, Brachiopods Through Time. Proceedings of

the Second International Brachiopod Congress, University of Otago, Dunedin, New Zealand, 5-9

February, 1990, pages 227-232. Rotterdam: A.A. Balkema.

1991. [with M.K. Nestell, A. Baud, and C. Jenny] Permian Stratigraphy of Hydra Island, Greece. Palaios,

6:479-497.

1992. [with B.F. Glenister and others] The Guadalupian: Proposed International Standard for a Middle

Permian Series. International Geology Review, 34:857-888.

1992. [with Xu Guirong] Permo-Triassic Brachiopod Successions and Events in South China. In W.C. Sweet,

Yang Zunyi, and Yin Hongfu, editors, Permo-Triassic Events in the Eastern Tethys, pages 98-108.

Cambridge: Cambridge University Press.

1993a. The Brachiopod Family Gemmellaroidea. Journal of Paleontology, 67:53-60.
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

1993b. Permian Brachiopods from Khios Island, Greece. Journal of Paleontology, 67(4)supplement: 21 pages.

[Paleontological Society Memoir, 33.]

1993. [with Shi Xiaoying] Jurassic Rhynchonellids: Internal Structures and Taxonomic Revisions.

Smithsonian Contributions to Paleobiology, 73: 190 pages.

1994. [with Xu Guirong] Brachiopods Near the Permian-Triassic Boundary in South China. Smithsonian

Contributions to Paleobiology, 76: 68 pages.

FRONTISPIECE.—Dick Grant, Bruce Wardlaw, Xu Guirong, and Shannon Rudine in the Sierra Del Norte, Texas.
1. Guadalupian Studies in West Texas

Richard E. Grant, Bruce R. Wardlaw,

and David M. Rohr

Murchison established the Permian System in the Ural

Mountains of Russia in 1841. The first North American

Permian fossils were discovered by Hall (1856) about 15 years

later. The fossils, which were collected in New York State,

were initially described as Carboniferous (Hall, 1856) but were

subsequently recognized as Permian by Girty (1902). Benjamin

F. Shumard (1858), however, was the first to place an

unequivocal Permian designation on some North American

fossils, which had been collected by his brother George G.

Shumard from the Guadalupe Mountains in Texas. A half

century passed before Girty (1908) made known an extensive

Guadalupian fauna, although his field work in Texas and his

study of this fauna already had led him to propose a

Guadalupian "period" (Girty, 1902). Girty's suggestion was

accepted only when it was formalized as the Guadalupe Series

by Adams et al. (1939). The "Guadalupian fauna" was based

upon fossils that Girty collected in 1901 on an expedition

headed by Robert T. Hill, a revered figure in Texas geology.

Hill (1901) was the first to recognize that the strata making

up most of the south-facing scarp of the Glass Mountains

(Sierra del Vidrio) are Paleozoic in age. Johan A. Udden visited

the Glass Mountains and the nearby Del Norte Mountains in

1904 and published a description of the section near Altuda

(Udden, 1907) in which he classified the rocks as Upper

Carboniferous. Udden, Baker, and Bose (1916) named the

Leonard, Word, Vidrio, and Gilliam formations in the Glass

Mountains, and the next year Udden (1917) added the

Wolfcamp, Hess, and Tessey formations, correlating the

section there with units in the Delaware and Guadalupe

mountains.

Philip B. and Robert E. King (brothers) mapped the Glass

and Del Norte mountains for their doctoral dissertations at Yale

University, under the direction of Carl O. Dunbar and Charles

Richard E. Grant {deceased), Department of Paleobiology, National

Museum of Natural History, Smithsonian Institution, Washington,

D.C. 20560-0121. Bruce R. Wardlaw, U.S. Geological Survey, 926A

National Center, Reston, Virginia 20192. David M. Rohr, Department

of Geology, Sul Ross State University, Alpine, Texas 79832.

Schuchert who were, at the same time, the graduate advisors of

G. Arthur Cooper. Robert E. King (1931) described the

Permian brachiopods and gave a faunal summary with

worldwide correlations. Philip B. King (1931) described the

geology and named the Altuda Member of the Capitan

Formation (P.B. King, 1927), the Bissett Formation (then

deemed entirely Triassic), and numbered the carbonate members of the Leonard and Word formations. Cooper and Grant

(1964) gave names to the numbered members of the Word,

calling "Limestone Number 1" the Road Canyon Member,

"Number 2" the China Tank Member, "Number 3" the Willis

Ranch Member, and "Number 4" the Appel Ranch Member.

They followed P.B. King (1931) in considering the Vidrio a

member of the Word. As studies continued, the Road Canyon

took on increasing importance and a more "Leonardian" aspect,

so Cooper and Grant (1966) elevated it to the rank of formation

and removed it to the Leonard Series. The formation was

accepted immediately, but the age assignment proved controversial. Fusulinid specialists insisted that because it contained

Parafusulina rothi it was Guadalupian; ammonoid specialists

saw Perrinites and agreed with the assignment to the

Leonardian. Furnish (1966, 1973) sought to cleave the Gordian

knot by creating a Roadian Stage, which he assigned to the

Leonard Series. Attempts to stifle the new stage name (Grant

and Wardlaw, 1984; Wardlaw and Grant, 1987, 1990) proved

futile, and participants at the Guadalupian Symposium seemed

to accept it wholeheartedly. Consensus did, however, support

the age assignment by Wardlaw and Grant (1990) that placed

the Leonardian-Guadalupian boundary at the change in

conodont species from Mesogondolella idahoensis to M.

serrata (now considered a synonym of M. nankingensis), within

the lower part of the Road Canyon Formation. This placed the

larger part of the formation, and the Roadian Stage, back into

the Guadalupian where P.B. King (1931) had placed it

originally.

The purpose of the Guadalupian Symposium was to

determine if the Permian Period should be divided into three

worldwide stages, instead of the currently recognized two. The

participants had differing opinions on where reference sections
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

for the Lower Permian and the Upper Permian might be

located; these are stated below in the individual contributions.

We agreed by vote, however, that the Middle Permian should

be the Guadalupian Stage, and that the reference section should

be in the Guadalupe Mountains National Park, where the rocks

are well exposed and access is assured. A formal statement that

proposed such a move was submitted for publication in the

proceedings of the International Congress on the Permian

System of the World that was held at Perm, Russia, 1991,

commemorating the 150th anniversary of the Permian System

(Glenister et al., 1992). The papers presented herein provide

detailed data that support the general area of West Texas as an

appropriate region for study of the middle part of the Permian.

The most abundantly fossiliferous Permian rocks in the

world are in the Glass Mountains. Thus, the first paper included

herein presents a guide to localities there and in the Del Norte

and Guadalupe mountains by the organizers of the symposium.

The Glass Mountains cannot be designated an international

reference section, however, because all of the land there is

privately owned, and access cannot be guaranteed. The

Guadalupe Mountains, on the other hand, are in a national park

where they are accessible to all who obtain the proper permits

from the U.S. Department of the Interior, National Park

Service, Southwest Region, Santa Fe, NM 87501.

Wardlaw and Grant (1987, 1990) described the conodont

zones in the Cathedral Mountain and Road Canyon formations

of the Glass and Del Norte mountains. Wardlaw's paper herein

continues that work for the Guadalupian of that region. Wilde

then presses formal recognition of the Guadalupian Series as

the standard for the Middle Permian of the world time scale,

based to some extent on his zonation of the fusulinids.

Fusulinid zones can be traced worldwide, except in the Arctic.

The top of the Guadalupian can be correlated with the

Dzhulfian of Iran via ammonoids of the section at Las Delicias,

Mexico.

Wardlaw's field and museum work in China, in 1992, under

the guidance of Jin Yu-gan revealed that M. serrata is a junior

synonym of M. nankingensis, and more importantly, that the

species is indeed worldwide in distribution. In addition, it

marks a biostratigraphic level within the Permian that can be

recognized wherever it occurs. This is the base of the

Guadalupian. In China it occurs at the base of the Kuhfeng

Formation, which may therefore be correlated to the lower part

of the Road Canyon Formation in Texas. The change from M.

idahoensis to M. nankingensis thus proves to be a recognizable

horizon that can be taken as the base of the Guadalupian

everywhere that Permian rocks occur, making the Middle

Permian a viable worldwide stage. The top of the Guadalupian,

of course, is defined by the base of the succeeding stage, which

will probably be defined in China by a zone succeeding that of

M. altudaensis. In Texas, the highest Guadalupian unit is the

Altuda Formation in the Glass and Del Norte mountains and the

Lamar Limestone Member of the Bell Canyon Formation in the

Guadalupe and Delaware mountains. The youngest Permian

conodont fauna within the Guadalupian units is found in the

uppermost part of the Altuda Formation and is highlighted by

M. altudaensis (Kozur, 1992).

Harris emphasizes the lower part of the Guadalupian in an

analysis of the Cutoff Formation of the Guadalupe Mountains.

He presents three new members of that formation, which can be

traced along the western escarpment. The Cutoff proves to be

more complex than hitherto recognized, and it contains the

Leonardian-Guadalupian boundary. Harris discusses correlations to the San Andres Formation farther north in the

Guadalupes, and to the Road Canyon Formation to the south in

the Glass Mountains. Harris, Lehrmann, and Lambert extend

the discussion of the Cutoff, interpreting the environments in

which the members were deposited. They make a detailed

comparison with the Road Canyon Formation and offer an

interpretation of that formation's relationship to the Permian

basin and shelf.

The discussion is continued by Lambert, Lehrmann, and

Harris, with emphasis on the place of the Cutoff in a proposed

world stratotype for the Middle Permian. They accept the idea

of a Roadian Stage based on conodont zones in the Road

Canyon Formation, with the base of the Guadalupian defined

on the transition from Mesogondolella idahoensis to M.

nankingensis.

Wardlaw, Ross, and Grant build on earlier work by Wardlaw

and Grant (1990) regarding the Road Canyon Formation by

recognizing cyclic sedimentary packages that have the "fining

upward" character that is seen so widely throughout the

geologic column. The environmental setting for these packages

was set forth by Stropoli, Grant, and Wardlaw (1991).

Yang and Yancey outline the fusulinid biostratigraphy of the

Guadalupian region that makes it possible to serve as a world

standard for the Middle Permian. They describe some new taxa

based upon excellently preserved material that was newly

collected by Yang from the Glass and Del Norte mountains.

The paper by Rathjen, Wardlaw, Rohr, and Grant presents a

fresh view of the deposition of the Word Formation in its type

area. The passage from shelf to slope to basin is marked by

distinct facies within the carbonate members that lie within the

generally siltstone matrix of the formation. The authorship

reflects a thesis by Rathjen that was revised for publication by

the supervising committee.

Rudine, Wardlaw, Rohr, and Grant offer an in-depth study of

the Guadalupian rocks of the Del Norte Montains. They clarify

the status of the lower massive and upper massive members of

the Capitan Limestone, and they describe carbonate mounds

(buildups) in the upper part of the Word Formation that,

heretofore, were thought to terminate in the Road Canyon. The

discussion is continued by Wilde and Rudine, who focus upon

fusulinid zones in the Altuda Formation of the western part of

the Glass Mountains. They demonstrate the correlation of the

Altuda to units in the Guadalupe Mountains, specifically to the

Tansill Formation (a shelf unit) and the Lamar Limestone

Member of the Bell Canyon Formation (a basinal unit).

Wardlaw and Rudine divide the Altuda Formation into five

informal units and demonstrate that the Altuda was deposited in

shelf as well as basinal settings.
NUMBER 32

Haneef documents the shelf edge to basinal facies associated

with the upper part of the Capitan Limestone. The collapse

breccias that have been confused with the Capitan are assigned

to the Tessey Formation, and an example of the unit is

documented and interpreted by Haneef and Wardlaw.

Wardlaw, Rudine, and Nestell use conodont zones to

correlate the Texas Guadalupian with rocks of the same age at

Las Delicias, Coahuila, Mexico. The Permian section at Las

Delicias is important to world correlations because it contains

ammonoids, conodonts, and fusulinids that link the Texas

sections to those of Armenia, Iran, and China. It contains

Permian rocks with diagnostic fossils that are younger than any

in Texas, so it is useful in defining the limits to the

Guadalupian. Spinosa and Glenister emphasize these links

from Texas to the world at large through northern Mexico, with

prime focus upon the zonation of ammonoids. The Dzhulfian is

demonstrably younger than the Guadalupian, and its base could

define the top of the Guadalupian. The section at Las Delicias

contains fossils that define this boundary.

The final paper, by Erwin and Kidder, addresses the

phenomenon of siliciflcation of fossils, a condition that is

widespread in Permian strata. Certain fossils, such as brachiopods and echinoderms, are silicified more commonly and more

completely than some others, such as bivalves and fusulinids.

Erwin and Kidder explain these biases by reference to

depositional conditions that favor silicification.

The Guadalupian Symposium was the culmination of a

decade of cooperative Permian studies by the Smithsonian

Institution, the U.S. Geological Survey, and Sul Ross State

University. What began as an attack on the "Road Canyon

problem" by Grant and Wardlaw burgeoned into a full scale

survey of biostratigraphy and depositional environments of the

entire section above the Wolfcampian in the Glass and Del

Norte mountains and of the Guadalupian of the Guadalupe

Mountains. The present volume testifies to the continuing and

widespread interest in this important segment of the history of

the Earth, the period that marked the end of the Paleozoic Era.

In the course of compiling this volume, it became obvious

that the formational names needed to be standardized. Several

new names are also introduced. Table 1-1 lists the names

accepted for use in this volume.

TABLE 1-1.—Recognized Permian formation names and units in the West

Texas area. (* not in GNULEX (1992).)

Altuda Formation

Bell Canyon Formation

Hegler Limestone Member*

Lamar Limestone Member*

McCombs Limestone Member*

Pinery Limestone Member*

Rader Limestone Member*

Bissett Conglomerate

Bone Spring Limestone

Brushy Canyon Formation*

Pipeline Shale Member*

Capitan Limestone

Castile Formation (Gypsum)

Cathedral Mountain Formation

Cherry Canyon Formation*

Getaway Limestone Member*

Manzanita Limestone Member*

South Wells Limestone Member*

Cutoff Formation* (redescribed by Harris, 1988a,b)

El Centro Member*, established this volume

Shumard Member*, established this volume (confusion from Glenister et al.,

1992, where Shumard and Shumard Canyon Member are used interchangably and Shumard Canyon is herein repressed)

Williams Ranch Member*, established this volume

Delaware Mountain Group

Gilliam Limestone

Goat Seep Limestone (Dolomite)

Grayburg Formation

Hess Formation

Lenox Hills Formation

Neal Ranch Formation

Queen Formation

Road Canyon Formation

Salado Formation

San Andres Formation (Limestone)

Seven Rivers Formation

Skinner Ranch Formation

Tansill Formation

Tessey Formation*, revised this symposium

Victorio Peak Limestone

Vidrio Formation*, revised this symposium

Word Formation

Appel Ranch Member

China Tank Member

Willis Ranch Member

Yates Formation

Yeso Formation

Literature Cited

Adams, J.E., M.F. Cheney, R.K. Deford, R.I. Dickey, CO. Dunbar, J.M. Hills,

R.E. King, R.E. Lloyd, A.K. Miller, and C.E. Needham

1939. Standard Permian Section of North America. Bulletin of the

American Association of Petroleum Geologists, 23(11): 1673-1681.

Cooper, G.A., and R.E. Grant

1964. New Permian Stratigraphic Units in Glass Mountains, West Texas.

Bulletin of the American Association of Petroleum Geologists,

48(9): 1581-1588.

1966. Permian Rock Units in the Glass Mountains, West Texas. United

States Geological Survey Bulletin, 1244-E:E1-E9, plates 1,2.

Furnish, W.M.

1966. Ammonoids of the Upper Permian Cyclolobus-Zone. Neues Jahrbuch fur Geologie und Paldontologie, Abhandlungen, 125:

265-296, plates 23-26.

1973. Permian Stage Names. In A. Logan and L.V. Hills, editors, The

Permian and Triassic Systems and Their Mutual Boundary.

Canadian Society of Petroleum Geologists, Memoir, 2:522-548.

Girty, G.H.

1902. The Upper Permian in Western Texas. American Journal of Science,

series 4, 14:363-368.
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

1909 ("1908"). The Guadalupian Fauna. United States Geological Survey

Professional Paper, 58: 651 pages, 31 plates. [Date on title page is

1908; actually published in 1909.]

Glenister, B.F., D.W. Boyd, W.M. Furnish, R.E. Grant, M.T. Harris, H. Kozur,

L.L. Lambert, W.W. Nassichuk, N.D. Newell, L.C. Pray, C. Spinosa,

B.R. Wardlaw, G.L. Wilde, and T.E. Yancey

1992. The Guadalupian: Proposed International Standard for a Middle

Permian Series. International Geology Review, 34(9):857-888.

GNULEX

1992. Geologic Names Unit Lexicon (GNULEX). In Stratigraphic Nomenclature Databases for the United States, Its Possessions and

Territories, Compiled by M.E. MacLachlan, W.A. Bryant, T.W.

Judkins, E.D. Koozmin, R.C. Orndorff, M.L. Hubert, C.R. Murdock,

S.W. Starratt, J.R. LeCompte. United States Geological Survey,

Digital Data Series, DDS-6. [Computer CD.]

Grant, R.E., and B.R. Wardlaw

1984. Redefinition of Leonardian-Guadalupian Boundary in Regional

Stratotype for the Permian of North America. [Abstract.] 27th

International Geological Congress, Moscow, USSR, Abstracts, 1:58.

Hall, James

1856. Descriptions and Notices of the Fossils Collected upon the Route. In

Whipple's Reconaisance near the 35th Parallel. United States

Thirty-third Congress, Second Session, Senate Executive Document

78 and House Exectuive Document 91, 4:99-105.

Harris, M.T.

1988a. Sedimentology of the Cutoff Formation (Permian), Western Guadalupe Mountains, West Texas. In S.T. Reid, R.O. Bass, and P. Welch,

editors, Guadalupe Mountains Revisited, Texas and New Mexico.

West Texas Geological Society, Publication, 88-84:133-140.

1988b. Postscript on the Cutoff Formation: The Regional Perspective and

Some Suggestions for Nomenclature. In S.T. Reid, R.O. Bass, and P.

Welch, editors, Guadalupe Mountains Revisited, Texas and New

Mexico. West Texas Geological Society, Publication, 88-84:141-

142.

Hill, R.T.

1901. Physical Geography of the Texas Region. United States Geological

Survey, Topographic Atlas of the United States, folio 3:4.

King, P.B.

1927. The Bissett Formation, a New Stratigraphic Unit in the Permian of

West Texas. American Journal of Science, series 5, 14:212-221.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part I:

Descriptive Geology. University of Texas Bulletin, 3038: 167 pages,

15 plates. [Date on title page is 1930; actually published in 1931.]

King, R.E.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part II: Faunal

Summary and Correlation of the Permian Formations with Description of Brachiopoda. University of Texas Bulletin, 3042: 245 pages,

44 plates. [Date on title page is 1930; actually published in 1931.]

Kozur, Heinz

1992. Dzhulfian and Early Changxingian (Late Permian) Tethyan Conodonts from the Glass Mountains, West Texas. Neues Jahrbuch fur

Geologie und Paldontologie, Abhandlungen, 187(1):99-114,

figures 1-21.

Murchison, R.I.

1841. First Sketch of Some of the Principal Results of the Second

Geological Survey of Russia. Philosophical Magazine, 19:417-422.

Shumard, B.F.

1858. Notice of New Fossils from the Permian Strata of New Mexico and

Texas, Collected by Dr. George G. Shumard of the United States

Government Expedition for Obtaining Water by Means of Artesian

Wells along the 32d Parallel, under the Direction of Capt. John Pope,

U.S. Corps of Top. Eng. Transactions of the Academy of Science of

St. Louis, 1 (2): 108, 113, 290-297.

Stropoli, C.K., R.E. Grant, and B.R. Wardlaw

1991. Wordian (Permian) Brachiopod Assemblages, Western USA. In D.I.

MacKinnon, D.E. Lee, and J.D. Campbell, editors, Brachipods

through Time. Proceedings of the Second International Brachiopod

Congress, University of Otago, Dunedin, New Zealand, 5-9

February 1990, pages 227-232. Rotterdam: A.A. Balkema.

Udden, J.A.

1907. Sketch of the Geology of the Chisos Country. University of Texas

Bulletin, 93:18-27.

1917. Notes on the Geology of the Glass Mountains. University of Texas

Bulletin, 1753: 59 pages.

Udden, J.A., C.L. Baker, and E. Bose

1916. Review of the Geology of Texas. University of Texas Bulletin, 44:

164 pages.

Wardlaw, B.R., and R.E. Grant

1987. Conodont Biostratigraphy of the Cathedral Mountain and Road

Canyon Formations, Glass Mountains, West Texas. In D. Cromwell

and L.J. Mazzullo, editors, The Leonardian Facies in W. Texas and

S.E. New Mexico and Guidebook to the Glass Mountains, West

Texas. Society of Economic Paleontologists and Mineralogists,

Permian Basin Section, Publication, 87-27:63-66.

1990. Conodont Biostratigraphy of the Permian Road Canyon Formation,

Glass Mountains, Texas. United States Geological Survey Bulletin,

1895-A:A1-A18, plates 1-4.
2. Guidebook to the Guadalupian Symposium

David M. Rohr, Bruce R. Wardlaw, Shannon F. Rudine,

Mohammad Haneef, A. John Hall, and Richard E. Grant

Introduction

Compared to the Guadalupe Mountains of Texas and New

Mexico the depositional environments of the Permian strata of

the Glass Mountains (and adjacent Del Norte Mountains) are

less well known. In general, the Guadalupian facies in the Glass

and Del Norte mountains changes from predominantly carbonate facies in the northeast to thicker clastic facies in the

southwest. Philip B. King (1931) originally considered this

trend to reflect an uplifted clastic source to the southwest, with

carbonate facies developing away from the source area. Ross

(1986) interpreted the eastern portion of the Road Canyon and

Word formations to consist of shelf, shelf-edge bioherm, and

reef facies, and the southwest area to consist of deeper water

siliceous shale, clastic limestone, and basinal sandstone facies.

Probably the best known controversy in the Glass Mountains

Permian involves the depositional environment of the Skinner

Ranch Formation (Leonardian according to Ross, 1986;

Wolfcampian according to Cooper and Grant, 1972) at its type

section on Leonard Mountain. Cooper and Grant (1964),

identified in situ patch reefs at the base of the section, which

were subsequently interpreted as displaced limestone blocks

deposited in a slope environment (Rogers, 1972; Cys and

Mazzullo, 1978; Ross, 1986). Later Flores, McMillan, and

Watters (1977) interpreted the same units as subtidal and

intertidal deposits. The Skinner Ranch Formation illustrates the

complexities involved in interpreting the paleogeography of the

Glass Mountains. If the Skinner Ranch contains displaced

blocks, some eroded from older units, it explains the

occurrence of Wolfcampian fossils in the Skinner Ranch (Ross,

1986). The slope facies interpretation also is used to place the

shelf edge at that time between the Skinner Ranch outcrops at

Leonard Mountain and the lagoonal, backreef deposits of the

Hess Formation to the east, although most of the actual shelf

edge is not preserved (Ross, 1987:30).

David M. Rohr, Shannon F. Rudine, Mohammad Haneef, and A. John

Hall, Geology Department, Sul Ross State University, Alpine, Texas

79832. Bruce R. Wardlaw, U.S. Geological Survey, 926A National

Center, Reston, Virginia 20192. Richard E. Grant {deceased),

Department of Paleobiology, National Museum of Natural History,

Smithsonian Institution, Washington, DC 20560-0121.

Similar conflicting interpretations exist in younger rocks in

the western facies of the Leonardian Guadalupian to the

southwest in the Del Norte Mountains. Ross (1986, 1987)

considered the western facies of the Road Canyon and Word

formations to be basinal shales and turbidites. Wardlaw et al.

(1990) and Rohr et al. (1987) have interpreted this area to be

shallow intertidal to lagoonal environments adjacent to an

uplifted area to the south.

The type section of the Road Canyon Formation is also a

subject of disagreement and will be discussed in more detail

later.

Conclusions from Recent Work in the Glass Mountains

Philip B. King (1931) superbly documented the geology of

the Glass and Del Norte mountains. Most of his map units and

his interpretations stand today. Over the last decade, collaboration between the Smithsonian Institution, the U.S. Geological

Survey, Sul Ross State University, and Chevron Oil Co. has

provided some critical observations that refine the depositional

setting and the geology first described by King (1931). These

key observations are as follows:

1. The lower massive member of the Capitan Limestone

and the Vidrio Member of the Word Formation (the Vidrio is

raised to formation status in this volume) are the same unit.

2. The Vidrio is unconformably bounded.

3. The supposed relationship of the Vidrio interfingering

with the Altuda Formation does not exist. The Vidrio is

everywhere unconformably overlain by the Altuda Formation

or Gilliam Limestone, implying that the Altuda and Gilliam

interfinger.

4. Permian rocks mapped as Capitan Limestone in, and

along, the margin of the Hovey-Sheffield channel are actually

post-Guadalupian. These rocks are collapse breccias, and they

indicate an evaporitic basin and basin margin infill similar to

the Castile Formation in the Delaware basin. This unit is herein

referred to as a basinal or a breccia facies of the Tessey

Formation.

5. The Word Formation generally shows a progression of

lithofacies from bioturbated lime mudstone/wackestone with
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

crinoid-fusulinid packstone/grainstone channels to skeletal

wackestone/packstone to peloidal packstone to siltstone. The

bioturbated lime mudstone/wackestone with crinoid-fusulinid

packstone/grainstone facies is commonly recrystallized or

dolomitized and represents a shoal facies that was repeatedly

exposed. The remaining lithofacies commonly appear in

succession in section and are repeated in several cycles (shown

as numbers in Figure 2-1).

6. Conodont distribution provides an important correlating

tool. The changeover from a transitional morphotype of

Mesogondolella idahoensis to M. nankingensis (= M. serrata)

is remarkably sharp in most sections and occurs within the

basal few meters of cycle 2 of the Road Canyon Formation.

7. The Altuda Formation shows a wide variety of

lithofacies, from shallow lagoon sediments to basinal turbidites.

8. Lithologically and paleontologically, the Road Canyon

Formation is more allied with the Word Formation, which is

where King (1931) originally placed it.

9. The top of the Skinner Ranch and Hess formations is

marked by a karstic surface. The base of the overlying

Cathedral Mountain Formation is generally conglomeratic,

CATHEDRAL MOUNTAIN FORMATION

SKINNER RANCH

FORMATION

FIGURE 2-1.—General stratigraphic relations of Leonardian to Dzhulfian age rocks in the Glass and Del Norte

mountains. Major sequence ties to the Guadalupe Mountains are shown at left. Cycles in the Road Canyon and

Word formations are represented by numbers. The conodont zonation is shown at right. (M. = Mesogondolella;

N. = Neostreptognathodus.)
NUMBER 32

PECOS

COUNTY

FIGURE 2-2.—Areal distribution of Capitan Limestone foreset beds (dashed lines), shelf margin crest to toe

margin in general northwest direction, general distribution of shoal facies in Word Formation (dot-dashed lines),

and relationship of proposed field trip stops (large black dots) to shelf margin facies.

indicating a major unconformity that ties exactly to the

sequence boundary between the Yeso and lower San Andres

formations in the Algerita Escarpment, northern Guadalupe

Mountains.

10. The top of the Willis Ranch Member of the Word

Formation is commonly recrystallized and dolomitized and

indicates subaerial exposure. The unconformity represented by

this surface ties with the Grayburg/Queen unconformity in the

Guadalupe Mountains.

11. The Vidrio appears to correspond to the Manzanita

Limestone Member of the Cherry Canyon Formation in the

Guadalupe Mountains.

12. The Tessey breccia is equivalent to the Castile and

Salado formations of the Delaware basin and unconformably

overlies the Capitan Limestone.

The deposition of the Capitan Limestone and its equivalents

is fairly straightforward and is summarized by Haneef et al.

(1990:46):

Capitanian stratigraphy of the Glass Mountains is not as well documented as the

type section in the Guadalupe Mountains. The Capitanian sequence is

represented by the Altuda, Capitan, and Gilliam formations. The Altuda

Formation and Gilliam Limestone have disconformable lower contacts with the

Vidrio Member of the Word Formation. The Altuda is siliciclastic, bioclastic,

dolomitic wackestone to packstone interbedded with thin-bedded sandstone.

The Gilliam Limestone is dolomitic fusulinid grainstone and stromatolitic

dolostone interbedded with fine sandstone and possible evaporites and contains

pisolite and tepee structures. The Capitan Limestone has an undulatory

erosional lower contact with the Altuda Formation and is massive, dolomitic,

heavily recrystallized mudstone to algal-sponge wackestone. The Capitan also

grades into the Altuda in large foresets where the Altuda displays thin planar to

graded bedding, slump structures, flow structures, and wavy channel bedding

with channel lag. Conodonts and fusulinids demonstrate that the Altuda, where

it underlies the Capitan, is equivalent to the lower Bell Canyon Formation, and,

where it is laterally equivalent to the Capitan, it is equivalent to the upper Bell

Canyon Formation. Lower Capitanian deposition is represented by dolomites

and elastics of the Gilliam and Altuda formations in a shelf to slope transition

on a ramp. Upper Capitanian deposition is represented by dolomites of the

Gilliam, Capitan, and Altuda formations in a shelf, margin, and slope-basin

transition on a platform.

The distribution of foresets of the Capitan Limestone can be

mapped (Figure 2-2), and they represent a clear demarcation of

the transition from a shelf margin to a basin. Recrystallized

limestone and dolostone of the bioturbated lime mudstone/

wackestone with crinoid-fusulinid packstone/grainstone chan-
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 2-3.—Isopachous map of the Word Formation from King (1931, fig. 25) but modified by drill-hole data,

showing area of minimum thickness as dot-dashed line.

nel facies (shoal facies) within the Word Formation show a

similar trend to the foreset distribution (Figure 2-2), but they

are slightly more shoreward. A modified isopach map of the

Word (from King, 1931, with the addition of drill hole data)

displays an area of minimum thickness that almost exactly

follows the front of the shoal facies (Figure 2-3). The location

of the Symposium's field trip stops are also shown on Figure

2-2, displaying their relationship to the proposed shoal-shelf

margin.

Recently, Sarg et al. (1988) developed a sea-level curve

based on the well-established sequence stratigraphy of the

Guadalupe Mountains. This sea-level curve can be taken and

compared to the sequence stratigraphy, conodont biostratigraphy, and depositional setting that has been developed for the

Glass Mountains (Figure 2-4). In order to compare the Glass

Mountains sequence to this curve, modeling has to be done

without scale because the sea-level curve developed for the

Guadalupe Mountains is based on the true thickness of the

sequence. In subsequent publications modeling will incorporate true thickness and distance. The Glass Mountain sequence

appears to show a relatively "deep" backbay of a foreland basin

that was largely infilled during Cathedral Mountain deposition.

This backbay, or lagoon, explains the relative shallow slope

deposition that is observed in many of the Permian units.

The Del Norte Mountains contain an abundance of sand and

silt sediments related to the encroachment of a delta complex

from the uplifted Marathon Thrust Belt (Rudine et al., 1987).

Day 1: Alpine to Marathon, Dugout Mountain,

Iron Mountain Ranch, Bruce Ranch

MILEAGE

Interval Cumulative

0.0 0.0 Head eastward on U.S. 90 from entrance #2 of

Sul Ross State University, Alpine. Most of the

rocks in the immediate Alpine area are Tertiary

volcanics. To the west is Twin Peaks (elev.

6084), a syenite intrusion. In the distance to the

north are the Davis Mountains, containing

Tertiary volcanics of Oligocene to Eocene age

and minor exposures of Cretaceous rocks. The

highest peak in the Davis Mountains is Mt.

Livermore at 8381 ft. Sul Ross State University

is located on Hancock Hill, which is composed

of the Eocene Crossen Trachyte with minor

interbeds of fresh-water limestone (Collinsworth and Rohr, 1986).

7.4 7.4 Junction with U.S. 67 (to Ft. Stockton); continue straight on U.S. 90, now heading southeastward. Ahead are the Glass Mountains on the

left side of the road and the Del Norte

Mountains to the right. The highest portions of

the Glass Mountains now visible are the

Capitan Limestone. Cretaceous limestone is
NUMBER 32

present south of the road and on the lower

slopes to the northwest.

2.8 10.2 The quarry on the left side of the road is in

Cretaceous limestone. The roadcut immediately

beyond the quarry exposes Cretaceous limestone lying unconformably over Upper Permian

(Tessey) limestone (Figure 2-5). Altuda (or

Bird) Mountain to the right (Figure 2-21)

consists of 73 m of Cretaceous limestone

overlying cliff-forming Upper Permian limestone breccias. Below the cliffs are interbedded

siltstones and limestones of the Word and

Altuda formations. To the right of the peak is

Bird Mine and a resistant breccia pipe.

In many previous guidebooks, the cliffforming unit has been identified as Capitan reef

facies prograding over basinal Altuda. A recent

study (Wardlaw et al., 1990) has shown this

0.6 10.8

interpretation to be incorrect. In this area, the

Word Formation and the underlying Cathedral

Mountain Formation (Leonardian) are shallow,

intertidal deposits of siltstone, sandstone, and

limestone. The Road Canyon equivalent is a

deltaic sequence containing fossil leaves

(Mamay et al., 1985, 1988) and silicified wood.

The overlying Altuda to the south of Bird

Mountain contains tidal channels and tidal flats;

deeper shelf-slope facies are found in the Bird

Mine area. The post-Guadalupian (Dzhulfian)

collapse breccia was formed by the solutioning

of evaporite (sabkha?) deposits.

Bissett Mountain is in the background at 9

o'clock. It is capped by Lower Cretaceous

limestones, and the main slopes are composed

of limestone conglomerates and red beds of the

Bissett Formation. Bissett conglomerate, sandaltudaensis

GILLIAM

LIMESTONE

CAPITAN

LIMESTON

WIDRIO FORMATION

APPEL RANCH MEMBER

WORD

FORMATION

WILLIS RANCH

MEMBER

CHINA TANK MEMBER UNDIFFERENTIATED

nankingensis ^ SILTSTONES ROAD CANYON FORMATION

CATHEDRAL MOUNTAIN

FORMATION SILTSTONES OF THE

CATHEDRAL MOUNTAIN

DOLOSTONE OR FORMATION

RECRYSTALLIZED LIMESTONE

FALLING

SEA-LEVEL CURVE

LIMESTONE

SILTSTONE

MIXED DOLOSTONE

AND CLASTICS

BRECCIA

FIGURE 2-4.—Model of depositional setting and sequence stratigraphy of the Glass Mountains in relation to the

sea-level curve of Sarg et al. (1988) for the sequence in the Guadalupe Mountains. The sequence ties to the

Guadalupe Mountains are shown as solid lines (dashed where inferred or unknown). Conodont datums (zone

boundaries) are shown as dot-dashed lines. The curve fits well the depositional sequence in the upper part,

implying that both are responding to the same eustatic signal. The lower depositional sequence does not, implying

that it is driven by local tectonics.
10 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

lipli- .* %*rfK-

:

-gi$i'P:~:-;'Si'•#»•••» .-;• *- » &--i,i ,::

FIGURE 2-5.—Section along U.S. 90 showing Cretaceous limestone unconformably overlying Upper Permian

(Tessey) limestone.

stone, and shale unconformably overlie the

Permian Tessey Limestone here. An angular

unconformity separates the Bissett Formation

from the overlying Fort Terrett Formation

(Cretaceous). The Bissett Formation has been

shown by Wilcox et al. (1986, 1987) to be

Cretaceous and not Triassic as previously

thought.

2.3 13.1 Altuda siding.

1.9 15.0 Approximate top of Altuda Pass. To the south,

the low hills nearest the road are the Vidrio and

Altuda formations, which make up the nose of

a north-trending anticline. To the north, the

lower slopes are Word siltstones, the limestone

bed about mid-slope is Appel Ranch-equivalent

limestone, the upper ledge of the hill is Vidrio,

and the cap is Altuda. The upper surface of the

Vidrio is irregular along the unconformable

contact.

1.4 16.4 Road bends to the left. To the left is the Vidrio

Formation. King (1931) recognized three members in the Capitan Limestone: the lower

massive, the Altuda, and the upper massive.

Later, King (1937) combined the lower massive

and Altuda members into an undivided Capitan

on his geologic map, but in the text he

considered the lower massive to be equivalent

to the lower tongue of the Vidrio Member.

Conodont biostratigraphy suggests that the

Vidrio (lower massive of King, 1931) is

age-equivalent to the upper part of the Word

Formation in the Glass Mountains; therefore, it

is Wordian, not Capitanian in age (Rudine et al.,

1987). Capitanian and Wordian strata are

separated by an unconformity (Rudine et al.,

1988). The unconformity is expressed in the

Del Norte Mountains by the irregular preservation and thickness of the Vidrio Formation. In

the Glass Mountains it is expressed by an

undulatory surface on top of the Vidrio Formation. The Altuda Formation overlies the Vidrio

in the Del Norte Mountains and western Glass

Mountains, and the Gilliam Formation overlies

the Vidrio in the eastern Glass Mountains. The

Vidrio is generally recrystallized to dolostone

and displays a karstic upper surface in the Del

Norte Mountains. The unconformity appears to

mark the change in fusulinid faunas from those

dominated by Parafusulina below, to those

dominated by Polydiexodina above. The conodont zone of Mesogondolella aserrata spans

the unconformity, occurring in units above and

below. These relationships compare directly to

the well known unconformity above the Goatseep/Manzanita in the Guadalupe Mountains

and imply that the Word-Capitan formational

boundary is marked by an unconformity that

may be correlated throughout the world.
NUMBER 32 11

FIGURE 2-6.—View of Cathedral Mountain representing the front of the Glass Mountains on the way to

Marathon. The Road Canyon Formation caps the low cuesta on the right. Word Formation elastics form the highly

dissected slopes below the massive dolomite cliffs of the Vidrio Formation. The Vidrio Formation unconformably

overlies the Word Formation in this portion of the Glass Mountains. Here, the Vidrio Formation can be

subdivided into three members, each of which is unconformably bound. The Altuda Formation unconformably

overlies the Vidrio Formation. Shelf margin carbonates of the Capitan Limestone form the hill behind Cathedral

Mountain.

Straight ahead and to the left of the road are

the Lenox Hills. A broad valley to the left of the

road gives a view of the scarp face of Cathedral

Mountain, with the high knob of Sullivan Peak

in the distance to the northeast (Figure 2-6). The

long, low dipping slope just below Sullivan

Peak, extending out into the valley and nearly

closing its upper end, contains the upper part of

the Cathedral Mountain Formation. The Cathedral Mountain Formation is capped by the Road

Canyon Formation, which forms the northwest

dipping upper surface.

3.5 21.0 Turn off to right to Catto-Gage Ranch. Dugout

Mountain is the large cuesta to the east of the

north-south trending Del Norte Mountains

(Figure 2-7). The Del Norte Mountains are the

upthrown side of a linear fault that exposes the

Cathedral Mountain through Road Canyon and

basal Word formations in its lower part. The

major part of the scarp, particularly to the south,

is Cretaceous limestone. Dugout Mountain

consists of the Pennsylvanian Gaptank Formation on the eastern slopes and the Permian

Lenox Hills through Skinner Ranch formations

on the upper slopes. Coombs (1990) completed

a detailed study of Dugout Mountain, and his

results are summarized below.

At Dugout Mountain the Lenox Hills and

Skinner Ranch formations represent deposition

in fluvial and shallow marine environments

along the southern shelf of the Delaware basin.

Intense deformation to the south created an

uplifted source area along the toe of the Dugout

and Marathon allochthons from which terrigenous sediments were derived. During Skinner Ranch deposition, coarse pebble-cobbleboulder conglomerate with shallow-marine bioclasts, and coarse sandy skeletal packstones

developed as sheetflood- and debris-flow

deposits on the distal fan-delta. Conglomerates

of the Decie Ranch Member of the Skinner

Ranch were deposited in response to renewed

tectonic activity along the Marathon foldbelt

through earliest Leonardian time, producing

local avalanche/landslide deposits with a maximum clast size of 40 m. The remainder of the

Skinner Ranch deposition was marked by a

prolonged period of relative tectonic quiescence. Fan deltas prograded into the Delaware
12 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 2-7.—View of Dugout Mountain. STOP 1.2 is just outside frame of photograph NE of Dugout Mountain.

basin, forming a complex delta plain composed

of intertidal siltstones with meandering tidal

channel deposits of sand and pebble conglomerates. Trace fossils of the Scoyenia ichnofacies

suggests at least intermittent exposure of the

delta plain.

0.2 21.7 Railroad crossing.

0.1 22.0 Road forks, take middle fork (private ranch

road).

4.1 26.1 Proceed on main ranch road to Payne Ranch site

of the Catto-Gage Ranch until junction. Continue straight.

1.3 27.4 Follow dirt track past substation to STOP 1.1

(Figure 2-8), which is the Road Canyon

Formation (Figure 2-9) and USNM loc. 732z.

This abundant ammonoid locality was mapped

as a limestone channel in the basal unit of the

Word Formation (Rudine, 1988). Furnish and

Glenister (in Cooper and Grant, 1977:3308)

noted that "this locality, discovered by Cooper

and Grant about 1965, has been the source of

the largest collection of Permian ammonoids in

West Texas. It is also a critical locality in that it

combines faunal elements from the basin with

those normally found on the shelf and is

believed to provide a basis for detailed correlation from the Glass Mountains to the Guadalupes." Furnish and Glenister also provided the

following faunal list:

0.6 28.0

0.5 28.5

Agathiceras uralicum (Karpinsky)

Epithalassoceras n. sp.

Eumedlicottia whitneyi (Bose)?

Glassoceras normani (Miller and Furnish)

Paraceltites elegans Girty

Peritrochia erebus Girty

?Propinacoceras sp.

Pseudogastrioceras cooperi Miller?

Texoceras texanum (Girty)

Wilde (in Cooper and Grant, 1977:3316)

identified the following fusulinids from USNM

loc. 732z:

Parafusulina attenuata Dunbar and Skinner [abundant]

P. boesi Dunbar and Skinner [abundant]

P. splendens Dunbar and Skinner [not

common]

A silty fusulinid skeletal packstone is overlain by an irregular channelform of massive

cherry, silty (sponge) skeletal packstone at the

base of the outcrop in the Road Canyon

Formation (Figure 2-10). Fusulinids are common in the silty skeletal packstone channels

above and below USNM loc. 732z.

Return on dirt track, but turn left on track

heading to substation.

Continue to knob to the south, which is the dip

slope of the Road Canyon Formation, STOP 1.2
NUMBER 32 13

(Figure 2-8). Studies by Rudine et al. (1987) of

the sedimentary structures, petrology, and

paleontology of the carbonates and elastics of 0.3 28.8

the Cathedral Mountain, Road Canyon, Word,

Vidrio, and Altuda formations in the Del Norte 0.4 29.2

Mountains indicate deposition in a delta-fan

complex on a shallow shelf, and in a tidal 4.4 33.6

lagoon for various units of these formations.

Channel conglomerates, overbank deposits,

stromatolitic limestones, and abundant sedimentary features indicate shallow shelf/delta

deposition of these units. Paleontological evidence includes shallow-shelf conodont biofacies and abundant, excellently preserved leaves

and logs that occur in parts of the section

(Figure 2-10). The outcrop here displays sev- 4.2 37.8

eral sedimentation cycles dominated by the

peloidal packstone facies. Note the weathering,

jointing, and chertification pattern at the top of

the outcrop. This rectangular pattern is common

to the top of peloidal packstones throughout the

Road Canyon and Word formations.

Return to main road to Payne Ranch site. Turn

left.

Return to junction of main road and road to

Payne Ranch site and backtrack to U.S. 90.

Turn right on U.S. 90 and head east to

Marathon. To the left of the road are the Decie

Hills, which are composed of the Skinner

Ranch Formation. Massive white Scacchinella

beds are visible near the end of the hills. The

deposition of these beds, as with many others in

the Glass Mountains, are controversial as it is

unknown whether they are displaced reef

blocks or in-place bioherms.

Roadcut on the right side of the road is USNM

loc. 708b. The upper ledge of limestone is

Wolfcampian (Neal Ranch Formation?) unconformably overlying the Pennsylvanian Gaptank

Formation.

FIGURE 2-8.—Location of STOPS I.I and 1.2; Dugout Mountain 7.5 min. quadrangle.
14

SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 2-9. View of STOP 1.1. Ledge is Road Canyon Formation. Section goes through ledge to barely

perceptible lens on hill above, which laterally yields abundant ammonoids.

STOP 1.1 STOP 1.2

75

50

• W86-8 (57.51)

(732-Z)

• W86-7 (12')

• W86-6 (71)

• W86-5 (I1)

R

• W87-27 (73')

I , \j W87-26 (45f

)

W87-25 (331)

W87-24 (13.51)

W87-23 (3f)

FIGURE 2-10.—Columnar sections of STOPS 1.1 and 1.2. (R = Road Canyon Formation; W = Word Formation.)
NUMBER 32 15

7.2 40.8 Proceed on U.S. 90 through Marathon. Turn left

just before Exxon station at east end of town.

0.3 41.1 Turn right at end of street.

1.5 42.6 Go one block east and turn north onto dirt road.

Proceed to Iron Mountain Ranch entrance and

continue through gate (private road).

4.9 47.8 Road enters from right; turn right over cattle

guard. Iron Mountain Ranch headquarters is on

the left. Leonard Mountain, on the right,

exposes the Haymond, Gaptank, Lenox Hills,

and Skinner Ranch formations. The western

slope of Leonard Mountain and the hill to the

north contain the type sections of the Skinner

Ranch, Cathedral Mountain, and Road Canyon

formations of Cooper and Grant (1964).

0.3 47.8 Road crossing, continue straight.

0.2 48.0 Road forks, stay left. Right fork goes to skeet

range.

0.3 48.3 Road forks, turn right.

1.6 49.9 Continue on dirt track bearing right at fork in

track at 0.7 miles. Stop at water trough. To the

north is STOP 1.3 (Figure 2-11), the cliffy

outcrop of the Road Canyon Formation type

section. The lower slopes are the Cathedral

Mountain Formation. The climb to the Road

Canyon stratotype is very strenuous. In the

gully immediately north of the water trough,

conglomeratic ammonoid and sparse brachiopod-bearing beds of the middle part of the

Cathedral Mountain Formation are exposed and

may prove of interest to those not making the

climb.

Mesogondolella idahoensis is common to the

top bed exposed in the gully. Xaniognathus

abstractus, Neostreptognathodus sulcoplicatus, Sweetina festiva, and sponge spicules are

rare. In the middle of the exposed beds scattered

ammonoids can be found and only sparse

Sweetina festiva is recoverable.

Cooper and Grant (1964) proposed replacing

King's (1931) First Limestone Member with

the Road Canyon as a member of the Word

Formation. Later, Cooper and Grant (1972)

moved the Road Canyon to the Leonardian. The

type section was designated by Cooper and

Grant (1964, 1972) along King's (1931) section

17, which is the same as Cys' (1981) proposed

lectostratotype (Figures 2-12-2-15). The Road

Canyon Formation has worldwide significance

as a candidate for a Permian stratotype to define

the base of the Guadalupian and the Lower/

Middle Permian boundary. The boundary is

defined by a marked changeover in conodont

faunas from a transitional morphotype of

Mesogondolella idahoensis to M. nankingensis

and by a nearly simultaneous change in

fusulinid faunas from the Parafusulina boesi

zone to the P. rothi zone.

Interpretations of the depositional setting of

the Road Canyon type section are varied.

Cooper and Grant (1972:65) described the

lower part of the Road Canyon type section as

"bioherms with Coscinophora at the base,

followed by bioherms abounding in Hercosestria." In their "concluding remarks" section,

Cooper and Grant (1977:3330) stated,

We had no problems with the Road Canyon fauna until we

started work in the hills northwest of the Hess Ranch. On

the east side of hill 5801 exposures are excellent, the

sequence fairly well provided with bioherms at the base and

near the top. Here we noted some brachiopods with Word

affinities such as Echinosteges, Costispinifera, Spiriferella,

and Paucispinifera. We suspected a possibility of having

collected float blocks from the Word (Willis Ranch

Member) higher on the hill, but a close search of the slopes

revealed no blocks.

Lehrmann (1988:123-124) interpreted the

lower portion of the type section to represent a

thick megabreccia interval, which he said

represents at least two amalgamated deposits. This interpretation is made on the basis of hints of internal bedding and

the transition from Mesogondolella idahoensis to M.

serrata [= M. nankingensis] occurring near the middle of

this interval. A debris flow deposit generally contains no

internal bedding. Possible internal bedding near the middle

of the interval might represent the interface between two

amalgamated debris flow units. A single debris flow deposit

is deposited essentially instantaneously. Clasts and fossils

within a debris flow deposit are generally randomly

distributed. If the thick megabreccia interval represented a

single debris flow deposit, it should not contain the

transition from M. idahoenesis to M. serrata (ie. the

conodonts should be randomly distributed). Therefore, the

thick megabreccia interval probably represents at least two

amalgamated debris flow deposits with the conodont

transition occurring between deposits.

Yancey (1989, in litt.) also favored a megabreccia origin for the lower Road Canyon with

lenticular conglomerate channel fills that have

exposed, through erosion, as much as 9 m of the

underlying units.

Measures and Wardlaw (1990:309) pointed

out that a heavy diagenetic overprint obscures

many primary features of the breccia in the

lower part of the type section and referred to

this portion of the section as a paleokarst. They

overstated their case, probably to stay in

keeping with previous workers.

The paleokarst is formed of a chaotic mixture of poorly

sorted boulders in a matrix of quartz silt, iron-rich clay, and

whole-body fossils. The boulders are composed of carbon-
16 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

. J ''

y MI T ri / \ r v/ y

FIGURE 2-11.—Location of STOP 1.3, the type section of the Road Canyon Formation; Iron Mountain Ranch,

Leonard Mountain, and Gilliland Peak 7.5 min. quadrangles.
NUMBER 32 17

FIGURE 2-12.—Views of the Road Canyon Formation type section at STOP 1.3: A, from the west; B, from the

south, immediately below outcrop.
18

SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 2-13.—Views of the Road Canyon Formation type section at STOP 1.3: A, from the east; B, close-up

showing breccia.
NUMBER 32 19

FIGURE 2-14.—Breccia in the lower part of Road Canyon Formation type

section at STOP 1.3.

ates of normal marine, shallow-shelf deposition found as

normally bedded deposits adjacent to the paleokarst. The

matrix shows extensive dissolution of grains, contains no

large spar-filled voids, and is cemented by fine crystalline

carbonate. The matrix is non-luminescent to rarely dully

luminescent indicating a large freshwater component.

Extensive dissolution and lack of blocky spar cement and

flow stone deposits indicate presence of waters undersaturated with calcium carbonate and possibly an arid environment at the time of cave collapse. The conodonts are

corroded, fractured, and broken throughout the paleokarst

interval and show mixing only in this section compared to

17 other measured sections.

Lehrmann (1989, in lift.) noted that "the

Road Canyon Formation is best exposed at its

type section; however, the type section exposes

some of the most complex stratigraphy in the

Road Canyon Formation. Understanding of the

sedimentologic and stratigraphic relationships

here is crucial to erecting correct biostratigraphy."

1.6 51.5 Return to main dirt road and turn right.

3.7 55.2 Proceed on main road up Gilliland Canyon to

fork in road; take sharp left to paved road that

leads to the Blakemore Hacienda. While traveling up Gilliland Canyon, note the small clay

slide on the cuesta that contains the Road

Canyon stratotype just visited. Immediately

above the small clay slide, which is in the upper

part of the Cathedral Mountain Formation, is

section RC II of Wardlaw and Grant (1990)

through the Road Canyon Formation. Here the

Road Canyon is not very conglomeratic and

shows only floating clasts, generally siltstone,

near the base of skeletal wackestones/

packstones.

1.3 56.5 Proceed up to Blakemore Hacienda and turn

around.

0.4 56.9 Drive back down road to outcrop of Willis

Ranch Member of the Word Formation (STOP

1.4, Alternate Stop, Figures 2-16, 2-17). Here

the Willis Ranch Member is dominantly peloidal packstone with locally common ammonoids. After examining the Willis Ranch,

note that the hill above the Blakemore Hacienda

displays in succession, the upper part of the

Word Formation, the Vidrio Formation, the

Altuda Formation, and the Capitan Limestone.

All contacts are undulatory and appear unconformable.

12.1 69.0 Backtrack to U.S. 90 in Marathon.

1.1 70.1 Turn left on U.S. 90 and proceed to intersection

of U.S. 385 and U.S. 90.

6.3 76.4 Take U.S. 385 North (turn left). Proceed to Hess

Ranch entrance.

6.0 82.4 Proceed on Hess Ranch private road to fork,

turn right to bypass ranch.

1.0 83.4 A road enters from left. Across Hess Canyon is

the eastern end of the cuesta containing the

Road Canyon stratotype. Section RC VII of

Wardlaw and Grant (1990) and Perrinites and

Waagenoceras faunas are found at this end of

the cuesta.

2.5 85.9 Proceed on main road. Just before Hess Tank, at

a small turnout on the right, is the path to the

knoll containing USNM loc. 702c. The was the

most prolific brachiopod locality of Cooper and

Grant (1972), which is in the Road Canyon

Formation.

1.4 87.3 Old Word Ranch site. Here the Road Canyon

Formation is a very thin ledge, exposed just

north of the road past the old ranch site and

tank.

0.7 88.0 Proceed to Bruce Ranch (previously the Appel
20 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

50

R

STOP 1.3

• W81-169 (110') w

• W81-168 (86')

• W81-167 (77.5')

• W81-166 (68')

• W81-165 (52.5')

• W81-164 (40')

• W81-163 (26')

• W81-162 (7.5')

• W81-161 (0')

200

150

W81-176 (272')

r V • W81-175 (250')

• W81-174 (229')

• W81-173 (212')

W81-172 (192)

• W81-171 (170')

• W81-170 (155')

FIGURE 2-15.—Columnar section of the Road Canyon Formation type section. (C = Cathedral Formation; R =

Road Canyon Formation; W = Word Formation.)

Ranch) to check-in. Backtrack 150 yards to

road heading east.

1.4 89.4 Proceed past Split Tank to saddle. STOP 1.5 is in

the gully to the right (Figures 2-18, 2-19). This

is the same section as displayed in Cooper and

Grant (1972, fig. 22), and it represents one of

the most carbonate-rich sections of the Cathedral Mountain Formation (Figure 2-20). Wardlaw and Chevron Oil Co. have worked on a

detailed chemostratigraphy of this section and

the overlying Word, which is exposed back at

Split Tank. Go down the section and examine

the karstified surface of the top of the Hess

Formation and the overlying basal conglomerate of the Cathedral Mountain Formation

(Figure 2-19A).

0.3 89.7 Backtrack to Split Tank, which is on a small hill

to the north of the road. STOP 1.6 is the

remainder of Wardlaw's reference section of

the Cathedral Mountain through the lower

Word formations, as shown in Figure 2-20.

20.1 109.8 Backtrack to Marathon.

30.1 139.8 Return to Alpine.
NUMBER 32 21

FIGURE 2-16.—Location of alternate STOP 1.4; Gilliland Peak and Old Blue Mountain 7.5 min. quadrangles.

STOP 1.4 (Alternate)

• W84-37 (65?)

50

Day 2: Alpine to Bird Mine, Benge Ranch,

and Old Blue Mountain

Bird Mine, on the north side of Bird (or Altuda) Mountain, is

near an intrusion of syenite porphyry into the Permian Altuda

and Tessey formations. This area and the Benge Ranch contain

the youngest Guadalupian rocks yet found in the Glass and Del

Norte mountains.

The thick section of the Capitan Limestone at Old Blue

Mountain differs markedly from the typical Capitan in the

Guadalupe Mountains. The large foresets on Old Blue

Mountain consist of dolomitic mudstone-wackestone, but no

boundstone has been observed on the south side of the

mountain (Faliskie, 1989). The shelf edge in the Glass

Mountains may have been more like a steepened bank-ramp

complex. Pray (1988) noted that a bank-ramp complex has

"bank-type" loose carbonate sediment and lacks depositional

boundstone. The 10° depositional dips on Old Blue Mountain

are steeper than the few degrees stated by Pray (1988), but they

are considerably less than the 30° dips in the Guadalupe

FIGURE 2-17.—Columnar section of the Willis Ranch Member of the Word Mountains. In the field mapping performed in preparation for

Formation at alternate STOP l .4. this symposium, and just subsequent to it, a few slightly

0

• W84-36 (551)

• W84-35 (501)

• W84-34 (38f)

• W84-33 (26.5')

• W84-32 (I1)
22 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 2-18.—Location of STOPS 1.5 and 1.6; Glass Mountain Ranch and Hess Canyon 7.5 min. quadrangles.

recrystallized windows in the bank deposits have been found

just above the proximal foreset beds on the north side of Old

Blue Mountain. These deposits contain abundant boundstone

fabrics of sponges and Tubiphytes, suggesting a similar

depositional setting to the Capitan Limestone in the Guadalupe

Mountains.

MILEAGE

Interval Cumulative

0.0 0.0 Head eastward on U.S. 90 from entrance #2 of

Sul Ross State University, Alpine.

7.4 7.4 Junction with U.S. 67 (to Ft. Stockton), continue straight on U.S. 90 toward Marathon.

4.5 12.3 Turn right onto small dirt track heading for Bird

Mine (private road). Continue up valley toward

intrusion (Figure 2-21).

2.4 14.7 Take right branch of road and proceed to stream

crossing near mine (Figure 2-22), STOP 2.1.

Walk up low slope WSW of road. The

2.4 17.1

4.5 21.6

limestone cropping out in this area is the upper

Altuda Formation and is about 30 m stratigraphically below the contact with the overlying

Tessey Formation (Figure 2-23). The cliffforming outcrops above the mine area to the

south are the Tessey Formation (Dzhulfian),

formerly mapped as the upper massive member

of the Capitan Limestone. The collapse breccias

of the Tessey are well exposed around the mine

opening just to the north. The ammonoidbearing beds contain abundant Mesogondolella

postserrata and the fusulinid Reichelina (Yang,

pers. comm., 1990).

Backtrack to U.S. 90; turn left to go toward

Alpine.

Junction with U.S. 67 (to Ft. Stockton), turn

right and continue northward. Tertiary volcanics of the Davis Mountains are on the left

(west), and the Glass Mountains are on the

right. The highest portions of the Glass Moun-
NUMBER 32 23

FIGURE 2-19.—STOP 1.5. A, View of the base of section showing conglomerate at the base of the Cathedral

Mountain Formation. B, Typical exposure of the Cathedral Mountain Formation in section.
24 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

200

150

100

50

H

400

W90-14 (195')

W90-13 /

W84-66 (1811)

W90-12 (172')

W90-11 (152.5')

W84-65 (134')

W90-10 (123')

W84-64 (101')

W90-9 (81')

W84-63 (57.51)

o

W90-8 (26')

W84-62 (91)

350

300

250

200

600

• W90-19/

W84-70 (354')

• W82-14 (327*)

• W84-69 (317")

• W90-18 (274")

} •W90-17 (258.51)

550

I I ) • W90-27 / W85-6 (544.51)

500

W

450 —

• W84-68 (246.5') R

• W90-16 (232')

• W90-15/

W84-67 (210')

400

.W85-9 (593.5')

W90-29 (592.5')

• W85-8 (581.5')

-W90-28 (564')

W85-7 (563.5')

• W90-26 (534.5')

I' J»W85-5 (517.5')

• W90-25 (505.5')

• W90-24/W85-4 (491.5')

,W90-23 (470.5')

*W85-3 (468.51)

S»W90-22/W85-2 (457')

o

.W90-20/W84-72 (448.5')

W90-21/W85-1 (446.5')

*W87-71 (443.5')

FIGURE 2-20.—Composite columnar section of STOPS 1.5 and 1.6. (C = Cathedral Mountain Formation; H = Hess

Formation; R = Road Canyon Formation; W = Word Formation.)
NUMBER 32 25

FIGURE 2-21.—View of Bird (Altuda) Mountain. Massive cliffs are the Tessey Formation. Ammonoid locality

(STOP 2.1) lies in arroyo north (right) of Bird Mountain.

tains now visible are the Capitan Limestone; the

hills in the foreground are Cretaceous.

4.5 26.1 Turn right onto gravel county road. Old Blue

Mountain is directly ahead on the horizon.

1.6 27.7 Cross first cattle guard.

1.9 29.6 Cross second cattle guard.

1.3 30.9 Cross third cattle guard. The low hills on the

right and left are Cretaceous carbonates. Bisset

Mountain is the high, flat-topped mountain on

the right.

1.4 32.3 Cross fourth cattle guard.

1.0 33.3 Cross fifth cattle guard. The Frenchman Hills

ahead are the Tessey Formation.

1.7 35.0 Road branches, bear left, go through next cattle

guard, and turn right to Benge Ranch headquarters (private road).

0.3 35.8 At Benge Ranch headquarters, continue straight

through gate by barn and go up hill to saddle.

0.2 36.0 STOP 2.2 is at crest of saddle in the lower Tessey

Formation (Figures 2-24-2-26). The Frenchman Hills were mapped by King (1931) as the

upper massive member of the Capitan

Limestone, but this member has since been

reinterpreted as a member of the postGuadalupian Tessey Formation. The Tessey

Formation is the youngest Permian formation

(Dzhulfian) in the Glass Mountains. The Dzhulfian age is based on a correlation between the

Tessey and the Rustler Formation of the

Guadalupe Mountains. This age was determined by Vacuum Oil Company's Elsinore

well No. 1 in Pecos County, Texas, and the

Rustler's stratigraphic position is above the

documented Lamar-post-Lamar (highest Bell

Canyon/Guadalupian) equivalent fusulinid horizons. The Tessey Formation was named for

the old Tessey Post Office, which marked the

northern extent of the Tessey outcrop. Udden

(1917) originally considered it to be a separate

formation, but it was reduced in rank to a

member of the Capitan Limestone by King

(1931). He considered the Capitan to consist of

three members: the Vidrio, Gilliam, and Tessey. The Tessey was returned to formation rank

in 1937 by P.B. King.

The Tessey Formation in the Frenchman

Hills (Figure 2-27) can be subdivided into three

lithologically distinct units. The lowermost unit

is a finely laminated lime mudstone ("papery

limestone" of King, 1931), which overlies the

Altuda Formation. This unit is characterized by

planar, millimeter-scale laminations formed by

alternating dark organic lime mudstone and

light lime mudstone/spar lamina. The spar

layers are a few millimeters to a few centimeters thick and exhibit depositional fabrics
26 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

rv

FIGURE 2-22.—Location of STOP 2.1 and sections nearby; Bird Mountain 7.5 min. quadrangle.

analogous to nodular mosaic and chicken wire

fabric of anhydrite. The unit is devoid of any

fossils and shows localized brecciation, fracturing, and folding of the beds with subsequent

spar filling.

Overlying the "papery limestone" is sparcemented, clast supported lime mudstone

breccia. It is a massive, ledge and slopeforming, angular to subangular, nonfossiliferous breccia composed of laminated

lime mudstone. Solution and karst features are

present with lenticular pods of lime mudstone

and spar-cemented limestone conglomerates.

The breccias are interpreted to have been

deposited as alternating beds of lime mudstone

and anhydrite in an euxinic salina setting.

Climatically controlled cyclic exposure of these

beds resulted in the solution of evaporites and

the collapse of the overlying beds. The presence

of anhydrite fabric, distinct karst features, and

localized brecciation support this interpretation.

The uppermost unit of the Tessey Formation

in the Frenchman Hills consists of matrixsupported dolomudstone breccias. The clasts

are exclusively dolomudstone in a dolostone

matrix. The clasts vary in size from a few

millimeters to 4 cm. Algal laminations, fenestral fabric, and a lack of fossils suggest a

supratidal depositional setting.

To the east, the Tessey Formation disconformably overlies the Gilliam Limestone. East

of Hess Canyon the formations are separated by

a persistant sandstone at the top of the Gilliam.

West of Hess Canyon the sandstone dies out,
NUMBER 32 27

STOP 2.1 BIRD MINE

T

A

150

100

50

0

AT1-

A ^

~] r~

I i

)

)

5

Hf

\

i i i

i i

\

\

T

A

4

A

I . I

0 «W90-46

O

• W90-50 (-18.5')

• W90-49 (-27')

• W90-48 (-30')

H • W90-47 (-761)

89BM-340 (-27')

89BM-343 (-102')

• 89BM-344 (-290')

FIGURE 2-23.—Columnar sections in the Bird Mine area. (A = Altuda Formation; T = Tessey Formation; open

circles represent subsequent collections.)
28 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

[?_._ A.Ai

FIGURE 2-24.—Location of STOPS 2.2, 2.3, and 2.4; Old Blue Mountain 7.5 min. quadrangle.

and the two formations are difficult to differentiate. Southwestern (Hovey channel) exposures

are delineated by a very thinly laminated

limestone that occurs at the base of the Tessey.

The Gilliam also contains a more varied

lithology with abundant fossils in some places.

The Tessey tends to be petroliferous, and the

first occurrence of a breccia horizon marks the

transition between the Tessey and the Gilliam.

Fossils in the Tessey are sparse and consist of

poorly preserved gastropods and brachiopods.

0.2

0.1

0.2

Udden (1917) reported oolitic textures and

foraminifera; however, this description appears

to be of the Gilliam instead. Robert E. King

(1931) collected Permophorus, a pelecypod,

from the Tessey in its northern extent.

36.2 At road junction, go left.

36.3 Take dirt road to right.

36.5 Go through gate and immediately turn left, go

across creek, and continue straight along fence

line to rock quarry.
NUMBER 32 29

FIGURE 2-25.—STOP 2.2. A, View of the Tessey Formation east of Benge Ranch. Lower slope of the hill is the

Altuda Formation with "paper limestone" just below the break in the slope. B, Collapse breccia typical of the

Tessey Formation. Note the laminated clasts.
30 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

STOP 2.2 STOP 2.3

A

A

9BR-1 (-20*)

100

88R-2 (-50')

50

§o

• 2 89BR-6 (-116')

O°

• 9BR-2 (1091)

O

• W90-30 (92.51)

• 89BR-5 (-83')

88R-3 (60')

FIGURE 2-26.—Columnar sections of STOPS 2.2 and 2.3. (A = Altuda

Formation; T = Tessey Formation; open circles represent subsequent

collections.)

0.7 37.2 Park in quarry and continue by foot up jeep trail

on ridge for about 300 m, STOP 2.3. This

section (Figure 2-26) exposes some of the

youngest Guadalupian beds in the Glass Mountains and probably represents a lower slope

facies equivalent of parts of the Altuda Formation and the Capitan Limestone. The Altuda

Formation here is thin- to medium-bedded

siltstone, fine quartz sandstone, and dolomudstone to lime wacke-packstone. It exhibits vertical as well as lateral variations in 'lithology,

texture, and sedimentary structures. These

variations can be attributed to two lithologically

different, but time equivalent, slope and basin

facies.

The basinal facies is planar, thin-bedded

siltstone, fine sandstone, and dolomudstone,

with interbeds showing distinct gradation from

coarse, shallow water, normal marine bioclastic

lags to fine, hemipelagic lime-mud with calcispheres, siliceous sponge spicules, and radiolaria. The beds display convolute bedding,

flame structures (Figure 2-28), dish structures,

chert-replaced anhydrite rosettes, rippled contourites, chert nodules, and horizontal branching burrows.

The slope facies includes interfingering Altuda Formation with the large foreset beds of

the Capitan Limestone. The slope facies of the

Altuda Formation contains features typical of

subaqueous gravity flows, such as slump

structures, ball and pillow structures, and

recumbent folds outlined by chert. In Old Blue

Mountain, several Capitan foresets are mappable (Figure 2-29). The individual foresets are

composed of brecciated dolomudstone with

spar-filled vugs and fractures and rare skeletal

debris. The base of each foreset is wavy with

sandstone and siltstone clasts of millimeter to

centimeter size. Their lower and upper contacts

with the Altuda Formation pinch and swell,

implying that these foresets were deposited as

prograding tongues of debris flows off of the

shelf. The foresets generally taper towards the

basin and die out. Locally, the slope facies

contain large, slightly rotated slump blocks

displaying similar lithologic characteristics to

that of the Capitan foresets. On the southwestern slope of Old Blue Mountain, a 15 m wide

bioclastic wacke-packstone slide block is surrounded by siltstone and fine sandstone of the

Altuda Formation. The basal part of the block

contains rounded to subrounded lithoclasts of

yellowish sandstone varying in diameter from 5

to 10 cm. The geopetal fabric does not indicate

any overturning or rotation.

Present in the limestone beds exposed on the

jeep trail above the quarry are the small
NUMBER 32 31

FIGURE 2-27.—Features associated with the Tessey Formation. 1, Planar laminated mudstone facies in the

Frenchman Hills. Note the alternating dark organic-rich mudstone and light spar layers. Hammer head is on

nodular mosaic fabric after anhydrite. 2, Calcite nodular fabric after precursor anhydrite within the middle facies.

3, Clast-supported breccia. Note the localized brecciation of laminated clasts. 4, Folding within the planar

laminated mudstone facies. 5, Clast-supported, spar-cemented breccia. Note the spar-filled fractures. 6,

Clast-supported conglomerate pod composed of limestone and chert clasts. These conglomerates are laterally

discontinous and are interpreted as indicators of subaerial exposure.

fusulinids Paraboultonia (Wilde, pers. comm.,

1990), and Lantschichites {- Paraboultonia)

(Yang, pers. comm., 1990), brachiopods, and

poorly preserved ammonoids. See Wilde and

Rudine (this volume) and Yang and Yancey

(this volume) for more detailed descriptions of

the fusulinids. Wardlaw (this volume) identified the conodonts Mesogondolella postserrata, M. shannoni, and M. altudaensis from

these beds.

The fossils listed above indicate a correlation

with the Lamar Member of the Bell Canyon or

post-Lamar Guadalupian according to Wilde

(1990). At the top of the hill is the Tessey

Formation. Separating the Altuda from the

Tessey breccias is a distinctive, dark gray,
32 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 2-28.—Bedforms displayed by slope facies. 1, Recumbent folding outlined by chert layers within Capitan

foreset beds. Hammer head is parallel to the subaqueous gravity flow direction. Note lower wavy contact with

dolomudstones of the Altuda Formation. 2, Allochthonous slump block of Capitan Limestone within the Altuda

Formation in the slope facies. The block contains sandstone lithoclasts. 3, Drag folding in thin-bedded siliciclastic

dolomudstones of the Altuda Formation caused by an overriding debris flow of Capitan foreset. 4, Soft sediment

deformation outlined by chert layers in the sandstone beds of the Altuda Formation (scale on the right in

centimeters). 5, Gypsum crystal casts in the planar, thin-bedded siltstone basinal facies of the Altuda Formation

(lens cap is 6 cm). 6, Thin planar bed of the Altuda Formation displaying several turbidite units. The base of each

turbidite unit is wavy, followed by a coarse bioclastic lag composed of shelf derived-fauna, and grades upward

into laminated silty mudstone with abundant sponge spicules, calcispheres, and radiolaria.

finely laminated lime mudstone, which King

(1931) called his "papery limestone." This unit

is generally only a few feet thick, but it was

reported by King (1931) to occur extensively in

the western Glass Mountains.

The Tessey Formation capping this hill (and

the Frenchman Hills to the west) consists of

massive carbonate breccias and conglomerate.

The Tessey in this area is interpreted to be

collapse breccias of late basin-filling stage,

probably equivalent to the Castile or Rustler in

the Delaware basin. The difference in lithology

is thought to be due to the proximity to the

southern entrance of the Delaware basin
NUMBER 32 33

FIGURE 2-29.—View of the northeast side of Old Blue Mountain that displays a series of foresets prograding to

the northwest. Benge Ranch is off of photo to the right.

(Hovey channel), which was becoming increasingly restricted during late Guadalupian and

Dzhulfian time. This is supported by the

presence of more limestone-rich conglomerates

to the south at Bird Mountain (Rudine, pers.

comm., 1990) and the transition to more

evaporitic facies to the north in the subsurface.

0.5 37.7 Backtrack to stream crossing, and turn left just

before stream.

1.2 38.9 Make sharp left turn onto road heading for

saddle.

0.7 39.6 Drive into saddle and park near deer feeder and

deer-hunting tower, STOP 2.4. The taller hill to

the east is an extension of Old Blue Mountain.

The lower hill to the west of the saddle is

Tessey breccia. Walk up the gully to the east,

which exposes Altuda siltstones and foresets of

Capitan carbonate, to the first large resistant

carbonate ledge (Figures 2-30, 2-31).

The cliffy ledge of carbonate to the left of the

gully is part of the Capitan foreset, which is

exposed across the hillside. The foreset is

dipping westward. The outcrop illustrates several features of foresets, including massively

bedded dolomicrites, channeling, and disturbed

thin bedding (Figure 2-31). Some evaporite

casts are present, as well as rare bioclastic beds

with brachiopods. These beds are interpreted to

be lower foresets of the Capitan interbedded

with siltstones that are also being shed off of the

shelf edge, which has at least 200 m of relief.

Penecontemporaneous slumping and folding of

carbonate beds is relatively common. The basin

margin at this location is oriented north-south.

Acknowledgments

We are grateful to those land owners who allowed us access

to their ranches to study the Permian rocks over the last 10

years. We are also grateful to those ranchers who allowed us on

their land for this field conference, including Mr. and Mrs. Mac

Benge, Mr. William Blakemore, and the Woodward family.

Research by those associated with Sul Ross State University

was supported by the Petroleum Research Fund of the

American Chemical Society and by the Sul Ross Research

Enhancement Fund. The Smithsonian Institution provided

collaborative research funds to Grant and Wardlaw for the last

decade, and the U.S. Geological Survey supported the

collaboration of Wardlaw with Rohr and many Sul Ross State

students.
34 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 2-30 (above).—View of hill north of Old Blue Mountain displaying

foreset. STOP 2.4 is located just left of major arroyo cutting foreset (ledge).

FIGURE 2-31 (left).—STOP 2.4. Close-up of foreset exposure. The lower half of

the photograph shows a foreset tongue, or channel, of recrystallized calcitic

dolomudstone bearing clasts of skeletal dolomudstone, which overlies thin,

load-deformed beds of dolomudstone. The upper surface is truncated by thin,

foreset beds of dolomudstone.
NUMBER 32 35

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Bulletin, 1881-A:A1-A14.

Wardlaw, B.R., and R.E. Grant

1990. Conodont Biostratigraphy of the Permian Road Canyon Formation,

Glass Mountains, Texas. United States Geological Survey Bulletin,

1895-A:A1-A18,plates 1-4.

Wilcox, R.E., W. Langston, Jr., and S.C. Good

1986. The Non-Marine Bissett Formation of the Western Glass Mountains,

Trans-Pecos Texas: Evidence for an Early Cretaceous (Neocomian?-

Albian) Age. [Abstract.] Geological Society of America, Abstracts

with Programs, 17:272.

Wilcox, R.E., and D.M. Rohr

1987. The Stratigraphy and Depositional Systems of the Bissett Formation;

an Early Cretaceous Alluvial Fan-Lacustrine Complex, Glass

Mountains, Trans-Pecos, Texas. [Abstract.] Geological Society of

America, Abstracts with Programs, 18:788.

Wilde, G.L.

1990. Practical Fusulinid Zonation: The Species Concept; with Permian

Basin Emphasis. West Texas Geological Society, Bulletin, 29(7):

5-34.

Yochelson, E.L.

1956. Permian Gastropoda of the Southwestern United States, 1: Euomphalacea, Trochonematacea, Pseudophoracea, Anomphalacea, Craspedostomatacea, and Platyceratacea. Bulletin of the American Museum

of Natural History, 110:177-275.

1960. Permian Gastropoda of the Southwestern United States, 3: Bellerophontacea and Patellacea. Bulletin of the American Museum of

Natural History, 119:209-293.
3. Guadalupian Conodont Biostratigraphy

of the Glass and Del Norte Mountains

Bruce R. Wardlaw

ABSTRACT

The Guadalupian Series in the Glass and Del Norte mountains is

divided into five conodont zones. One zone, Mesogondolella

nankingensis, is divided into two subzones; the subzone boundary

nearly coincides with the Roadian-Wordian stage boundary as

perceived by Glenister et. al. (1992). The base of the Guadalupian is

easily defined by the evolutionary transition from Mesogondolella

idahoensis to M. nankingensis (Grant and Wardlaw, 1986; Lambert

and Wardlaw, 1992; Lambert et al., this volume).

The depositional setting of the majority of the rocks found in the

Glass and Del Norte mountains is that of a foreland basin, with the

clastic sediments derived from the Marathon Fold Belt and the

carbonate and carbonate debris derived from a shoal formed on the

geanticline between the foreland basin and the "deep" Delaware basin

depositional complex.

The taxonomy of the many serrated Mesogondolella species is

clarified, and several species are synonomized. New species described

are Sweetina crofti, Hindeodus wordensis, Iranognathus punctatus,

and Sweetognathus bicarinum.

Introduction

Shortly after Cooper and Grant (1972, 1974, 1975, 1976a,b,

1977) finished publishing their monographs on the Permian

brachiopods of West Texas, Richard E. Grant and I started a

project to describe in detail the conodont biostratigraphy, with

special reference to the incredibly diverse brachiopod localities

in the Glass Mountains. Our first year in the field was 1981, and

one or both of us has not missed a field season since. David M.

Bruce R. Wardlaw, U.S. Geological Survey, 926A National Center,

Reston, Virginia 20192.

Rohr had just become a professor at the small, nearby

university (Sul Ross State), and much of this work and that of

this volume evolved from the special relationship developed

with the Sul Ross State University Geology Department and,

specifically, with David Rohr and his students. I have

suggested many topics and have worked alongside many

students, and our thoughts and work have intermingled so that

it is now difficult to identify where individual ideas began. This

spirit of cooperation has expanded to most other workers in the

field, including those that still do not agree with our

interpretations of the biostratigraphy of this region. This

volume, and in particular this article, is dedicated to that spirit

of cooperation in our quest to unravel the complex history of

the Permian of West Texas.

Brief descriptions of the general depositional setting (based

on my interpretations) and of conodont biostratigraphic

distribution are presented first. This is followed by a revision of

conodont systematics, which comprises the bulk of this paper.

All figured conodont specimens are reposited at the National

Museum of Natural History, formerly the United States

National Museum (USNM). Unfigured specimens are retained

in the conodont collections at the U.S. Geological Survey in

Reston, Virginia.

GENERAL DEPOSITIONAL SETTING

The outcrop belt of the Permian rocks in the Glass and Del

Norte mountains does not intersect depositional strike as

clearly as it does in the Guadalupe Mountains. Instead, it

parallels depositional strike, for the most part. The general

Permian deposition can be summarized in two north-south

schematics: one for the Glass Mountains (Figure 3-1) and one

for the Del Norte Mountains (Figure 3-2). Deposition for each

schematic transect can be generalized into three broad

depositional regimes (trending from south to north): foreland

basin, shoal, and Delaware basin (Hovey and Sheffield

channels). Deposition in the Delaware basin is dominated by

37
38 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

LITHIC SYMBOLS

COLLAPSE BRECCIA

p=a EVAPORITIC CLASTICS

1

 ' AND CARBONATES

[=T=| RECRYSTALIZED LIMESTONE

OR DOLOMITE

$PB CONGLOMERATE

p—I LIMESTONE WITH LARGE

^

J=^ REEF DEBRIS

Wfc SKELETAL LIMESTONE ^

I I SILTSTONE

SANDSTONE

APPEL RANCH MEMBER

SILTSTONES OF THE

CATHEDRAL MOUNTAIN

FORMATION

LENOX HILLS FORMATION - ^

FORMATION

FIGURE 3-1.—Schematic north-south transect through the central Glass Mountains, West Texas, showing the

stratigraphic relationships of Permian formations.

siltstone turbidites with rare limestone (skeletal lime mudstone)

throughout the Permian. Carbonate appears more common in

the basin during deposition of the Hess Formation (Leonardian)

and the Capitan Limestone (Capitanian) on the shoal, implying

more carbonate shedding. Deposition in the foreland basin is

dominated by coarse conglomerate in the Lower Permian and

siltstone and mudstone in the middle Permian. During the

Wolfcampian and Leonardian, conglomerate represents shoreward deposition of fan- and braid-deltas (Rudine, 1988;

Coombs, 1990; Wardlaw et al., 1990). Conglomeratic deposition commonly swamped the whole foreland basin and

infringed on the shoal. Carbonate, conglomeratic carbonate,

conglomerate, and siltstone were deposited on the shoal in both

schematic transects during the Wolfcampian, and this process

continued into the Leonardian in the Del Norte Mountains. In

the Glass Mountains during the early Leonardian, shoal

deposition is represented by dolomitic and silty lime mudstone

of the Hess Formation. Skeletal and conglomeratic wackestones, packstones, and rudstones shed from the shoal and/or

deposited on the shoal flanks into the foreland basin represent

the Skinner Ranch Formation. Conglomerate deposition was

still widespread through the Cathedral Mountain deposition in

the foreland basin along the Del Norte schematic transect.

Sandstone, containing some conglomerate and generally

capped by conglomerate, dominated deposition of the Cathedral Mountain Formation in the Del Norte Mountains.

Common channeliform limestones, laterally discontinuous,

also occur. In the Glass Mountain schematic transect, the

Cathedral Mountain Formation is dominantly represented by

siltstone. Carbonate, richly skeletal, is limited to a narrow part

of the shoal and is commonly interbedded with siltstone. The

foreland basin appears to have been largely filled in with

siltstone during this time.

The Guadalupian was deposited on top of this accumulation

of the Permian, thus continuing the general depositional

setting. The Road Canyon Formation is represented by
NUMBER 32 39

FIGURE 3-2.—Schematic north-south transect through the northern part of the Del Norte Mountains, West Texas,

showing the stratigraphic relationships of Permian formations.

extensive channeliform, skeletal, sparsely conglomeratic limestones separated by sandstone and siltstone in the Del Norte

Mountains in both the shoal area and the foreland basin,

perhaps indicating a cessation of significant differentiation of

the two sedimentary regimes. In the Glass Mountains, the Road

Canyon is represented by a series of conglomeratic to skeletal

limestones separated by siltstones deposited on the flank of the

shoal. Foreland basin deposition is characterized by pelloidal

packstone (marginal to the shoal) and siltstone. The shoal facies

is rarely discernible, but it is characterized by bioturbated lime

mudstone to wackestone cut by several skeletal packstone to

grainstone channels. This depositional sequence continues

upward through the entire Word Formation where the shoal

facies becomes more common, more recrystallized and

dolomitized, and the siltstone becomes finer, changing to

mudstone. In contrast, in the Del Norte Mountains, following

Road Canyon deposition, the foreland basin is filled with

siltstone with scattered channeliform skeletal limestones, rarely

conglomeratic, followed by the shoal and foreland basin being

covered by a blanket delta/delta front sand. The foreland basin

is dominated by siltstone deposition following the blanket sand

deposition. The upper limestone of the Willis Ranch Member

extends across most of the basin as channeliform carbonates

and thin skeletal beds interbedded with siltstone and sandstone,

and this interrupts the siltstone deposition in the foreland basin.

The upper part of the Word Formation is represented by sand

deposition on the shoal and silt deposition in the foreland basin.

Within the basin, the Appel Ranch Member is represented by

siltstone and numerous carbonate masses that appear to have

been shed from a carbonate shoal that is now eroded away.

The Vidrio Formation is found only along the shoal and

flanks to the foreland basin in both the Del Norte Mountains

and Glass Mountains transects and is represented by extensive

carbonate buildup that has been heavily recrystallized and

dolomitized. This strongly suggests repeated subaerial exposure and shallow deposition. A limey siltstone divides the

Vidrio in the middle of the Glass Mountains (Figure 3-3),

suggesting deposition similar to the upper part of the Appel

Ranch Member of the Word Formation, but on a much more

extensive carbonate shoal. The Vidrio is also everywhere

unconformably bounded.
40 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

500-

r300

-200

-100

FIGURE 3-3.—Interpretative diagram of formations in a general east-west transect in sedimentary packages, true

thickness, and true distance from the first stratigraphic section (A) 12PW, displaying conodont ranges and

zonation. Letters represent stratigraphic sections from A to Ii (listed below). Numbers represent all recognized

conodont species (same as Table 3-1).

A = 12PW

B = Word I

C = 9AR

D = Upper Hess Canyon

E = AR I (Middle Hess Canyon)

F = Lower Hess Canyon

G = ARIII

H = RCX

I = Little Blue Mountain

J= 10AR

K = AR II

L = BRII

M = RC VII

N = 10 (Wardlaw and Rudine)

0 = 9 (Wardlaw and Rudine) & WR III

P = RCI

Q = RC II

R = 8 (Wardlaw and Rudine) & WR IV

S = 7 (Wardlaw and Rudine)

T = Word II

U = RCV

V = RC VI

W = RC III

X = RC IV

Y = RC IX

Z = RC XIV

Aa = RC XV

Bb = RC XVI

Cc = SEC III

Dd = SEC VI

Ee = DAV III

Ff=DAVIV

Gg = AL 1

Hh = AL 2

Ii = AL 3

In the Del Norte Montains transect, the Vidrio Formation is

overlain by the Altuda Formation. The Altuda thickens and

develops more flow features and soft-sediment deformation

northward, suggesting a change from shelf to slope deposition

in a northern direction. In the Glass Mountain transect, the

Gilliam Limestone, dominated by limey sandstones in its lower

part, was deposited in the foreland basin and on the shoreward

side of the shoal. The Altuda Formation, dominated by

carbonates and limey siltstones, was deposited on the basinward side of the shoal and into the Delaware basin. Either the

Altuda or Gilliam overlies the Vidrio Formation in the Glass

Mountains, indicating that the lower parts of both formations
NUMBER 32 41

are laterally equivalent. In the Glass Mountains, the Capitan

Limestone developed on the shoal after deposition of unit 1 of

the Altuda Formation (of Wardlaw and Rudine, this volume),

which everywhere underlies the Capitan. The upper part of the

Gilliam Limestone, represented by pisolitic limestones, evaporitic siltstones, and sandstone replete with tepee structures, is

deposited in the foreland basin. Foresets of the Capitan

Limestone interfinger with the upper part of the Altuda

Formation on the basinward side of the shoal, and deposits

from the upper part of the Altuda are on the slope and in the

Delaware basin. A thin finger of the Gilliam appears to overlie

the Capitan in a few sections. No Capitan Limestone (as

currently defined) has been found in the Del Norte Mountains,

as was suspected to be the case. Three informal units of the

Altuda Formation (Wardlaw and Rudine, this volume) are

found over its entire extent in the Del Norte Mountains, which

indicates that Altuda deposition continued on the shoal/

foreland basin, whereas it had ended on the shoal in the Glass

Mountains and was restricted to just the foreslope and basin. It

is unknown what, if anything, was deposited above the third

unit of the Altuda in the southern part of the Del Nortes as

erosion has destroyed any evidence of deposition. Additional

units of the Altuda are found in the northern part (slope

deposition) of the Del Norte Mountains.

BlOSTRATIGRAPHY

Because the nature of outcrops in the Glass and Del Norte

mountains is one of cuestas commonly capped by carbonate

and because the intervening valleys are dominated by poorly

exposed siltstone and mudstone, complete long sections are

difficult to find and measure. The measured sections are pieced

together from several good, but relatively short, exposures. To

understand the stratigraphic zonation of conodont species, each

section was graphically correlated to standardize their relative

distributions. The methodology used is that of Shaw (1964) and

Edwards (1984). The data used is the presence-absence data in

the distribution table (Appendix 3-1). Table 3-1 lists the

composite ranges for each species recognized for this study.

Five conodont zones, based on the range zones of Mesogondolella species, are recognized in the Guadalupian. These are the

Transition Zone (transitional morphotype between M. idahoensis and M. nankingensis), the M. nankingensis Zone, the M.

aserrata Zone, the M. postserrata Zone, and the M. shannoni

Zone. An overlying, post-Guadalupian zone is suggested by the

occurrence of M. altudaensis Kozur. In addition, an underlying

zone, the M. idahoensis-N. sulcoplicatus Zone (Wardlaw and

Grant, 1987), is represented at a few places in the very base of

the Road Canyon Formation. The M. nankingensis zone can be

subdivided into two subzones based on the "synchronous" first

occurrences of Sweetina triticum Wardlaw and Collinson and

Hindeodus wordensis, new species, within the upper part of the

range of Mesogondolella nankingensis (Ching). Sweetina

festiva (Bender and Stoppel), and Hindeodus excavatus

TABLE 3-1.—Composite ranges of conodont species (in meters).

Species Range

1. Sweetina festiva

1. Sweetina triticum

3. Sweetina crofti

4. Mesogondolella idahoensis

5. Mesogondolella idahoensis-nankingensis

transition

6. Mesogondolella nankingensis

7. Mesogondolella aserrata

8. Mesogondolella postserrata

9. Mesogondolella shannoni

10. Mesogondolella altudaensis

11. Xaniognathus abstractus

12. Xaniognathus hydraensis

13. Hindeodus excavatus

14. Hindeodus wordensis

15. Diplognathodus?

16. Diplognathodus sp.

17. Iranognathus aff. /. punctatus

18. Pseudohindeodus ramovsi

19. Neostreptognathodus clinei

20. Neostreptognathodus sulcoplicatus

21. Neostreptognathodus newelli

22. Sweetognathus bicarinum

23. Reworked Ordovician-Permian Conodonts

0.15-74.75

55.84-236.14

210.00-290.18

-29.20-2.29

0.15-22.10

13.47-128.03

136.07-223.79

210.00-288.08

272.96-290.18

290.18-292.09

-29.20-236.14

210.00-290.18

0.00-82.45

55.84-290.18

280.07-290.18

22.10-272.96

279.92

0.15-280.07

-27.22-153.60

11.94-13.47

13.47-14.66

0.15-162.46

113.24-123.40

(Behnken) are common within the lower part of the range of M.

nankingensis. These subzones are referred to as A (lower) and

B (upper).

The base of the Transition Zone occurs at or near the base of

the Road Canyon Formation. The base of the M. nankingensis

A Zone occurs within the lower third of the Road Canyon

Formation, near the base of cycle 2 (Wardlaw, Ross, and Grant,

this volume). The base of the M. nankingensis B Zone occurs at

the base of the China Tank Member of the Word Formation and

its equivalents (base of cycle 5 of Wardlaw, Ross, and Grant,

this volume). The base of the M. aserrata Zone occurs just

above the top of the Willis Ranch Member of the Word

Formation. The base of the M. postserrata Zone occurs within

the lower part of the Altuda Formation (within unit 2 of

Wardlaw and Rudine, this volume) and the lower part of the

Gilliam Limestone. The base of the M. shannoni Zone occurs in

the upper part of the Altuda Formation (within unit 5 of

Wardlaw and Rudine, this volume) and the upper part of the

Capitan Limestone. The M. altudaensis Zone occurs at the

uppermost beds of the Altuda Formation. It appears that M.

shannoni Wardlaw may represent a short-lived transitional

morphotype and zone between M. postserrata (Behnken) and

M. altudaensis.

Reworked conodonts are common in a few samples from the

upper part of the Willis Ranch Member of the Word Formation

(upper part of the M. nankingensis B Zone) and may indicate

the last significant tectonic signal from the Marathon Orogenic

belt in the Permian in the Glass and Del Norte mountains.
42 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Systematics

Phylum CONODONTA Pander, 1856

Class CONODONTI Branson, 1938

Order PRIONIODINIDA Sweet, 1988

Family ELLISONIIDAE Clark, 1972

Sweetina Wardlaw and Collinson, 1986

Sweetina was established for common ellisoniid ramiform

elements that occur in the Lower and middle Permian. The

apparatus is very similar to Merrillina and Stepanovites. Kozur

(1975) named the type species of Stepanovites, S. meyeni,

based on a partial apparatus. The apparatuses for Sweetina and

Merrillina have been described by Wardlaw and Collinson

(1986). In large collections, Stepanovites does not display the

diagnostic Pa element of either Sweetina or Merrillina (Kozur,

pers. comm., 1993) but appears to be like Ellisonia with two

digyrate elements in its apparatus.

Sweetina crofti, new species

PLATE 3-4: FIGURES 14-23

DIAGNOSIS.—Characterized by a Pa element with a short,

posteriorly directed lateral process bearing 0-1 denticle.

DESCRIPTION.—The Pa element is pastinate and arched. A

posteriorly directed lateral process emerges from the outside of

the cusp. The cusp is fairly large and recurved. The denticles on

the anterior process of the cusp are evenly spaced; of nearly

equal size, about half the size of the cusp, but decrease slightly

anteriorly; and generally number just two or three. The

denticles on the posterior process alternate in size, either

minuscule or large, and generally there are at least two of each

size. The lateral process bears either no denticle or one poorly

developed denticle. The lower side has a groove under each

process that merges with a triangular basal cavity under the

cusp.

The Pb element is similar to the Pa element, except it lacks

the lateral process and is oriented in the opposite direction (i.e.,

the anterior process of the Pb is more like the posterior process

of the Pa). The cusp is slightly longer than the closest large

denticles. The anterior process is downturned with a slight

distal inflection or upturning. It bears three to six denticles,

alternating thin and thick anterior to the first denticle next to the

cusp, which is thick and nearly as large as the cusp. The

denticles generally decline in height distally. The posterior

process bears four to six denticles. The first denticle is

definitely thinner and shorter than the cusp. The next two

denticles are thick and relatively long; additional denticles

decline in size distally. The lower side has a prominent groove

and a small zone of recessive attachment surface.

The Sa element is alate and bears a large cusp, short lateral

processes, and a long posterior process. Each lateral process

bears two to four denticles, depending on the size of the

element, that decrease in size distally. The cusp is long and

strongly recurved. Thin costae are directed to the top of each

denticle, which are generally worn and not apparent. The

denticles on the posterior process alternate in size, either

minuscule or large, and are widely spaced immediately behind

the cusp, becoming regularly spaced, but not compressed, after

the second or third large denticle. Minuscule denticles on the

posterior half of process commonly are overgrown and barely

noticeable on larger specimens. The lower side is characterized

by a large groove under each process and a zone of recessive

attachment surface along the lateral sides of each process.

The Sb element has a large recurved cusp, an inward directed

anterior-lateral process, and a long somewhat curved posterior

process. The anterior-lateral process bears two to four denticles,

decreasing in size distally. The posterior process bears many

slightly compressed denticles; small thin denticles are sporadically preserved between the larger denticles. The lower surface

is similar to the Sa element.

The Sc element has a large recurved cusp and a short anterior

process that is directed slightly laterally; the process is straight

to upturned. Sc elements are common but usually only as

fragments. The denticulation of the Sc element is very similar

to that of the Sa, with the anterior processes of the Sc

comparing to the lateral processes of the Sa and with the

posterior processes of both elements virtually the same. The

lower surface of the Sc element is also similar to that of the Sa

element.

The M element is digyrate and has a large reclined cusp, two

short lateral processes, and a large flared basal cavity. The

processes are denticulate, bearing one to three small to

medium-sized denticles. The lower surface has a pronounced

groove under each process.

TYPE SPECIMEN.—USNM 482636, Plate 3-4: Figure 20.

OCCURRENCE.—Sweetina crofti is common to the Capitanian rocks of the Permian basin (West Texas and New

Mexico) and Wuchiapinian rocks of South China.

REMARKS.—Sweetina crofti differs from S.festiva by having

a much less developed lateral process on the Pa element and

having more small denticles between large denticles on the

anterior and posterior processes. It is like S. triticum in having

a reduced lateral process, but S. triticum has many more small

denticles between large denticles on each process. The anterior

process of both S. triticum and S.festiva are much longer than

S. crofti.

Sweetina/estiva (Bender and Stoppel)

PLATE 3-12: FIGURES 6-8

Lonchodinafestiva Bender and Stoppel, 1965:345-346, pi. 15: figs. 9, 10.

Stepanovites festiva (Bender and Stoppel).—Kozur, 1975:23; 1978, pi. 5: fig.

29.—Kozur and Movschovitsch in Movschovitsch et al., 1979:119, pi. 4:

figs. 1,2.

Sweetina festiva (Bender and Stoppel).—Wardlaw and Collinson, 1986:138.
NUMBER 32 43

DIAGNOSIS.—Characterized by a Pa element with a large

lateral process bearing 2-5 large denticles.

REMARKS.—Typically, S./estiva has only one small denticle

anterior to the cusp.

Sweetina triticum Wardlaw and Collinson

PLATE 3-12: FIGURE 9

Sweetina triticum Wardlaw and Collinson, 1986:135, fig. 20.

DIAGNOSIS.—Characterized by a Pa element with a short

lateral process generally bearing 1 or 2 denticles of variable

size.

REMARKS.—When broken, the Pa element looks similar to

that of S. crofti (see Plate 3-4: Figure 19), but the lateral process

is more laterally directed and the break shows a much larger

process than is typical for S. crofti.

Family GONDOLELLIDAE Linstrom, 1970

Mesogondolella Kozur, 1989

Kozur (1989) established the genus Mesogondolella, although he (Kozur, 1989) refered to an abstract (Kozur, 1988) as

the citation. Clearly, Permian gondolellids are different from

Triassic ones, and this has been common knowledge since

Clark and Mosher (1966) demonstrated the distinctive bottom

features of Permian and Triassic gondolellids. There is also a

hiatus between the last of the Permian forms and the first of the

Triassic forms (true Neogondolella), suggesting a new name is

needed. The differentiation of the two genera of Permian

gondolellids recognized by Kozur (1989), Mesogondolella and

Clarkina, is less clear but is provisionally accepted herein

pending more detailed work and better definition. The

suspicion is that cool-water faunas, exemplified by Clarkina?

bitteri Wardlaw and Collinson, gave rise to most Late Permian

gondolellids, and they can be differentiated from Mesogondolella on the basis of bottom features, including a more complex

basal pit and loop along with the presence of a free blade (the

difference cited by Kozur, 1989). Nevertheless, all the forms

recognized herein from the Permian of West Texas belong to

the genus Mesogondolella.

The succession of Mesogondolella species generally show

transitional forms for a short interval between species. The

transitional form between M. idahoensis and M. nankingensis

was described by Lambert and Wardlaw (1992) and persists for

a significant, though short, stratigraphic interval. The transitional forms from M. aserrata to M. postserrata and M.

postserrata to M. shannoni appear to be much shorter lived.

They are illustrated and described herein, but they are not given

specific recognition. Mesogondolella^ of the "serrata" complex (Clark and Behnken, 1979) appear to have evolved from

species to species through transitional forms that combined the

features diagnostic for predecessor and successor. Lambert and

Wardlaw (1992) described the evolution of the transitional

form from M. idahoensis to M. nankingensis (= M. serrata) as

a heterochronic process of neoteny that produced progressive

juvenilization.

Clark and Behnken (1979) described several species that are

not recognized. These species were established on visual

determination of symmetry (aserrata, postserrata, babcocki,

wilcoxi), or preservation (denticulata), or on the presence of a

split carina (rosenkrantzi). Split carinae occur in all examined

samples of abundant Mesogondolella, Clarkina, and Neogondolella from the Early Pennsylvanian to the Late Triassic at a

frequency of about 2%-5% in each sample. It is not a useful

species determiner, and the topotypes of M. rosenkrantzi (= M.

phosphoriensis) commonly do not display this feature at a

different frequency (for examples of types and topotypes see

Bender and Stoppel, 1965; Sweet, 1976; Wardlaw and

Collinson, 1979). The pristine preservation of the denticles of

the carina, a rare occurence as they are commonly abraded or

worn in most specimens, is also a poor species determiner of no

stratigraphic utility or biologic basis.

Clark and Behnken (1979:265, fig. 2) devised a visual

determination of symmetry that at best is tenuous. The platform

of species of the "serrata" complex is variable. The platform

normally has different widths on each side of the carina, rarely

forms a brim around the posterior cusp, and commonly

terminates at unequal positions on each side of the cusp. The

cusp is commonly directed laterally. A nonqualified or

unsystematic measure for symmetry could be very misleading.

For instance, 1,000 whole specimens of M. postserrata were

tallied from one sample of the Rader Limestone Member of the

Bell Canyon Formation using the symmetry diagram of Clark

and Behnken (1979, fig. 2). Four categories were counted:

symmetric elements, asymmetric elements with symmetrically

placed cusp, sinistral elements, and dextral elements, which

yielded 8, 6,494, and 492 for each category, respectively. That

is, at best, 1.4% symmetrical for a unit that Clark and Behnken

reported 22% (1979, table 1) symmetrical elements. The

methodology, which is questionable, is unreproducable, and

therefore invalid. What is interesting is the 50 : 50 division of

sinistral and dextral elements that was obtained from both

Clark and Behnken's data (1979) and the above tallies. If all

asymmetric aspects are considered, the percentage of symmetric elements (those not placed in sinistral or dextral categories)

ranges from 0.8% to 6.7%. In the case of the 1,000 elements

counted from the Rader, 49.7% are sinistral and 49.5% are

dextral. It appears Mesogondolella postserrata occurs as a pair

of sinistral and dextral Pa elements. Croft (1978, pi. 3: figs. 1,

2) recovered one such pair fused together in his material from

the Bell Canyon Formation. The species Mesogondolella

aserrata (see below) and M. wilcoxi (= serrated morphotype of

Clarkina bitteri, Wardlaw and Collinson, 1979) can be

differentiated on other criteria, so they are retained and

redefined.

Mesogondolella, Clarkina, Gondolella, and Xaniognathus

all have similar apparatuses. Mesogondolella and Clarkina
44 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

generally lose their apparatuses through growth and can be

treated as a paired Pa element in species determinations.

Xaniognathus, the successor of "nude" Gondolella species, has

an apparatus that is the same as Gondolella and does not occur

in studied collections below the late Wolfcampian. Mesogondolella probably derived from Idioprioniodus in the late

Morrowan, although no direct predecessor is clear. It occasionally occurs with an apparatus that can be differentiated from

that of Gondolella or Xaniognathus, although it is similar.

Xaniognathus is included as the apparatus of Mesogondolella

and Clarkina by many workers, and this may be due to the lack

of detailed work or descriptions.

Finally, the examination of the two extant topotypes of M.

nankingensis, which were part of the paradigm for the species

concept, leads one to conclude that M. serrata and M.

nankingensis are one in the same and coincident in time;

therefore, M. nankingensis has priority, and the commonly used

M. serrata is a junior synonym. Lambert and Wardlaw (in

prep.) attempt to demonstrate this with their morphometrics to

distinguish species.

Mesogondolella idahoensis (Youngquist, Hawley,

and Miller), new combination

PLATE 3-10: FIGURES 1-3

Gondolella idahoensis Youngquist, Hawley, and Miller, 1951:361, pi. 54: figs.

1-3, 14, 15.—Clark and Ethington, 1962:108, figs. 15, 16.—Clark and

Mosher, 1966:388, pi. 47: figs. 9-12.—Clark and Behnken, 1971:431, pi. 1:

fig. 9.

Neogondolella idahoensis (Youngquist, Hawley, and Miller).—Behnken,

1975:306-307, pi. 1: figs. 28-30.—Wang, 1978:220-221, pi. 2: figs.

23-26.—Igo, 1981:38, pi. 1: figs. 11-13, 15, 16.

Gondolella phosphoriensis Youngquist, Hawley, and Miller, 1951:362, pi. 54:

figs. 27, 28 [in part].—Clark and Ethington, 1962:108, pi. 2: figs. 17, 18.

DIAGNOSIS.—Platform (Pa element) of moderate width,

gradually narrowing in the anterior two-thirds of length, and

with a blunt, squared posterior platform margin. Cusp

moderately large, prominent, circular in cross section; denticles

generally increase in size anteriorly, except for anterior one or

two; furrows well-developed. Lower side with a simple loop

around posterior of slit-like basal pit, loop terminal on posterior

of lower attachment surface; lower attachment surface a

moderate-sized V-shaped impression posteriorly, becoming

either a narrow V-shaped impression anteriorly (Plate 3-10:

Figure 1), an inverted elevated scar anteriorly (Plate 3-10:

Figure 2), or a slightly elevated keel in anterior one-fourth of

element (Plate 3-10: Figure 3).

REMARKS.—Mesogondolella idahoensis can be distinguished from M. zsuzsannae (Kozur) by its more blunt

posterior platform termination, larger, more robust cusp, more

parallel-sided margins, different denticulation pattern (M

zsuzsannae has at least one smaller denticle in the middle of the

posterior carina, whereas denticles on M. idahoensis increase in

size anteriorly), more fused carina, and generally lacks a

distinct buttress. Mesogondolella idahoensis differs from the

transitional form to M. nankingensis by not having serrations in

small forms or showing the faint overgrown serrations along

the furrow in large specimens as does the transitional form.

Morphological Transition from Mesogondolella idahoensis

to Mesogondolella nankingensis

PLATE 3-2: FIGURES 38, 39; PLATE 3-10: FIGURES 4-7

Morphological transition from Mesogondolella idahoensis to Mesogondolella

nankingensis, Lambert and Wardlaw, 1992:879-880.

DIAGNOSIS.—Platform (Pa element) displaying characters

transitional between M. idahoensis and M. nankingensis, the

most striking being appearance of serrations in small specimens. In large specimens, serrations initially masked at

margins, leaving faint relict serrations adjacent to furrows;

serrations eventually fully masked beneath successive growth

laminae. In stratigraphically higher samples, moderate-sized

specimens displaying faint serrations; on small specimens

serrations better defined. Incrementally increasing pattern of

serration carried progressively later through ontogeny with

increasingly younger faunas, until pronounced serrations

distinctly visible in side view as notches cut into anterior

platform margins. Notches not discernible from this perspective on earlier transitional forms. In lower view, broad, flat, and

commonly recessed basal attachment surface of large specimens of Mesogondolella idahoensis becoming narrower and

developing a consistently elevated keel through transition. In

large specimens of M. idahoensis, fused anteriormost denticles

of carina separate, becoming discrete during the transition, a

character of both M. nankingensis and small specimens of M.

idahoensis. Cusp subtly migrates posterolaterally, becoming

less pronounced.

All these characters can be seen to have evolved through a

mosaic heterochronic paedomorphocline.

REMARKS.—Lambert and Wardlaw (1992, and in prep.)

detailed the transitional morphotype, especially in the later

paper where they used morphometrics on tightly constrained

stratigraphic samples to illustrate this morphocline transition.

Mesogondolella nankingensis (Ching [Jin]),

new combination

PLATE 3-10: FIGURES 8-10

Gondolella nankingensis Ching [Jin], 1960:246, pi. 2: figs. 5-8.

Gondolella serrata Clark and Ethington, 1962:108-109, pi. 1: figs. 10, 11, 15,

19, pi. 2: figs. 1, 5, 8, 9, 11-14.—Clark and Mosher, 1966:389, pi. 47: figs.

13-15.—Clark and Behnken, 1971:431, pi. 1: fig. 10.

Neogondolella serrata (Clark and Ethington).—Clark and Behnken, 1979:

268-271, pi. 1: fig. 12.—Wang, 1978:222, pi. 2: figs. 6-8, 14, 15,

20-22.—Wardlaw and Collinson, 1984:270, pi. 2: figs. 13-15.

Neogondolella serrata serrata (Clark and Ethington).—Behnken, 1975:308, pi.

2: figs. 21-24, 37.
NUMBER 32 45

DIAGNOSIS.—Platform of moderate width, generally short

and arched, narrowing anterior to middle, and with round to

blunt posterior margin; lateral platform margin variably

serrated, usually with at least 3 or more paired serrations on the

anterior tapering part, rarely serrated for almost entire margin.

Cusp moderate, circular in cross section; denticles generally

increasing in size anteriorly, except commonly 1 or 2 smaller

denticles along middle of carina and 1 or 2 denticles at anterior

end; furrows moderately developed, smooth. Lower side with

well-developed single loop around posterior of slit-like basal

pit; loop subterminal on posterior of lower attachment surface;

lower attachment surface a relatively narrow V-shaped impression with slightly elevated margins, becoming a keel in anterior

one-fourth of element.

REMARKS.—Mesogondolella nankingensis is clearly different from M. idahoensis by its retention of lateral serrations in

all growth stages, its more rounded (less blunt) posterior

platform margin termination, and its more sharply narrowing

anterior platform.

Mesogondolella aserrata (Clark and Behnken),

new combination

PLATE 3-3: FIGURES 1-16; PLATE 3-5: FIGURES 1-7;

PLATE 3-10: FIGURES 11-17

Neogondolella aserrata Clark and Behnken, 1979:271-272, pi. l:figs. 1-11.

DIAGNOSIS.—Platform of moderate width and length,

slightly arched and bowed, widest posterior to middle,

narrowing gradually to anterior from widest point; platform

with a bluntly rounded posterior end with a brim in most large

specimens. Nearly 50% of specimens with slight to marked

inflection along inner lateral margin in posterior one-third of

specimen; lateral platform margin serrated to slightly serrated

(1 or 2 poorly developed pairs) on anterior one-third of

platform. Cusp small to moderate, circular to elongate in cross

section; denticles generally of varying size and height on

posterior one-third to one-half of platform before increasing

steadily in size anteriorly, except distalmost, which decrease in

size; generally denticles in middle section of carina the lowest

and most fused; furrows shallow and not well demarcated

(micro-ornamentation infringing on furrows), and margins only

slightly upturned (reflecting the shallower furrows). Lower side

with poorly to well-developed double loop posterior to slit-like

basal pit; loop posteriorly terminal on lower attachment

surface; lower attachment surface appears as a shallow

V-shaped impression with slightly elevated margins forming a

keel anteriorly and a narrow, slightly elevated groove as an

inner keel in anterior one-third of element.

REMARKS.—The poorly defined and shallow furrows that

are not completely smooth distinguish this species from its

predecessor (M. nankingensis) and successor species (M

postserrata), both of which have nicely incised, smooth

furrows. Most specimens of M. aserrata are less arched and

have a less upturned margin than either M. nankingensis and M.

postserrata. In addition, the anterior platform shows less

dramatic narrowing toward the anterior than it does in the other

two species.

Mesogondolella postserrata (Behnken),

new combination

PLATE 3-4: FIGURE 28; PLATE 3-5: FIGURES 13-20; PLATE 3-6: FIGURES 1-7;

PLATE 3-7: FIGURES 1-11; PLATE 3-10: FIGURES 18,19;

PLATE 3-11: FIGURES 1-4

Neogondolella serratapostserrata Behnken, 1975:307-308, pi. 2: figs. 31, 32,

35.

Neogondolella postserrata Behnken.—Clark and Behnken, 1979:272, pi. 1:

figs. 13-17,21.

Neogondolella babcocki Clark and Behnken, 1979:272-274, pi. 2: figs. 5, 6,

11-15, 17, 18.

Neogondolella denticulata Clark and Behnken, 1979:272, pi. 1: figs. 18-20,

22, 23.

Neogondolella rosenkrantzi (Bender and Stoppel).—Clark and Behnken, 1979:

272-273, pi. 2: figs. 1-4,7-9.

Mesogondolella "babcocki" (Clark and Behnken).—Kozur, 1992:103, fig. 4

[in part].

DIAGNOSIS.—Platform of narrow width but moderate length,

arched and bowed, widest usually posterior to middle, but

rarely widest near posterior end; platform narrowing gradually

or platform margins subparallel from anterior of widest point to

anterior one-fourth at position of both a slight increase to

anterior narrowing and a sharp downward turn to platform;

platform with asymmetric and blunt posterior end, subrounded

to rounded, if rounded, generally very narrow, with a very

narrow brim in most large specimens; many specimens with

slight inflection along inner lateral margin in posterior

one-third of specimen; lateral platform margin serrated on

anterior one-third. Cusp moderate size, circular to elongate in

cross section; denticles generally decreasing in size to middle

of platform, except first and third or fourth denticles anterior to

cusp may be larger; denticles anterior to middle of platform

increasing steadily in size anteriorly except distalmost decreasing in size; denticles in mid-section of carina generally the

lowest and most fused; platform margin in many specimens

upturned and nearly equal to height of carina in its mid-section;

furrows well developed, narrow, generally deeply incised, and

smooth. Lower side with well-developed double loop around

posterior of slit-like basal pit; loop terminally located on

posterior of lower attachment surface; lower attachment surface

shallow V-shaped impression with slightly elevated margins

forming a keel anteriorly and forming a narrow, slightly

elevated groove as an inner keel in anterior one-half of element.

REMARKS.—Mesogondolella postserrata displays transitional morphologies during its short overlap with its predecessor, M. aserrata (e.g., Plate 3-5: Figures 13-20; Plate 3-10:

Figures 18, 19), and its successor, M. shannoni (e.g., Plate 3-6:

Figures 1-7; Plate 3-7: Figures 1-11; Plate 3-11: Figures 1-4).

Commonly, M. postserrata can be easily distinguished by its
46 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

subparallel posterior platform margins, slight inflection on the

inner posterior margin, and smooth well-incised furrows. In

many respects M. postserrata more closely resembles M.

nankingensis, but it can be differentiated by its narrower

platform, rounded posterior platform termination, common

presence of a brim, serrations restricted to the anterior

one-third, and double loop around the basal pit.

The figure caption for the specimens illustrated by Clark and

Behnken (1979, pi. 1) as M. denticulata is confusing. Their

figs. 18,19, and 22 are listed as upper, lateral, and lower views,

respectively, implying that they are the views of the same

specimen when, in fact, they are views of different specimens

from the same locality. The holotype, fig. 19, with its highly

upturned margin, is different from most M. postserrata and

may be a pathological morphotype. Similar specimens were not

found in the moderately extensive Guadalupe Mountains

material from the same or nearby beds. The specimens

illustrated in figs. 18,20,22, and 23 (Clark and Behnken, 1979,

pi. 1) do not possess this highly upturned margin and are not

different from M. postserrata.

Mesogondolella shannoni Wardlaw in Mei, Jin,

and Wardlaw

PLATE 3-4: FIGURES 26, 27,29,30; PLATE 3-6: FIGURES 8-15; PLATE 3-7:

FIGURES 12-25 ; PLATE 3-8: FIGURES 1-22; PLATE 3-9: FIGURES 1-27;

PLATE 3-11: FIGURES 5-14

Mesogondolella shannoni Wardlaw in Mei, Jin, and Wardlaw, 1994:228, pi. 1:

% 21.

Clarkina? wilcoxi (Clark and Behnken).—Kozur, 1992, figs. 7, 8.

? Clarkina cf. subcarinata (Sweet).—Kozur, 1992, fig. 21.

DIAGNOSIS.—Platform broad, arched and slightly bowed,

widest in posterior one-third, narrowing gradually from widest

point with a slight increase in narrowing or a "pinch" near

beginning of anterior one-fourth of platform; platform with

broadly rounded posterior end, and with well-developed brim

in large specimens; lateral platform margin with a few to many

serrations on anterior (narrower or narrowing) one-fourth. Cusp

generally high conical, occasionally merging with small

posterior denticle or first denticle anterior to cusp to form a

large elongate denticle in some large specimens; denticles

crudely decreasing in size anteriorly to midpoint and then

increasing in size until distalmost, with distalmost being

smaller; posterior denticles with general pattern of crudely

decreasing size, but denticles alternate between relatively larger

and smaller size, especially in width; furrows generally narrow

and well incised, but variable, ranging from those like M.

postserrata to those like M. altudaensis; commonly, boundary

between reticulate and smooth ornament near furrow edge

indistinct. Lower side with well-developed double loop around

posterior of basal pit; loop subterminally located on posterior of

lower attachment surface; lower attachment surface a shallow

V-shaped impression with slightly elevated margins forming a

keel anteriorly and forming a narrow, slightly elevated groove

as an inner keel in anterior one-third to one-half of element.

TYPE SPECIMEN.—USNM 482680, Plate 6: Figure 14.

OCCURRENCE.—Mesogondolella shannoni is found in the

uppermost part of the Altuda Formation in the Glass and Del

Norte mountains and is common in the upper part of the

Wuchiaping Formation in South China.

REMARKS.—Mesogondolella shannoni and M. altudaensis

are very similar, and M. shannoni is the morphologically

transitional form from M. postserrata to M. altudaensis.

Mesogondolella shannoni has a short but significant range, so

it is separated herein. Meogondolella shannoni differs from M.

postserrata by having a broader platform that has a wellrounded posterior termination, a generally well-developed

brim, and a less-upturned inner lateral margin. Its denticulation

pattern is similar to that of M. postserrata, but it lacks the

variablity of M. postserrata in the posterior carina. Mesogondolella postserrata has denticles of different sizes (height and

width) that occur in an overall pattern of decreasing size,

whereas the denticles of M. shannoni just display a general

decrease in height but vary in width. Mesogondolella shannoni

has a much better developed double loop around the posterior

of the basal pit that is generally raised much higher than that of

M. postserrata.

Large samples of this species have shown many large

"pathologically" unusual and bizarre morphotypes (e.g., Plate

3-7: Figure 25). The form illustrated by Kozur (1992, fig. 21)

appears to be a corroded pathological morphotype of this

species. Transverse ridges are common to a small percentage of

large specimens in most large populations (Plate 3-7: Figures

20, 24; Plate 3-8: Figure 20).

Mesogondolella altudaensis (Kozur),

new combination

PLATE 3-5: FIGURES 8-12; PLATE 3-11: FIGURES 15-17

Clarkina altudaensis Kozur, 1992:103-106, figs. 9-12, 14-17.

Mesogondolella "babcocki" (Clark and Behnken).—Kozur, 1992:103, figs. 5,

6 [in part].

Clarkina n. sp. Kozur, 1992, fig. 13.

DIAGNOSIS.—Platform broad, widest near midline or posterior to midline, narrowing smoothly, but sharply, posteriorly

and narrowing gradually anteriorly, commonly with a small

"pinching" of platform at or about where the anterior denticles

become high, platform then turns slightly downward at this

point to the anterior; most specimens slightly to subtly serrated

at, and anterior to, platform pinching, only rare specimens

appearing smooth; platform forming small brim around the

posterior end; specimens with a narrow posterior platform

develop primitive buttress. Cusp of small to moderate size,

elongate-oval in cross section; generally at least one of the first

posterior denticles clearly larger than cusp, first 4-6 denticles

posterior to the cusp initially increase then decrease in size,

then denticles generally increase in size anteriorly, except for

distalmost one or two; furrows generally broad and shallow,

with vague boundary between smooth and reticulate microornamentation. Lower surface with well-developed double loop

around posterior of basal pit; posterior of inner loop very
NUMBER 32 47

elevated; loop subterminally located on posterior of lower

attachment surface; lower attachment surface a shallow

V-shaped impression with slightly elevated margins forming a

keel anteriorly and forming a narrow slightly elevated groove

as an inner keel in anterior one-half or more of element.

REMARKS.—Kozur (1992:105) implied in his remarks (but

not in his diagnosis!) that all specimens have smooth anterior

margins, although his illustrations, with the exception of the

holotype, all display distinct to indistinct serrations. An

examination of the abundant material from large samples from

studied sections (including that used by Kozur) indicates that

the apparently smooth morphotypes are rare.

Mesogondolella altudaensis can be distinguished from M.

shannoni by its much smaller, very reduced cusp, less distinct

furrows, and slightly less upturned platform margin. Also, the

platform of M. altudaensis is widest near the midline, whereas

that of M. shannoni is widest nearer the posterior end, and this

is expressed as narrower posterior shoulders in M. altudaensis,

less distinct serrations, more pronounced anterior pinching or

narrowing of the platform, and more fused denticles, especially

in the middle part of the carina.

Xaniognathus Sweet, 1970

Xaniognathus abstractus (Clark and Ethington)

Subbryantodus abstractus Clark and Ethington, 1962:112-113, pi. 1: figs. 16,

20, 21, pi. 2: fig. 2.

Lonchodina mulleri Tatge.—Clark and Ethington, 1962:110-111, pi. 1: fig. 4.

Apatognathus tribulosus Clark and Ethington, 1962:107, pi. 1: figs. 3, 7, 13,

17.—Wardlaw and Collinson, 1984:271 [placed in synonymy].

Ozarkodina tortilis Tatge.—Clark and Behnken, 1971:433, pi. 2: fig. 8.

Xaniognathus abstractus (Clark and Ethington).—Behnken, 1975:313, pi. 1:

fig. 15.—Wardlaw and Collinson, 1984:271, pi. 2: figs. 1-12; 1986:135, fig.

18.17-23.—Behnken, Wardlaw, and Stout, 1986:185, figs. 5.4-7, 6.7-

20.—Wardlaw and Grant, 1990:A8, pi. 4: figs. 1-22.

Xaniognathus tortilis (Tatge).—Behnken, 1975:313, pi. 2: fig. 13.

Xaniognathus sp. Malkowski and Szaniawski, 1976:83, pi. 1: fig. 2.

Sweetocristatus arcticus Szaniawski, 1979:254, pi. 9: figs. 1-7.—Wardlaw and

Collinson, 1984:271 [placed in synonymy].

DIAGNOSIS.—Sb {Apatognathus tribulosus) element delicate, greatly recurved, with large cusp and low denticles on one

process; large variable Pb element with a twisted posterior

process commonly bearing 5-8 denticles, rare specimens with

more denticles; anterior process variable, robust to relatively

thin and delicate, commonly bearing 7-11 or more denticles,

with midlateral rib extending most of process length.

REMARKS.—The apparatus of X. abstractus from West

Texas material is well illustrated in Wardlaw and Grant (1990).

Xaniognathus hydraensis Nestell and Wardlaw

PLATE 3-4: FIGURES 1-13; PLATE 3-12: FIGURES 3-5

Xaniognathus hydraensis Nestell and Wardlaw, 1987:770-771, figs. 7.1-7.13.

Gondolella orientalis Barskov and Koroleva.—Kozur, 1975:18-19, pi. 2: figs.

11-15 [in part]; 1978, pi. 8: figs. 9-11,13.

Gondolella leveni Kozur, Mostler, and Pjatakova.—Kozur, 1975:16-17, pi. 3:

figs. 6, 7 [in part, not fig. 8a,b (= Merrillinal sp.)]; 1978, pi. 7: figs. 8, 9 [in

part, not fig. 1 la,b (= Merrillinal sp.)].

DIAGNOSIS.—Pb element with long large cusp, nearly

straight anterior process, and short twisted posterior process

generally with 4 or 5 denticles.

REMARKS—Nestell and Wardlaw (1987) first illustrated the

apparatus of this species from scrappy material from Hydra

Island, Greece. The material figured herein better illustrate all

the elements of the apparatus. Xaniognathus hydraensis is

distinguished from X. abstractus by a Pb element that has a

shorter, less twisted posterior process, a larger cusp, slightly

more discrete denticles, and a thinner anterior process.

Order OZARKODINIDA Dzik, 1976

Family ANCHIGNATHODONTIDAE Clark, 1972

Hindeodus Rexroad and Furnish, 1964

Hindeodus excavatus (Behnken)

PLATE 3-2: FIGURES 1-21

Ellisonia excavata Behnken, 1975:302-303, pi. 1: figs. 9-14.

Anchignathodus minutus (Ellison).—-Behnken, 1975:297, pi. 1: figs. 16-18.—

Kozur, 1975:5-7, pi. 1: fig. 16 [in part].

Anchignathodus minutus permicus Igo, 1981:26-27, pi. 10: figs. 1-4. [New

synonymy.]

Hindeodusl excavatus (Behnken).—Sweet, 1977:215-217, pi. 1: figs. 7-11.

DIAGNOSIS.—Pa element with narrow, pointed cusp and

with denticles of nearly equal width except for the posteriormost few, these being narrower and decreasing in height

posteriorly; 3-4 denticles immediately posterior to cusp less

fused than more posterior denticles. Small specimens (the most

common) triangular in lateral profile. Sa element with

downward-directed processes at about a 40° angle from

horizontal; processes nearly straight and bearing thin, fine

denticles of variable height, with 2-3 large lateral denticles at

or near distal end, and with a small distal denticle only

sometimes developed; denticles on processes straight to

slightly recurved.

Hindeodus wordensis, new species

PLATE 3-4: FIGURES 24, 25; PLATE 3-12: FIGURES 1, 2

Hindeodus excavatus (Behnken).—Wardlaw and Collinson, 1984:268-269, pi.

5: figs. 1, 2, 4-9; 1986:133, fig. 17.13-20.—Wardlaw and Grant, 1990: A6,

pi. 2: figs. 1-15, pi. 3: figs. 4, 5, 9-11 [in part, not figs. 3, 6-8].-<Jullo and

Kozur, 1992:218, fig. 5E.

DIAGNOSIS.—Pa element with large cusp; denticles increasing in width posteriorly, except for posteriormost, and

generally decreasing in height posteriorly, except for posteriormost three, which may be of subequal height; cusp much higher

than denticles; Sa element with short lateral processes;
48 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

processes slightly upturned laterally and bearing, for at least

part of their length, denticles of alternating (smaller versus

larger) sizes.

TYPE SPECIMEN.—USNM 404252 (Wardlaw and Collinson,

1986, fig. 17.20).

OCCURRENCE.—Hindeodus wordensis is common in the

Word, Altuda, and Bell Canyon formations of West Texas and

in the Gerster Limestone and the upper part of the Phosphoria

and related rocks in the Great Basin and nothern Rocky

Mountains.

REMARKS.—Gullo and Kozur (1992) correctly pointed out

that two different types of Pa elements have been included in H.

excavatus and that one is illustrated by Igo (1981) as H.

permicus and the other is illustrated by Wardlaw and Collinson

(1984, 1986) as H. excavatus. The ramiform elements of

Hindeodus are diagnostic (Wardlaw and Stamm, 1992), and

those originally described by Behnken (1975) as Ellisonia

excavata belong to the Pa described as H. permicus, thus

leaving Wardlaw and Collinson's illustrated material in open

nomenclature. It is proposed here that the specimen illustrated

in Wardlaw and Collinson (1986, fig. 17.20) serves as the

holotype of Hindeodus wordensis and that the apparatus

illustrated from sample 3LM1628 in fig. 17.13-20 represents

the entire apparatus of the species. The description of Wardlaw

and Collinson (1984:268-269) will serve as the diagnosis of

the species. Wardlaw and Stamm have a much more detailed

description of all recognized Hindeodus species in preparation

(Wardlaw and Stamm, 1992). Wardlaw and Grant (1990)

illustrated many well-preserved specimens (all but the Sa

element) from material at the top of the Road Canyon

Formation stratotype taken from a bed that is considered

equivalent to the China Tank Member of the Word Formation.

Family SWEETOGNATHIDAE Ritter, 1986

Diplognathodus Kozur and Merrill, 1975

Diplognathodus sp.

PLATE 3-1: FIGURES 1-4

REMARKS.—Two corroded Pa elements were recovered

from sample USGS 31535-PC. Both are illustrated herein. No

specific determination was attempted based on such poor

material. Another very poorly preserved specimen is from

sample USGS 31600-PC, and it is questionably assigned to

Diplognathodus.

Iranognathus Kozur, Mostler, and Rahimi-Yazd, 1975

Iranognathus punctatus, new species

PLATE 3-12: FIGURES 12-25

DIAGNOSIS.—Pa element bearing several lateral nodes or

"punctae" on upper surface of flaring basal cavity; single carina

covered with nodes posteriorly and forming a ridge anteriorly;

lateral and carinal nodes and carinal ridge with pustulose

micro-ornamentation; some lateral nodes merging in larger

specimens.

DESCRIPTION.—The Pa element is carminiscaphate with a

wide, flaring basal cavity. The free blade is commonly

one-third of the element, and it becomes a carinal ridge

posteriorly, extending to the posteriormost of the element. The

free blade/carinal ridge is slightly bowed laterally and may

become very bowed laterally at its posteriormost end in large

specimens. The ridge is ornamented by pustulose nodes

posteriorly and is only pustulose anteriorly. The upper surface

of the flaring basal cavity is ornamented by numerous lateral

nodes, or punctae, which are more common on the inner side

and generally become larger with some merging with the

nearest nodes during growth. The anteriormost inner nodes are

arranged in a diverging pattern from the carinal ridge, with the

anteriormost nodes most likely to merge to form one or two

short diverging "adcarinal" ridges, whereas the outer nodes are

arranged in a roughly subparallel pattern, with the anteriormost

nodes most likely to merge to form one adcarinal ridge.

The remainder of the apparatus is poorly represented. The Pb

element is angulate and has a large reclined cusp, a relatively

broad anterior process, and a distally narrowing posterior

process. Both processes bear short, laterally compressed but

thick denticles. The denticles on the posterior processes appear

to alternate in size (small versus moderate) but are generally

overgrown with apatite. The Sa element is alate, with short

lateral processes that are downward directed and emerge at a

nearly 90° angle from the posterior process, and bears a very

large slightly reclined cusp. The M element is dolabrate and has

small denticles on the anticusp, a proclined cusp of moderate

size, and a posterior? process bearing subequal-sized and

subevenly spaced moderate denticles that slightly increase in

size and spacing distally.

TYPE SPECIMEN.—USNM 482789, Plate 3-12: Figure 23.

OCCURRENCE.—Iranognathus punctatus is common to the

middle part of the Wargal Formation, Salt Range, Pakistan.

REMARKS.—The described species of Iranognathus, I.

unicostatus and /. tarazi, are very unlike other specimens

studied from the Wargal Formation of the Salt Range, Pakistan,

and the Del Norte Mountains, West Texas, in that they lack

nodose ornamentation of the upper surface of the flaring basal

cavity. This species shows a lot of variability (plasticity), which

is common for very shallow, nearshore forms. The forms from

Pakistan and West Texas (Plate 3-2: Figures 36, 37) are

dissimilar in node pattern, but the mutual presence of nodes

make them more similar to each other than to the other

described species. Until more material is illustrated (especially

from China), the one recovered specimen from West Texas is

illustrated herein and is placed as /. aff. punctatus. The

apparatus of Iranognathus, although poorly represented,

appears to be a fairly typically sweetognathid apparatus.
NUMBER 32 49

Iranognathus aff. /. punctatus Wardlaw

PLATE 3-2: FIGURES 36, 37

REMARKS.—A single, poorly preserved specimen from the

Del Norte Mountains has nodose ornamentation on the upper

surface of the flaring basal cavity. The nodes roughly form two

lines that merge on the inner side of the basal cavity to form an

adcarinal ridge. This specimen is like /. punctatus in that it has

nodose ornamentation, but it differs in that it does not have

additional nodes between the two lines of nodes or adcarinal

ridges. In addition, the line of nodes on each side curve outward

distally, whereas the lines on /. punctatus curve inward distally.

Neostreptognathodus Clark, 1972

Species of Neostreptognathodus, which are common in the

late Artinskian and Leonardian, are rare in the Guadalupian.

Neostreptognathodus sulcoplicatus, which occurs in a few

samples at the base of the Road Canyon Formation and is

diagnostic of the uppermost Leonardian, is listed in the

distribution table and is used for biostratigraphy, but it is not

described herein. Neostreptognathodus newelli is characteristic

of the basal Guadalupian zone in the Great Basin (Wardlaw and

Collinson, 1986) and is only rarely found in the West Texas

section. The best specimen was illustrated in Wardlaw and

Grant (1990) where the species was discussed. Neostreptognathodus clinei also was illustrated and discussed in

Wardlaw and Grant (1990), but it is only sporadically found

through the Road Canyon Formation and the lower part of the

Word Formation. Small specimens are easily confused with

Sweetognathus bicarinum, so it is illustrated and discussed

herein.

Neostreptognathodus clinei Behnken

PLATE 3-12: FIGURE 10

Neostreptognathodus clinei Behnken, 1975:309-310, pi. 2: figs. 15, 16.—

Sweet, 1977:237, pi. 1: fig. 4.—Wardlaw and Collinson, 1984:270, pi. 5: fig.

13.—Behnken, Wardlaw, and Stout, 1986:183, fig. 4.6, 7.

DIAGNOSIS.—Platform element (Pa) with 2 carinae; carinae

either smooth or only faintly ornamented posteriorly by poorly

developed nodes; carinae separated by a distinct groove; blade

joins platform at center.

REMARKS.—Small specimens of N. clinei are difficult to

distinguish from small specimens of Sweetognathus bicarinum,

and the two species may be closely related. They have similar

Gnathodid apparatuses, and pustulose micro-ornamentation

occurs on the denticles or nodes of many specimens of

Neostreptognathodus, attesting to their close relationship. It

appears that N. clinei consistently has a groove dividing the

carinae, even in very small specimens, which appears to be the

distinguishing feature. It also has less pustulose microornamentation than similar-sized specimens of Sweetognathus

bicarinum.

Pseudohindeodus Gullo and Kozur, 1992

This genus is based on small platform elements that are

common in the middle Permian. These elements look like those

of Hindeodus, but they can be identified as belonging to

sweetognathid appatatuses by the moderate length of the

posterior process on the Sa element. Sweetognathid apparatuses follow the typical Gnathodid apparatal layout, but

sweetognathoid apparatuses have ramiforms of moderate

length and more robust elements (especially the M), and they

commonly display a recessive zone of basal attachment. These

characters are indicative of the preferred habitat of sweetognathids of nearshore, high energy environments.

The species that clearly belong to Pseudohindeodus, namely

P. ramovsi, P. augustus (Igo), and P. oertlii (Kozur, especially

as illustrated by Igo, 1981), all have a diagnostic crimp around

the fringe of the extremely flared basal cavity, which may be

diagnostic of the genus.

Pseudohindeodus ramovsi Gullo and Kozur

PLATE 3-1: FIGURES 5-24

Pseudohindeodus ramovsi Gullo and Kozur, 1992:223-224, fig. 4A-H.

Anchignathodus minutus (Ellison).—Ramovs, 1982:425, fig. 4/7 [in part].

Anchignathodus typicalis Sweet.—Behnken, 1975:297-298, pi. 2: fig. 12.

Hindeodus excavatus (Behnken).—Wardlaw and Grant, 1990:A6, pi. 3: figs. 3,

6, 7, 8 [in part].

DIAGNOSIS.—Pa element completely denticulate; denticles

compressed and laterally expanded, but posteriormost 3 or 4

less compressed and decreasing in size distally; in upper view,

surface above fringing crimp spade-shaped.

DESCRIPTION.—The Pa element is segminate, and an

anterior "blade" or cusp is formed by the fusion of two high and

postero-anteriorly wide, but laterally thin, denticles. The first

denticle posterior to the cusp is commonly one-half the height

of the cusp and one-half again the height of the next posterior

denticle. The denticles give the general impression of decreasing in height from the cusp; however, the laterally widest three

denticles, which are also the posteriormost compressed

denticles (3 or 4 from the posterior end), are commonly slightly

higher than surrounding denticles, forming a slight hump. The

denticles following the first posterior denticle are very

compressed and fused and are of near equal height or slightly

decreasing or increasing in height, but they consistently

increase in lateral width posteriorly. The posteriormost three or

four denticles are much less compressed and fused, become

free posteriorly, and sharply decrease in size distally (in all

aspects). The posteriormost denticle is small and is located just

above the fringing crimp. The fringing crimp extends nearly

completely around the element; in large specimens it may be

absent on the anteriormost part of the cusp, or it may form a

slight notch in lateral profile at the anterior end. The lower

surface is made up of an extremely flared and wide basal cavity

that is deep, widest near the midline, and narrows to a deep

groove beneath the cusp.
50 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

The Pb element is angulate and laterally twisted posteriorly.

The anterior process bears several relatively high denticles that

decrease in size distally. The posterior process bears several

small denticles that are partly fused and appear to decrease in

size slightly to the posterior. The first posterior denticle is

considerably higher than the others and is mostly fused to the

cusp. The lower surface has a small pit below the cusp, a

well-developed groove, and a zone of recessive attachment

laterally.

The M element is digyrate. The cusp is high and sinuous.

The antero-lateral process is more like an anticusp and bears

one to three small, highly fused denticles. The posterolateral

process bears seven or eight well-developed denticles that

decrease in size anteriorly; the denticle closest to the cusp is

approximately one-half the size of the cusp. The lower surface

has a pit beneath the cusp, grooves under each process, and a

well-developed zone of recessive attachment surface that tapers

away distally on the anterolateral process before the anterior

end and abruptly curves away near the end of the posterolateral

process.

The Sa element is alate and of moderate length and has two

short lateral processes that bear two to four slightly compressed

denticles. The cusp is large and reclined and bears costae

directed toward each process. The posterior process bears four

or five moderately high, compressed and partly fused denticles

behind the cusp. Posteriorly, the denticles become less fused

and compressed and more reclined. The lower surface is

represented by a groove under all the processes.

The Sb element is bipennate, with a sharply downturned and

slightly incurved anterior process bearing several compressed

denticles. The first denticle anterior to the cusp is noticeably

smaller than all but the most distal denticle. The remainder of

the denticles appear to decrease in size distally. The cusp is

moderately high (broken in all examined specimens) and

recurved. The posterior process is moderately long and bears

many denticles. The first five to seven denticles behind the cusp

appear to alternate in size between small and moderate, and

they are more compressed and fused than the remainder. The

remainder are of subequal height, becoming more relcined and

longer posteriorly. A few smaller denticles occur on the

process, but they do not form a recognizable pattern. The lower

surface is represented by a groove under each process.

The Sc element is bipennate, with a slightly downturned and

incurved anterior process that generally bears four denticles

that alternate in size. The denticle closest to the cusp is small,

whereas the anteriormost is the largest. The cusp is of moderate

height and is reclined. The posterior process is of moderate

length and shows either the same or a similar denticulation

pattern as the Sb element. The lower surface is represented by

a groove under each process.

OCCURRENCE.—Pseudohindeodus ramovsi is a rare form

that occasionally occurs abundantly. It sporadically occurs

throughout the Road Canyon, Word, and Altuda formations. It

also has been recovered abundantly from a sample of the South

Wells Limestone Member of the Cherry Canyon Formation.

Gullo and Kozur (1992) reported it from Wordian strata in

Sicily.

REMARKS.—The abraded and poorly preserved large specimens referred to as Diplognathodus sp. (Plate 3-1: Figures

1-4), which are from the same sample that was used to

illustrate Pseudohindeodus, are clearly different in that they

have a well-developed top notch posterior to the cusp and a

marked posterior side notch observed in lateral profile, and,

although abraded, they do not show signs of pronounce

denticulation. The fringing crimp is absent.

Sweetognathus Clark, 1972

A species of Sweetognathus is common in the collected

samples. It is difficult to see any differentiation in the

specimens through the stratigraphic column examined in this

study. They do, though, have a marked ontogenetic change,

developing a second carinae through growth (see Wardlaw and

Grant, 1990), and this appears to be a diagnostic characteristic.

A complete apparatus has been recovered, and it is illustrated

herein.

Sweetognathus bicarinum, new species

PLATE 3-2: FIGURES 22-35; PLATE 3-3: FIGURES 17-20;

PLATE 3-12: FIGURE 11

Sweetognathus iranicus Kozur, Mostler, and Rahimi-Yazd.—Wardlaw and

Grant, 1990:A8, pi. 3: figs. 12-17.

DIAGNOSIS.—Pa element with carina of rounded denticles or

nodes having pustulose micro-ornamentation; primary row of

nodes connected by thin, pustulose, laterally (not centrally)

placed longitudinal ridge; secondary row of nodes variably

developed but with growth becoming larger than, and merging

with, primary row to form transverse ridges; mature specimens

with shallow depression (or furrow) separating two rows of

nodes (now carina) and depressing transverse ridges (see

Wardlaw and Grant, 1990, pi. 3: fig. 16).

DESCRIPTION.—The upper surface of the Pa element is

described in the diagnosis. The lower surface has a moderately

flared basal cavity (generally broken) that becomes a groove

anteriorly.

The Pb element is angulate, thick, and arched. The anterior

process is downturned and very thick and bears five to nine,

highly fused, short denticles that become more reclined

posteriorly. The cusp is moderately high, thick, and very

reclined. The posterior process is downturned but has a slight

inflection or upturning at the distal end. The four or five

denticles next to the cusp are fused but become less fused

distally. The lower surface has an oval basal cavity below the

cusp and grooves beneath the processes.

The M element is dolabrate, with a short anticusp and long

denticulate process. The cusp reclines over the anticusp so that

it is posterior and the long process is anterior (this is the

opposite from Hindeodus). The anterior process bears nine or

more well-developed, moderately high denticles that are
NUMBER 32 51

strongly reclined distally, becoming less so near the cusp.

Either the first (usually) or the second (occasionally) denticle is

the smallest. The third denticle is usually the largest, and

thereafter the denticles decrease in size distally. The lower

surface has a small pit below the cusp and a groove under the

anterior process.

The Sa element is alate, with short lateral processes that are

anteriorly directed and bear about three denticles. The posterior

process is broken and has not been observed, but it should be

like that of the Sb and Sc elements, namely, moderately long

with denticles of alternating size close to the cusp and

becoming more equal-sized, longer, and more reclined distally

except for probably the distalmost. The lower surface has a

groove under each process.

The Sb element is bipennate, with a low cusp and a short

downward and inward curving anterior process and a moderately long posterior process. The anterior process bears four to

six denticles that increase in size anteriorly except when a small

distalmost denticle is developed; then the largest is the next to

last denticle. At the position of the largest denticle, the anterior

process turns strongly inward. The posterior process bears

many denticles. Generally two short denticles are followed by

a low cusp (several of the posteriormost denticles are larger

than the cusp). Posterior to the cusp, the denticles alternate in

size from long and wide to short and narrow. These alternating

pairs become progressively longer and wider distally, except

for the distalmost, which is smaller. The lower surface has a

groove under each process.

The Sc element is bipennate, with a moderately high cusp, a

slightly downward and inward turned anterior process, and a

moderately long posterior process. The anterior process bears

about six denticle pairs that alternate in size, the pairs become

progressively larger distally, with the distalmost denticle the

largest. The posterior process bears many denticles similar in

pattern to the Sb element, except the smaller denticles

following the cusp may be more numerous (2-4) before the

alternating pairs develop. The lower surface has a groove under

each process.

TYPE SPECIMEN.—USNM 406952 (Wardlaw and Grant,

1990, pi. 3: figs. 12, 16).

OCCURRENCE.—Sweetognathus bicarinum is common to the

Guadalupian of West Texas, appearing at the base of the Road

Canyon Formation and ranging nearly to the top of the Altuda

Formation.

REMARKS.—Middle and Late Permian Sweetognathus species are not well documented, so they are difficult to compare

or identify. The species at hand differs from S. guzhouensis

Bando et al. (1980) and most Early Permian forms by lacking

a well-defined carinal "midline" ridge, rib, or train of pustules.

The nodes on the anterior carina of S. hanzhongensis (Wang,

1978) become completely fused and form a flat ridge in lateral

profile. Both S. iranicus and S. hanzhongensis have a single

carina and do not display the development of two carina in

larger forms that is diagnostic for S. bicarinum. The similarity

of small specimens of N. clinei and S. bicarinum is discussed

under N. clinei.
52 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Appendix 3-1: Section and Conodont Sample Location

and Contained Fauna

USG S

P C #

Field

#

1 1

S

§ I

i

Heigh t

( m) JJJJJJJJJJJjilJ j JJii *

31407

31408

31409

31410

31411

31412

31413

31414

31415

31416

31417

31418

31419

31420

31421

31422

31423

31424

31425

31426

31427

31428

31429

31430

31431

31432

31433

31434

31435

31436

31437

31438

31439

31440

(W81161)

(W906)

(W81162)

(W81163)

(W81164)

(W81165)

(W81166)

(W81167)

(W81168)

(W81169)

(W81170)

(W81171)

(W81172)

(W81173)

(W81174)

(W81175)

(W81176)

(W81189)

(W81188)

(W81187)

(W81186)

(W81185)

(W81184)

(W81183)

(W81182)

(W81181)

(W81180)

(W81191)

(W8239)

(W8240)

(W81192)

(W81193)

(W81194)

(W81195)

(W81196)

(W81197)

(W81198)

(W81199)

0.15

1.50

2.29

7.93

12.20

16.00

20.73

23.63

26.22

33.54

47.26

51.83

58.54

64.63

69.82

76.22

82.93

0.00

3.66

11.59

18.60

33.23

39.33

43.90

50.00

64.33

71.34

0.30

0.76

1.22

5.18

8.54

9.76

11.89

13.72

18.29

22.56

26.22

RC I, bas e at 30°20.76'N, 103°15.27'W

+ - - + + ---- - + - -

+ - - + + ---- - + - -

+ - - + + ------- -

+ -- - + + ----- - +

+ --- - + ------ -

---- - + ------ -

+ --- - + ------ -

---- - + --- - + - -

--------- - + - -

---- - + --- - + - +

---- - + --- - + - +

_ + __ _ + ___ _ + _ _

RC II, base at 30°21.05'N, 103°15.93'W

— — — — _|_ _f_ — — -^- —

+ --- - + ------ -

---- - + --- - + - -

--------- - + - -

____ _ + _____ _ +

+ --- - + ----- - +

_--- - + --- - + - -

RC III, base at 30°18.23'N, 103°18.93'W

____ _ + ___ _ + _ +

____ _ + ___ _ + - -

___________ _ +

____ _ + ___ - + - +

— — — — — — — — — — — — +

+ ___ _ + ___ - + - +

---- - + --- - + - +

___________ _ +
NUMBER 32 53

APPENDIX 3-1.—Continued.

USGS

PC#

Field

#

8 -I

•s -a -a S

11!

s a a

111!i 11

1 ...

11

11

Hi

Height

(m)

1111III ii if II11111!11fI

IllllllllllllittllliilJ

RC IV, base at 30°18.13'N, 103°18.95'W

---- - + ----- - + ------- - + -

RC V, base at 30°18.35'N, 103°18.26'W

--- - + + ---------------- -

RC VI, base at 30°18.17'N, 103°18.38'W

--- - + + ----- - + --------- -

---- - + --- - + ----------- -

--------- - + - + --------- -

RC VII, base at 30°22.02'N, 103°13.21'W

+ _ _ + _____ _ + _ + _________ _

_ _ _ + _____ _ + ___________ _

_i_

+ --- - + --- - + - + --------- -

_ + _- _ + ___ _ + _ _ + ________ _

RC VIII, base at 30°23.61'N, 103°08.45'W

31441

31442

31443

31444

31445

31446

31447

31448

31449

31450

31451

31452

31453

31454

31455

31456

31457

31458

31459

31460

31461

31462

(W81200)

(W8241)

(W81201)

(W81202)

(W81203)

(W81204)

(W81205)

(W81209)

(W81208)

(W81207)

(W81206)

(W81214)

(W81213)

(W81212)

(W81211)

(W81210)

(W81217)

(W81218)

(W81219)

(W827)

(W828)

(W81220)

(W829)

(W81221)

(W81222)

(W81223)

(W81224)

(W81215)

(W81216)

(W81226)

(W81227)

(W8210)

(W8211)

(W8212)

(W81228)

(W81229)

(W81230)

0.76

0.91

5.18

11.89

20.43

24.39

29.88

1.37

11.13

14.94

23.48

1.52

9.15

15.40

21.95

25.52

0.46

4.12

5.49

5.79

8.23

10.67

10.67

14.94

21.34

27.13

34.15

39.63

59.45

0.46

7.93

8.38

8.69

8.99

9.30

11.89

17.99
54 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

APPENDIX 3-1.—Continued.

USGS

PC#

31463

31464

31465

-

-

-

-

-

-

31466

31467

31468

31469

31470

31471

31628

31472

31473

31474

31475

31476

31477

31478

31479

31480

31481

31482

-

-

31483

31484

31485

31486

31487

31488

31489

31490

Field

#

(W81244)

(W81243)

(W81241)

(W8242)

(W8244)

(W8243)

(W81242)

(W8245)

(W8246)

(W81236)

(W81237)

(W81238)

(W81239)

(W81240)

(W8734)

(W8735)

(W877)

(W878)

(W879)

(W8710)

(14WR5)

(W87I1)

(14WR72)

(W8712)

(W8713)

(14WR172)

(W8714)

(14WR285)

(W8715)

(14WR345)

(W8716)

(W81225)

(W876)

(702c)

(W8471)

(W8472)

(W9020)

Height

(m)

0.00

1.52

22.56

28.96

34.76

42.53

43.90

48.78

59.45

75.00

76.68

83.08

85.82

88.72

103.96

263.87

0.30

8.84

15.85

45.43

46.04

52.59

60.98

63.72

80.18

81.01

100.30

110.98

113.72

121.95

127.74

0.15

1.07

1.68

0.15

1.68

1.68

2 -2 -2 S M!!** 1! i

I -a

.!- a Q a a a s

RC IX, bases at 30°18.00'N, 103°20.26'Wand 30°18.39'N, 103°20.12'W

- - - + ----- - + ------ - + -

- — _j_ _|_ _|_ .

i i

---- - + ------------- -

---- - + --- - + - + ------ -

---- - + --- - + -------- -

- + -- - + --- - + - - + ----- -

- + --- - + -- - + - - + ----- -

RC X (14WR), base at 30°23.26'N, 103°10.42'W

+ --- - + --- - + - + ------ -

---- - + --- - + - + ------ -

- + -- - + --- - + - - + ----- -

---- - + --- - + - - + ----- -

- + -- - + --- - + - - + ----- -

---- - + ------ - + ----- -

- + -- - + ------ - + ----- -

--------- - + - - + ----- -

- + -- - + --- - + - - + ----- -

- + -- - + ------ - + ----- -

- + -- - + --- - + - - + ----- -

R C X I (USN M loc . 702c), bas e a t 30°22.99'N , 103°09.57' W

+ -- - + + --- - + - + ----- - +

+ --- - + --- - + - + ------ -

---- - + --- - + - + ------ -

R C XII , bas e a t 30°24.47'N , 103 o07.01' W
NUMBER 32 55

APPENDIX 3-1.—Continued.

USGS

PC#

Field

#

c

"3 2

g- I

l l l

1

il

Height

(m)

•Mlllllll l

lllljjllll

U

•$ -5 "5

lliflff!

lllljjlllllllllljjll jljl

31491

31492

31493

31494

31495

31496

31497

31498

31499

31500

31501

31502

31503

31504

31505

31506

31507

31508

31509

31510

31511

31512

29808

29809

29810

29811

29812

29813

29814

29815

29816

29817

29818

29819

(W8723)

(W8724)

(W8725)

(W8726)

(W8727)

(W865)

(W866)

(W867)

(W868)

(W901s)

(W902s)

(W903s)

(W904s)

(W905s)

(W906s)

(W869)

(W8610)

(W8611)

(W8612)

(W8613)

(W873)

(W874)

(W8510)

(W8511)

(W8512)

(W8513)

(W8514)

(W8515)

(W8516)

(W8517)

(W8518)

(W8519)

(W8520)

(W8521)

0.91

4.12

10.06

13.72

22.26

0.30

2.13

3.66

17.53

0.91

1.68

14.02

19.66

22.56

30.18

41.46

195.73

228.35

235.67

263.11

0.60

1.20

2.69

41.25

59.18

85.41

121.95

130.92

136.30

140.33

164.99

174.41

231.80

245.25

RC XIII (= base of Word I; refer to Word I section)

RC XIV (STOP 1.2), base at 30°13.85'N, 103°26.05'W

RC XV (RUD I, STOP 1.1), base at 30°14.35'N, 103°26.93'W

RC XVI (RUD II), base of Word Formation, 30°14.30'N, 103°27.48'W

Supplemental to RC XVI, limestone channel (1.5 m thick) in first siltstone member,

Word Formation, at 30°14.46'N, 103°27.40'W

RC XVII (DAV III), base at 30°18.44'N, 103°31.49'W
56 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

APPENDIX 3-1.—Continued.

USGS

PC#

Field

#

.32 c

2 -a -5 8

I II I I ! !

£11 1

I I

111 3 1

I 11

Height

(m)

illl

l IIIIjj 411

1 3 3

H1

111

1J

1 t fiil

!! 1

ll II11

29403

29404

29405

29406

29407

29408

29409

29410

31513

31514

31515

31516

31517

31518

31519

31520

31521

31522

31523

31524

31525

31526

31527

(W8347)

(W8348)

(W8222)

(W8223)

(W8350)

(W8351)

(W8352)

(W8353)

(W8617)

(W8618)

(W8619)

(W8620)

(W8621)

(W8622)

(W8623)

(W8627)

(W8624)

(W8626)

(W8614)

(W8615)

(W8616)

(W875)

(W8728)

(W8729)

(W8730)

(W8731)

(W8732)

(W8733)

1.57

3.81

162.30

171.05

352.44

372.26

389.33

419.21

3.05

10.37

23.93

27.44

41.16

60.67

79.57

0.91

12.21

17.99

85.37

85.37

100.61

110.98

47.56

62.20

68.60

74.70

96.04

125.91

31528

31529

31530

31531

31532

(W9047)

(W9048)

(W9049)

(W9050)

(W9050-2)

0.00

14.02

14.94

17.53

17.53

RC XVIII (DAV IV), base at 30°18.80'N, 103°30.86'W

RUD III, base in Word Formation, 30°15.69'N, 103°28.99'W

RUD IV, base in Word Formation, 30°14.86'N, 103°27.51'W

RUD V, base in Word Formation, 30°15.00'N, 103°28.83'W

RUD VI, base in Word Formation, 30°17.09'N, 103°28.92'W

AL 1 (STOP 2.1), base at 30°20.22'N, 103°30.47'W, no conodont samples

AL 2 (STOP 2.1), base at 30°20.23'N, 103°30.93'W
NUMBER 32 57

APPENDIX 3-1.—Continued.

USGS

PC#

Field

#

.52 c

1 I

•5 -^

Height

(m)

Si Si S>

o o o

OL. ci. a.

f ^ •5 .5 -S- •&-

31533 (W912)

(W9046)

31534 (89BM344)

31535 (89BM343)

31536 (W911)

31537 (89BM340)

21.34

23.99

0.00

57.32

62.96

80.18

31538

31539

31540

-

31541

31542

31543

31544

31545

31546

31547

31548

31549

31550

31551

-

31552

31553

-

-

-

31554

31555

31556

-

31557

-

31558

(W8215)

(W8216)

(W8217)

(W8218)

(W8219)

(W8220)

(W849)

(W8410)

(W8411)

(W8412)

(W8413)

(W81233)

(W81234)

(706e)

(W8225)

(W8226)

(W8227)

(W8228)

(W8229)

(W8230)

(W8231)

(W8232)

(W8233)

(W8234)

(W8235)

(W8236)

(W8237)

(W8238)

0.00

7.77

15.55

25.00

28.96

32.93

42.84

44.82

48.78

53.20

57.01

48.93

53.20

53.20

0.61

4.57

16.77

25.00

30.79

42.68

48.78

61.89

76.07

0.30

4.57

21.34

33.99

38.11

AL 3 (STOP 2.1), base at 30°20.42'N, 103°30.94'W

5CT, base at 30°23.37'N, 103°10.67'W, no conodont samples

CT I (USNM loc. 706e, WR IV), bases at 30°23.53'N, 103°10.58'W (CT I) and

30°23.79'N, 103°10.35'W(WR IV)

---- - + ------ - + -------- -

- + -- - + ---------------- -

_ + __ _ + ___ _ + _ _ + ___ _ + ___ _

- + -- - + --- - + - - + --- - + --- -

_ + __ _ + ___ _ + _ _ + ________ _

____ _ + ___ _ + _ _ + _______ _ +

- + -- - + --- - + - - + -------- -

- + -- - + --- - + - - + -------- -

7 CT (CT II), bas e at 30°23.74'N, 103°09.81'W

_i_ _ _

_i_

- + -- - + --- - + - - + -------- -

_____ _ + _____ _ + ________ _

WR I, base at 30°22.80'N, 103°13.41'W
58 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

APPENDIX 3-1.—Continued.

USGS

PC#

Field

#

•g

I i

.g

i l

i 11 I

lii lt lH

illlil

i!i!if

llll

Height

(m) IIIIIIIIIIII11II

f

31559

31560

31561

31562

31563

(W8252)

(W8253)

(W8247)

(W8248)

(W8249)

(W8250)

(W8251)

WR II, base at 30°23.92'N, 103°09.53'W

0.61

5.64

8.84

11.28

15.24

18.75

21.95

1WR, base at 30°22.48'N, 103°13.80'W,no conodont samples

WR III, base at 30°21.44'N, 103°14.07'W

31564

31565

31566

31567

31568

31569

31570

31571

31572

31573

31574

31575

31576

31577

31578

31579

31580

31581

31582

(W841)

(W842)

(W843)

(W844)

(W845)

(W846)

(W847)

(W848)

(W8432)

(W8433)

(W8434)

(W8435)

(W8436)

(W8437)

(W871)

(W872)

(W8423)

(W863)

(W81232)

1.68

8.99

16.92

19.81

25.15

34.76

43.29

51.22

0.30

8.08

11.59

15.24

16.77

19.82

2.13

5.49

17.53

17.53

17.53

WR V (STOP 1.4), base at 30°22.58'N, 103°17.18'W

2TL (USNM loc. 706b), baseat30°24.18'N, 103°10.12'W

1TL, base at 30°24.00'N, 103°10.30'W, no conodont samples

Word I (STOP 1.6), base at 30°24.06'N, 103°07.86'W

31583

31584

31585

31586

31587

31588

31589

31590

(W851)

(W9021)

(W852)

(W9022)

(W853)

(W9023)

(W854)

(W9024)

0.00

0.00

3.20

3.20

6.71

7.32

13.72

13.72
NUMBER 32 59

APPENDIX 3-1.—Continued.

USGS

PC#

31591

31592

31593

31594

31595

31596

31597

31598

31599

31600

_

31601

31602

-

-

-

-

-

-

-

-

-

31603

31604

31605

31606

31607

31608

31609

31610

31611

31612

31613

31614

31615

-

31629

31630

31616

Field

#

(W9025)

(W855)

(W9026)

(W856)

(W9027)

(W857)

(W9028)

(W858)

(W9029)

(W859)

(W8329)

(W8330)

(W8331)

(W8332)

(W8335)

(W8333)

(W8334)

(W8336)

(W8337)

(W8338)

(W8339)

(W8340)

(W81231)

(10AR4)

(10AR130)

(10AR200)

(15AR)

(W8414)

(W8415)

(W8416)

(W8417)

(W8418)

(W8419)

(W8420)

(W8421)

(W8422)

(W8717)

(W8719)

(W8718)

Height

(m)

17.99

21.65

26.83

29.88

29.88

35.67

35.82

41.16

44.51

44.82

0.00

9.76

14.94

28.51

35.37

36.43

42.99

47.87

62.80

70.12

81.10

94.82

100.30

1.22

39.63

60.98

0.00

3.66

8.84

0.46

1.37

25.15

29.88

42.38

55.49

60.37

71.65

75.46

83.23

to O O "K ml

i

•§

o o p 5b So t>o

o o o

11

1 •~> U 09

> ^ s I il

l

.a.

i

---- - + ----- - + ---- -

- + -- - + --- - + - + ---- -

- + -- - + --- - + - + ---- -

___________ _ + ____ _

- + -- - + --- - + - - + + -- -

8AR (AR I, USNM loc. 73 lz), base at 30°24.28'N, 103°09.83'W

____________ _ + ___ _

i

- + --- - + ----- - + --- -

9AR, bas e at 30°24.43'N, 103°09.33'W

i _| _ —

- + --- - + ---------- -

AR II, base at 30°23.56'N, 103°12.07'W

----- - + -- - + ------ -

- + --- - + -- - + - - + --- -

- + --- - + -- - + ------ -

AR III, base at 30°24.02'N, 103°10.07'W
60 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

APPENDIX 3-1.—Continued.

USGS

PC#

Field

#

.S -S2 -2

I I

Height

(m)

iticw etina tr

1

&•ofti, etina a

1

CO

ahoen

^2

1

1

ahoen

^2

1mking

<3•te//a 1Mes

I

8•fe/to 1

1

so

ft.>lella

1

%annoh 'lella

1

|"3

1

1

S

IXan,

"a

IXan,

lU li

lllll l ffi

lj

ifl

l l l

31617

31631

31632

31618

(W8720)

(W8721)

(W8722)

(W9031)

(W9032)

(W9033)

31619 (W81235)

(W886)

(W881)

31620 (89PR1)

143.29

202.74

229.88

1.00

15.24

18.90

28.96

-

31621

31622

-

31621

31624

-

31625

31626

31627

(88R2)

(9BR1)

(89BR2)

(88R1)

(88R3)

(89BR5)

(W9030)

(9BR5)

(89BR6)

(W913)

(W882)

(W883)

(W884)

(W885)

(W887)

(W888)

0.00

9.15

10.67

137.20

18.29

25.30

28.20

33.23

35.37

37.20

49.70

52.35

56.10

59.15

63.41

98.78

10AR, base at 30°23,53'N, 103°l 1.42'W, no conodont samples

4AR, base at 30°23.97'N, 103°10.79'W, no conodont samples

12PW, base at 30°25.34'N, 103°06.96'W, no conodont samples

CAP I, base at 30°22.79'N, 103°18.27'W

CAPII,baseat30°27.65'N, 103°15.11'W

China Tank, 30°23.45'N, 103°10.94'W

---- - + ------ - +

Word, 30°13.95'N, 103°28.11'W

Capitan, 30°24.64'N, 103°16.55'W

PR I, base of Capitan at 30°21.82'N, 103°20.48'W

------ - + ---- - +

BR I, base at 30°27.39'N, 103°20.01'W

BR II, base at 30°26.72'N, 103°19.67'W

Word II, base at 30°20.50'N, 103°17.75'W
NUMBER 32 61

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editor, Conodont Biofacies and Provincialism. Geological Society of

America, Special Paper, 196:263-281, plates 1-5.

1986. Paleontology and Deposition of the Phosphoria Formation. University of Wyoming, Contributions to Geology, 24:107-142, 20 figures.

Wardlaw, B.R., R.A. Davis, D.M. Rohr, and R.E. Grant

1990. Leonardian-Wordian (Permian) Deposition in the Northern Del

Norte Mountains, West Texas. United States Geological Survey

Bulletin, 1881-A:A1-A14, plates 1-4.

Wardlaw, B.R., and R.E. Grant

1987. Conodont Biostratigraphy of the Cathedral Mountain and Road

Canyon Formations, Glass Mountains, West Texas. In D. Cromwell

and L.J. Mazzullo, editors, The Leonardian Facies in W. Texas and

S.E. New Mexico and Guidebook to the Glass Mountains, West

Texas. Society of Economic Paleontologists and Mineralogists,

Permian Basin Section, Publication, 87-27:63-66.

1990. Conodont Biostratigraphy of the Permian Road Canyon Formation,

Glass Mountains, Texas. United States Geological Survey Bulletin,

1895-A.-A1-A18, plates 1-4.

Wardlaw, B.R., C.A. Ross, and R.E. Grant

2000. Cyclic Deposition of the Permian Road Canyon Formation, Glass

Mountains, West Texas. In B.R. Wardlaw, R.E. Grant, and D.M.

Rohr, editors, The Guadalupian Symposium. Smithsonian Contributions to the Earth Sciences, 32:121-126, 3 figures.

Wardlaw, B.R., and S.F. Rudine

2000. The Altuda Formation of the Glass and Del Norte Mountains. In

B.R. Wardlaw, R.E. Grant, and D.M. Rohr, editors, The Guadalupian Symposium. Smithsonian Contributions to the Earth Sciences,

32:313-318,4 figures.

Wardlaw, B.R., and R.L. Stamm

1992. Hindeodus. [Abstract.] Geological Society of America, Abstracts

with Programs, 24:70.

Youngquist, W.L., R.W. Hawley, and A.K. Miller

1951. Phosphoria Conodonts from Southeastern Idaho. Journal of Paleontology, 25(3):356-364, plate 54.
Plates 3-1-3-12
64 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 3-1

Diplognathodus and Pseudohindeodus

FIGURES 1-4.—Diplognathodus sp.: 1, 2, lateral view (xl56) and upper view (xl58), Pa element, USNM

482540; 3, 4, lateral view (x80.6) and upper view (x79.4), Pa element, USNM 482541. All specimens from

USGS 31535-PC (89BM-343). (Reduced to 72% of original for publication.)

FIGURES 5-24.—Pseudohindeodus ramovsi Gullo and Kozur: 5, lateral view, Sa element (x81.5), USNM

482542; 6, inner view, Sb element (x82.9), USNM 482543; 7, inner view, Sb element (x82.9), USNM 482544;

8, inner view, Sb element (x81.5), USNM 482545; 9, inner view, Sc element (x82.9), USNM 482546; 10,

oblique upper view, Pa element (x82.9), USNM 482547; 11, upper view, Pa element (x80.9), USNM 482548;

12, upper view, Pa element (x80.8), USNM 482549; 13, upper view, Pa element (x80.8), USNM 482550; 14,

lateral view, Pa element (xl60), USNM 482551; 15, lateral view, Pa element (xl61), USNM 482552; 16,

lateral view, Pb element (x80.8), USNM 482553; 17, posterolateral view, M element (x80.8), USNM 482554;

18, posterolateral view, M element (x80.8), USNM 482555; 19, 20, lateral view (x 160) and upper view (xl62),

Pa element, USNM 482556; 21, 22, lateral view (xl60) and upper view (xl62), Pa element, USNM 482557;

23, 24, lateral view (xl62) and upper view (xl59), Pa element, USNM 482558. Figures 5-13 from USGS

29813-PC (W85-15); Figures 14-24 from USGS 31535-PC (89BM-343). (Reduced to 72% of original for

publication.)
NUMBER 32 65

"T"~ *$>.

u "•' * <" ~-
66 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 3-2

Hindeodus, Sweetognathus, Iranognathus, and Mesogondolella

FIGURES 1-21.—Hindeodus excavatus (Behnken): 1, posterior view, Sa element (x79.4), USNM 482559; 2,

posterior view, Sa element (x79.4), USNM 482560; 3, posterior view, Sa element (x79.4), USNM 482561; 4,

posterolateral view, Sb element (x79.4), USNM 482562; 5, posterolateral view, Sb element (x79.4), USNM

482563; 6, posterolateral view, Sb element (x79.4), USNM 482564; 7, inner view, Pb element (x79.4), USNM

482565; 8, inner view, Pb element (x79.4), USNM 482566; 9, posterolateral view, M element (x79.4), USNM

482567; 10, posterolateral view, M element (x79.4), USNM 482568; 11, inner view, Sc element (x79.4),

USNM 482569; 12, inner view, Sc element (x79.4), USNM 482570; 13, inner view, Sc element (x79.4),

USNM 482571; 14, inner view, Sc element (x79.4), USNM 482572; 15, inner view, Sc element (x81.6),

USNM 482573; 16, lateral view, Pa element (x79.1), USNM 482574; 17, lateral view, Pa element (x79.1),

USNM 482575; 18, lateral view, Pa element (x80.8), USNM 482576; 19, lateral view, Pa element (x80.8),

USNM 482577; 20, lateral view, Pa element (x81.5), USNM 482578; 21, lateral view, Pa element (x79.1),

USNM 482579. All specimens from USGS 31500-PC (W90-ls). (Reduced to 72% of original for publication.)

FIGURES 22-35.—Sweetognathus bicarinum, new species: 22, posterolateral view, M element (x79.4), USNM

482580; 23, posterolateral view, M element (x79.4), USNM 482581; 24, lateral view, Pb element (x79.4),

USNM 482582; 25, lateral view, Pb element (x79.4), USNM 482583; 26, lateral view, Pb element (x79.4),

USNM 482584; 27, anterolateral view, Sa element (x79.4), USNM 482585; 28, inner view, Sb element

(x79.4), USNM 482586; 29, inner view, Sc element (x79.4), USNM 482587; 30, inner view, Sc element

(x79.4), USNM 482588; 31, inner view, Sc element (x79.4), USNM 482589; 32, inner view, Sb element

(x79.4), USNM 482590; 33, upper view, Pa element (xl59), USNM 482591; 34, upper view, Pa element

(xl59), USNM 482592; 35, upper view, Pa element (xl59), USNM 482593 (Figures 33-35 illustrate growth

sequence from young adult to juvenile). All specimens from USGS 31500-PC (W90-ls). (Reduced to 72% of

original for publication.)

FIGURES 36, 37.—Iranognathus aff. /. punctatus Wardlaw: 36, upper view, Pa element (x 161.6), showing

pustulose ornament; 37, upper view, Pa element (x80.8), showing whole specimen, USNM 482594. Specimen

from USGS 31531-PC (W90-50). (Reduced to 72% of original for publication.)

FIGURES 38, 39.—Mesogondolella idahoensis transitional to M. nankingensis, juvenile specimens showing faint

serration along anterior margin, which is lost in adult: 38, upper view, Pa element (x79.4), USNM 482595; 39,

upper view, Pa element (x 159), USNM 482596. All specimens from USGS 31500-PC (W90-1 s). (Reduced to

72% of original for publication.)
NUMBER 32 67
68 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 3-3

Mesogondolella and Sweetognathus

FIGURES 1-16.—Mesogondolella aserrata (Clark and Behnken): 1, upper view, Pa element (x79.5), USNM

482597; 2, upper view, Pa element (x80.8), USNM 482598; 3, upper view, Pa element (x80.8), USNM

482599; 4, upper view, Pa element (x80.8), USNM 482600; 5, upper view, Pa element (x80.8), USNM

482601; 6, upper view, Pa element (x80.8), USNM 482602; 7, upper view, Pa element (x80.8), USNM

482603; 8, upper view, Pa element (x80.8), USNM 482604; 9, upper view, Pa element (x80.8), USNM

482605; 10, upper view, Pa element (x80.8), USNM 482606; 11, upper view, Pa element (x80.8), USNM

482607; 12, upper view, Pa element (x80.8, USNM 482608; 13, upper view, Pa element (x80.8), USNM

482609; 14, upper view, Pa element (x80.8), USNM 482610; 15, upper view, Pa element (x80.8), USNM

482611; 16, upper view, Pa element (x80.8), USNM 482612. All specimens from USGS 29814-PC (W85-16).

(Reduced to 72% of original for publication.)

FIGURES 17-20.—Sweetognathus bicarinum, new species: 17, inner view, Sb element (xlOO), USNM 482613;

18, lateral view, Pb element (xlOO), USNM 482614; 19, inner view, Sc element (xlOO), USNM 482615; 20,

upper view, Pa element (xl30), USNM 482616. All specimens from USGS 31583-PC (W85-1). (Reduced to

72% of original for publication.)
NUMBER 32 69
70 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 3-4

Xaniognathus, Sweetina, Hindeodus, and Mesogondolella

FIGURES 1-13.—Xaniognathus hydraensis Nestell and Wardlaw: 1, posterolateral view, Sb element (x79.4),

USNM 482617; 2, posterolateral view, Sb element (x79.4), USNM 482618; 3, posterior view, Sa element

(x80.8), USNM 482619; 4, posterior view, Sa element (x79.4), USNM 482620; 5, posterior view, M element

(x79.4), USNM 482621; 6, posterior view, M element (x79.4), USNM 482622; 7, lateral view, Pa element

(x79.4), USNM 482623; 8, lateral view, Pa element (x79.4), USNM 482624; 9, inner view, Pb element (x79.4),

USNM 482625; 10, inner view, Pb element (x79.4), USNM 482626; 11, lateral view, Sc element (x79.4),

USNM 482627; 12, lateral view, Sc element (x80.8), USNM 482628; 13, lateral view, Sc element (x80.8),

USNM 482629. All specimens from USGS 31535-PC (89BM-343). (Reduced to 72% of original for

publication.)

FIGURES 14-23.—Sweetina crofti, new species: 14, lateral view, Sc element (x79.4), USNM 482630; 15, lateral

view, Sc element (x79.4), USNM 482631; 16, posterolateral view, M element (x79.4), USNM 482632; 17,

lateral view, Sa element (x79.4), USNM 482633; 18, inner view, Sb element (x79.4), USNM 482634; 19,

lateral view, Pa element (x81.5), USNM 482635; 20, lateral view, Pa element (x81.5), USNM 482636,

holotype; 21, lateral view, Pb element (x79.4), USNM 482637; 22, lateral view, Pb element (x79.4), USNM

482638; 23, lateral view, Pb element (x79.4), USNM 482639. All specimens from USGS 31528-PC (W90-47).

(Reduced to 72% of original for publication.)

FIGURES 24, 25.—Hindeodus wordensis, new species: 24, lateral view, Pa element (x80.8), USNM 482640,

specimen abraded and broken so that it appears like H. julfensis; 25, lateral view, Pa element (x80.8), USNM

482641. Both specimens from USGS 31625-PC (9BR-5). (Reduced to 72% of original for publication.)

FIGURES 26, 27, 29, 30.—Mesogondolella shannoni Wardlaw: 26, upper view, anterior fragment of Pa element

(x80.8), USNM 482642; 27, upper view, Pa element (x80.8), USNM 482643; 29, upper view, Pa element

(x80.8), USNM 482644; 30, upper view, Pa element (x80.8), USNM 482645. Figures 26, 27 from USGS

31618-PC (W90-33); Figures 29, 30 from USGS 31625-PC (9BR-5). (Reduced to 72% of original for

publication.)

FIGURE 28.—Mesogondolellapostserrata (Behnken): upper view, Pa element (x80.8), USNM 482646. Specimen

from USGS 31620-PC (89PR-1). (Reduced to 72% of original for publication.)
NUMBER 32 71
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 3-5

Mesogondolella

FIGURES 1-7.—Mesogondolella aserrata (Clark and Behnken): 1, upper view, Pa element (x80.8), USNM

482647; 2, upper view, Pa element (x80.8), USNM 482648; 3, upper view, Pa element (x80.8), USNM

482649; 4, upper view, Pa element (x80.8), USNM 482650; 5, upper view, Pa element (x80.8), USNM

482651; 6, upper view, Pa element (x80.8), USNM 482652; 7, upper view, Pa element (x80.8), USNM 482653.

All specimens from USGS 29818-PC (W85-20). (Reduced to 72% of original for publication.)

FIGURES 8-12.—Mesogondolella altudaensis (Kozur): 8, upper view, Pa element (x80.8), USNM 482654; 9,

upper view, Pa element (x80.8), USNM 482655; 10, upper view, Pa element (x80.8), USNM 482656; 11, upper

view, Pa element (x80.8), USNM 482657; 12, upper view, Pa element (x80.8), USNM 482658. All specimens

from USGS 31627-PC (W91-3). (Reduced to 72% of original for publication.)

FIGURES 13-20.—Meosogondolellapostserrata (Behnken): 13, upper view, Pa element (x80.8), USNM 482659;

14, upper view, Pa element (x80.8), USNM 482660; 15, upper view, Pa element (x80.8), USNM 482661; 16,

upper view, Pa element (x80.8), USNM 482662; 11, upper view, Pa element (x80.8), USNM 482663; 18, upper

view, Pa element (x80.8), USNM 482664; 19, upper view, Pa element (x80.8),USNM 482665; 20, upper view,

Pa element (x80.8), USNM 482666. All specimens from USGS 29818-PC (W85-20). (Reduced to 72% of

original for publication.)
NUMBER 32 73
74 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 3-6

Mesogondolella

FIGURES 1-7.—Mesogondolella postserrata (Behnken): 1, upper view, Pa element (x80.8), USNM 482667; 2,

upper view, Pa element (x80.8), USNM 482668; 3, upper view, Pa element (x80.8), USNM 482669; 4, upper

view, Pa element (x80.8), USNM 482670; 5, upper view, Pa element (x80.8), USNM 482671; 6, upper view,

Pa element (x80.8), USNM 482672; 7, upper view, Pa element (x80.8), USNM 482673. All specimens from

USGS 31536-PC (W91-1). (Reduced to 72% of original for publication.)

FIGURES 8-15.—Mesogondolella shannoni Wardlaw: 8, upper view, Pa element (x80.8), USNM 482674; 9,

upper view, Pa element (x80.8), USNM 482675; 10, upper view, Pa element (x80.8), USNM 482676; 11, upper

view, Pa element (x80.8), USNM 482677; 12, upper view, Pa element (x80.8), USNM 482678; 13, upper view,

Pa element (x80.8), USNM 482679; 14, upper view, Pa element (x80.8), USNM 482680, holotype; 15, upper

view, Pa element (x80.8), USNM 482681. All specimens from USGS 31536-PC (W91-1), same as above,

showing transitional morphotypes between each species. (Reduced to 72% of original for publication.)
NUMBER 32 75
76 SMITHSONIAN CONTRIBUTIONS TO TH E EARTH SCIENCES

PLATE 3-7

Mesogondolella

FIGURES 1-11.—-Mesogondolellapostserrata (Behnken): 1, upper view, Pa element (x80.8), USNM 482682; 2,

upper view, Pa element (x80.8), USNM 482683; 3, upper view, Pa element (x80.8), USNM 482684; 4, upper

view, Pa element (x80.8), USNM 482685; 5, upper view, Pa element (x80.8), USNM 482686; 6, upper view,

Pa element (x80.3), USNM 482687; 7, upper view, Pa element (x81.3), USNM 482688; 8, upper view, Pa

element, (x80.3), USNM 482689; 9, upper view, Pa element (x81.3), USNM 482690; 10, upper view, Pa

element (x80.8), USNM 482691; 11, upper view, Pa element (x80.8), USNM 482692. All specimens from

USGS 31621-PC (9BR-1). (Reduced to 72% of original for publication.)

FIGURES 12-25.—Mesogondolella shannoni Wardlaw: 12, upper view, Pa element (x79.4), USNM 482693; 13,

14, upper view (x79.4) and oblique lateral view (x80.3), Pa element, USNM 482694; 15, 16, upper view

(x79.4) and oblique lateral view (x82.3), Pa element, USNM 482695; 17, upper view, Pa element (x81.3),

USNM 482696; 18, 19, upper view (x80.8) and oblique lateral view (x82.3), Pa element, USNM 482697; 20,

21, upper view (x80.8) and lateral view (x80.3), Pa element, USNM 482698, showing large transverse ridge;

22, 23, lateral view (x80.3) and upper view (x81.3), Pa element, USNM 482699; 24, upper view, Pa element

(x80.8), USNM 482700, showing large (pathologic?) development of transverse ridge; 25, upper view, Pa

element (x80.8), USNM 482701, showing large pathologic specimen. All specimens from USGS 31621-PC

(9BR-1), same as above, showing transitional morphotypes between each species. (Reduced to 72% of original

for publication.)
NUMBER 32 77
78 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 3-8

Mesogondolella

FIGURES 1-16, 20.—Mesogondolella shannoni Wardlaw: 1, 2, lateral view (x81.6) and upper view (x83.3), Pa

element, USNM 482702; 3, 4, lateral view (x81.4) and upper view (x81.6), Pa element, USNM 482703; 5,

upper view, Pa element (x81.4), USNM 482704, transitional form to M. altudaensis; 6, 7, upper view (x79.3)

and lateral view (x80.0), Pa element, USNM 482705; 8, 9, upper view (x78.2) and lateral view (x79.8), Pa

element, USNM 482706; 10, 11, lateral view (x81.6) and upper view (x81.4), Pa element, USNM 482707,

transitional form to M. altudaensis; 12, lateral view, Pa element (x79.9), USNM 482708; 13, upper view, Pa

element (x79.3), USNM 482709; 14, 15, lateral view (x79.5) and upper view (x78.2), Pa element, USNM

482710; 16, oblique lateral view, Pa element (x79.4), USNM 482711; 20, upper view, Pa element (x81.4),

USNM 482712, showing development of transverse ridges. All specimens from USGS 31531-PC (W90-50).

(Reduced to 72% of original for publication.)

FIGURES 17-19, 21, 22.—Mesogondolella shannoni transitional to Mesogondolella altudaensis: 17, 18, upper

view (x81.6) and lateral view (x81.6), Pa element, USNM 482713; 19, oblique upper view, Pa element,

(x80.8), USNM 482714; 21, 22, upper view (x82.3) and lateral view (x81.4), Pa element, USNM 482715. All

specimens from USGS 31531-PC (W90-50). (Reduced to 72% of original for publication.)
NUMBER 32 79
80 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 3-9

Mesogondolella

FIGURES 1-27.—Mesogondolella shannoni Wardlaw: 1, 2, upper view (x81.8) and lateral view (x81.4), Pa

element, USNM 482716; 3, 4, upper view (x79.6) and lateral view (x79.5), Pa element, USNM 482717; 5, 6,

upper view (x79.9) and lateral view (x81.5), Pa element, USNM 482718; 7, lateral view, Pa element (x81.6),

USNM 482719; 8, upper view, Pa element (x82.0), USNM 482720; 9, 10, upper view (x81.8) and lateral view

(x81.4), Pa element, USNM 482721; 11,12, lateral view (x81.8) and upper view (x79.9), Pa element, USNM

482722; 13, 14, lateral view (x79.9) and upper view (x79.6), Pa element, USNM 482723; 15, 16, lateral view

(x77.8) and upper view (x77.7), Pa element, USNM 482724; 17, 18, lateral view (x79.5) and upper view

(x79.6), Pa element, USNM 482725; 19, upper view, Pa element (x79.6), USNM 482726; 20, 21, upper view

(x79.6) and lateral view (x80.0), Pa element, USNM 482727; 22, 23, upper view (x82.0) and lateral view

(x82.0), Pa element, USNM 482728; 24, 25, lateral view (x79.9) and upper view (x79.6), Pa element, USNM

482729; 26, 27, upper view (x81.6) and lateral view (x81.6), Pa element, USNM 482730. All specimens from

USGS 31533-PC (W91-2). (Reduced to 72% of original for publication.)
NUMBER 32 81
8 2

 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 3-10

Mesogondolella

FIGURES 1-3.—Mesogondolella idahoensis (Youngquist, Hawley, and Miller): 1, lower view, Pa element

(x82.9), USNM 482731; 2, lower view, Pa element (x80.8), USNM 482732; 3, lower view, Pa element (x81.5),

USNM 482733. All specimens from USGS 31639-PC (W90-8), Cathedral Mountian Formation, Split Tank

section. (Reduced to 72% of original for publication.)

FIGURES 4-7.—Mesogondolella idahoensis transitional to M. nankingensis: 4, lower view, Pa element (x80.8),

USNM 482734; 5, lower view, Pa element (x81.5), USNM 482735; 6, lower view, Pa element (x80.8), USNM

482736; 7, lower view, Pa element (x80.8), USNM 482737. Figures 4, 5 from USGS 29403-PC (W83-47) and

Figures 6, 7 from USGS 29404-PC (W83-48). (Reduced to 72% of original for publication.)

FIGURES 8-10.—Mesogondolella nankingensis (Ching [Jin]): 8, lower view, Pa element (x81.5), USNM 482738;

9, lower view, Pa element (x80.8), USNM 482739; 10, lower view, Pa element (x81.5), USNM 482740. All

specimens from USGS 31421-PC (W81-176). (Reduced to 72% of original for publication.)

FIGURES 11-17.—Mesogondolella aserrata (Clark and Behnken): 11, lower view, Pa element (x79.3), USNM

482741; 12, lower view, Pa element (x80.8), USNM 482742; 13, lower view, Pa element (x82.9), USNM

482743; 14, lower view, Pa element (x82.9), USNM 482744; 15, lower view, Pa element (x80.8), USNM

482745; 16, lower view, Pa element (x81.5), USNM 482746, transitional form to M. postserrata; 17, lower

view, Pa element (x80.8), USNM 482747, transitional form to M. postserrata. Figures 11-15 from USGS

29814-PC (W85-16) and Figures 16, 17 from USGS 29818-PC (W85-20). (Reduced to 72% of original for

publication.)

FIGURES 18, 19.—Mesogondolella postserrata (Behnken): 18, lower view, Pa element (x81.5), USNM 482748;

19, lower view, Pa element (x81.5), USNM 482749. Both specimens from USGS 29818-PC (W85-20).

(Reduced to 72% of original for publication.)
NUMBER 32 83
84 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 3-11

Mesogondolella

FIGURES 1-4.—Mesogondolella postserrata transitional to M. shannoni: 1, lower view, Pa element (x80.8),

USNM 482750; 2, lower view, Pa element (x81.5), USNM 482751; 3, lower view, Pa element (x80.8), USNM

482752, showing attached basal plate; 4, lower view, Pa element (x80.8), USNM 482753. All specimens from

USGS 31536-PC (W91-1). (Reduced to 72% of original for publication.)

FIGURES 5-14.—Mesogondolella shannoni Wardlaw: 5, lower view, Pa element (x79.8), USNM 482754; 6,

lower view, Pa element (x80.8), USNM 482755; 7, lower view, Pa element (x82.2), USNM 482756, showing

attached basal plate; 8, lower view, Pa element (x80.8), USNM 482757; 9, lower view, Pa element (x82.9),

USNM 482758; 10, lower view, Pa element (x80.8), USNM 482759; 11, lower view, Pa element (x80.8),

USNM 482760; 12, lower view, Pa element (x80.8), USNM 482761; 13, lower view, Pa element (x80.8),

USNM 482762; 14, lower view, Pa element (x81.3), USNM 482763. Figures 5-8 from USGS 31536-PC

(W91-1), Figures 9-12 from USGS 31531-PC (W90-50), and Figures 13, 14 from USGS 31533-PC (W91-2).

(Reduced to 72% of original for publication.)

FIGURES 15-17'.—Mesogondolella altudaensis (Kozur): 15, lower view, Pa element (x80.8), USNM 482764; 16,

lower view, Pa element (x82.9), USNM 482765; 17, lower view, Pa element (x80.8), USNM 482766. All

specimens from USGS 31533-PC (W91-2). (Reduced to 72% of original for publication.)
NUMBE

R 32

85
86 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 3-12

Iranognathus, Hindeodus, Neostreptognathodus, Sweetognathus, Sweetina,

and Xaniognathus

FIGURES 1, 2.—Hindeodus wordensis, new species: 1, lateral view, Pa element (x76.0), USNM 482767; 2, lateral

view, Pa element (x76.0), USNM 482768. Both specimens from USGS 31570-PC (W847). (Reduced to 72%

of original for publication.)

FIGURES 3-5.—Xaniognathus hydraensis Nestell and Wardlaw: 3, inner view, Pb element (x76.0), USNM

482769; 4, outer view, Pa element (x76.0), USNM 482770; 5, inner view, Pa element (x76.0), USNM 482771.

All specimens from USGS 31535-PC (89BM-343). (Reduced to 72% of original for publication.)

FIGURES 6-8.—SweetinaJ"estiva (Bender and Stoppel): 6, lower lateral view, Pa element (x76.0), USNM 482772;

7, lateral view, Pa element (x76.0), USNM 482773; 8, upper lateral view, Pa element (x76.0), USNM 482774.

Figure 6 from USGS 31472-PC (W877); Figures 7, 8 from USGS 31640-PC (W9016), Cathedral Mountain

Formation, Split Tank section. (Reduced to 72% of original for publication.)

FIGURE 9.—Sweetina triticum Wardlaw and Collinson: lateral view, Pa element (x76.0), USNM 482775.

Specimen from USGS 31569-PC (W846). (Reduced to 72% of original for publication.)

FIGURE 10.—Neostreptognathodus clinei Behnken: 10, upper view, Pa element (x76.0), USNM 482776.

Specimen from USGS 31575-PC (W8435). (Reduced to 72% of original for publication.)

FIGURE 11.—Sweetognathus bicarinum, new species: upper view, Pa element (x76.0), USNM 482777. Specimen

from USGS 31575-PC (W8435). (Reduced to 72% of original for publication.)

FIGURES 12-25.—Iranognathus punctatus, new species: 12, lateral view, Pb element (x76.0), USNM 482778,

from USGS 31641-PC (WP8635); 13, upper oblique view, Sa element (x76.0), USNM 482779, from USGS

31642-PC (WP8634); 14, lateral view, Pb element (x76.0), USNM 482780, from USGS 31643-PC (WP8611);

15, lateral view, Pb element (x76.0), USNM 482781, from USGS 31644-PC (WP8617); 16, lateral view, M

element, (x76.0), USNM 482782, from USGS 31645-PC (WP8632); 17, lateral view, M element (x76.0),

USNM 482783, from USGS 31646-PC (WP8634); 18, upper view, Pa element (x76.0), USNM 482784, from

USGS 31641-PC (WP8635); 19, upper view, Pa element (x76.0), USNM 482785, from USGS 31641-PC

(WP8635); 20, upper view, Pa element (x76.0), USNM 482786, from USGS 31642-PC (WP8634); 21, upper

view, Pa element (x76.0), USNM 482787, from USGS 31647-PC (WP8613); 22, upper view, Pa element

(x76.0), USNM 482788, from USGS 31645-PC (WP8632); 23, upper view, Pa element (x76.0), holotype,

USNM 482789, from USGS 31645-PC (WP8632); 24, upper view, Pa element (x76.0), USNM 482790, from

USGS 31643-PC (WP8611); 25, upper view, Pa element (x76.0), USNM 482791, from USGS 31643-PC

(WP8611). (Reduced to 72% of original for publication.)
NUMBER 32 87
4. Formal Middle Permian (Guadalupian) Series:

A Fusulinacean Perspective

Garner L. Wilde

ABSTRACT

The Guadalupian Symposium brought into focus the remarkable

agreement that exists between workers from a number of disciplines as

to the importance of proposing the Guadalupian Series as an

International Standard for the Middle Permian. Glenister (1991) and

Glenister et al. (1992) have outlined both the criteria required and the

desirable attributes of the Guadalupian Series (Girty, 1902, 1908) for

fulfilling the necessary requirements. The present paper seeks to

elucidate the importance of fusulinaceans in helping to fulfill these

requirements. Fusulinaceans occur, often in abundance, throughout the

Carboniferous and Permian, and species of this large group of

microfossils form an ideal evolutionary continuum. Along with

conodonts and ammonoids, in particular, fusulinaceans offer an

excellent means by which the well-established sedimentological

history of the West Texas Permian can be zoned and applied on a

worldwide basis.

Introduction

Since the early establishment of the Guadalupian Series by

Girty (1902), there has been an abundance of research on the

fauna and flora, as well as the sedimentology, of this diverse

group of rocks, particularly in the Guadalupe and Glass

mountains. Indeed, the way was paved for later research by the

publication of the Guadalupian Fauna (Girty, 1908) and the

mapping by P.B. King (1931) in the Glass Mountains and the

Guadalupe Mountains (1948).

Early work on the fiisulinids by Dunbar and Skinner (1937),

on the brachiopods by R.E. King (1931), and on the

ammonoids by Miller and Furnish (1940) established the

Garner L. Wilde, GLWInternational, 5 Auburn Court, Midland, Texas

79705.

importance of these faunas for local as well as worldwide

correlation. The more recent work on the fiisulinids by Ross

(1963), Skinner and Wilde (1954, 1955), Wilde (1955,

1986a,b, 1988, 1990), and Wilde and Rudine (this volume), on

the brachiopods by Cooper and Grant (1964, 1966, 1972, 1974,

1975, 1976a,b, 1977), and on the ammonoids by Furnish et al.

(1991), Glenister (1991), and Glenister et al. (1991) has served

to emphasize the importance of these fossil groups in zoning

the Permian rocks of North America. Very recently the

conodonts have achieved an important place in zonation,

particularly in the middle Permian (Guadalupian) rocks

(Behnken, 1975; Grant and Wardlaw, 1984; Wardlaw, 1991;

Wardlaw and Grant, 1987, 1990; and Lambert et al., this

volume).

The continuing work on all of these fossil groups has been

augmented tremendously by modern sedimentological methods (Newell et al., 1953; Boyd, 1958; Pray and Esteban, 1977;

Harris, 1982, 1988a,b; Sarg, 1986; Sarg and Lehman, 1986a,b).

Lloyd Pray has made enormous contributions to the overall

knowledge of the stratigraphy and sedimentology of the region

through his students and colleagues, who are too numerous to

list here. As a consequence, a well-understood Guadalupian

concept has emerged that should fulfill the necessary requirements for the establishment of the Guadalupian Series as the

international standard for the Middle Permian. Notwithstanding the closeness of understanding among the various workers,

much detailed effort still remains to be done before the task is

accomplished. Thus, suggestions put forth in the present paper,

based largely upon an understanding of fusulinaceans, are

offered to inspire a further effort in finalizing this important

work.

The Guadalupian study group (Glenister et al., 1992)

proposed that the Guadalupian Series comprises three stages; in

ascending order these are the Roadian Stage, the Wordian

Stage, and the Capitanian Stage. For convenience, these are

commonly referred to as early, middle, and late Guadalupian

(King, 1948; Wilde and Todd, 1968). Complete agreement has

not been reached as to the manner in which certain rock units fit

into these categories, but the basic understandings are in place.

89
90 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Guadalupian Series

EARLY GUADALUPIAN

Roadian Stage

The Roadian Stage was originally proposed by Furnish

(1966, 1973), although at the time he included the Roadian as

the youngest stage of the Leonardian (Artinskian) Series, based

largely upon the supposed index Perrinites ammonoid fauna.

Recent field work (Lambert et al., 1991, this volume) provided

a basis for a better understanding of the lateral relationships of

Roadian rocks from basin to shelf, thus helping to clarify earlier

stratigraphic concepts regarding ammonoid occurrences. Indeed, Furnish et al. (1991) currently recognizes both Leonardian and Guadalupian elements in the Roadian.

Wilde has reported in numerous publications (Wilde and

Todd, 1968; Wilde, 1986a,b, 1988, 1990) the typical fusulinid

faunas of the Roadian, particularly those that occur in the Road

Canyon Formation of the Glass Mountains and those of the

Cutoff Formation and its lateral equivalents (lower and middle

San Andres Formation) of the Guadalupe Mountains. In the

Guadalupe and Apache mountains, some stratigraphic detail

has been offered; however, in the Glass and northern Del Norte

mountains, stratigraphic data has been reported in only a

general way. Such generalized reporting could result in

criticism as to occurrences reported, even though the author is

unaware of queries of such nature. On the other hand, the

literature ought to reflect the close stratigraphic control that is

available.

Notwithstanding many years of data gathering at the surface

and in the subsurface, which produced data that are basically

unavailable for general publication, there are abundant data

recorded in Cooper and Grant (1977) of fusulinid identifications from many localities in the Glass and Del Norte

mountains. The majority of these identifications were made by

Wilde, including practically all that were made from the Road

Canyon Formation.

As is often the case in the early stages of stratigraphic work,

fusulinacean identifications by various workers were preliminary determinations, having been made from broken rock

surfaces; however, numerous sets of thin sections of a portion

of the Cooper and Grant material fortunately have been

retained. At the time they were sent, Cooper (pers. comm.,

1991) also supplied some basic stratigraphic data. From this

data eight measured sections were able to be reconstructed

(Figures 4-1, 4-2) in the northern Del Norte and western Glass

mountains to demonstrate some of the fusulinid control of the

Road Canyon Formation. Keeping in mind that these collections represent a very small percentage of the total that was

available, one is struck by the amazing consistency from

section to section. The measured sections shown herein have

not been rechecked in the field, and of necessity they are

generalized. Recent field work, conducted by numerous

workers, particularly of the type Road Canyon Formation, will

be more definitive in terms of thickness and bed description.

Wilde's zonation paper (1990) listed the assemblage zone of

Parafusulina boesei-Skinerina (PG-1) as the main zone of the

Roadian. At present, two main subzones of the Roadian are

recognizable in the Road Canyon Formation on the basis of

fusulinid species occurrences (PG-1-A, PG-l-B), and these

subzones appear to coincide with two basic lithofacies in the

eight measured sections herein being considered. The lowest

lithofacies is dominated by gray to bluish gray shale intervals,

with shale thickness of up to 50 feet (15.2 m). These are

interbedded with clastic carbonates (calcirudites), conglomerates, and occasional biohermal beds. This lower unit contains

Parafusulina boesei Dunbar and Skinner, P. splendens Dunbar

and Skinner, P. attenuata Dunbar and Skinner, and undescribed

Rauserella (PG-1-A). Individual shells of P, boesei are

commonly small for the species but appear to fall well within

the range of size variation.

The upper of the two lithofacies is dominated by yellowish

shales interbedded with cherty, platy limestones, and thick

biohermal beds. A greater diversity of fusulinid species is

found in this unit, including Parafusulina boesei, P. splendens,

P. rothi Dunbar and Skinner, P. attenuata, P. bakeril Dunbar

and Skinner, P. sullivanensis Ross, P. ironensis Ross,

Skinnerina rotundata (Dunbar and Skinner), and Rauserella sp.

(PG-l-B). Skinnerina has not been identified with any certainty

in the collections, but the approximate stratigraphic position for

two collections of Ross (1964) have been located in the present

sections. Ross collected his material from sections very near the

two reported herein.

In the Apache and Guadalupe mountains, similar fusulinid

faunas are present, and a guarded possibility occurs for the

correlation of the two lithofacies of the Glass Mountains-Del

Norte Mountains area with the described members of the

Cutoff Formation, especially in the Guadalupe Mountains area.

Harris (1982, 1988a) originally separated the Cutoff Formation of King (1948) into five correlation units, to which he

simply applied numbers. The lowest, unit 1, appears to rest

unconformably upon Leonardian (Bone Spring, Victorio Peak)

rocks, and it is overlain unconformably by the next three

successive units, units 2-4. These, in turn, are overlain

unconformably by unit 5. In the Guadalupe Mountains, Wilde

(1986a,b, 1988) reported the occurrence of the following

fusulinid species from the Cutoff Formation and/or its lateral

shelf equivalent, the lower and middle San Andres Formation:

Parafusulina boesei, P. splendens, P. maleyi Dunbar and

Skinner, Rauserella sp., and Skinnerina fusiformis Skinner

(originally reported as S. rotundata (Dunbar and Skinner)).

In the Cutoff Formation of the Apache Mountains, Wilde

identified the following (in Wilde and Todd, 1968): Parafusulina cf. P. boesei, P. cf. P. splendens, P. attenuata, P. maleyi, P.

sp., Skinnerina rotundata, Rauserella sp., and Boultonia sp.

In the Guadalupe Mountains type section of the Cutoff

Formation at Cutoff Mountain, Skinnerina fusiformis was

collected from the lower part of Harris' unit 5, whereas in the

Apache Mountains, S. fusiformis and S. rotundata were
NUMBER 32 91

103 20'

30 20'

30 15'

APPEL ^ ^

CHINA TANK yj RANCH S o SPLIT TANK

 rQ

103 25'

FIGURE 4-1.—Map of the Glass and Del Norte mountains, Brewster County, Texas, showing the location of the

sections illustrated in Figure 4-2 (modified after Cooper and Grant, 1977).

collected from the lower part of the Cutoff section, not far

above the Leonardian Victorio Peak. The specimens of S.

fusiformis from Cutoff Mountain were badly abraded, but they

appeared to belong to an allodapic sequence. It is possible that

two entirely different zones of Skinnerina are represented by

these occurrences.

Harris (this volume) has now given member names to his

(1982, 1988a) original correlation units of the Cutoff Formation, as follows:

Unit 5 = Williams Ranch Member

Units 2-4 = El Centro Member

Unit 1 = Shumard Member

Closer stratigraphic control than that, which the fusulinids

can provide, might possibly be provided by the conodonts. It is

conceivable, however, that the El Centro Member of the Cutoff

Formation in the Guadalupe Mountains is coeval with the

lower, gray shale-dominated lithofacies of the Glass and Del

Norte mountains, and the Williams Ranch Member may be

coeval with the yellow shale-dominated lithofacies of the same

areas. A serious question still exists as to the presence or

absence of a Shumard Member equivalent unit in the Glass

Mountains, one which is also poorly represented in the

Guadalupe Mountains because of severe erosion on the

unconformity at its top. If the Skinnerina zone of the basal

Cutoff in the Apache Mountains is an older zone than that of

the Road Canyon occurrences in the Glass and Del Norte

mountains, it is also conceivable that this section and the

section of the Cutoff Formation at South Mesa, Sierra Diablo

(western Texas), also represent lithofacies equivalents of the El

Centro and Williams Ranch members (Wilde in Wilde and

Todd, 1968, fig. 3).

Lambert et al. (this volume) suggests that because the

transition between the Leonardian conodont elements known as

Mesogondolella idahoensis (= Neogondolella) and the Roadian

conodont elements M. serrata [= nankingensis] begins at the

base of the El Centro Member of the Cutoff Formation, the

lower boundary of the Guadalupian should fall somewhere

within the El Centro Member. The logical boundary point

would seem to occur at about the contact of Harris' original

units 2 and 3. This could possibly represent the actual base of

the Road Canyon Formation of the Glass Mountains. The break
92 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES ROA

D CANYO

N FORMATIO

N CATHEDRAL MTN. FM.

YELLO

W SHALE

UNI

T

GRAY SHALE

UNI

T

k

 _

 2.

250S

•2001-

1501

100'

YELLOW SHALE UNIT:

T-1120 (732i)*

P. cf. bakeri

P. rothi

P. splendens

GRAY SHALE UNIT:

T-1119 (732h)

Parafusulina attenuata

P. bakeri

P. splendens

P. sullivanensis

T-1118 (732g)

Parafusulina attenuata

P. cf. rothi

P. splendens

P. sullivanensis

YELLOW SHALE UNIT:

T-1123 (732p)

Parafusulina sp.

T-1122 (732o)

Parafusulina spp.

T-1121 (732m)

Parafusulina attenuata

YELLOW SHALE UNIT:

T-1127 (732w)

Parafusulina attenuata

P. splendens

T-1126 (732t)

Parafusulina attenuata

P. boesei

P. splendens

P. sullivanensis

Rauserella sp.

YELLOW SHALE UNIT:

T-1130(732z)

Parafusulina attenuata

P. boesei

P. splendens

P.sp.

T-1129(732y)

Parafusulina ironensis

P. sp., as in T-1128

GRAY SHALE UNIT:

T-1128 (732x)

Parafusulina boesei

P. splendens

P.sp.

Rauserella sp., abundt

AMMONOIDS

THIN-BEDDED SS

SMALL-PEBBLE

CONGLOMERATE

CONGLWITH

PERRINITIES AT

BASE OF SLOPE

PERRINITIES

AT BASE

0.62 mi., S 69° W

of Old Payne Ranch

NO HORIZONAL SCALE

Conical Hill, 0.25 mi, N 28° W

of Old Payne Ranch

Hill 4861, 1.12 mi. N 58° W

of Old Payne Ranch

1.32 mi. N52° W

of Old Payne Ranch,

1.15 mi. N4° W

of Hill 4806

EXPLANATION

1

 |°'

1

Calcirudite

Limestone

Shale

A 1 Bioherms

Conglomerate

Chert

Sandstone

*(732i) etc., Cooper & Grant colln. nos. (1972)

FIGURE 4-2.—Stratigraphic cross section of the Road Canyon Formation in

the Glass and Del Norte mountains, Texas. Location of sections shown on

Figure 4-1.
NUMBER 32 93

YELLOW SHALE UNIT:

T-1134 (733e)

Parafusulina splendens

T-1133 (733d)

Parafusulina splendens

©Ross (1964)

T-1132 (733c)

Parafusulina aff. rothi

P.^pp.

GRAY SHALE UNIT:

T-1131 (733b)

Parafusulina boesei

YELLOW SHALE UNIT:

T-1163 (736e)

Parafusulina splendens

P. boesei

T-1164 (736f)

Parafusulina cf. sullivanensis

T-1165 (736g)

Parafusulina boesei •

YELLOW SHALE UNIT:

T-1066 (724d)

Parafusulina rothi

P. sullivanensis

T-1068 (724h)

Parafusulina boesei

P. sullivanensis

T-1067 (724e)

Parafusulina sullivanensis

©Ross (1964)

T-1046 (721qc)

Parafusulina cf. splendens

Psp.

T-1065 (724c)

Parafusulina splendens0.

P. rothi

P. sp.

T-1066

T-1068

T-1067

Jjl ^1 *,l ^ (2) SKINNERIN^.

(T) SKINNERINA

T-1132

E^^^5EiiS

T-1165

YELLOW SHALE UNIT:

T-1142 (733u)

Parafusulina boesei

P. sullivanensis

GRAY SHALE UNIT:

T-1143 (733v)

Parafusulina attenuata

P. boesei

P. sp.

Rauserella sp.

1

 i ' i ' i ' \

i i I I i

I I I I T

T-1046

T-1065

T-1142

• J_l \ T-1143

C> \ PERRINITIES

CONGLOMERATE

PERRINITIES

HILLI

1.55 mi. N 64° W

of Old Payne Ranch

Hill 0.55 mi. N 75° W

of Hill 4861, 1.6 mi. N 72° W

of Old Payne Ranch

Road Canyon Fm. Type Section 1.82 mi. N 84° W,

SE face of spur, 0.5 mi. due Hess Ranch House

north of Skinner Ranch 0.27 mi. S 28°E of Hill 5674,

Hess Canyon quadrangle
94 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

does not contradict the presently known fusulinid occurrences

at the outcrop; however, this horizon ought to correlate

stratigraphically to within the lower San Andres Formation of

the Algerita Escarpment, northern Guadalupe Mountains (Sarg,

1986; Sarg and Lehmann, 1986a,b; Wilde, 1986a). Such a

position seems somewhat high inasmuch as lower San Andres

fusulinid faunas have been found throughout the Permian Basin

in thousands of well bores, and they are always of Guadalupian

aspect rather than Leonardian. Dolomitization of the San

Andres shelf on the Algerita Escarpment has left much to be

desired for recovery of identifiable fusulinid faunas in the

critical intervals.

At present, it is little more than speculation to suggest that

the Pipeline Shale Member (King's southern Cutoff) at the

mouth of Brushy Canyon could be equivalent to any part of the

type Cutoff Formation as suggested by Wilde (Wilde and Todd,

1968), and this problem is still being explored. Although there

seems to be little support for this correlation at present, it is

believed that a genetic relationship does exist based upon

certain fusulinid occurrences. Glenister (oral comm., 1991)

suggested that indeed the ammonoid faunas are not as yet

sufficiently studied, but that the Pipeline Shale Member can

definitely be shown to lie above the highest Cutoff; however,

its lithic aspect seems closer to the Cutoff than to the Brushy

Canyon.

A rather sticky problem exists also regarding various

"reworked" occurrences of Boultonia guadalupensis Skinner

and Wilde. The types came from the large allocthonous blocks

in the Cutoff Formation of the Bone Canyon area on the

western side of the Guadalupe Mountains. There they are well

preserved, occur in large clasts, and are accompanied by other

clasts containing species of Parafusulina. Skinner and Wilde

collected similar material from King's southern Cutoff (Pipeline Shale) at the mouth of Brushy Canyon, except that the

individual specimens of B. guadalupensis were abraded. The

same was true in collections made by Lehmann, Sarg, Rossen,

and Wilde at Chinaman's Hat, about 2.5 miles (4.0 km) south

of Brushy Canyon, and in recent collections made by Lloyd

Pray and Mark Harris (pers. comm., 1991) of grainstones from

a debris flow at the well-known black cut near the highway,

which is a little more than a mile north of the Brushy Canyon

locality. This last material, which has been examined by the

author, appears to belong to the Williams Ranch Member of the

Cutoff, according to Pray and Harris. Occurring with the

abraded Boultonia guadalupensis were also abraded Parafusulina, one of which appeared to be close to P. attenuata Dunbar

and Skinner.

Harris (per. comm., 1991) believed that the allocthonous

blocks in the south wall of Bone Canyon ("patch reefs" of

Newell et al., 1953) possibly fall somewhere near the base of

the El Centro Member of the Cutoff Formation, but he

suggested that the solution to this problem of stratigraphic

placement is further complicated because of the presence of

erosion surfaces, channelizing, and intertonguing of strata in

strategic areas.

It is possible that all of the above-cited occurrences of B.

guadalupensis represent a single genetic package, beginning

with the large, and possibly older, megabreccias at Bone

Canyon, and proceeding basinward to the finer grainstones and

microbreccias farther out into the basin. It makes little

difference whether or not the original material was reworked

from the Leonardian (Victorio Peak) or from an unrecognized

Roadian shelf margin, not seen on the west face of the

Guadalupe Mountains. The essential question to be answered is

whether these disparate occurrences represent a package of

similar events during a short period of geologic time

comprising the Roadian Stage.

MIDDLE GUADALUPIAN

Wordian Stage

"Brushyan"

There is little doubt that a close relationship exists between

the fusulinid faunas of the Cutoff Formation and the overlying

Brushy Canyon Formation (Wilde and Todd, 1968; Wilde,

1990). For this reason, the "Brushyan" has been retained in the

early Guadalupian (Figure 4-3) as a younger fusulinid zone

than the Roadian. There could be many problems associated, on

the other hand, with making the Brushy Canyon part of the

middle Guadalupian (Wordian). Because of the difficulty in

establishing an unequivocal shelf equivalent for the Brushy

Canyon, most workers have avoided dealing with this

important rock sequence. Until the upper boundary of the

Roadian is sufficiently understood, most workers will continue

to carry the "Brushyan" as the basal Wordian, notwithstanding

a history (similar faunas, eroded shelf margin, etc.) analogous

to the Cutoff Formation.

Suffice it to say that the main zone of Parafusulina rothi-P.

maleyi (PG-2, Wilde, 1990) embraces the Brushy Canyon

Formation of the Delaware basin. The type locality for each

species is the Brushy Canyon of the Guadalupe and northern

Delaware mountains (Dunbar and Skinner, 1937). In fact, the P.

maleyi types came from only 250 feet (76 m) below the top of

the Brushy Canyon. It is likely that the Brushy Canyon was

deposited rapidly (perhaps 1 M.Y.), which could easily explain

the seemingly long range of its main zonal species. If the

Roadian Stage covered 2 M.Y., this would give an absolute

maximum of about 3 M.Y. for these forms, which is not

unreasonable for most fusulinid species, whose span varies

from 1 to 3 M.Y. and averages perhaps 1.5 M.Y.

Parafusulina sullivanensis Ross is another species that

occurs commonly in the Roadian and has been seen in lower

Brushy Canyon beds (Wilde, 1990). As to whether the upper

Road Canyon Formation represents, in part, a Brushy Canyon

equivalent, is at present unknown; however, if such correlation

were to be fusulinid-dependent, the answer would be one of

affirmation. Numerous undescribed Parafusulina that have

been found in the Brushy Canyon should serve to strengthen

this correlation once they are authenticated in the literature.
NUMBER 32 95

248

1

h

1

249

/

/ -

/

/ 250 -

251 *"

-

252

-

253 -

PR3.R .

STAGEJLFI

A

Q

z

Q

o

UJLAT

ASSEMBLAGE ZONE

ZONE OF

Palaeofusulina

sinensis

ZONE OF

Palaeofusulina

simplex

and

Dunbarula

ZONE OF

Paraboultonia

splendens

ZONE OF

Polydiexodina

LATE

GUADALUPIAN

AND

DJULFIAN

248 + 10

250-

285-

286 ±6

SYSTEM

DC

LU

Q_

STAGE

DJULFIAN

O

SUBUNIT

CAPITAN

CHERRY

CANYON

BRUSHY

ROADIAN

n i g

BURSUM

WILDE

ZONE

PD-2

PD-1

PG-6

PG-5

PG-4

PG-3

PG-2

PG-1

PL-3

PL-2

PL-1

PW-3

PW-2

PW-1

/

^

253 5^-i

254 -

255 -

256 -

257 ~

-

258

\259 -

\

\

ill

CD

H

UJIDDL \RLY

LU

H

m

3

CO

1

O

OC

LU

o

X

en

ocm

z

Q

*f RO/

ASSEMBLAGE ZONE

ZONE OF

LATEST

Parafusulina

ZONE OF

Parafusulina

lineatadeliciasensis

ZONE OF

Parafusulina

rothi-maleyi

ZONE OF

Parafusulina

boseiSkinnerina

EARLY

AND

MIDDLE

GUADALUPIAN

FIGURE 4-3.—The fusulinid zonation of the Permian, with emphasis on the Guadalupian (modified after Wilde,

1990).
96 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

"Cherryan"

Two important zones ofParafusulina comprise the main part

of the middle (Wordian) Guadalupian Series, which is

represented lithically by the Cherry Canyon Formation of the

Delaware basin and its shelf equivalents, namely, the upper San

Andres, Grayburg, and Queen formations. The Goat Seep reef

separates the Queen from the basinal Cherry Canyon. In the

Glass Mountains, the lithic equivalents are portions of the

Word and Vidrio formations.

The lowest zone is Parafusulina lineata-P. deliciasensis

(PG-3, Wilde, 1990). The marker species are accompanied by

the tiny fusulinid Leella fragilis Dunbar and Skinner, progenitor to the larger L. bellula Dunbar and Skinner of the

Capitanian. Parafusulina sellardsi Dunbar and Skinner is an

outstanding and readily recognizable species of this zone,

which occurs, often in abundance, in the Word Formation of

the Glass Mountains and elsewhere.

Parafusulina sellardsi Dunbar and Skinner is indeed a large,

strongly fluted species, but the zone of latest Parafusulina

(PG-4, Wilde, 1990) contains species of extremely large size.

These include P. kingorum Dunbar and Skinner, P. wordensis

Dunbar and Skinner, and P. antimonioensis Dunbar, as well as

numerous undescribed species. Leella fragilis Dunbar and

Skinner also occurs in this zone. The author does not accept the

reported occurrence of Rauserella erratica in the Word

Formation as reported by Ross (1964). It is believed that Ross'

species is not the same and that R. erratica is restricted to the

late Guadalupian (Capitanian).

Eopolydiexodina Wilde (1975) is a rather unique representative of zone PG-4 in the Asian world, but it has not been

identified with certainty in North America. Eopolydiexodina is

a transitional genus between Skinnerina and Polydiexodina; its

sporadic supplementary tunnels and lack of a well-defined

central tunnel is characteristic of the former genus, whereas its

elongation with heavy axial filling and squared septal folds is

characteristic of the latter genus.

At the outcrop in the Guadalupe Mountains, the prominent

unconformity that separates the Grayburg of the shelf from the

Goat Seep reef (Fekete et al., 1986) and overlying Queen

Formation may also separate zones PG-3 and PG-4. The only

evidence of this, however, is provided by the presence of

Parafusulina deliciasensis Dunbar and Skinner and P. lineata

Dunbar and Skinner at a single locality on the outcrop (Wilde,

1986a) where dolomitization is pervasive and in the subsurface

Grayburg of the McElroy Field, Upton County, Texas.

Fusulinid faunas of the Queen Formation are very poorly

known, but they appear to be a continuation of the P. lineataP. deliciasensis types of the Grayburg, judging from poor

collections that Wilde examined of those reported on by Newell

et al. (1953). The Goat Seep reef is strongly dolomitized, and

the youngest Cherry Canyon (Manzanita Limestone Member)

is poor in fusulinaceans; however, presumed equivalents in

Sonora, Mexico, contain some of the largest and most advanced

parafusulinid shells known (Dunbar, 1953).

LATE GUADALUPIAN

Capitanian Stage

The two main zones of the Capitanian from oldest to

youngest are Polydiexodina (PG-5) and Paraboultonia splendens (PG-6) (Figure 4-3), although a number of subzones

should be recognizable within this framework. The Capitan

Limestone is actually the reef portion of the shelf margin of the

late Guadalupian in the Guadalupe Mountains. On the shelf, but

behind the reef tract are, from oldest to youngest, the Seven

Rivers, Yates, and Tansill formations. These are represented in

the Delaware basin by the Bell Canyon Formation, which is

largely a basinal sand, as are the underlying Cherry Canyon and

Brushy Canyon formations. Interspersed throughout the Bell

Canyon are limestone members that were deposited during

highstand periods when sand deposition was either choked off

completely or severely constrained. The uppermost limestone

member of the Capitan is the Lamar Limestone, which is coeval

with the Tansill Formation on the shelf. We may speak of the

pre-Lamar Capitan and the Lamar-post Lamar Capitan when

we consider the two main zones, for although the post-Lamar

beds were not included by King (1948) in the Guadalupe

Series, they are clearly late Guadalupian rather than Ochoan in

lithologic as well as faunal aspect. Representative species of

zone PG-5 are Polydiexodina capitanensis Dunbar and Skinner, P. shumardi Dunbar and Skinner, Codonofusiella paradoxica Dunbar and Skinner, Rauserella erratica Dunbar and

Skinner, and Leella bellula Dunbar and Skinner. An evolutionary continuum appears to be represented in Polydiexodina, but

at present there are no published studies to corroborate this

observation.

Polydiexodina ranges upward in the Capitan to the McCombs Limestone Member (pre-Lamar), where it vanishes.

This level is represented within the Yates Formation on the

shelf. In the McCombs occurs Codonofusiella extensa Skinner

and Wilde, which developed from C. paradoxica Dunbar and

Skinner. These changes represent important steps in the

evolution of a group of genera that are extremely important for

zonation purposes. Evidence of the abrupt demise of Polydiexodina, with an attendant proliferation of the codonofusiellid

line, has recently been documented in the basinal Altuda

Formation (Bell Canyon equivalent) of the Glass Mountains

(Wilde and Rudine, this volume) and constitutes an extremely

important change in late Guadalupian fusulinacean evolution.

The zone of Paraboultonia splendens Skinner and Wilde

comprises the remainder of the late Guadalupian (PG-6, Wilde,

1990). This zone encompasses the Lamar and post-Lamar units

of King (1948). Within this framework, from oldest to

youngest, are the following subzones: Yabeina texana Skinner

and Wilde (PG-6-A), Paradoxiella pratti Skinner and Wilde

(PG-6-B), Reichelina lamarensis Skinner and Wilde (PG-6-C),

and Paraboultonia splendens Skinner and Wilde (PG-6-D).

This identical zonation has been observed both in the

Lamar-post Lamar of the basin side and in the Tansill

Formation on the shelf side (see especially Tyrrell et al., 1978).
NUMBER 32 97

Wilde and Rudine (this volume) have discovered an almost

identical sequence in the Altuda Formation of the Glass

Mountains. Yabeina has not been located, but Paradoxiella,

Reichelina, and Paraboultonia have been observed in that

order, with some overlap, from oldest to youngest. Occurring

with Paraboultonia is the Asian form Lantschichites, with

which Paraboultonia has been consistently confused.

Lantschichites always uncoils and is really an elongated

codonofusiellid, whereas Paraboultonia never uncoils (Wilde,

1975:80). Strangely, Lantschichites has not been seen in the

Guadalupe Mountains or Delaware Mountains sequence, but in

time it will probably be discovered, as will Yabeina, in the

Glass Mountains.

Returning to the Codonofusiella evolutionary line, the

following scenario is suggested. Codonofusiella probably

developed out of Boultonia, a common genus in Wolfcampian,

Leonardian, and early Guadalupian equivalents. Uncoiling,

which is not uncommon, has been observed in numerous

fusulinacean groups throughout the Carboniferous and Permian. Well-known examples are Millerella, a simple, discoidal

profusulinellid, and Nipponitella, a schwagerinid.

The simple Codonofusiella paradoxica gave rise to new

species, such as C. extensa, by elongation of the axis of coiling.

Ultimately, more and more elongation of shells gave rise to

forms such as Lantschichites. In fact, C. extensa and

Lantschichites are very close in their development, the main

difference being in the size and shape of the coiled portion. But

because uncoiling was proceeding at the same time, the shells

developed an irregular axis in the polar extremities. Next, this

extension and uncoiling gave rise to the implantation of

succeeding septa on the back side of the coiled portions of the

shell. This process continued until the septa from opposing

ends of the shell actually met, causing a bridging over of the

septa. Finally, the whorls became completely annular, giving

rise to Paradoxiella (Skinner and Wilde, 1955).

Somewhere along the way, the paraboultonids developed,

possibly directly from the boultonids, with a mere inflation of

the final whorl. The essential difference, then, between the

paraboultonids and the codonofusiellids is that the antetheca of

the former never lifted off of the coiled portion of the shell,

whereas septa of the latter group always lifted off and then

succeeding septa implanted themselves on the previously

uncoiled septation. That is precisely what happened in

Lantschichites and is precisely why no generic synonymy

exists with Paraboultonia.

Termination of the Guadalupian

Recently, largely in oral presentations and discussions,

consideration has been offered as to which taxa should be

utilized for stabilization of the top of the Guadalupian Series

and coincident Capitanian Stage. The top must also, by

definition, determine, or be determined by, the base of the

highest Permian, the Dzhulfian Series.

Glenister et al. (1992) discussed the range of the cyclolobin

ammonoid genus Timorites and its possibilities, inasmuch as its

species start early in the Capitanian Stage and range into the

Dzhulfian. Here, as is often a common problem for the

ammonoids, rarity of specimens from critical zones can cause

difficulties. The ammonoids, however, still offer some of the

best tools for long-range correlation due to their pelagic nature.

The conodonts offer, as they have for the base of the

Guadalupian, excellent potential for helping to establish a

Guadalupian-Dzhulfian boundary, particularly within the

Mesogondolella postserrata continuum and its related genus

Clarkina.

Fusulinaceans offer an excellent resource for determining the

Guadalupian-Dzhulfian boundary. Unless conodont elements

or ammonoids can be recovered from evaporitic sequences,

which overly the Capitanian, the fusulinids may be the most

useful group. A brief consideration of just how and why this

may be true deserves some attention.

The highest zone of the Capitanian, Paraboultonia splendens (PG-6, Wilde, 1990), includes the Lamar and post-Lamar

beds of the Bell Canyon Formation. These, in turn, are overlain

by the Castile Formation, a thick, thinly laminated, evaporitic

unit, which appears at first glance to be an extremely shallow

water deposit. At its contact with the underlying Bell Canyon,

best seen at Seven Heart Gap, in the southern Delaware

Mountains, the two formations are gradational (Wilde, 1975;

Cys, 1975, 1978). In fact, one has some difficulty in deciding

the proper lithologic boundary. The Bell Canyon, on the other

hand, appears to have been deposited in deep water; indeed,

Newell et al. (1953) have shown that water depths at the close

of Bell Canyon deposition must have been in excess of 1700

feet (518 m). Whatever the cause, the Delaware basin must

have become a sealed, or partly sealed, basin at the time. This

insured deep water evaporite deposition at least until the basin

had become sufficiently filled with sediment to allow for a

rapid change to shallow-water evaporitic conditions, including

thick salt deposits (Salado Formation).

Thus, conditions at the close of the Capitanian (Bell Canyon)

became totally unfavorable for life in the Delaware basin. But,

just prior to these events some of the most uniquely important

fusulinaceans ever seen in the geologic column had lived,

assuring the establishment of a worldwide correlation of the top

of the Guadalupian Series.

The tiny Yabeina texana at the base of the Lamar Limestone

Member (Subzone PG-6-A) was considered an enigma when

first reported (Skinner and Wilde, 1955). It was thought to be

too small, possibly another genus. But the advanced development of septula in the species placed it within the Yabeina zone.

A few feet above was the strange Paradoxiella pratti (Subzone

PG-6-B), a Codonofusiella gone awry. Later Ishii and

Takahashi (1960) described Paradoxiella japonica from

conglomerates of the Kwanto Massif in Japan, but its

stratigraphic position was undetermined until Sada and Skinner

(1977) discovered Paradoxiella in the Akasaka Limestone,

Gifu Prefecture, Japan. Its associated fauna included
98 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Codonofusiella sp., Kahlerina sp., and Yabeina globosa

(Yabe), this last being the main zone fossil of the Japanese

Yabeina zone.

At the top of the Bell Canyon Formation the occurrence of

Paraboultonia splendens (Subzone PG-6-D) is definitive. For

a number of years some workers have assumed that Paraboultonia is a junior subjective synonym of Lantschichites

Toumanskaya (1953). Indeed, Toumanskaya described one

species as L. splendens (Skinner and Wilde). Now, however,

Wilde and Rudine (this volume) have shown that the two

genera are different, as discussed above, but that they

commonly occur together. Toumanskaya's forms came from

late Guadalupian equivalents of the Ussuri Region of Russia.

Sheng (1963), Sosnina (1968), and Wang et al. (1981) also

have described material from Kwangsi Province of South

China, from Russia, and from the Qinghai-Xizang Plateau of

China, respectively, all of which they identify as Lantschichites. Some of their material represents that genus, with its

characteristic uncoiling, but some of the material also appears

to represent true Paraboultonia.

Reichelina lamarensis (Subzone PG-6-C) is mentioned last

for a reason. In the Guadalupe and Glass mountains, the

subzone is clearly older than the Paraboultonia splendens

subzone (Skinner and Wilde, 1954, 1955; Wilde, 1955; Tyrrell,

1962, 1969; Tyrrell et al., 1978; Wilde and Rudine, this

volume). But the genus is long ranging, overlapping with

numerous zones below and occurring commonly in the higher

Dzhulfian Series in other parts of the world. Nestell (pers.

comm.), who has been studying all occurrences of the genus,

believes that R. lamarensis might not belong to the genus

Reichelina. Be this as it may, R. lamarensis is one of the

subzonal markers with which the late Guadalupian is partly

defined. In fact, Tyrrell et al. (1978:85) stated that "Reichelina

(referring to R. lamarensis) slightly overlaps the lower part of

the Paraboultonia zone, but otherwise is restricted to the

middle Tansill and to all except the lower Lamar."

As regards overlapping ranges of zonal and subzonal

markers, this represents the real world of fossil ranges.

Furthermore, this also represents a continuum that helps to

insure the absence of major breaks in a given sequence, which,

in turn, strengthens the definition of series such as the

Guadalupian.

Dzhulfian equivalent rocks younger than the Guadalupian,

being evaporitic and unfossiliferous in the Delaware basin,

must be defined in fossiliferous sequences in such areas as the

Dzhulfa region of northern Iran and southern China. There, two

main zones of fusulinids are fairly well known. The lower zone

of Palaeofusulina simplex and Dunbarula (PD-1) and the upper

zone of Palaeofusulina sinensis (PD-2) are not presently

known anywhere in North America (Wilde, 1990). Continuity

is assured, however, in the upper La Colorada beds at La

Difunta, Mexico, where the ammonoids Eoaraxoceras, Kingoceras, and Timorites occur in the youngest Permian beds,

precisely as they do in Iran in basal Dzhulfian beds (Glenister

etal., 1991).

The close of the Permian was marked by major extinctions of

many faunal and floral groups. The fusulinaceans appear to

have succumbed to these extinctions also, for no survivors are

known to have extended into the Triassic.

Acknowledgments

The author thanks Brian Glenister for recommending this

paper for inclusion in the present volume, and for critically

reading the manuscript. Thanks also are extended to Bruce

Wardlaw, David Rohr, and Richard Grant for their critical

reading of the manuscript. Rex Doescher converted the

typescript to diskette.

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Expedition of the Qinghai-Xizang Plateau. 80 pages, 21 plates.

Beijing: Palaeontology of Xizang, Science Press, Book 111.

Wardlaw, B.R.

1991. Conodont Biostratigraphy and Depositional Setting of the Guadalupian Rocks of the Glass and Del Norte Mountains. [Abstract.] In

B.R. Wardlaw, R.E. Grant, and D.M. Rohr, editors, Proceedings of

the Guadalupian Symposium, March 13-15, 1991, Sul Ross State

University, Alpine, Texas, page 17.

Wardlaw, B.R., and R.E. Grant

1987. Conodont Biostratigraphy of the Cathedral Mountain and Road

Canyon Formations, Glass Mountains, West Texas. In D. Cromwell

and L.J. Mazzullo, editors, The Leonardian Facies in W. Texas and

S.E. New Mexico and Guidebook to the Glass Mountains, West

Texas. Society of Economic Paleontologists and Mineralogists,

Permian Basin Section, Publication, 87-27:63-66.

1990. Conodont Biostratigraphy of the Permian Road Canyon Formation,

Glass Mountains, Texas. United States Geological Survey Bulletin,

1895-A:A1-A18, plates 1-4.

Wilde, G.L.

1955. Permian Fusulinids of the Guadalupe Mountains. In Permian Field

Conference, October 1955. Society of Economic Paleontologists and

Mineralogists, Permian Basin Section, Publication, 55-1:59-62.

1975. Fusulinid-Defined Permian Stages. In J.M. Cys and D.F. Toomey,

editors, Permian Exploration, Boundaries, and Stratigraphy. Society

of Economic Paleontologists and Mineralogists, West Texas

Geological Society and Permian Basin Section, Publication,

75-65:67-83.

1986a. Stratigraphic Relationship of the San Andres and Cutoff Formations,

Northern Guadalupe Mountains, New Mexico and Texas. In G.E.

Moore and G.L. Wilde, editors, Lower and Middle Guadalupian

Facies, Stratigraphy, and Reservoir Geometries, San Andres/

Grayburg Formations, Guadalupe Mountains, New Mexico and

Texas. Society of Economic Paleontologists and Mineralogists,

Permian Basin Section, Publication, 86-25:49-63, plates 1-5.

1986b. An Important Occurrence of Early Guadalupian (Roadian) Fusulinids from the Cutoff Formation, Western Guadalupe Mountains,

Texas. In G.E. Moore and G.L. Wilde, editors, Lower and Middle

Guadalupian Facies, Stratigraphy and Reservoir Geometries, San

Andres/Grayburg Formations, Guadalupe Mountains, New Mexico

and Texas. Society of Economic Paleontologists and Mineralogists,

Permian Basin Section, Publication, 86-25:65-68, plate 1.

1988. Fusulinids of the Roadian Stage. In S.T. Reid, R.O. Bass, and P.

Welch, editors, Guadalupe Mountains Revisited, Texas and New

Mexico. West Texas Geological Society, Publication, 88-84:143-

147, plates 1,2 [no text].

1990. Practical Fusulinid Zonation: The Species Concept; with Permian

Basin Emphasis. West Texas Geological Society, Bulletin, 29(7): 5-

34.

Wilde, G.L., and S.F. Rudine

2000. Late Guadalupian Biostratigraphy and Fusulinid Faunas, Altuda

Formation, Brewster County, Texas. In B.R. Wardlaw, R.E. Grant,

and D.M. Rohr, editors, The Guadalupian Symposium. Smithsonian

Contributions to the Earth Sciences, 32:343-371,3 figures, 9 plates.

Wilde, G.L., and R.G. Todd

1968. Guadalupian Biostratigraphic Relationships and Sedimentation in

the Apache Mountain Region, West Texas. In B.A. Silver, editor,

Guadalupian Facies, Apache Mountains Area, West Texas. Society

of Economic Paleontologists and Mineralogists, Permian Basin

Section, Publication, 68-11:10-31.
5. Members for the Cutoff Formation,

Western Escarpment of the

Guadalupe Mountains, West Texas

Mark T. Harris

ABSTRACT

The boundary between the Leonardian and Guadalupian Stages

(North American usage) occurs within the Cutoff Formation, which

crops out along the western escarpment of the Guadalupe Mountains,

West Texas. The internal stratigraphy within the Cutoff Formation is

complex, and to date only informal schemes have been proposed.

Three members are defined, which in ascending order are the Shumard

Member, the El Centro Member, and the Williams Ranch Member.

Type sections for these members are all located in the southern part of

the western escarpment within the Guadalupe Mountains National

Park.

These members are proposed to reinforce the revisions in the

stratigraphic framework for these beds since the pioneering work of

King (1942, 1948) and Newell et al. (1953). These members can be

traced throughout the western escarpment region and are stratigraphically distinct units separated by unconformities or lithologic changes.

The proposed members probably represent the extent to which

previous faunal collections can be located. These collections are

important because these strata are a candidate for an international

boundary stratotype (Glenister et al., 1991; Glenister, 1991). Three

measured sections of basinal Cutoff Formation are included as a

framework for future paleontological collections.

Introduction

The strata within the Cutoff Formation comprise the

boundary beds between the Leonardian and Guadalupian stages

(North American usage). The stratigraphic position of Cutoff

faunas relates directly to the definition of this boundary. Recent

Mark T. Harris, Department ofGeosciences, University of WisconsinMilwaukee, Milwaukee, Wisconsin 53201.

proposals to designate this section as a candidate for an

international boundary stratotype were presented to the

Subcommission on Permian Stratigraphy of the International

Commission on Stratigraphy (Glenister, 1991). This paper

proposes formal lithostratigraphic members for these strata,

which will replace the earlier, informal subdivisions.

General Nomenclature Review

The Cutoff Formation crops out in various ranges located

around the edges of the Permian Delaware basin in West Texas.

The type section is located at Cutoff Mountain in the

Guadalupe Mountains (King, 1942, 1948), and equivalent

strata occur in the northern Guadalupe Mountains (Boyd, 1958;

Hayes, 1959), Sierra Diablo (King, 1965), Wylie Mountains

(Hay-Roe, 1957), and Apache Mountains (Wood, 1968)

(Figure 5-1).

King (1942, 1948) established the basic stratigraphic

nomenclature for the type area in the Guadalupe Mountains,

designating the Cutoff Shale as a member of the Bone Spring

Limestone (Figure 5-2). At the Cutoff type section (Cutoff

Mountain) and southward to Shumard Canyon, the dark gray

color and shale content of the basal Cutoff strata contrast with

the underlying light gray dolomites of the Victorio Peak.

However, to the south the Victorio Peak changes facies into the

black limestone beds of the Bone Spring Limestone, and King

(1942, 1948) did not separate out the Cutoff Shale Member.

Newell et al. (1953) recognized the basinal shaly equivalent

to the shale at the base of the Cutoff and adjusted the

terminology accordingly. They also realized that the overlying

basinal limestones ("Upper Bone Spring Limestone") equate to

the limestone in the upper part of the Cutoff Shale shelf section.

King (1965) raised the Cutoff to formational status as the

Cutoff Shale, which Harris (1988a) suggested be redefined as

the Cutoff Formation (without change of formation rank, type

section, or boundaries) based upon the lithological predominance of limestone (60%-70%) over shale (30%-40%).

101
102 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

NMITX

Guadalupe

Mountains

t

km 100

miles 100

FIGURE 5-1.—Location of the Guadalupe Mountains and other ranges mentioned in the text relative to Permian

paleogeography. Modified from King (1948).

CHERRY CANYON FORMATION

BRUSHY

CANYON

FORMATION

VICTORIO PEAK

GRAY MEMBER

KING 1965

CHERRY CANYON FORMATION

CUTOFF SHALE

VICTORIO PEAK

LIMESTONE

BRUSHY CANYON FORMATION

CUTOFF SHALE

"PIPEUNE SHALE" ^

BONE SPRING LIMESTONE

* WARREN 1955

CHERRY CANYON FORMATION

BRUSHY CANYON FORMATION

MACDANIEL AND PRAY, UNPUBL; HARRIS 1987

CUTOFF

VICTORIO PEAK

FORMATION*

CHERRY CANYON FORMATION

S . BRUSHY CANYON FORMATION

^ C ~ CUTOFF FM

BONE SPRING LIMESTONE

FIGURE 5-2.—Nomenclature changes in the Leonardian-Guadalupian boundary strata in the Guadalupe

Mountains.

VERTICAL

SCALE IN

METERS

300-1

200-

100

0
NUMBER 32 103

King (1948) recognized informal "upper" and "lower"

Cutoff units in the slope exposures (Shumard Canyon). Harris

(1982, 1988a) extended these to the shelf and basin areas and

introduced a succession of five informal "correlation units,"

which clarified the shelf-to-basin physical correlation of the

Cutoff strata (Figure 5-3). In the basin, the lowermost

correlation unit (#1) is separated from the lithologically similar

underlying Bone Spring Limestone by an unconformity;

therefore, Harris (1988b) suggested that the basin part of

correlation unit 1 be included within the Bone Spring

Limestone. That suggestion is not being used in this proposal.

Instead, the unconformity is used to define the base of the

Cutoff Formation in all areas.

The transition of Cutoff strata into the shallow-water shelf

facies of the San Andres Formation in the northern Guadalupe

Mountains was mapped by Boyd (1958) and was subsequently

interpreted by Sarg and Lehmann (1986a) in terms of sequence

stratigraphy.

Due to Permian erosion and syndepositional slope processes,

the Cutoff Formation is discontinuous along the outcrop belt. It

overlies the Leonardian carbonate bank and basin deposits of

the Victorio Peak-Bone Spring Limestone (Figures 5-4, 5-5).

Prior to Cutoff deposition, erosion steepened the Leonardian

bank shelf-to-basin profile to approximately 20° and formed a

paleoslope with a relief of 300 m (McDaniel and Pray, 1968;

Pray, 1971; Harms and Pray, 1974; Pray et al., 1980; Harris,

1982, 1988a; Kirkby, 1988). Post-Cutoff erosion locally

removed the Cutoff strata along the paleoslope, making

correlation of the Cutoff from shelf to basin problematical

(King, 1948; Wilde and Todd, 1968) until recent work (Harris,

1982, 1988a). Preserved strata occur in three distinct areas, as

defined by the pre-Cutoff shelf profile (Figure 5-5): (1) a flat

shelf (0°-l° dip), (2) a steeply dipping slope (5°-20°),and (3)

a low relief basin that flattens out to a low angle (l°-5°).

Proposed Members

The three members formally proposed below subdivide the

Cutoff Formation into units that are unambiguously recognizable in slope and basinal areas. Figure 5-4 is a geological map of

the Cutoff Formation and adjacent formations in the slope and

basin margin areas. The locations of the type sections of each

member are indicated in Figure 5-6. Lithotype designations

follows the Embry and Klovan (1971) modification of Dunham

(1963). Bedding terminology follows Ingram (1954). The rock

color follows the GSA Rock-Color Chart (Goddard et al.,

1970).

SHUMARD MEMBER

SELECTION AND DERIVATION OF NAME.—The geographic

name derives from Shumard Canyon, where the characteristic

features of the member are apparent. This canyon is the area

where the member was first recognized by King (1948) as an

informal unit.

STRATOTYPE.—The type section for the Shumard Member is

located on the north side of the south fork of Shumard Canyon

(western escarpment of the Guadalupe Mountains) (Figures

5-6, 5-7; Appendix 5-1, section A).

DESCRIPTION.—The total thickness of the Shumard Member

measured at the type section is 49 m. The predominant

lithology is black to dark gray (Nl to N3), medium-bedded,

cherty lime mudstone. Black chert is abundant (5%-15%),

occurring as thin (2 cm) seams and nodules in nearly every bed.

Thin laminations are common. In the type section, three

additional lithologies occur below the lime mudstone. From the

base upward, these are (1) 1-2 m of thinly-laminated, very

fine-grained, quartz sandstone, (2) intraclastic rudstone lenses

up to 2 m thick, and (3) 1 m of shale.

BOUNDARIES.—The Shumard Member is bounded above

King 1942,1948

Brushy Canyon Fm.

Bone

Spring

Limestone

Bon

e Sprin

g Lst.

Newell etal. 1953

Brushy Canyon Fm.

"Upper Bone Spring"

Cutoff Member

"Middle Bone Spring"

Cutoff Formati o

3

Harris 1987,1988

Brushy Canyon Fm.

correlation

unit 5 "upper

unit" 4

corr. 3

units 2

"lower unit" corr. unit 1

Bone Spring Limestone

Cutoff Formati o

3

Harris in press

Brushy Canyon Fm.

Williams Ranch Member

El Centro Member

Shumard Member

Bone Spring Limestone

FIGURE 5-3.—History of nomenclature for basin Cutoff strata in the Guadalupe Mountains from Bone Canyon to

the south. Beds assigned to the Cutoff were first identified by Newell etal., 1953. (NOTES: 1. King(1942, 1948)

recognized informal upper and lower units for his Cutoff member for slope outcrops (Shumard Canyon). He

suggested that the basal beds of the Brushy Canyon may be Cutoff basinal equivalents. 2. The Pipeline Shale of

Warren (1955) is a basinward shale at the base of the Brushy Canyon Formation that pinches out south of Bone

Canyon. 3. All correlation units of Harris (1988a,b) are informal stratigraphic units.)
104 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Modified from: King, 1948; MacDaniel and Pray, unpubl.; Harris, 1982.

FIGURE 5-4.—Geologic map of the Bone Canyon-Shumard Canyon area in the western Guadalupe Mountains.

This area is the lower slope environment during Cutoff Formation deposition (compare with Figure 5-5).

and below by unconformities. The lower boundary is the

pre-Cutoff unconformity, which truncated the Victorio Peak

and Bone Spring strata. The Shumard Member stratotype

occurs within a 40 m deep channel cut into the Victorio Peak

Limestone. The upper boundary occurs at an intra-Cutoff

unconformity, which truncated the Shumard Member strata.

The contact with the overlying El Centro Member is marked by

an abrupt lithological change. These unconformities bound the

Shumard Member throughout the western escarpment outcrops.

HISTORICAL BACKGROUND.—These strata were recognized

by King (1948) as a distinct unit within the Cutoff based upon

their lithology and bounding unconformities (see King, 1948,

pi. 12B). He gave them the informal designation of the Cutoff
NUMBER 32 105

Shelf Basin

[--•- I Cherry Canyon Formation

H I Brushy Canyon Formation

EXPLANATION

Cutoff Formation

[ 1 El Centra and Williams Ranch Members

I I Shumard Member

| H megabreccias

\//\ Victoria Peak Formation

I'l l Bone Spring Limestone

FIGURE 5-5.—North-south cross section of the Cutoff Formation as seen along the western escarpment of the

Guadalupe Mountains. Note that the vertical exaggeration is x2.

"lower unit." Subsequently, Harris (1982, 1988a) informally

termed them "correlation unit 1" while retaining the informal

"lower Cutoff' nomenclature.

DISTRIBUTION AND THICKNESS.—In Shumard Canyon, the

Shumard Member is limited to the channel fill that is bisected

by the south fork of the canyon. The type section records the

thickest expression of the unit in this area. The similar section,

which occurs on the opposite canyon wall, includes a

megabreccia lens at the top of the member. These strata fill the

extension of the channel occupied by the stratotype.

The member occurs in the Cutoff Formation type section at

Cutoff Mountain where it varies between 1.6 and 5 m in

thickness. South of Cutoff Mountain, this member is not

present in the western escarpment between Bartlett Peak and

Shirttail Canyon. This distribution is interpreted to be the result

of truncation along the unconformity at the top of the member.

Laminations are faint or not present in this shelf setting. A

low-angle truncation surface separates the Shumard Member

from the underlying Victorio Peak Limestone. Where the

Shumard Member is absent, the pre-Cutoff unconformity and

the intra-Cutoff unconformity are merged.

To the south of Bone Canyon, a black cherty limestone

below the El Centro Member is interpreted as the Shumard

Member (Figure 5-8). The unconformity at the base of the

Shumard Member, which separates it from the underlying Bone

Spring Limestone, can be traced and mapped in the field to the

limit of the outcrop (Figure 5-4). The Shumard Member (as

interpreted by tracing this unconformity) is approximately 33.5

m thick below the El Centro Member type section. This section

of the Shumard Member contains thin skeletal and intraclastic

rudstone lenses, chert bands, and small (2 m) folds. Thin

laminations mark the lower 17 m. Three different lamination

styles occur in the overlying beds: well-laminated textures,

laminations disrupted by horizontal burrows, and nonlaminated

textures. The upper boundary of the Shumard Member is placed

at an obvious truncation surface that is interpreted as the

intra-Cutoff unconformity. A reference section for the Shumard

Member in the basin area is located in the first canyon south of

Bone Canyon (0.85 km south of Bone Canyon) along the

western escarpment of the Guadalupe Mountains (Appendix

5-1, section B).

GEOLOGICAL AGE.—The Shumard Member is probably

latest Leonardian (Artinskian), based upon paleontological

studies in progress (Lambert, pers. comm., 1991; Lambert et

al., this volume).

LATERAL EXTENT AND CORRELATIONS.—The Shumard

Member is recognizable along the western escarpment of the

Guadalupe Mountains at Cutoff Mountain (shelf area), Shumard Canyon (slope area, including the type section), and south

of Bone Canyon to its disappearance into the subsurface (basin

area). Correlation of this member beyond the western escarpment is uncertain because of the lack of faunal studies of this

strata.

EL CENTRO MEMBER

SELECTION AND DERIVATION OF NAME.—The geographic

name derives from El Centro Draw, an arroyo south of Bone

Canyon. The northeastern part of the drainage includes

lithologies characteristic of the member.

STRATOTYPE.—The type section of the El Centro Member is

located in the first canyon south of Bone Canyon (0.85 km

south of Bone Canyon) along the western escarpment of the

Guadalupe Mountains (Figure 5-6; Appendix 5-1, section B).
106 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

1000 2000 3000 «XX> 5000 6000 7000 FEET

1 KILOMETER

CONTOUR INTERVAL 200 FEET

FIGURE 5-6.—Location of the type sections for the proposed members of the Cutoff Formation. Section A is the

stratotype for the Shumard Member. Section B is the stratotype for the El Centro Member and the Williams Ranch

Member. Section B is also a reference section for the Shumard Member, and Section C is a reference section for

the El Centro Member and the Williams Ranch Member. The dark lines delineate longitude 104°52'30" and

latitude 31°52'30", which are the borders of the four Vli quadrangle topographic maps that make up this

composite, namely, PX Flat (northwest), Patterson Hills (southwest), Guadalupe Peak (northeast), and Guadalupe

Pass (southeast).

DESCRIPTION.—The total thickness of the El Centro Member

measured at the type section is 20.5 m. It consists of two

lithologies: interbedded lime mudstone-shale and mediumbedded lime mudstone.

Interbedded thinly-laminated lime mudstone, shale, and

siltstone are characteristic of the El Centro Member. The lime

mudstone and shale are both dark gray (N3) to black (Nl) to

dark brown (10YR 4/3). They locally alternate in centimeterthick intervals, but typically one lithology occurs vertically for

several meters. The lithologies intergrade, as the lime mudstone

is argillaceous and the shale may be calcareous. They are

virtually identical in field appearance and can only be

distinguished by testing with dilute hydrochloric acid. The

shale contains carbonate concretions (up to 0.3 m across) that

formed prior to the bulk of shale compaction. Scattered thin to

very thin beds of dark brown to tan, thinly laminated siltstone

occur within the interbedded lime mudstone-shale lithology.

A pronounced interval of dark gray (N2 to N4), mediumbedded, lime mudstone occurs within the interbedded lime

mudstone-shale in most locations. The lime mudstone lacks
NUMBER 32 107

Brushy Canyon Formation

Victorlo Peak Formation

Stratotype for Shumard Member

FIGURE 5-7.—Location of the Shumard Member stratotype in the north wall of south Shumard Canyon.

Cutoff Formation

Williams Ranch Member |i| | Shumard Member

El Centro Member megabreccias

Victorio Peak Formation

A

A AA AA

Shumard Canyon

1000 m 500 m

Brushy Canyon Formation

Bone Spring Limestone

250 m

A A A

Bone

Canyon

B

A A

Base of section covered

Not mapped in detailFIGURE 5-8.—Cross section of the Cutoff Formation (western Guadalupe Mountains) in the slope and basin areas

(right side of Figure 5-5), illustrating the thickness variations in the proposed members. Measured section

locations are indicated by arrows along the base of the diagram. Thickness and paleotopography are properly

scaled. Vertical exaggeration is x2.5.
108 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

chert, in contrast to the Shumard Member, and is similar to the

limestones that make up the overlying Williams Ranch

Member. This lime mudstone interval comprises about one-half

of the member (11 m the of 20.5 m total) in the El Centro type

section. This interval serves as a useful marker horizon within

the member (see the section below on regional aspects).

BOUNDARIES.—The lower boundary of the El Centro

Member is placed along an intra-Cutoff unconformity that

truncates the underlying Shumard Member. An abrupt shift

from cherty lime mudstone to interbedded lime mudstoneshale marks this boundary in the El Centro type section. The El

Centro Member unconformably overlies the cherty limestones

of the Bone Spring Limestone where the Shumard Member is

absent.

The upper boundary with the overlying Williams Ranch

Member is conformable except where minor channel scours are

present, as in the type section. Locally within Shumard Canyon

the Williams Ranch Member is missing and the El Centro

Member is unconformably overlain by the sandstones, siltstones, and conglomerates of the Brushy Canyon Formation.

HISTORICAL BACKGROUND.—The interbedded lime mudstone-shale of the El Centro Member are the strata that resulted

in the establishment of the Cutoff Shaly Member of the Bone

Spring Limestone by King (1942, 1948). He did not recognize

the basin equivalent of these shaly beds and included the strata

of the type section in the Bone Spring Limestone. Newell et al.

(1953) recognized the basin equivalents, which they termed the

Cutoff Member of the Bone Spring Limestone. King's (1965)

elevation of the Cutoff to formational rank, as the Cutoff Shale,

reflected his focus on these shaly beds. Harris (1982, 1988a)

informally named the vertical succession of interbedded lime

mudstone-shale, lime mudstone, interbedded lime mudstoneshale as "correlation units 2, 3 and 4," respectively.

DISTRIBUTION AND THICKNESS.—The El Centro Member is

thin to absent in the slope sections but is present in all shelf and

basin sections. It is always the last part of the Cutoff strata

truncated by the post-Cutoff unconformity.

The vertical lutite triplet of interbedded lime mudstoneshale with middle lime mudstone beds is recognizable across

the depositional profile. All three units thicken basinward from

the El Centro type section. The member is 78 m thick in a

section 0.85 km to the south, and the middle limestone unit is

34 m thick. In contrast, the lime mudstone unit thins rapidly to

the north; 0.5 km north (just south of the mouth of Bone

Canyon) it thins to 5.5 m thick, with a total El Centro Member

thickness of 19 m. The lime mudstone unit pinches out in the

south wall of Bone Canyon where the entire member is about

20 m thick. The entire member disappears in the north wall of

Bone Canyon due to onlap of the pre-Cutoff surface and

truncation along the post-Cutoff surface. The channel-filling

megabreccias, which occur at the base of the El Centro Member

in the south wall of Bone Canyon (Pray and Stehli, 1963), are

tentatively assigned to the El Centro Member.

In the slope area (Shumard Canyon) the Williams Ranch

Member is thinned or absent due to truncation along the

post-Cutoff unconformity (Figure 5-8). However, the El Centro

lutite triplet can be traced across these exposures. It is 13-18 m

thick where complete, but it is irregularly thinned from the top.

The large megabreccia sheet, which occurs below the interbedded lime mudstone-shale in northern Shumard Canyon

(Figures 5-4, 5-5, 5-8), is assigned to the El Centro Member.

A section measured southwest of Bartlett Peak contains a

shelf section (north of Shirttail Canyon) of the El Centro

Member that is about 43.5 m thick. The lime mudstone interval

expands to 26 m, a similar proportion as in the basinal outcrops.

In the Cutoff Formation's type section, the member is 34.5 m

thick, but its unique middle lime mudstone cannot be

recognized because the approximate interval of the lime

mudstone unit is more argillaceous than the Bartlett Peak

section.

GEOLOGICAL AGE.—The El Centro Member is probably

latest Leonardian (Artinskian) to earliest Guadalupian, based

upon paleontological studies in progress (Lambert, pers.

comm., 1991; Lambert et al., this volume).

LATERAL EXTENT AND CORRELATIONS.—The El Centro

Member is the most widespread of the Cutoff members along

the western escarpment of the Guadalupe Mountains. It is

roughly equivalent to the lower part of the Road Canyon

Formation of the Glass Mountains, based upon paleontological

studies (Lambert et al., this volume). Sarg and Lehmann

(1986a) interpreted these strata as the equivalent of the lower

San Andres Formation of the northern Guadalupe Mountains.

WILLIAMS RANCH MEMBER

SELECTION AND DERIVATION OF NAME.—The geographic

name derives from the Williams Ranch House located at the

mouth of Bone Canyon. The lime mudstone outcrops that form

the low hills, which extend from Bone Canyon south to U.S.

62/180, contain typical exposures of this member.

STRATOTYPE.—The type section of the Williams Ranch

Member is located in the north fork of the first canyon south of

Bone Canyon (0.85 km south of Bone Canyon) along the

western escarpment of the Guadalupe Mountains (Figure 5-6;

Appendix 5-1, section B).

DESCRIPTION.—The total thickness of the Williams Ranch

Member measured at the type section is 13 m. Dark gray (N2 to

N4), medium-bedded lime mudstone predominates in the type

section. The beds are defined by thin shaly partings, and

individual bed thickness varies due to minor (cm scale) scours

at the top of beds. A well-laminated texture predominates in the

type section and other basinal areas, although burrows disrupt

laminations in some beds. Faint laminations and nonlaminated

textures are more common in a shelfward direction (to the

north). Small (< 1 m thick) intraclastic and skeletal rudstone

lenses occur in the Williams Ranch Member, and these
NUMBER 32 109

typically occur as small channel fills. An intraclastic rudstone

marks the base of the member in the type section.

BOUNDARIES.—The lower boundary is conformable with the

El Centra Member except where small channel scours occur

along the contact. In the type section, the boundary is abrupt.

Generally, the lower boundary is placed at the top of the

uppermost bed of the interbedded lime mudstone-shale that is

characteristic of the El Centro Member.

The upper boundary is placed at the post-Cutoff unconformity. The overlying Brushy Canyon Formation is marked by

sandstone, siltstone, conglomerates containing sandstone within the matrix or as clasts (as in the type section), or shale

(basinward sections).

HISTORICAL BACKGROUND.—King (1948) included these

strata within his Bone Spring Limestone in the area from Bone

Canyon to the south. Newell et al. (1953) termed these strata

the "Upper Bone Spring Limestone." Harris (1982, 1987)

informally termed them "correlation unit 5" within an upper

Cutoff unit.

DISTRIBUTION AND THICKNESS.—The Williams Ranch

Member varies in thickness due to truncation along the

post-Cutoff unconformity (Figure 5-8). The maximum preserved thickness occurs to the south in the basinmost sections

(13 m in the Williams Ranch type section expands to 16 m in

a section 0.85 km to the south) and to the north in shelf sections

(approximately 43 m in the Cutoff type section). In the slope

area, the Williams Ranch Member is thinned or entirely absent

due to truncation along the post-Cutoff unconformity. A

ammonoid-rich zone at the top of the member occurs in the

Williams Ranch type section (Lambert, pers. comm., 1991) and

in the U.S. 62/180 highway cuts to the south (Spinosa et al.,

1975; Lambert, pers. comm., 1991). The persistence of this

faunal occurrence may indicate that erosion of the Williams

Ranch Member was minor southward from its type section.

The lithology and definition of the lower boundary of the

member varies along the depositional profile. The dark gray

color predominates in basin and slope areas (from Shumard

Canyon south). Laminated texture increases basinward. The

lower contact is relatively sharp and unambiguous; however,

the lithologies within the Williams Ranch Member change in

the shelf section (Cutoff Mountain to the pinchout north of

Shirttail Canyon). Here, the dark gray lime mudstone passes

upwards into medium gray (N5 to N6), medium-bedded lime

mudstone. Southwest of Bartlett Peak the Williams Ranch

Member is 17-18 m thick; the upper 4 m consist of the medium

gray lime mudstone. At Cutoff Mountain, the member is

approximately 43 m thick. Only the lower 4.5 meters are dark

gray lime mudstone; the remainder is medium gray lime

mudstone with interbedded beds of graded lime packstone to

wackestone (interpreted as storm deposits). In these shelf

sections, white chert nodules locally occur in the uppermost

beds of the Williams Ranch Member.

GEOLOGICAL AGE.—The Williams Ranch Member is probably earliest Guadalupian, based upon paleontological studies in

progress (Lambert, pers. comm., 1991; Lambert et al., this

volume) and the fusulinid identification of Wilde (1986b).

LATERAL EXTENT AND CORRELATIONS.—The Williams

Ranch Member occurs widely in the western escarpment of the

Guadalupe Mountains, although in the slope areas it is thinned

and locally truncated by the post-Cutoff unconformity. The

Williams Ranch Member is equivalent, at least in part, to the

upper Road Canyon Formation in the Glass Mountains

(Lambert et al., this volume) and the upper San Andres

Formation of the northern Guadalupe Mountains (Sarg and

Lehmann, 1986a; Wilde, 1986a,b).

Discussion

The revised Cutoff stratigraphy for the western escarpment

of the Guadalupe Mountains is illustrated by Figure 5-8. The

interrelations of the members and the positions of the

unconformities are shown.

Formal members for the Cutoff Formation are proposed for

three principle reasons. First, use of this nomenclature will help

reinforce the revisions made in the stratigraphic framework for

these beds since the pioneering work of King (1942, 1948) and

Newell et al. (1953). Clarifying the stratigraphic succession

will allow better understanding of the overall geologic history.

Second, these members can be traced throughout the western

escarpment region and are stratigraphically distinct units

separated by unconformities or lithologic changes. Subsurface

differentiation of the Shumard Member in well-log sections

will rely upon recognition of the pre-Cutoff unconformity. The

overlying El Centro and Williams Ranch members are

sufficiently thick and lithologically distinct for subsurface

recognition.

Third, this level of stratigraphic detail probably represents

the extent to which previous faunal collections can be located.

The black limestone hills south of El Capitan are largely

formed by the Williams Ranch Member to which the "Upper

Bone Spring" collections of Newell et al. (1953) should be

related. Many of King's (1948) Bone Spring Limestone faunal

collections are from the member as well. Similarly, faunal

collections from shaly Cutoff strata are probably from the El

Centro Member. The proper placement of the prior faunal

collections will be important if these strata become an

international boundary stratotype (Glenister, 1991).

A reference section for the El Centro Member and Williams

Ranch Member is located near the southern limit of complete

exposures of the El Centro Member (Appendix 5-1, section C).

To the south, the base of the El Centro is covered. The hills of

black lime mudstone, which extend to U.S. 62/180, predominantly consist of the overlying Williams Ranch Member. This

reference section is included as a framework for future

paleontological collections at the thickest and most basinward

outcrop of the complete El Centro-Williams Ranch section.
110 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Acknowledgments wants to thank the attendees at the 1991 Guadalupian

Symposium, particularly Bruce R. Wardlaw and Garner L.

The author wishes to thank Lloyd C. Pray, Lance L.Lambert, Wilde, for their encouragement to finally name these units,

and Nancy J. Harris for their advice and patience. Richard A. Reviews by Richard E. Grant and Bruce R. Wardlaw helped

Paull considerably improved this manuscript. The author also clarify some points.
NUMBER 32 111

Appendix 5-1: Stratigraphic Sections

Format

The stratigraphic nomenclature uses the members proposed herein. The informal

"correlation units" of Harris (1982, 1988a) are provided for convenience and reference to

earlier work.

The scale of the graphic log is presented in both feet and meters. The profile represents

the weathering profile noted in the field.

The lithology presentation involves three columns. The predominant lithology is either

carbonate (limestone for all Cutoff sections shown) or noncarbonate (siliceous shales and

sandstones). Both carbonate and siliciclastic lithologies are described using Dunham

(1962) depositional texture terminology; therefore, in this column, grain-supported

sandstones (arenites) are graphed as packstones or grainstones (dependent upon mud

content), shales are graphed as mudstones, and megabreccias with mud-filled intraclastic

spaces are graphed as packstone. The maximum grain size completes the description by

illustrating the maximum obvious grain size. This log depicts the size of the coarsest

common grains; a single large grain is ignored. For example, a single large fossil in several

feet of lime mudstone would not be shown, but silt distributed throughout would appear.

Used together, these three columns describe the basic lithology.

The final columns indicate the color and darkness of the rock (increasing to the right).

KEY FOR GRAPHIC COLUMN

OF STRATIGRAPHIC SECTIONS

Interbedded lime mudstone-shale

Medium-bedded limestone

Intraclastic rudstone or megabreccia

Sandstone

Chert seams and nodules

Carbonate concretions
112 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

APPENDIX 5-1.—Continued.

Section A

20-40 meters

Section A

0-20 meters

North wall of South

Shumard Canyon.

North wall of South

Shumard Canyon.

Depositional

Texture

Depositional

Texture

Dunham

Decrees.

Micrite

Graphic

Column

Graphic

Column

Victorio

Peak

Fm.

SECTION A.—Graphic representation of Section A, the type section for the Shumard Member. Letters and

numbers to the right of the graphic column indicate the described units.
NUMBER 32 113

APPENDIX 5-1.—Continued.

North wall of South

Shumard Canyon.

Section A

40-48 meters

SECTION A.—Continued.
114 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

APPENDIX 5-1.—Continued.

Section B

0-20 meters

Section B

20-40 meters

Canyon 0.85 km south of

Bone Canyon.

Canyon 0.85 km south of

Bone Canyon.

Depositional

Texture

Depositional

Texture

Graphic

Column

Graphic

Column

Bone

Spring

Limest.

SECTION B.—Graphic representation of Section B, a reference section for the Shumard Member and the type

section for the El Centra Member and the Williams Ranch Member. Letters and numbers to the right of the

graphic column indicate the described units.
NUMBER 32 115

APPENDIX 5-1.—Continued.

Section B

40-60 meters

Section B

60-70 meters

Canyon 0.85 km south of

Bone Canyon.

Canyon 0.85 km south of

Bone Canyon.

Deposit lonal

Texture i

Dunham I Maximum

Decrees. Grain Size

Micrrte (mm)

m

 G'

Depositional

Texture

Graphic

Column

Graphic

Column

SECTION B.—Continued.
116 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

APPENDIX 5-1.—Continued.

Section C

0-20 meters

Section C

20-40 meters

1.7 km south of Bone Canyon,

approximately at King's (1948)

section 17.

1.7 km south of Bone Canyon,

approximately at King's (1948)

section 17.

Depositional

Texture i

Depositional

Texture

Graphic

Column

Graphic

Column

SECTION C.—Graphic representation of Section C, a reference section for the El Centro Member and the Williams

Ranch Member. This section is located near the southern limit of complete exposures of the El Centro Member.

To the south, the base of the unit is covered. Letters and numbers to the right of the graphic column indicate the

described units.
NUMBER 32 117

APPENDIX 5-1.—Continued.

Section C

60-80 meters

Section C

40-60 meters

1.7 km south of Bone Canyon,

approximately at King's (1948)

section 17.

1.7 km south of Bone Canyon,

approximately at King's (1948)

section 17.

Depositional

Texture

Depositional

Texture

Graphic

Column

Graphic

Column

SECTION C.—Continued.
118 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

APPENDIX 5-1.—Continued.

Section C

80-95 meters

1.7 km south of Bone Canyon,

approximately at King's (1948)

section 17.

Depositional

Texture

SECTION C.—Continued.
NUMBER 32 119

Literature Cited

Boyd, D.W.

1958. Permian Sedimentary Facies, Central Guadalupe Mountains, New

Mexico. Bulletin of the New Mexico Bureau of Mines and Mineral

Resources, 49: 100 pages, 5 plates.

Dunham, R.J.

1962. Classification of Carbonate Rocks According to Depositional

Texture. In W.E. Ham, editor, Classification of Carbonate Rocks: A

Symposium. American Association of Petroleum Geologists, Memoir, 1:108-121, plates 1-7.

Embry, A.V., and J.E. Klovan

1971. A Late Devonian Reef Tract on Northeast Banks Island, Northwest

Territories. Bulletin of Canadian Petroleum Geology, 19:730-781.

Glenister, B.F.

1991. The Guadalupian: A Proposed International Standard for Middle

Permian Series. [Abstract.] International Congress on the Permian

System of the World, Program and Abstracts, Perm, USSR—1991,

pages A9-A10. Urals Branch, USSR Academy of Sciences; and

Earth Sciences and Resources Institute, University of South

Carolina.

Glenister, B.F., C. Spinosa, W.M. Furnish, and Zhou Zuren

1991. Ammonoid Correlation of the Guadalupian/Dzhulfian Boundary.

[Abstract.] In B.R. Wardlaw, R.E. Grant, and D.M. Rohr, editors,

Proceedings of the Gaudalupian Symposium, March 13-15, 1991,

Sul Ross State University, Alpine, Texas, page 14.

Goddard, E.N., P.D. Trask, O.N. Rove, J.T. Singewald, Jr., and R.M. Overbeck

1970. Rock Color Chart. Geological Society of America (reprinting).

Harms, J.C., and L.C. Pray

1974. Erosion and Deposition along the Mid-Permian Intracratonic Basin

Margin, Guadalupe Mountains, Texas. [Abstract.] In R.H. Dott, Jr.,

and R.H. Shaver, editors, Modern and Ancient Geosynclinal

Sedimentation. Society of Economic Paleontologists and Mineralogists, Special Publication, 19:37.

Harris, M.T.

1982. Sedimentology of the Cutoff Formation (Permian), Western Guadalupe Mountains, West Texas and New Mexico. 186 pages.

Unpublished master's thesis, University of Wisconsin, Madison,

Wisconsin.

1988a. Sedimentology of the Cutoff Formation (Permian), Western Guadalupe Mountains, West Texas. In S.T. Reid, R.O. Bass, and P. Welch,

editors, Guadalupe Mountains Revisited, Texas and New Mexico.

West Texas Geological Society, Publication, 88-84:133-140.

1988b. Postscript on the Cutoff Formation: The Regional Perspective and

Some Suggestions for Nomenclature. In S.T. Reid, R.O. Bass, and P.

Welch, editors, Guadalupe Mountains Revisited, Texas and New

Mexico. West Texas Geological Society, Publication, 88-84:141 —

142.

Hayes, P.T.

1959. San Andres Limestone and Related Permian Rocks in Last Chance

Canyon and Vicinity, Southeastern New Mexico. Bulletin of the

American Association of Petroleum Geologists, 43(9):2197-2213.

Hay-Roe, H.

1957. Geology of Wylie Mountains and Vicinity, Culberson and Jeff Davis

Counties, Texas. Bureau of Economic Geology, University of Texas,

Austin, Geologic Quadrangle Map, 21.

Ingram, R.L.

1954. Terminology for the Thickness of Stratification and Parting Units in

Sedimentary Rocks. Bulletin of the Geological Society of America,

65(9):937-938.

King, P.B.

1942. Permian of West Texas and Southeastern New Mexico. Bulletin of

the American Association of Petroleum Geologists, 26(4):535-763.

1948. Geology of the Southern Guadalupe Mountains, Texas. United

States Geological Survey Professional Paper, 215: 183 pages, 23

plates.

1965. Geology of the Sierra Diablo Region, Texas. United States

Geological Survey Professional Paper, 480: 185 pages, 16 plates.

Kirkby, K.C.

1988. Deposition and Permian Erosion of the Upper Victorio Peak

Formation (Leonardian), Western Escarpment, Guadalupe Mountains, West Texas. In S.T. Reid, R.O. Bass, and P. Welch, editors,

Guadalupe Mountains Revisited, Texas and New Mexico. West

Texas Geological Society, Publication, 88-84:149-154.

Lambert, L.L., D.J. Lehrmann, and M.T. Harris

2000. Correlation of the Road Canyon and Cutoff Formations, West Texas,

and Its Relevance to Establishing an International Middle Permain

(Guadalupian) Series. In B.R. Wardlaw, R.E. Grant, and D.M. Rohr,

editors, The Guadalupian Symposium. Smithsonian Contributions to

the Earth Sciences, 32:153-183, 11 figures, 4 plates, 3 tables.

McDaniel, P.N., and L.C. Pray

1968. Bank to Basin Transition in Permian (Leonardian) Carbonates,

Guadalupe Mountains, Texas. Bulletin of the American Association

of Petroleum Geologists, 51(3):474.

Newell, N.D., J.K. Rigby, A.G. Fisher, A.J. Whiteman, J.R. Hickox, and J.S.

Bradley

1953. The Permian Reef Complex of the Guadalupe Mountains Region,

Texas and New Mexico: A Study in Paleoecology. 236 pages. San

Francisco: W.H. Freeman and Company.

Pray, L.C.

1971. Submarine Slope Erosion along Permian Bank Margin, West Texas.

Bulletin of the American Association of Petroleum Geologists,

55(2):358.

Pray, L.C, G.A. Crawford, M.T. Harris, and K.C. Kirkby

1980. Early Guadalupian (Permian) Bank Margin Erosion Surfaces,

Guadalupe Mountains, Texas. Bulletin of the American Association

of Petroleum Geologists, 64(5):768.

Pray, L.C, and F.G. Stehli

1963. Allochthonous Origin, Bone Spring "Patch Reefs," West Texas.

[Abstract.] Geological Society of America, Special Paper, 73:218-

219.

Sarg, J.F., and P.J. Lehmann

1986a. Lower-Middle Guadalupian Facies and Stratigraphy, San Andres/

Grayburg Formations, Permian Basin, Guadalupe Mountains, New

Mexico. In G.E. Moore and G.L. Wilde, editors, Lower and Middle

Guadalupian Facies, Stratigraphy, and Reservoir Geometries, San

Andres/Grayburg Formations, Guadalupe Mountains, New Mexico

and Texas. Society of Economic Paleontologists and Mineralogists,

Permian Basin Section, Publication, 86-25:1-8.

Spinosa, C, W.M. Furnish, and B.F. Glenister

1975. The Xenodiscidae, Permian Ceratitoid Ammonoids. Journal of

Paleontology, 49(2):239-283, plates 1-8.

Wilde, G.L.

1986a. Stratigraphic Relationship of the San Andres and Cutoff Formations,

Northern Guadalupe Mountains, New Mexico and Texas. In G.E.

Moore, and G.L. Wilde, editors, Lower and Middle Guadalupian

Facies, Stratigraphy, and Reservoir Geometries, San Andres/

Grayburg Formations, Guadalupe Mountains, New Mexico and

Texas. Society of Economic Paleontologists and Mineralogists,

Permian Basin Section, Publication, 86-25:49-63, plates 1-5.

1986b. An Important Occurrence of Early Guadalupian (Roadian) Fusulinids from the Cutoff Formation, Western Guadalupe Mountains,

Texas. In G.E. Moore, and G.L. Wilde, editors, Lower and Middle

Guadalupian Facies, Stratigraphy, and Reservoir Geometries, San

Andres/Grayburg Formations, Guadalupe Mountains, New Mexico
120 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

and Texas. Society of Economic Paleontologists and Mineralogists, of Economic Paleontologists and Mineralogists, Permian Basin

Permian Basin Section, Publication, 86-25:65-68, plate 1. Section, Publication, 68-11:10-31.

Wilde, G.L., and R.G. Todd Wood, J.W.

1968. Guadalupian Biostratigraphic Relationships and Sedimentation in 1968. Geology of the Apache Mountains, Trans-Pecos Texas. Bureau of

the Apache Mountain Region, West Texas. In B.A. Silver, editor, Economic Geology, University of Texas, Austin, Geologic QuadranGuadalupian Facies, Apache Mountains Area, West Texas. Society gle Map, 33: 32 pages.
6. Cyclic Deposition of the Permian

Road Canyon Formation,

Glass Mountains, West Texas

Bruce R. Wardlaw, Charles A. Ross,

and Richard E. Grant

ABSTRACT

The Road Canyon Formation represents a maximum of four

apparent transgressive (progradational) depositional cycles of conglomeratic skeletal wackestone over a minor exposure surface,

followed in succession by peloidal packstone and siltstone. These

cycles actually represent carbonate shedding from a shoal on the

geanticline developed between the Delaware basin and the Marathon

foreland basin. The Road Canyon was deposited in the foreland basin

as (1) a skeletal wackestone deposited behind a shoal (geanticline), (2)

a peloidal packstone deposited on the slope, and (3) a siltstone

deposited in the basin. The cycles represent shoalward progradation of

the basinal deposits. Rudstone was deposited in channels immediately

behind the shoal. Back shoal facies are represented by bioturbated lime

mudstone with common channels of conglomeratic wackestone.

Introduction

The depositional setting of the Permian rocks of the Glass

Mountains on the southern shelf of the Permian basin (see Rohr

et al., this volume) is controversial. Unlike the rather

straightforward setting for rocks in the Guadalupe Mountains

on the north side of the Delaware basin where shelf, shelf

margin, abrupt slope, and basin are clearly discernible, the

Bruce R. Wardlaw, U.S. Geological Survey, 926A National Center,

Reston, Virginia 20192. Charles A. Ross, GeoBioStrat, 600 Highland

Drive, Bellingham, Washington 98225-6410. Richard E. Grant

{deceased), Department ofPaleobiology, National Museum of Natural

History, Smithsonian Institution, Washington, D.C. 20560-0121.

basinal aspects of the southern shelf of the Permian basin have

long been debated (see Cys and Mazzullo, 1978; Flores et al.,

1978). The Glass Mountains contain most of the North

American Permian regional stratotype.

The Road Canyon Formation is a fossiliferous unit that has

been variously placed in the Guadalupian or Leonardian Series.

Brachiopods show a strong Leonardian affinity, whereas

fusulinids show a strong Wordian (lower Guadalupian) affinity,

and various ammonoids show a strong affinity to either series.

The Road Canyon was originally mapped as the base of the

Word Formation, but it was later separated from the Word

because of its faunal affinities. The mixture of faunal affinities

led Furnish (1973) to propose a separate stage between the

Leonardian and Wordian based on the Road Canyon. The

Guadalupian has been recognized worldwide, but it is best

represented in West Texas, and the definition of its lower

boundary is important for international correlation. Grant and

Wardlaw (1984) proposed that a significant conodont fauna

changeover within the Road Canyon provides an excellent

marker for the definition of the base of the Guadalupian. It is

very important to understand the depositional setting of the

Road Canyon Formation in order to properly establish the base

of the Guadalupian.

Stratigraphy

The Road Canyon Formation was measured at 18 sections in

the Glass Mountains and northern Del Norte Mountains

(Figures 6-1, 6-2). Sections that appear incomplete in Figure

6-2 were measured only to the top of the exposure (commonly

a hill) and were not continued over dip slopes and covered

valleys. The sections were measured and collected and

remeasured and recollected over annual spring field trips from

1981 to the present. Section RC I (Figure 6-2) represents the

stratotype of the Road Canyon Formation.

121
122 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

30°30'

103°30' 103°15" 103°00*

30° 15*

FIGURE 6-1.—Location of sections of the Road Canyon Formation in the Glass Mountains and northern Del Norte

Mountains.

Originally, the Road Canyon Formation was described as the

first limestone member of the Word Formation (King, 1931).

Cooper and Grant (1964) named the informal members

proposed by King and designated the first limestone member of

the Word Formation as the Road Canyon Member. Later, for

largely faunal reasons, Cooper and Grant (1966) elevated the

Road Canyon to formation status to separate it from the Word.

The Road Canyon Formation is the predominantly limestone

unit situated between the shales (actually siltstones and

mudstones) of the Cathedral Mountain Formation below and

the Word Formation above. Thus, it is both easily visible and

easily mappable. The Word Formation continues the cyclic

deposition of the Road Canyon, but it does not display much

conglomeratic deposition within the basal skeletal wackestones

and it also contains more siltstone in each cycle. As a

consequence of the transitional nature of the upper contact and

the inability of finding a mappable boundary atop a predominantly limestone unit, the top of the Road Canyon Formation is

drawn through various cycles of deposition from section to

section (Figure 6-2).

A major faunal changeover of conodonts from Mesogondolella idahoensis (Youngquist, Hawley, and Miller) to M.

nankingensis (Ching) (see Wardlaw, this volume; Lambert et

al., this volume) occurs at the base of, or within the lower part

of, cycle 2 deposition of the Road Canyon Formation (Figure

6-2). This faunal changeover is sharp and is found in many

sections throughout the world, so it represents a significant

correlatable horizon. Lambert and Wardlaw (1992) documented the transition from M. idahoensis to M. nankingensis

through a short-lived transitional form. The major faunal

changeover is marked as the first occurrence of M. nankingensis (sensu strictu; = M. serrata) above the transitional form in

sequential samples.

General Lithofacies

Throughout the outcrop area, the majority of the rocks of the

Road Canyon Formation can be placed into seven general

lithofacies: rudstone, conglomeratic skeletal wackestone, skeletal wackestone/packstone, peloidal packstone/grainstone,

siltstone, sandstone, and bioturbated skeletal lime mudstone.

RUDSTONE.—This fades is rare and is commonly found only

in sections RC I and RC IX. It is composed of a variety of

cobble- to boulder-size clasts of carbonate, which range from

skeletal wackestone to boundstone, and scattered clasts of

siltstone. The clasts are irregular in shape and size. The matrix
NUMBER 32

123

RUDSTONE

_ (MEGABRECCIA)

~ X

o

E H LIMESTONE, LIMY

EE1 DOLOMITE, DOLOMITIC

E 3 SANDSTONE, SANDY

E r ] SILTSTONE, SILTY

H MUDDY

=1 CHERTY 100

CONGLOMERATIC

5 0'

r400

•300

CYCLE BOUNDARIES

CONODONT DATUM

MAPABLE TOP OF

ROAD CANYON FORMATION

200

100

0

FT

FIGURE 6-2.—Columnar sections of the Road Canyon Formation and some underlying and overlying beds that

display four cycles of sedimentation and the beginning of a fifth cycle.

is generally lime-mud and silt when present, and there is

abundant evidence for postdepositional corrosion and meteoric

diagensis (Measures and Wardlaw, 1990) in the matrix. The

rudstone can be classified as a megabreccia. It forms massive

beds that are confined laterally in channelform lenses.

CONGLOMERATIC SKELETAL WACKESTONE.—This fades is

similar to the skeletal wackestones, but it contains scattered

pebble- to small boulder-size clasts of carbonate and siltstone.

The carbonate clasts are generally skeletal wackestones and

peloid packstones. The siltstone clasts are flat or irregular in

shape. It forms beds that are generally massive.

SKELETAL WACKESTONE/PACKSTONE.—Wackestones are

common and consist of very coarse grains of broken to whole

skeletal elements, peloids, lime and terrigenous mud, and

minor quartz silt. It forms beds that are generally thick to

massive.

PELOIDAL PACKSTONE/GRAINSTONE.—Peloidal packstones

are very common. They are sparsely fossiliferous and primarily

consist of fecal pellets, algal peloids, and lime-mud (when

packstones). The algal peloids are coated and micritized

rounded grains representing a variety of allochems that include

unrecognizable debris, skeletal grains, and quartz sand.

Commonly, these rocks are poorly sorted. Peloidal packstones

are generally medium bedded.

SILTSTONE.—Siltstones are common and consist of quartz

silt and sand, silicified calcispheres, radiolarians?, sponge

spicules, and clay. They vary from moderately sorted to poorly

sorted and generally form thin, platy to medium-thick beds.

The siltstones are largely unfossiliferous, with only scattered

traces and burrows and sparse brachiopods and fusulinids.

SANDSTONE.—Sandstones are rare and occur only in the

westernmost exposures in the northern Del Norte Mountains,

where they are poorly exposed. They appear to be similar to the

sandstones that were described by Wardlaw et al. (1990) as

overlaying the lower part of the Word Formation in the same

area as lower delta plain deposits. They consist of generally

fine, immature to submature quartz sand that contains siliceous

and calcareous cement.

BlOTURBATED SKELETAL LlME MUDSTONE.—Lime mudstones are rare and occur in only three sections, RC V, RC VI,

and RC IX. The skeletal grains are broken, abraded, and

scattered and commonly are derived from brachiopods. This

facies is similar to the bioturbated wackestone found commonly in the Appel Ranch Member of the Word Formation

where Rathjen (1985) interpreted the facies to represent a shelf

flat. In the Appel Ranch Member, the carbonate is generally

recrystallized and dolomitized. In the Road Canyon it is only

recrystallized.
124 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Depositional Cycles in the Road Canyon

Each cycle begins over a minor exposure surface, which is

represented by reworked siltstones from the underlying unit or

cycle. The overlying basal carbonate commonly has an

undulating base, and it rarely cuts out, or channels, through the

underlying beds. Rarely, an overlying cycle erodes through a

significant part of the underlying cycle. Generally, when

erosion reaches to a carbonate in an underlying cycle, the

carbonate shows chertification and minor recrystallization near

its upper surface. The idealized cycle (Figure 6-3) begins with

a conglomeratic skeletal wackestone at its base and grades

upward to skeletal wackestone and then to peloidal packstone.

Peloidal packstone grades to siltstone by becoming more silty

and displays alternating beds of peloidal packstone and

siltstone, which gradually gives way to entirely siltstone. This

idealized sequence is represented throughout the area in most

of the cycles, but each lithology is represented by vastly

varying thicknesses of rock. Cycle 1 (Figure 6-2) is the only

cycle that is commonly cut out, thus indicating a more

significant erosional surface between cycles 1 and 2. Cycle 2 is

the most widespread cycle represented in the Road Canyon.

Cycles 3 and 4 are lost in the deltaic sandstones in the western

part of the Del Norte Mountains (section RC XVIII) and

become obscure in the dolostones of the eastern Glass

Mountains (the section above RC XII and eastward, Figure

6-1).

Sequences that truly vary from the model appear to be those

that contain bioturbated lime mudstone, which only occur at

section RC IX in cycle 2, section RC V in cycles 1-3, and

section RC VI in cycle 1. In each, a conglomeratic base is

followed by generally cherty lime mudstone, with the chert

replacing burrows. The basal unit is commonly a lens or

channel of skeletal, conglomeratic carbonate. Peloidal packstones and siltstones are rare or absent. Channels of skeletal

wackestone occur within some cycles. These deposits appear to

be related to the encroachment of the shoal facies, which is

represented by a recrystallized, channelized mud flat similar to

that described for the Word Formation (Rathjen, 1985; Rathjen

et al., this volume), but this facies is rarely preserved in the

Road Canyon Formation.

In addition, in apparent variation from the model, cycle 1 at

sections RC I and RC IX is obscured by a tremendous amount

of conglomerate.

FAUNAS FROM THE CYCLES.—Conondonts show a major

faunal changeover from a transitional form of Mesogondolella

idahoensis to M. nankingensis at or near the base of cycle 2.

Fusulinids appear to show clear Cathedral Mountain affinities

in cycle 1 and change to Word affinities in cycle 2. Ammonoids

show a less clear distribution, with most indicating Leonardian

affinities, but the one definite occurrence of Waagenoceras

(Wordian affinities) within the Road Canyon appears to be in

cycle 4. Brachiopods show general Lower Permian (Leonardian) affinities throughout the Road Canyon, and cycles 1-4 all

contain abundant Coscinophora, which is absent in cycle 5. It

appears that the most marked faunal changeover is at or near

the base of cycle 2, which involves both conodonts and

fusulinids.

CORRELATION OF THE CYCLES.—The boundary between

cycle 1 and cycle 2 is the most extensive exposure surface

within the Road Canyon. This surface occurs just below the

first appearance of Mesogondolella nankingensis. In the

Guadalupe Mountains, the downlap surface of Sarg and

Lehmann (1986a), which is within the Cutoff Formation and

divides the lower San Andres Formation from the middle San

Andres Formation, occurs just below the first appearance of M.

nankingensis. These surfaces appear to strongly correlate. A

downlap surface separates a transgressive system from a

highstand depositional system. To have an exposure surface in

the Glass Mountains at the same time as a highstand in the

Guadalupe Mountains suggests that there is a local relative

uplift in the Glass Mountains area that outstripped sea level at

stillstand (highstand) and caused exposure. During sea level

rise (transgressive deposition), the relative sea level rise

exceeded any local uplift depositing the first cycle in the Road

Canyon Formation at the same time the upper part of the lower

San Andres Formation in the Guadalupes was being deposited.

The sequence boundary below the lower San Andres Formation

(an exposure surface) correlates well with the exposure surface

below the Cathedral Mountain Formation in the Glass

Mountains (within the same conodont zone, Neostreptognathodus prayi-Mesogondolella idahoensis Zone). The upper

sequence boundary at the top of the middle San Andres

Formation (a rather major unconformity) is less well constrained by conodonts (falling within the relatively longranging Mesogondolella nankingensis Zone) but may correlate

to cycle 5, the base of the China Tank Member of the Word

Formation in the Glass Mountains. The exposure surfaces at the

base of cycles 1, 3, and 4 do not have easily correlated

counterparts in the Guadalupe Mountains. This suggests that

although part of the cyclicity is due to response to regional sea

level changes, most of it appears to be due to local uplift and

subsidence.

Depositional Setting

The Road Canyon Formation was deposited on the narrow

southern shelf of the Permian basin of West Texas adjacent to

the Marathon folded belt (see Rohr et al., this volume). The

Marathon folded belt was an active thrust belt (accretionary

wedges overriding the North American plate) in the Pennsylvanian and Early Permian (Ross, 1986). The sequence of

lithofacies, lack of any significant flow features, and the

peloidal packstones with well-coated, poorly-sorted grains

indicate reasonably shallow shelf deposition of the Road

Canyon Formation. The abundance of silt- and clay-sized

material in all the lithofacies indicates a relatively low energy
NUMBER 32 125

MODEL FOR DEPOSITION

FORELAND

BASIN

DELAWARE

BASIN

REEF OR

CARBONATE

BUILDUP

IDEALIZED SEQUENCE OBSERVED IN ROAD CANYON FM. CYCLES 1-3

Siltstone

|.. . .| Peloid packstone

Conglomeratic

wackestone to rudstone

Lime mudstone

FIGURE 6-3.—Idealized cycle of sedimentation and its relation to change in relative sea level and the generalized

depositional setting of the lithofacies.

depositional regime. Models for similar lithofacies in the Word

Formation (Rathjen, 1985) suggest a shoal and back-bay

setting, with peloidal packstones representing the deepest bay

depositional environment. Conodonts are abundant in the

skeletal wackestones, but they are sparse in the peloidal

packstones, and, when found in such packstones, they are

generally in shallow, nearshore biofacies (Wardlaw and Grant,

1990). This distribution is very unlike that of the basinal

deposits of the Guadalupe Mountains and Delaware basin and

suggests that the peloidal packstones do not represent normal

marine basinal deposition. Brachiopods and other normal

marine fossils are also sparse in the peloidal packstones,

suggesting they represent elevated salinities, which would be

expected in a shoaled bay.

The generalized depositional setting (Figure 6-3) appears to

be one of skeletal wackestones deposited behind a shoal, which

is represented by recrystallized bioturbated lime-mudstone

containing skeletal channels. Peloidal packstones represent

shallow back-bay deposition, and siltstones represent nearshore

and back-bay deposition shed from the still active Marathon

folded belt. The cycles are transgressive depositional cycles

over exposure surfaces that represent relative deepening (to

peloidal packstone deposition) and then shallowing (to siltstones and then exposure). In this depositional setting, the cycles

also represent the progradation of shore facies over a shelf

margin shoal. The cycles appear to be largely in response to

local uplift and subsidence rather than to changes in regional

sea level.
126 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Literature Cited

Cooper, G.A., and R.E. Grant

1964. New Permian Stratigraphic Units in Glass Mountains, West Texas.

Bulletin of the American Association of Petroleum Geologists,

48(9): 1581-1588.

1966. Permian Rock Units in the Glass Mountains, West Texas. United

States Geological Survey Bulletin, 1244-E:E1-E9, plates 1,2.

Cys, J.M., and S.J. Mazzullo

1978. Lithofacies and Sedimentation of Lower Permian Carbonate of the

Leonard Mountain Area, Glass Mountains, Western Texas: A

Discussion. Journal of Sedimentary Petrology, 48(4): 1363-1368.

Flores, R.M., T.L. McMillan, and G.E. Watters

1978. Lithofacies and Sedimentation of Lower Permian Carbonate of the

Leonard Mountain Area, Glass Mountains, Western Texas: A Reply.

Journal of Sedimentary Petrology, 48(4): 1368-1377.

Furnish, W.M.

1973. Permian Stage Names. In A. Logan and L.V. Hills, editors, The

Permian and Triassic Systems and Their Mutual Boundary.

Canadian Society of Petroleum Geologists, Memoir, 2:522-548.

Grant, R.E., and B.R. Wardlaw

1984. Redefinition of Leonardian-Guadalupian Boundary in Regional

Stratotype for the Permian of North America. 27th International

Geological Congress, Moscow, USSR, Abstracts, 1:58.

King, P.B.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part I:

Descriptive Geology. University of Texas Bulletin, 3038: 167 pages,

15 plates. [Date on title page is 1930; actually published in 1931.]

Lambert, L.L., D.J. Lehrmann, and M.T. Harris

2000. Correlation of the Road Canyon and Cutoff Formations, West Texas,

and Its Relevance to Establishing an International Middle Permain

(Guadalupian) Series. In B.R. Wardlaw, R.E. Grant, and D.M. Rohr,

editors, The Guadalupian Symposium. Smithsonian Contributions to

the Earth Sciences, 32:153-183, 11 figures, 4 plates, 3 tables.

Lambert, L.L., and B.R. Wardlaw

1992. Appendix II: Morphological Transition from Mesogondolella idahoensis to M. serrrata: Basal Guadalupian Definition. In Glenister et

al., The Guadalupian: Proposed International Standard for a Middle

Permian Series. International Geology Review, 34(9): 876-880.

Measures, E.A., and B.R. Wardlaw

1990. Recognition of Paleokarst in the Road Canyon Formation, Permian

Regional Stratotype, West Texas. [Abstract.] Geological Society of

America, Abstracts with Programs, 22(7):A309.

Rathjen, J.D.

1985. Microfacies and Depositional Environment of the Word Formation

(Permian) Glass Mountains, Texas. 139 pages. Unpublished master's thesis, Sul Ross State University, Alpine, Texas.

Rathjen, J.D., B.R. Wardlaw, D.M. Rohr, and R.E. Grant

2000. Carbonate Deposition of the Permian Word Formation, Glass

Mountains, West Texas. In B.R. Wardlaw, R.E. Grant, and D.M.

Rohr, editors, The Guadalupian Symposium. Smithsonian Contributions to the Earth Sciences, 32:261-289, 22 figures.

Rohr, D.M., B.R. Wardlaw, S.F. Rudine, M. Haneef, J.A. Hall, and R.E. Grant

2000. Guidebook to the Guadalupian Symposium. In B.R. Wardlaw, R.E.

Grant, and D.M. Rohr, editors, The Guadalupian Symposium.

Smithsonian Contributions to the Earth Sciences, 32:5-36, 31

figures.

Ross, C.A.

1986. Paleozoic Evolution of Southern Margin of Permian Basin. Bulletin

of the Geological Society of America, 97(5):536-554.

Sarg, J.F., and P.J. Lehmann

1986a. Lower-Middle Guadalupian Facies and Stratigraphy, San Andres/

Grayburg Formations, Permian Basin, Guadalupe Mountains, New

Mexico. In G.E. Moore and G.L. Wilde, editors, Lower and Middle

Guadalupian Facies, Stratigraphy, and Reservoir Geometries, San

Andreas/Grayburg Formations, Guadalupe Mountains, New Mexico

and Texas. Society of Economic Paleontologists and Mineralogists,

Permian Basin Section, Publication, 86-25:1-8.

Wardlaw, B.R.

2000. Guadalupian Conodont Biostratigraphy of the Glass and Del Norte

Mountains. In B.R. Wardlaw, R.E. Grant, and D.M. Rohr, editors,

The Guadalupian Symposium. Smithsonian Contributions to the

Earth Sciences, 32:37-87, 3 figures, 12 plates, 1 table.

Wardlaw, B.R., R.A. Davis, D.M. Rohr, and R.E. Grant

1990. Leonardian-Wordian (Permian) Deposition in the Northern Del

Norte Mountains, West Texas. United States Geological Survey

Bulletin, 1881-A:A1-A14.

Wardlaw, B.R., and R.E. Grant

1990. Conodont Biostratigraphy of the Permian Road Canyon Formation,

Glass Mountains, Texas. United States Geological Survey Bulletin,

1895-A:A1-A18,plates 1-4.
7. Comparison of the Depositional Environments

and Physical Stratigraphy of the Cutoff Formation

(Guadalupe Mountains) and the Road Canyon

Formation (Glass Mountains): Lowermost

Guadalupian (Permian) of West Texas

Mark T. Harris, Daniel J. Lehrmann,

and Lance L. Lambert

ABSTRACT

Major paleoenvironmental changes near the LeonardianGuadalupian boundary are recorded in both the Cutoff Formation

(Guadalupe Mountains) and the Road Canyon Formation (Glass

Mountains). The Cutoff Formation is composed of a basinal facies

dominated by carbonate and siliciclastic lutites that were deposited

over an eroded Leonardian (Victorio Peak-Bone Spring) bank margin.

These lithologies resulted from an abrupt eustatic deepening (40-50

m), which brought anoxic (dysaerobic) conditions onto the outer shelf

and caused the shallow-water shelf to retreat 19-23 km to the

northwest. Coarse rudstone and megabreccia deposits consisting of

allochthonous clasts occur in slope channels. Prominent submarine

unconformities at the base, as well as within and at the top of the

Cutoff strata, extend from the shelf to the basin. Pre-Cutoff erosion

steepened the underlying bank margin to a 5°-20° slope. Post-Cutoff

erosion locally removed Cutoff strata, resulting in a discontinuous

outcrop along the slope. The recognition of five intra-Cutoff

correlation units, based upon lutite composition, provides a detailed

stratigraphic framework that helps resolve shelf-to-basin correlations.

A complete shelf-to-basin profile, exposed at a high angle to the shelf

margin, provides unambiguous evidence that the unconformities are

regional surfaces, and that the coarse deposits are down-slope debris.

Mark T. Harris, Department of Geosciences, University of WisconsinMilwaukee, Milwaukee, Wisconsin 53201. Daniel J. Lehrmann,

Department of Geology, University of Kansas, Lawrence, Kansas

66045. Lance L. Lambert, Physics Department, Southwest Texas State

University, San Marcos, Texas 78666-4616.

The Road Canyon Formation consists largely of organic-rich lutites

bearing spiculites and radiolarians. Like the Cutoff Formation, it

contains allochthonous megabreccias, conglomerates, and sand sheets.

Megabreccias and conglomerates occur as channelized deposits,

whereas coarse carbonate sands occur in sheet geometries. Lamination

textures in the lutites indicate that the allochthonous material was

deposited in an anoxic (dysaerobic to anaerobic) slope or deep shelf

setting. The recognition of a succession of seven depositional units

allows correlation across the central Glass Mountains. No regionally

extensive unconformity surfaces were noted.

The comparison of the two formations indicates a similar

depositional environment: an anoxic slope-to-basin setting with both

fine-grained autochthonous sediments and coarse-grained allochthonous debris. The Road Canyon outcrop belt, however, nearly

parallels depositional strike, making its interpretation more difficult

(and comparison to Cutoff strata more useful). The recognition of the

depositional environments, detailed internal successions, and relative

stratigraphic completeness provides the necessary framework for

better interpreting the biostratigraphic data relevant to defining the

Leonardian-Guadalupian boundary as discussed in an accompanying

contribution (Lambert, Lehrmann, and Harris, this volume).

Introduction

Leonardian-Guadalupian boundary sections are exposed in

various mountains around the rim of the Permian basin. In

addition to the Leonardian and Guadalupian type areas,

respectively located in the Glass Mountains (King, 1931) and

127
128 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

the southern Guadalupe and Delaware mountains (King, 1942,

1948; Newell et al., 1953), these rocks occur in the northern

Guadalupe Mountains (Boyd, 1958; Hayes, 1959), Sierra

Diablo (King, 1965), Wylie Mountains (Hay-Roe, 1957), and

Apache Mountains (Wood, 1968) (Figure 7-1).

This report focuses on the physical stratigraphy and

depositional environment of two important areas in this region:

the western Guadalupe Mountains (Cutoff Formation) and the

Glass Mountains (Road Canyon Formation). The Guadalupe

Mountains expose a complete shelf-to-basin transect, which

provides a useful comparison to the Glass Mountains. Detailed

stratigraphic studies are essential for evaluating the Roadian

stage and defining the Leonardian-Guadalupian series boundary. Identification of depositional settings, internal stratigraphies, and relative stratigraphic completeness provides a

stratigraphic framework for interpreting paleontological data.

Lambert, Lehrman, and Harris (this volume) present new

biostratigraphic data and stratigraphic revision of past collections.

The Cutoff Formation of the Guadalupe Mountains

The Cutoff Formation is a drape of basin-style facies that

overlies Leonardian carbonate bank deposits of the Victorio

Peak-Bone Spring limestones (Figure 7-2). Prior to Cutoff

deposition, erosion steepened the Leonardian shelf-to-basin

profile to approximately 20° and formed a paleoslope with a

relief of 300 m (McDaniel and Pray, 1967; Pray, 1971; Harms

and Pray, 1974; Harris, 1982, 1988a; Kirkby, 1988). PostCutoff erosion locally removed Cutoff strata along the

paleoslope making correlation of the Cutoff from shelf to basin

problematical (King, 1948; Wilde and Todd, 1968). Strata are

preserved in three distinct areas as defined by the pre-Cutoff

shelf profile (Figures 7-2, 7-3): (1) flat shelf (0°-l° dip), (2)

steeply-dipping slope (5°-20° dip), and (3) low-relief basin

edge (dip less than 5°) that flattened basinward. Herein, "slope"

is used to describe a depositional setting with a perceptible dip

and water depths greater than about 50 m.

Stratigraphic nomenclature used in this paper follows Harris

(this volume) (Figure 7-4). The Cutoff Formation consists of

three members in most of the study area. In ascending order

these are the Shumard Member, the El Centro Member, and the

Williams Ranch Member. The Shumard Member is equivalent

to King's (1948) informal lower Cutoff unit; the two overlying

members are equivalent to his upper Cutoff unit. The Cutoff is

Roadian (early Guadalupian) age (Lambert et al., this volume)

(Figure 7-5); for a review of the nomenclature history see

Harris (this volume).

NMITX

Mexico

Guadalupe

Mountains

t

km 100

miles 100

FIGURE 7-1.—Location of the mountain ranges mentioned in the text relative to Permian paleogeography.

Modified from King (1948).
NUMBER 32 129

BARTLETT

PEAK

N

SHIRTTAIL

CANYON

SHUMARD

CANYON

Shelf Basin

L

EXPLANATION

Cutoff Formation

[...... | Cherry Canyon Formation I 1 El Centro and Williams Ranch Members

^ H Brushy Canyon Formation I I Shumard Member

H I megabreccias

\//\ Victoria Peak Formation

I'l l Bone Spring Limestone

FIGURE 7-2.—North-south cross section of the Cutoff Formation along the western escarpment of the Guadalupe

Mountains. Note that the vertical exaggeration is x2.

The most significant observations concerning the Cutoff

Formation in the context of this paper are as follows: (1) the

strata were deposited over a paleoslope with a relief of 300 m;

(2) draping lutites are the dominant lithology; (3) these lutites

occur in correlatable units that help resolve the shelf

margin-to-basin correlation; (4) eroded channels and coarsergrained lithologies occur along the slope and basin edge; and

(5) three erosional unconformities bracket and subdivide the

formation.

LUTITE LITHOLOGIES

The Cutoff Formation consists of lime mudstone and shale

(95%+ of the strata), with coarser-grained lithologies that

locally occur along the slope and basin edge (for details, see

Harris, 1982, 1988a). (Herein we use the carbonate rock

classification of Embry and Klovan's (1971) modification of

Dunham (1962).) In slope and basin areas, three types of lutites

occur: (1) medium-bedded, black, cherty lime mudstone with

abundant black chert seams (5%-15%) and variable laminations; (2) medium-bedded, dark gray lime mudstone with shaly

partings, variable laminations, a very sparse brachiopod fauna,

and minor quartz silt; and (3) interbedded argillaceous lime

mudstone and calcareous shale, which are both dark brown to

dark gray to black, unfossiliferous, thinly laminated, and

fissile. In places, thin to very thin beds of finely laminated

siltstone occur. In outer (more basinward) shelf areas (Shirttail

Canyon to Cutoff Mountain), medium-bedded medium gray

lime mudstone comprises the top of the section. Several thin

skeletal-rich wackestone layers occur within the medium gray

lime mudstone at the type section.

The lutites are suspension deposits that drape pre-existing

topography. Slight bedding thickness variations indicate only

minor current activity during deposition. The distribution of

skeletal fauna, bioturbation, and lamination styles within the

lime mudstones indicate deposition in an anoxic basin (Byers,

1971; Harris, 1988a). Dysaerobic (oxygen-poor) waters extended northward onto the outer shelf where the initial water

depth during Cutoff deposition was approximately 40-50 m.

Anaerobic (oxygen-depleted) conditions in the lower slope and

basin areas existed at paleodepths of over 250 m. Shelf sections

thicken northward, and carbonate textures indicate upward and

landward shallowing that was probably related to the progradation of the shallow-water skeletal facies of the San Andres

Formation (Boyd, 1958; Sarg and Lehmann, 1986a).

SHELF-TO-BASIN CORRELATION

A vertical succession of five correlation units is recognized

within the Cutoff strata from the shelf edge to the basin. This

succession provides a stratigraphic framework that helps

resolve shelf-to-basin correlation (Figure 7-6). The five-fold

succession is as follows:

Williams Ranch Member Unit 5: Medium-bedded lime mudstone

Unit 4: Interbedded lime mudstone and shale

El Centro Member Unit 3: Medium-bedded lime mudstone

Unit 2: Interbedded lime mudstone and shale

Shumard Member Unit 1: Black, cherty lime mudstone

The Shumard Member has the most restricted distribution in

the shelf and slope areas due to erosion along an intraforma-
130 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Modified from: King, 1948; MacDaniel and Pray, unpubl.; Hams, 1982.

FIGURE 7-3.—Geologic map of the Bone Canyon-Shumard Canyon area in the western Guadalupe Mountains.

This area is the lower slope environment during Cutoff Formation deposition (compare with Figure 7-2).

tional unconformity that separates the Shumard and El Centro

members. The El Centro Member (units 2, 3, and 4) consists of

a distinct "triplet" of two shale packages separated by a thin

limestone bench. The Williams Ranch Member locally thins

beneath the unconformity at the top of the Cutoff Formation. It

thickens basinward to comprise about one-half of the upper

Cutoff strata south of Bone Canyon.

The textures and faunal content within the lime mudstone

units support the anoxic basin model; but within the interbedded lime mudstone and shale (units 2 and 4), diagenesis of

these clay-rich rocks has obliterated any variation in depositional laminations. The cause of the alternation of limestone

and shale units is unclear. It may relate to variations in

carbonate shelf position related to backstepping and prograda-
NUMBER 32 131

Formations Members

Brushy Canyon Formation

Cutoff Formation

Bone Spring Limestone

undifferentiated

Williams Ranch Member

El Centra Member

Shumard Canyon Member

undifferentiated

FIGURE 7-4.—Stratigraphic nomenclature for the Cutoff Formation of the

western Guadalupe Mountains (modified from Harris, this volume).

tion (Sarg and Lehmann, 1986a). Because the correlation units

consist of suspension deposits, they are interpreted to be the

result of synchronous changes in shelf-derived lutite material.

Faunal correlations support synchroniety (Lambert et al., this

volume).

COARSER ROCK TYPES

Coarser-grained lithologies (sandstone, rudstone, and megabreccia) occur as lens-shaped channel fills or as sheet-like

bodies in slope and basin areas. They are distributed vertically

throughout the Cutoff strata, and most overlie truncation

surfaces. These grain-supported rocks are ungraded and may be

divided into two groups: poorly-sorted textures with mud-filled

intergranular spaces, and well-sorted textures with mud-free

intergranular spaces. The first group includes megabreccias and

most intraclastic rudstones. Skeletal rudstones, quartz sandstones, and some intraclastic rudstones comprise the second

group. For both groups, grain-supported textures, erosive

bases, and channel morphologies all suggest that these rocks

are turbulent flow deposits. The poorly sorted lithologies may

be modified debris flows. The well-sorted lithologies are

probably normal traction deposits.

Megabreccia and rudstone clasts produce most of the

megafauna attributed to the Cutoff strata in the western

escarpment area. Megabreccia clasts in channel lenses at the

base of the Cutoff section are derived from the underlying

Victorio Peak Limestone and Bone Spring Limestone. Higher

in the section, the principal clast source shifts to the lutites of

the Cutoff Formation, indicating erosion of the shelf edge

and/or upper slope.

Guadalupe

Mountains

Important Biostratigraphic Ranges

Fusulinids Conodonts Ammonoids

Glass

Mountains

Brushy

Canyon

Fm.

Pipeline Sh

Williams

Ranch

 cu

-

5

c.u. 4

O

~' c.u.3

Centro

c.u. 2

Shumard

Canyon

 c 'u

'

Mn

Pa

Te Pr St

i i i

Gl

Ep

Bone

Spring

Limestone

iMt

Word

Formation

Wa

Road

Canyon

Formation

Mi

Pe Cathedral

Mountain

Formation

Fusulinids:

P = Parafusulina boesei, P. maleyi,

P. attenuata and P. rothi

Conodonts:

Mn = Mesogondolella nankingensis

Mt = Mesogondolella transitional forms

Mi = Mesogondolella idahoensis

Ammonoids:

Pe = Perrinites

Pa = Paraceltites

Te = Texoceras

Pr = Peritrochia

St = Stenolobulites

Ep = Epithalassoceras

Gl = Glassoceras

Wa = Waagenoceras

FIGURE 7-5.—Correlation of the Cutoff Formation (Guadalupe Mountains) to the Road Canyon Formation (Glass

Mountains). Dashed ranges only occur in the Glass Mountains. Glassoceras may include specimens now

assignable to Demarezites. Fusulinid data from Wilde, 1990. (For more information, see Lambert et al., this

volume.)
132 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Williams

Ranch

Member

Shelf >«* • Slope Basin

north south

Williams

Ranch

Member

limestone

cherty limestone

shale

• • I rudstone

South

Shumard

Canyon

Shumard

Canyon

 Cutof f

Member Mountain Shumard

Canyon

Member

Canyon south

of Bone Canyon

FIGURE 7-6.—Correlation of representative sections of the members of the CutoffFormation (western Guadalupe

Mountains), illustrating the informal correlation units. (Thin lines = correlation lines; thick lines = the three major

unconformities of the CutoffFormation.)

TRUNCATION SURFACES

Submarine truncation surfaces occur vertically throughout

the Cutoff Formation and are concentrated at the slope and

basin edge. They occur in three forms: (1) channel crosssections with a relief ranging from a few centimeters to 50 m,

(2) spoon-shaped "half-channels" that truncate more than 100

m of strata at the shelf edge (Pray et al., 1980; Franseen et al.,

1988), and (3) low-angle (l°-5°) truncation of beds in shelf

and basin areas over a distance of several kilometers.

Several points should be noted about these truncation

surfaces (for a fuller discussion see Harris, 1987). First, three

widespread shelf-to-basin unconformities occur at the base and

top of the Cutoff strata (Pray, 1971) and between the Shumard

and El Centro members throughout the western escarpment

outcrops (Harris, 1982, 1988a) (Figure 7-6). Second, truncation

surfaces cause the discontinuous distribution of Cutoff strata

along the shelf-to-basin transect. This is due to both truncation

along the unconformities and intraformational surfaces. Third,

both coarse, channel-filling lithologies and lutites overlie these

truncation surfaces. The coarse channel fills occur in a lower

slope to basin-edge position along the profile (Figure 7-6). The

megabreccia-filled channels (Pray and Stehli, 1963; "patch

reefs" of Newell et al., 1953) only occur along unconformity

surfaces. Fourth, the sandstone at the base of the Shumard

Member in Shumard Canyon sits immediately above the lower

unconformity. It may be correlative to a more basinward,

thicker sandstone unit in a similar stratigraphic position in

Brushy Canyon (Delaware Mountains, Christine Rossen, pers.

comm., 1991). Finally, the basinal sections (south of Bone

Canyon) appear to be the most complete, based upon the

thickness of the different correlation units.

The Cutoff truncation surfaces are interpreted as subaqueous

because of (1) a lack of features typical of vadose, subaerial, or

shallow marine environments, (2) the basinal nature of Cutoff

strata, and (3) the similarity of these surfaces to features in the

overlying deep-water deposits of the Delaware Mountain

Group (Harms and Pray, 1974; Harris, 1988a). The occurrence

of channel forms along truncation surfaces and the coarse

redeposited clasts in the channel fills imply the surfaces are, at

least in part, erosional in origin.
NUMBER 32 133

FIELD RELATIONS

This section describes the field relations along a north-tosouth transect from the top of the steep paleoslope north of

Shumard Canyon to the edge of the basin south of Bone

Canyon. The preserved depositional dip profile allows truncation surfaces, lutites, and coarser lithologies to be located in

their appropriate depositional setting.

SHELF (Cutoff Mountain to north of Shirttail Canyon).—The

Cutoff shelf strata overlies a low angle unconformity surface

that truncates beds of the Victorio Peak Limestone (Harris,

1987; Kirkby, 1988). The Cutoff Formation is 60-75 m thick

from the type section southward to the outer shelf edge (Figures

7-2, 7-6). The Shumard Member is absent from the outer shelf

area, but 2-4 m occur at the Cutoff type section; this

distribution is due to truncation along the undulatory intraformational unconformity between the Shumard and the overlying

El Centro. The upper Cutoff strata consists of a lower

shale-dominated section (El Centro Member) and an upper

carbonate section (Williams Ranch Member). Near Bartlett

Peak, 2.5 km north of the shelf edge, a large channel filled with

Cherry Canyon sandstone and two carbonate megabreccia

sheets cuts through 75 m of Cutoff strata and 30 m into the

Victorio Peak Limestone (Harms, 1974; Harris, 1988a; Kirkby,

1988). The southernmost Cutoff shelf section is delineated by

an erosional surface, which truncates the entire Cutoff

Formation and the uppermost Victorio Peak Limestone north of

Shirttail Canyon (Harris, 1988a; Kirkby, 1988; Rossen and

Sarg, 1988) (Figure 7-7).

SLOPE (north of Shirttail Canyon to Bone Canyon).—The

Cutoff Formation is discontinuous in the slope area because of

erosion along the intraformational and post-Cutoff unconformities (Figures 7-2, 7-3, 7-6). A broad lens of Cutoff strata occurs

in the Shumard Canyon area (Figure 7-8), separated from the

shelf equivalents by a distance of 1.5 km. A less extensive gap

(350 m wide) separates these exposures from the Bone Canyon

outcrops.

The recognition of Cutoff correlation units 2-5 facilitates

correlation of the outcrops in southern Shumard Canyon and

the draw to the south (informally termed Williams Gulch) with

those in Bone Canyon. The distinctive El Centro shalecarbonate-shale triplet, overlain by the thick Williams Ranch

carbonate, is recognizable in both areas despite truncation

along the post-Cutoff unconformity (Figures 7-6, 7-9, 7-10). In

southern Shumard Canyon, cherty lime mudstones of the

Shumard Member occur within a single channel fill along with

minor basal beds of intraclastic rudstone and quartz sandstone

(Figures 7-8, 7-9). This channel is oriented south to southwest

and cuts 47 m into the underlying Victorio Peak.

Numerous channels locally truncate strata in the upper

Cutoff Formation. Channel forms are best exposed at the base

of the slope in Bone Canyon (Figures 7-11, 7-12). Two channel

types occur: broad (100-160 m) forms with flattened (< 10°)

sides predominantly filled with lutites and minor intraclastic

rudstone lenses, and narrow (< 30 m), steep-sided (> 10°) forms

with megabreccia channel fillings (Pray and Stehli, 1963; the

"patch reefs" of Newell et al., 1953). Megabreccias at the base

of the Cutoff Formation contain Victorio Peak and Bone Spring

clasts, reflecting erosion of the pre-existing Leonardian bank.

Victorio Peak and Cutoff clasts within upper Cutoff intraclastic

rudstones record the continued shelfward retreat of the shelf

edge.

BASIN (south of Bone Canyon).—The Cutoff thickens

basinward by the stratigraphic thickening of individual units

and by the decreasing truncation along unconformity surfaces.

The Shumard Member appears about 450 m south of Bone

Cherry Canyon Formation

Cutoff Formation

r 50

Brushy Canyon Formation

Victorio Peak Formation

meters

50

FIGURE 7-7.—Pinchout of the Cutoff Formation at the shelf edge. (Adapted from an original by Kirkby for Pray

etal., 1980.)
134 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Brushy Canyon Formation

Victorio Peak Formation

sw

r 50

m

50

Cutoff Formation

El Centro and Williams Ranch Members

Shumard Canyon Member

megabreccias

FIGURE 7-8.—Overview of Shumard Canyon from the north. Note the channel-filling geometry of the lower

Cutoff strata. (Adapted from an original by Kirkby for Pray et al., 1980.)

Canyon and overlies an unconformity that separates it from the

Bone Spring Limestone. Its contact with the El Centro Member

is also an unconformity, similar to that in the slope settings.

Stratal truncation along this unconformity decreases to the

south, so that the Shumard Member increases in thickness from

its truncated feather edge to 34 m over a distance of 0.5 km.

Further south it disappears into the subsurface.

The El Centro and Williams Ranch members thicken

basinward from 40 m, in the south wall of Bone Canyon, to 93

m over a distance of 1.7 km to the south. Truncation along the

upper Cutoff surface decreases basinward to essentially zero

within a kilometer of Bone Canyon. This expanded upper

Cutoff section has been traced into the low black hills south and

southwest of El Capitan. King (1948) and Newell et al. (1953)

considered these hills to be composed of the Bone Spring

Limestone. Conodonts confirm the correlation of these strata

with the upper Cutoff to the north (Lambert et al., this volume).

In the most basinward sections, the Shumard Member

constitutes approximately one-fourth of the entire Cutoff

section, although it is absent over most of the steeply dipping

paleoslope.

Small, poorly exposed channels, with relief of up to 1 m, and

rare slump features occur within the basinal Cutoff strata.

These are inferred to be similar in their geometry to the

well-exposed channels in the slope area. The Bone Spring

fauna reported by King (1948) from this area was collected

from these channel deposits.

CUTOFF FORMATION DEPOSITIONAL SETTING

The Cutoff Formation records an abrupt deepening of the

outer Northwest Shelf of the Delaware basin. Shallow-water

shelf deposition retreated to southern New Mexico (Boyd,

1958; Sarg and Lehmann, 1986a) and fine-grained shales and

lime-muds mantled the underlying shallow-water lithologies of

the Victorio Peak Limestone. Anoxic waters transgressed over

the outer shelf, estimated at 40-50 m in depth (Harris, 1988a).

These anoxic conditions, recorded in the lime mudstone units,

indicate that a stable, stratified water column existed throughout Cutoff deposition. Submarine truncation and erosion

disrupted stratigraphic continuity. Coarse megabreccia and

rudstone deposits containing shallow-water lithoclasts are

readily identifiable as downslope allochthonous debris because

of the preserved depositional profile.

The depositional style and associated erosion surfaces of the

Cutoff strata are consistent with the density current model

proposed by Harms (1974) and Harms and Pray (1974) for the

overlying Brushy Canyon Formation, but modified for an

anoxic carbonate basin setting. The Cutoff suspensiondeposited lutites are punctuated by erosional features and

traction deposits from denser, bottom-hugging currents. The

predominance of lutites is probably due to the general lack of

sand-sized particles. Bottom currents are recorded largely by

erosion surfaces. The abundance of megabreccias and intraclastic rudstones was probably due to the availability of clasts from

erosion of updip lithified Victorio Peak and Cutoff carbonates.

Alternations of erosion and deposition along the slope

produced a complex pattern of truncation and bedding surfaces.

The Road Canyon Formation of the Glass Mountains

The Road Canyon Formation consists of organic-rich

spiculitic lutites and coarse allochthonous limestones. It is

sandwiched between silicious shales, siltstones, and spiculitic

lutites of the Cathedral Mountain Formation (Leonardian) and

similar lithologies of the lower Word Formation (Guadalupian)

(Figure 7-13). In the eastern Glass Mountains the Road Canyon

Formation occurs above the Hess Formation shelf facies,

whereas in the western Glass Mountains it occurs above the
NUMBE

R 32

135
136 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Brushy Canyon Formation

Victorio Peak Formation

FIGURE 7-10.—South wall of Williams Gulch, illustrating the basinward pinchout of the Cutoff strata in the lower

slope position. Note the channel-like morphology of the stratal onlap (C. Rossen, pers. comm., 1991).

slope and basinal facies (King, 1942; Rogers, 1972, 1978; Cys

and Mazzullo, 1978; Cys, 1981; Ross, 1986, 1987) of the

Skinner Ranch and Cathedral Mountain Formations. Philip B.

King (1931) interpreted the Glass Mountains as exposing a

highly oblique cross section through a northeast-southwest

trending shelf-to-basin margin with reef and backreef environments to the southeast and the basin to the northwest. Thus, in

the Glass Mountains, shelf facies in the east contrast with more

basinward facies in the west.

The stratigraphic nomenclature used herein follows Cooper

and Grant's (1966) modification of King (1931) (Figures 7-13,

7-14, 7-16); see Ross (1987) and Lehrmann (1988) for further

nomenclature history. The Road Canyon Formation is the basis

of the Roadian Stage (Furnish, 1966,1973), and its type section

lies in the central Glass Mountains (Cooper and Grant, 1964).

Its contact with the overlying Word Formation is gradational

and is generally selected on the relative proportion of carbonate

to siliceous shale. In this study, the bed selected for the contact

is the uppermost persistent (50-100 m laterally) limestone

greater than 60 cm thick. This definition includes a variable

proportion of lutites but agrees with King's (1931) original

definition. To the east (Old Word Ranch area), the Road

Canyon Formation merges with the next higher carbonate unit

(China Tank Member of Cooper and Grant, 1966) in the Word

Formation by pinch out of the intervening shale. Strata

equivalent to the Road Canyon are included within undifferentiated Word Formation in this area (Figure 7-15; section 1 of

Figure 7-16).

The most significant observations and interpretations concerning the Road Canyon Formation for this paper are (1) the

outcrop trend is highly oblique to depositional dip, (2) the strata

consists of fine-grained spiculitic lutites (which indicate a deep
NUMBER 32 137

u

I

u

o .ts

=2 S
138 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

3 I

2

 2

ll i

13 £ °

> u u

3 2 U

S l 5

•5 •> J£

us O

D | S

rTM «*3 S
NUMBER 32 139

TESSEY

LIMESTONE OCHOA

SERIES ?

POST-PERMIAN

r CAPITAN LIMESTONE

GUADALUPIAN

SERIES Apple Ranch Mbr UNDIFFERENTIATED

WORD

FORMATION

ROAD

CATHEDRAL MOUNTAIN

SKINNER RANCH

FORMATION

LEONARDIAN

SERIES

WOLFCAMPIAN

SERIES

wsw ENE

FIGURE 7-13.—Stratigraphic cross section of the Glass Mountains. (Modified from Ross, 1986.)

King 1930

Third Lst.

Word S60011*

1 Ls t

Formation

First Lst.

Leonard

Formation

(top)

Cooper and Grant 1964

Apple Ranch Mbr

Word Willis Ranch Mbr.

Formation

Road Canyon Mbr.

Cathedral

Mountain

Formation

Cooper and Grant 1966

Apple Ranch Mbr

Wnrrl

Formation

Willis Ranch Mbr.

Road Canyon Formation

Cathedral

Mountain

Formation

FIGURE 7-14.—Changes in Road Canyon nomenclature.

shelf or slope setting into which allochthonous deposits were

introduced) with allochthonous channelized breccia and sandsheet deposits, (3) two major intervals of megabreccia (with

locally truncational bases) and a graded carbonate sand sheet

(higher in the section) can be traced across the central Glass

Mountains, and (4) channelized deposits and sparse current

indicators support King's (1948) interpretation of basin

direction.

LUTITE LlTHOLOGIES

Lutites in the Road Canyon Formation are composed of

lime-mud and fine-grained siliciclastics, with variable amounts

of sponge spicules, radiolarians, and silicification. The lutites

can be subdivided into dark organic-rich lutite and orange

lutite. Dark organic-rich lutite occurs in recessive fissilelaminated beds (Figure 7-17A) as well as resistant beds ranging

from 3 to 12 cm thick with discontinuous wavy laminations

(Figure 7-17B). This lithology locally contains synsedimentary

faults, which displace laminae up to 2.5 cm (Figure 7-17B), and

folds adjacent to conglomeratic lens deposits. Orange lutite

commonly weathers into thin, recessive, highly fissile beds or

into more resistant silicified beds up to 13 cm thick.

Spiculite/radiolarian-rich laminae and muddy layers alternate

with coarser skeletal concentrations and organic-lean lenses

and form fine parallel (Figure 7-17D) to thicker (1-2 mm)

wavy, discontinuous (Figure 7-17B) laminations. Flattened
140 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

103° 16'

FIGURE 7-15.—Glass Mountains location map. SI through S6 are the locations of the stratigraphic sections of

Figure 7-16. (Modified from Cooper and Grant, 1966.)

organic-lean lenses are interpreted as horizontal feeding traces.

In thin section, the high organic content causes the matrix to be

dark-colored to opaque (Figure 7-17c). The major difference

between orange and dark organic-rich lutite lithologies is the

organic content. Orange weathering lutite has a lighter matrix,

indicating lower organic content and more common silicification. Both lithologies contain silt-size sponge spicules and

radiolarians, which have a patchy distribution (Figures 7-17C,

7-18). The internal lattice structures of radiolarians are

preserved in some samples (Figure 7-18).

The lamination style and fossil content of the dark lutites

indicate dysaerobic conditions that are similar to the Cutoff

slope strata. Fine lamination, laminae-parallel bioturbation

structures, lack of shelly fauna, and the high organic content

suggest suspension deposition in the dysaerobic zone. Bottom

currents that interrupted pelagic deposition formed the skeletal

concentrations within the wavy laminations. The orange

weathering lutite differs from the dark lutite in having a lower

organic content and more common silicification. Dark lutite

predominates in the eastern and western Glass Mountains, but

it occurs only locally in the central Glass Mountains, where it

grades laterally into the orange lutite (Figure 7-16). Orange

lutite occurs predominantly in the upper half of the Road

Canyon Formation in the central Glass Mountains. The

transition from dark to orange lutite represents an environmental change to a more oxygenated depositional setting or a

diagenetic effect (silicification?).

SKELETAL PACKSTONES AND GRAINSTONES

Fossiliferous packstones and grainstones occur as both

bedded and lenticular deposits. These allodapic carbonates

contain abundant peloids and skeletal grains and are locally

oolitic (Figure 7-19A; P.B. King, 1931). Common skeletal

grains include fine sand to granule-size bryozoans, brachiopods, crinoids, and fusulinids, all of which are commonly

abraded and micritized.

Medium-bedded (15-30 cm thick beds) packstone to

grainstone deposits occur in the central Glass Mountains within

the lower half of the Road Canyon Formation, and they overly

both the lower and upper megabreccia units (Figure 7-16).

They are thicker over the edges of the underlying megabreccias, and they onlap over the central portions of the

megabreccias. In the type section (section 5 of Figure 7-16), the

medium-bedded grainstone unit overlying the lower megabreccia contains tabular cobble-size intraclasts near its base.

Scour and drag marks at the base of this unit probably formed

via dragging of the cobble-size intraclasts during transport.

Skeletal packstone lenses (1-60 cm thick and 1-6 m wide)

with flat upper surfaces (Figure 7-19C) truncate the underlying

spiculite laminations (Figure 7-19B). Thicker, normally graded

skeletal packstone lenses (> 30 cm) occur in the upper portion

of the Road Canyon Formation in the central Glass Mountains

(Figure 7-19D), whereas thinner lenses tend to occur in the

eastern and western Glass Mountains.

These packstones and grainstones are interpreted to be
NUMBER 32 141

Word Formation

S6

Road Canyon Formation

Base of Mesogondolella serrata s.s.

Cathedral Mountain Formation

wsw

Conglomeratic limestone

Conglomeratic dolomite

Megabreccia

Lime packstone to grainstone

Dark lutite

Orange lutite

ENE

1X1 Covered interval

^ Normal grading

* Geopetal orientation

FIGURE 7-16.—Road Canyon Formation stratigraphic cross section. Section locations are shown in Figure 7-15.

Section datum is the lowest occurrence of Mesogondolella serrata s.s. (now = M. nankingensis s.s.). Note

widespread channeling at Road Canyon-Cathedral Mountain Formation contact. Distribution of conodonts

detailed in Lambert et al. (this volume).

allodapic deposits transported downslope from shallow-water

carbonate environments by bottom currents. The basal cobblesize clasts, scour and drag marks, and onlap against adjacent

strata observed in the bedded units correspond to Harms (1974)

model for deep-water clastic deposition. Skeletal packstone

lenses are interpreted as carbonate turbidites based upon their

erosive bases, planer upper surfaces, well-developed grading,

and laminations in the upper portion.

COARSE INTRACLASTIC CONGLOMERATE AND MEGABRECCIA

Two size categories of coarse lithologies occur in the Road

Canyon Formation: conglomeratic limestone and dolomite, and

megabreccia. The conglomeratic limestone occurs as resistant,

partially silicified lenses and sheets that weather to a light gray

to brown color. The clast-supported texture contains prominent

pebble- to cobble-size clasts (up to 1 m across; Figure 7-20A) in

a fossiliferous rudstone to packstone matrix. Clasts are angular

to subrounded and include skeletal wackestone, packstone and

grainstone, Tubiphytes boundstone, dark lutite, and orange

lutite lithologies (Figure 7-20B). The matrix contains fragments

of brachiopods, bryozoans, crinoids, fusulinids, rugose corals,

Tubiphytes, and quartz silt. Conglomeratic limestones commonly truncate underlying beds and exhibit normal or inverse

grading with parallel-bedded upper parts. In the Old Word

Ranch area, conglomeratic limestones occur as conspicuous

channel fills that truncate the underlying black spiculitic lutite

at different levels (Figure 7-20C) up to 12 m above the base of
142 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 7-17.—Spiculitic lutite lithologies of the Road Canyon Formation. A, finely laminated black spiculitic

lutite, eastern Glass Mountains, section 2. B, wavy, discontinuously laminated black spiculitic lutite with

synsedimentary faults, eastern Glass Mountains, section 2. C, radiolarians in spiculitic lutite. Spherical grains are

silica. Internal radiolarian lattice structure is preserved in darker grains, possibly due to organic films, central

Glass Mountains, section 5 (scale = 1 mm). D, fine parallel laminations in orange spiculitic lutite, central Glass

Mountains, section 5 (scale = 1 cm).
NUMBER 32 143

FIGURE 7-18.—Radiolarians from insoluble residues of black spiculitic lutites of the Road Canyon Formation in

the central and eastern Glass Mountains in reflected light (A and B) and transmitted light (C, D, E). Spherical

Spumellarians with lattice wall structure and with radial symmetry as indicated by preserved radial spines (a).

Spongodiscid and/or Hagiastrid Spumellarians with spongy wall structure and discoidal-triradiate morphology

(b). Discoidal radiolarians with spongy wall structure and triangular to circular discoidal shape with poorly

developed radial arms (c).

the Road Canyon Formation. Overlying conglomerates in the

upper Road Canyon are dolomitized and form the crests and dip

slopes of hills in the area.

Megabreccia lenses are restricted to the central and western

Glass Mountains (Figure 7-16), where they generally occur

within the lower half of the Road Canyon Formation. This

resistant lithology weathers gray or tan and forms ledges and

cliffs. It is composed of pebble- to boulder-size limestone clasts

(including blocks greater than 1 m across) in a skeletal rudstone

to packstone matrix. Clast support is more common than matrix

support. Within the matrix, pebble-size limestone clasts are

commonly clast supported. Finer matrix material consists of

fossil fragments, lime-mud, and minor quartz silt (Figure

7-20D). In some areas, a normally graded lithology (conglomeratic rudstone to mudstone) caps the megabreccia deposits.

Geopetals show these clasts to be randomly oriented. Geopetal

data is summarized in Figure 7-16; arrows indicate the original

top for measured geopetals.

Megabreccia clast lithologies include skeletal lime wackestones, packstones and grainstones (Figure 7-20E, F), boundstones (Tubiphytes boundstone, branching bryozoan framestone, and "reefal" brachiopod packstone), and dark lutite

(Figure 7-20G). Rounded lutite clasts contain deformed internal

laminations and margins sheared into the matrix (Figure

7-20G). Tubiphytes boundstone megaclasts contain geopetals

with irregular cavities that are similar to those described from

the Skinner Ranch Formation (Rogers, 1978). Further details of

the megabreccia geometries and clast orientations in the Road

Canyon type area (central Glass Mountains) are presented in

Appendix 7-1.
144 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 7-19.—Packstone and grainstone lithologies of the Road Canyon Formation. A, coated grains in

medium-bedded packstone to grainstone lithofacies. Most grains contain one to a few coatings ("superficial

oolites") (scale = 1 mm). B, skeletal lime packstone lens truncating laminations of underlying black spiculitic

lutite, eastern Glass Mountains, section 2. C, skeletal lime packstone lens interbedded with fissile orange spiculitic

lutite, central Glass Mountains, section 5. Note the concave base and flat top. Maximum lens thickness is

approximately 20 cm. D, normally graded packstone lens, central Glass Mountains, section 5 (scale = 10 cm).

The determination that the conglomeratic carbonates and

megabreccias are allochthonous deposits that were transported

as turbulent gravity flows is based upon (1) the fabric contrast

with surrounding lutites, (2) the channelized geometry with

erosive bases, (3) sedimentary structures, such as normal

grading and cap facies, and (4) the shearing of the lutite clast

boundaries into the matrix. The numerous clast types represent

mixed sources from both the shelf and slope environments.

INTERNAL STRATIGRAPHY

The following internal stratigraphy of the Road Canyon

Formation can be traced over 4 km in the central Glass

Mountains (Figure 7-21):

Road Canyon spiculitic lutite

Formation graded limestone sheet

spiculitic lutite

medium-bedded packstone/grainstone

upper megabreccia

spiculitic lutite

medium-bedded packstone/grainstone

lower megabreccia

Cathedral Mountain

Formation

spiculitic lutite

Recognition of a detailed internal stratigraphy provides a

framework that facilitates biostratigraphic studies. The lower

and upper megabreccia units contain more than one amalgamated gravity flow deposit. These megabreccia units are
NUMBER 32 145

FIGURE 7-20.—Conglomerates and megabreccias of the Road Canyon Formation. A, cobble to boulder

conglomerate channel-filling lens from the base of the Road Canyon Formation, eastern Glass Mountains, section

1. Note that this lens was interpreted as a bioherm by Cooper and Grant (1972). B, conglomeratic limestone with

recessively weathering clasts of grey spiculite (a) and orange spiculite (b). Upper part of the Road Canyon

Formation, central Glass Mountains, section 5. C, conglomeratic limestone channel fill with truncation of

spiculitic lutite lamination at the channel margin. Lower part of the Road Canyon Formation, eastern Glass

Mountains, section 1. D, packstone matrix of megabreccia with bryozoan and crinoid fragments, lime-mud, and

quartz silt, central Glass Mountains, section 5. E, conglomeratic texture within megabreccia, central Glass

Mountains, section 5. The different clasts lithologies are obviously due to weathering differences. Matrix texture

is packstone to rudstone. F, conglomerate from megabreccia containing brachiopod wackestone (a), fusulinid

packstone (b), and boundstone (c) clasts within a packstone matrix. G, dark orange spiculite clast from

megabreccia illustrating deformed internal lamination and shearing of laminations into the matrix, central Glass

Mountains, section 5.

discontinuous but widespread across the outcrop and are

interpreted to represent two major episodes of downslope

transport.

ROAD CANYON FORMATION DEPOSITIONAL SETTING

The Road Canyon Formation represents a deep shelf or slope

setting. Organic-rich spiculite- and radiolarian-bearing lutites

were deposited from suspension in quiet anaerobic to dysaerobic waters. Lutite deposition was interrupted episodically by

scour and by the deposition of coarse allochthonous carbonate

that was transported downslope from shallower aerobic

environments.

The direction of the shelf-to-basin transition in the Glass

Mountains has remained problematical. Basin directions

toward the Hovey channel to the west (Ross, 1987), toward the

Delaware basin to the northwest (King, 1931, 1942), and

toward the east (Ross, 1962) have been suggested. The major

difficulty for reconstructing the Road Canyon shelf-to-basin

transition in the Glass Mountains is its highly oblique cross

section. Sole marks in the Road Canyon Formation have a

mean southeast-northwest orientation, but the downslope
146

sw

SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

NE

5510 5376

S5

Persistant conglomeratic

limestone sheet

Persistant

conglomeratic

limestone sheet

Upper megabreccia Lower

megabreccia

A B

Channels with concave-up

bases and flat tops

Upper megabreccia

Lower

megabreccia

1 Kilometer

FIGURE 7-21.—Road Canyon Formation in the central Glass Mountains (southeast facing flank of triangular

group of hills north of Leonard Mountain). Inserts A and B illustrate channels within the formation.

transport direction is indeterminate (Figure 7-22). This orientation is perpendicular to King's interpreted northeast-trending

shelf margin. King's interpretation of the paleoslope is herein

agreed with based on the northeast-southwest trending facies

belts, the northwest primary dips overlain by nearly flat-lying

Cretaceous strata, and the abrupt stratal thinning to the

northwest (King, 1931, 1948). Supporting this model, the Road

Canyon Formation occurs over the Hess Formation shelf facies

in the east and the slope facies to the west (Ross, 1986, 1987).

Ross (1986) interpreted the Skinner Ranch and Cathedral

Mountain formations to step progressively shelfward over the

Hess Formation, representing drowning of the outer shelf. This

probably represents the major flooding event that caused the

shelfward transgression of the Cutoff facies in the Guadalupe

Mountains.

Comparison of the Cutoff and Road Canyon Formations

The Cutoff Formation and the Road Canyon Formation

provide two stratigraphic sections that straddle the Leonardian-Guadalupian boundary at opposite ends of the Delaware

basin. The Cutoff exposures along the western escarpment of

the Guadalupe Mountains are oriented nearly perpendicular to

the shelf margin, whereas the Road Canyon outcrops in the

Glass Mountains lie nearly parallel to the shelf margin. Because

of these contrasting orientations, the Cutoff strata more clearly

express large-scale depositional relations and provides a model

that helps to interpret the Road Canyon Formation.

Key elements in the Cutoff depositional model are the abrupt

sea-level rise that resulted in the drowning of the eroded

Leonardian bank by fine-grained carbonates and siliciclastics,

the facies variations in the lutites that relate to anoxic basin
NUMBER 32 147

— 30° 20"

103° 16'

FIGURE 7-22.—Current indicators and inferred basin direction during Roadian time. Sole markings were

measured near the base of the medium-bedded packstone and grainstone units in section 5 (25 measurements).

conditions, the occurrence of numerous channels and erosion

surfaces with associated allochthonous fauna and coarse

lithoclasts in the slope and basin areas, and the three major

unconformities extending from the shelf to the basin that

control the distribution of Cutoff strata.

Most of these key points also apply to the Road Canyon

Formation. The Road Canyon extends above both the shelf

(Hess Formation) and the slope-to-basinal facies (Skinner

Ranch and Cathedral Mountains formations), which indicates

drowning of a shallow-water Leonardian carbonate bank. The

fine-grained lutites that dominate the Road Canyon section

record the deepening to dysaerobic depths (estimated minimum

water depth of 40-50 m for the Cutoff strata), and perhaps to

the edge of the anaerobic zone (estimated as 250 m depth in

Cutoff rocks). The lithoclastic and fossiliferous conglomerate

and megabreccia lenses and sheets found in both formations are

virtually identical in clast type, range of grain size, and erosive

bases. Intraformational clasts are mixed with shallow-water

carbonates irrespective of their source area. Any regional

unconformities bracketing Road Canyon strata are not presently recognized, although this may be a function of available

outcrop.

The implication of this comparison is that the Road Canyon

records an intrusion of deeper-water facies over the Leonardian

bank-top. Biostratigraphic correlation studies of the sections

suggests that the two deepening events may have been

synchronous (Figure 7-5). The coincidence of two orders

(second-order and third-order) of eustatic sea-level rise may

have produced a large, rapid flooding event (Sarg and

Lehmann, 1986a). One result was that the shelf margin

retreated 19-23 km in the Guadalupe Mountains, and its

progradation did not extend that far basinward again until late

Capitan time. Such a eustatic change would have had a major

effect on middle Permian stratigraphy; therefore, it is suggested

that this event be considered when examining the strata of this

age for recognition of time-rock units.

Recommendations for Future Work Related

to the Series/Stage Boundary

A significant implication of comparing the Cutoff and Road

Canyon strata is the importance of integrating sedimentological

and paleontological data. Downslope megabreccia lenses in the

Cutoff Formation (Newell et al., 1953) and discontinuous

limestone bodies in the Road Canyon Formation (Cooper and

Grant, 1972) have been interpreted as in-place bioherms. Pray

and Stehli (1963) recognized the Cutoff examples as allochthonous mixtures of carbonate debris from different environments; similarly we interpret the Road Canyon lenses as

allochthonous channel fills. A majority of the reported

macrofauna from these formations was derived from alloch-
148 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

thonous deposits, stressing the importance of considering the

lithologic setting for interpreting paleontologic collections.

Regional correlation of the mid-Permian shelf-drowning

events in the Guadalupe Mountains (Victorio Peak Limestone

overlain by the Cutoff Formation) and the Glass Mountains

(Hess Formation overlain by the Cathedral Mountain and Road

Canyon formations) will require biostratigraphic confirmation.

The important implications of a regional or global sea-level

control (Sarg and Lehmann, 1986a) should be tested in other

mid-Permian sections.

The detailed stratigraphic framework developed herein also

allows paleontologic sampling to be tied into finer lithologic

units. Lambert et al. (this volume) use this approach to better

define the biostratigraphic ranges in these units. Recognition of

this fine-scale physical stratigraphy is vital for identifying an

appropriate datum for this important time-rock unit boundary

(Glenister et al., 1992).

Conclusions

The Cutoff Formation (Guadalupe Mountains) provides a

model of slope depositional processes that is applicable to the

Road Canyon Formation (Glass Mountains). The Cutoff

basinal facies are dominated by fine-grained lime mudstones

and shales that were deposited across an eroded Leonardian

bank margin. These facies record an abrupt deepening (40-50

m) that brought anoxic (dysaerobic) conditions onto the outer

shelf. Coarse rudstone and megabreccia deposits consisting of

allochthonous clasts fill downslope channels. Prominent

submarine unconformities bracket Cutoff strata and extend

from shelf to basin. Five intra-Cutoff correlation units provide

a detailed internal stratigraphy that resolves shelf-to-basin

correlations and increases biostratigraphic resolution.

The Road Canyon Formation consists largely of fine-grained

organic-rich spiculite- and radiolarian-bearing lutites with

channelized megabreccia and conglomerate and sand sheets.

Lutite lamination textures indicate an anoxic slope or deep

shelf setting. The coarser deposits are interpreted as downslope,

allochthonous deposits. A succession of seven depositional

units within the Road Canyon Formation allows correlation

across the central Glass Mountains. No extensive unconformity

surfaces were noted. Interpretation of the Road Canyon

depositional setting is difficult because the outcrop belt is

oriented nearly parallel to depositional strike; however,

sedimentological features indicate a slope position similar to

the Cutoff Formation.

Biostratigraphic studies of the Leonardian-Guadalupian

boundary are significantly improved by the increased resolution offered by the fine-scale internal stratigraphies within the

Cutoff and Road Canyon formations (Lambert et al., this

volume). This greater biostratigraphic resolution provides

opportunities to test the global eustatic sea-level rise postulated

to have occurred at the beginning of the Roadian. If confirmed,

such an event would assist world-wide correlation of this

important chronostratigraphic boundary.

Acknowledgments

The authors would like to thank many people for sharing

their insights on Permian stratigraphy with them, particularly

Lloyd C. Pray, David L. Clark, Rick Sarg, Patrick Lehmann,

Christine Rossen, Evan Franseen, Brian F. Glenister, William

M. Furnish, and Fred Behnken. They also wish to thank the past

and present staff of the Guadalupe Mountains National Park, in

particular Roger Reisch, Donald Dayton, and Vidal Davila, for

their assistance with these studies. They also acknowledge

Windy Lewis, Ed Hammond, Mary Hess, William Blackemore

II, Vernon Williams, Joseph Courand, Jr., and Lloyd Stuessey

for kindly allowing access to their ranchlands.
NUMBER 32 149

Appendix 7-1: Features at the Road Canyon Type Section

(Central Glass Mountains)

This appendix presents pertinent field data regarding the

Road Canyon type area (type section = S5, Figure 7-15). It was

prepared by Lehrmann and was based on his thesis research

(Lehrmann, 1988).

Detailed depositional geometries of megabreccia units and

associated strata are well exposed in the Road Canyon

Formation type section area. The lower one-third of the Road

Canyon Formation, including the lower and upper megabreccia

units, fills a northwest-trending channel. Viewed from the

southeast (Figure 7-23), the lower Road Canyon strata pinch

out to the northeast by onlap against a channel margin cut into

recessive (slope forming) Cathedral Mountain Formation.

Although this level is covered northeast of the breccias (Figure

7-23), the absence of outcrop suggests the underlying lithology

is recessive Cathedral Mountain Formation. Viewed from the

southwest, the lower Road Canyon Formation appears to pinch

out to the northwest (Figure 7-24), with the lower and upper

megabreccias represented by thin exposures northwest of the

type area (Figure 7-24). In three dimensions, however, the

megabreccia units thin and pinch out toward the southwest.

Thus, the lower Road Canyon Formation fills a broad

northwest-oriented channel and pinches out to the northeast

sw

PERSISTANT

CONGLOMERATIC

LIMESTONE SHEET

INTERBEDDED

CONGLOMERATIC

LIMESTONE

AND LUTITE

BEDDED PACKSTONE

UPPER -GRAINSTONE

MEGABRECCIA

LOWER

MEGABRECCIA

CATHEDRAL

MTN. FM.

10 METERS

Block at least 4 m across; tilted slighlty to E.

B Pinch-out by onlap of medium-bedded

packstone/grainstone against megabreccia.

C Thick part of lower megabreccia; ~20 m.

D Block at least 1.5 x 3 m. across; original top

downward.

E Block at least 1 m. across; original top 90°

from present vertical toward W.

E 2 blocks: (1) at least 6 m. across tilted 40° to E;

(2) another overturned, original top 135° from present

vertical toward SW.

ONLAP ONTO CHANNEL

MARGIN IN

CATHEDRAL MTN. FM.

G Truncation of bedded lutite at base of upper

megabreccia unit.

H Block at least 1 x 3 m. across original top tilted

90° to W.

I Hummocky upper surfaces of breccia units.

J Random oriented blocks up to 1.5 m. diameter.

K Truncation and deformation (downward and upward)

of bedded packstone at base of megabreccia.

L Normally graded texture (pebble to mud).

FIGURE 7-23.—Road Canyon Formation type section area (section 5) viewed from the southeast.
150 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

NW

CONGLOMERATIC LIMESTONE

AND BEDDED GRAINSTONE TO

PACKSTONE SHEETS

INTERBEDDED WITH LUTITE SE

S 5

PERSISTANT

CONGLOMERATIC

LIMESTONE SHEET

UPPER

MEGABRECCIA

THIN EXPOSURES OF BRECCIA

REPRESENT NW TRENDING EDGE

OF CHANNELIZED DEPOSITS

BEDDED PACKSTONE

 u

-GRAINSTONE Q

LOWER O

N MEGABRECCIA DC

CATHEDRAL

MTN. FM.

NW TRENDING CHANNELIZED DEPOSIT

FIGURE 7-24.—Road Canyon Formation type section area (section 5) viewed from the southwest.

and southwest. Thin exposures of megabreccia northwest of the

type area (Figure 7-24) represent the northwest-trending edge

of the southwest side of the channel.

The lower and upper megabreccia units vary in thickness

across the outcrop because of their truncational bases and

hummocky upper surfaces (Figure 7-23). The lower megabreccia unit thickens from 9 m east of the section line to 20 m

west of it (Figure 7-23C). The upper megabreccia varies from

4.5 to 10 m in thickness. Near the base of the Road Canyon

Formation, the lower megabreccia truncates approximately 3 m

of medium-bedded skeletal packstone (Figure 7-23 K). These

beds are deformed upward and downward by the adjacent

megabreccia. The upper megabreccia truncates up to 2 m of

underlying lutite beds (Figure 7-23G).

Weathering accentuates the margins between clasts and

matrix east of the section line (Figures 7-20E, 7-23J). In

contrast, to the west (Figure 7-23 D,E), the lower megabreccia

weathers massively, obscuring clast margins. Aligned geopetals define two megaclasts (Figure 7-25): one is at least 1.5 x 3

m in size and is overturned (15 aligned geopetals; Figure

7-23D); the other is at least 1 m across and is tilted on its side

(8 aligned geopetals, original top toward west; Figure 7-23E).

Above this massively weathered area, approximately 6 m from

the cliff base (Figure 7-25), the lower megabreccia contains a

4.5 m long horizontal, tabular block composed of laminated

lime packstone with its margins sheared into the breccia matrix.

Farther west at the cliff base, a tabular megaclast composed of

laminated grainstone is tilted on end (Figure 7-25).

Massively weathered limestone cliffs of the upper megabreccia (Figure 7-23 A,F) were interpreted to be composed of

in-place biohermal limestone by Cooper and Grant (1972). East

of the section line (Figure 7-23F), a block composed of

branching bryozoan and Tubiphytes boundstone is at least 6 m

across and contains 12 aligned geopetals tilted toward the east;

the original top is 40° from present vertical. Farther east (Figure

7-23F), a brachiopod skeletal packstone block, at least 2.5 m

across and defined by 5 geopetals, is overturned with the

original top 135° from present vertical. The boundary between

these two blocks is obscured by weathering. Immediately west

of the section line (Figure 7-23A) a brachiopod packstone

block, at least 4.5 m across, is tilted slightly to the east.

Medium-bedded packstone and grainstone overlies the lower

megabreccia unit and onlaps a thickened part west of the

section line (Figure 7-23B). Scouring, sole markings, and

intraclasts indicate an allodapic origin. The upper megabreccia

unit is overlain by a graded (pebble to laminated mud) cap

(Figure 7-23L).

On the southeast-facing flank of the hills northeast of the

type section, megabreccia units have hummocky to flat upper

surfaces and channelized to flat bases (Figure 7-22). The

channel fills that are roughly symmetrical in cross section

(Figure 7-22) indicate the mountain front is a strike section cut

perpendicular to the channel axes.

Measures and Wardlaw (1990) interpreted the megabreccia

at the base of the Road Canyon type section (section 5 of Figure

7-15) as a Permian karst collapse feature. Similar megabreccias, however, occur across the central and western Glass

Mountains (sections 3, 4, 5, and 6 of Figure 7-15), and similar

but less coarse channel-filling conglomerates occur in the

eastern Glass Mountains. A karst collapse origin is unlikely for

the Road Canyon Formation megabreccia for several reasons.

First, lutite lithologies surround the megabreccia, and there is

no obvious source for coarse carbonate debris. Second,

medium-bedded packstone and grainstone deposits thin and

onlap over thicker portions of the megabreccia, indicating the

topography over the megabreccias predates the deposition of
NUMBER 32 151

the packstone and grainstone beds. Third, collapse breccias

typically contain intergranular cement, whereas the intergranular spaces in the Road Canyon megabreccias are completely

filled with packstone and rudstone matrix. Fourth, the

channeled bases and deformed clasts with their sheared

margins appear more consistent with a depositional origin.

W

Tabular laminated

block oriented

Thick expression horizontally

of lower megabreccia

Bedded lutite

truncated at base of

upper megabreccia

Possible internal

channeling within

lower megabreccia

Overturned block

at least 1 X 3 m.

Block at least 1 m

across with original

top oriented 90

toward the west.

Truncation of

Cathedral Mountain

Formation packstone

at base of lower

megabreccia.

E

UPPER

MEGABRECCIA

BEDDED PACKSTONE

-GRAINSTONE

LOWER

MEGABRECCIA

FIGURE 7-25.—Road Canyon Formation type section area (section 5) viewed from the south.

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8. Correlation of the Road Canyon and

Cutoff Formations, West Texas, and Its

Relevance to Establishing an International

Middle Permian (Guadalupian) Series

Lance L. Lambert, Daniel J. Lehrmann,

and Mark T. Harris

ABSTRACT

Recent detailed field mapping and a new understanding of the

internal stratigraphy of the Road Canyon and Cutoff formations have

provided the necessary framework to improve the biostratigraphic

resolution of the Roadian Stage (early Guadalupian Series). Shumard's

(1860) basal "black limestone" at the bottom of Guadalupe Pass was

explicitly included as the lowermost unit when Girty (1902) proposed

the Guadalupian Series. Adams et al. (1939) considered the black

limestone to represent the Bone Spring Limestone, and its fossils to be

Leonardian. Accurate correlation demonstrates that the black limestone is the upper unit of the basinal Cutoff Formation. The

reassignment of previously described fossil localities to their correct

stratigraphic position clarifies temporal faunal relationships, and the

Road Canyon and Cutoff formations are proven to be largely

correlative. Roadian ammonoid, conodont, and fusulinid faunas are

distinctive, and the biostratigraphy records when each of these

important groups is first represented by characteristic Guadalupian

forms. Predicated on both the improved database and consideration of

priority and stability, a return to Girty's original Guadalupian Series

concept is recommended. This supports retaining the Roadian as the

basal stage of the Guadalupian Series. It is also proposed that the

mutual basal boundary of the Guadalupian and Roadian be established

within the morphological continuum through which the conodont

species Mesogondolella idahoensis evolved into M. nankingensis.

Thus defined, the Guadalupian Series is a leading candidate as the

Lance L. Lambert, Physics Department, Southwest Texas State

University, San Marcos, Texas 78666-4616. Daniel J. Lehrmann,

Department of Geology, University of Kansas, Lawrence, Kansas

66045. Mark T. Harris, Department of Geosciences, University of

Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201.

international standard for establishing a formal Middle Permian

Series.

Introduction

One of the most outstanding records of Permian marine

sedimentation is present in the mountain ranges of Trans-Pecos

Texas (Figure 8-1). These strata have been intensively studied

for both their scientific merit and economic value in the nearby

Permian basin petroleum province. As a result, they have been

used as a regional standard for many years. A large proportion

of these rocks accumulated during the middle part of the

Permian Period, and they rank among the world's most

diversely fossiliferous and well exposed. Several excellent

sections exist for selecting the primary reference types (body

stratotypes and boundary stratotypes) necessary to establish a

formal Middle Permian Series. That series would be equivalent

to the Guadalupian of North America.

Definition of the basal Guadalupian (the LeonardianGuadalupian boundary) has remained unsettled, in part because

of evolving stratigraphic nomenclature and previous misunderstanding of important faunal ranges. This reflects historical

contingency: the Guadalupian Series was defined in the

Guadalupe Mountains, whereas the preceding Leonardian

Series was based on strata exposed 150 miles (240 km) to the

southeast in the Glass Mountains (Figure 8-2). Precise

correlation between the two mountain ranges has long

remained elusive. Different expressions of corresponding

paleoenvironments and complex facies relationships have

contributed to equivocal correlations.

153
154 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

NMITX

Guadalupe

Mountains

miles

FIGURE 8-1.—Location of the Guadalupe Mountains, Glass Mountains, and other ranges mentioned in the text

relative to Permian structural elements. (Modified from King, 1948.)

Resolution of the Leonardian-Guadalupian boundary is

ultimately tied to the disposition of the Roadian Stage.

Numerous workers have recognized the Roadian worldwide

since its proposal (Furnish, 1966, 1973; Furnish and Glenister,

1970); however, some have misapplied the concept, which has

lead others to advocate its abandonment by incorporating the

Roadian into overlying and/or underlying stages. The distinctive nature of Roadian faunas has been repeatedly demonstrated

in comparison to both Leonardian and Guadalupian taxa. Yet a

more thorough assessment of faunal ranges through the

Roadian needs to be documented within carefully measured

and sampled sections, especially in the Leonardian and

Guadalupian type areas. Only then can a more meaningful

biostratigraphic analysis firmly establish the Roadian Stage

boundaries.

Subdivision of the Road Canyon and Cutoff formations into

recognizable lithostratigraphic components provides a consistent internal stratigraphy amenable to field mapping (Harris et

al., this volume). This finer stratigraphic resolution results in

unambiguous recognition of the basinal Cutoff Formation and

improved correlation of the Road Canyon Formation from the

eastern to the western Glass Mountains. The lateral integrity of

these units establishes a lithostratigraphic framework for

increasing biostratigraphic precision and for interpreting faunal

data relevant to defining boundaries of the Roadian Stage. The

greater biostratigraphic resolution distinguishes taxa previously blurred by stratigraphic uncertainties, clarifies the

stratigraphic assignment of previously described ammonoid

faunas, and upholds previous fusulinid correlations between

the Glass and Guadalupe mountains. A better understanding of

facies relationships strengthens established correlations between shelf and basin faunas, and these correlations are

confirmed by conodonts collected along shelf to basin

transects.

This paper summarizes the increased biostratigraphic resolution by (1) correcting errors introduced through changes in

stratigraphic nomenclature that resulted in misassignment of

previous faunal collections, and (2) incorporating significant

new data. The results support the formal recognition of the

Roadian as the basal stage of the Guadalupian Series.

Discovery of a morphological continuum in the evolution of

the conodont Mesogondolella idahoensis (Youngquist,

Hawley, and Miller) into M. nankingensis (Ching) near the base

of classic Roadian strata provides an opportunity to select a

boundary definition meeting all criteria for establishing a

Global Stratotype Section and Point. This lower boundary

definition closely matches Girty's (1902) original concept for

the Guadalupian Series. It is therefore recommended that the
NUMBER 32 155

SERIES

OCHOAN

GUADALUPIAN

LEONARDIAN

WOLFCAMPIAN

GENERAL LOCATION

OF REFERENCE

Subsurface: T24S, R34E,

Lea County, New Mexico

Guadalupe Mountains

Glass Mountains

Glass Mountains

BASIS OF CONCEPT

Superposition

(unfossiliferous)

UPPER = CAPITANIAN

Ammonoids

Waagenoceras + Timorites

Fusulinids

Polydiexodina

LOWER = WORDIAN

Ammonoids

Waagenoceras

Fusulinids

Advanced Parafusulina

Ammonoids

Perrinites

Fusulinids

Primitive Parafusulina

Prorichthofenia

Scacchinella

Dictyoclostus bassi

Properrinites

Fusulinids

Schwagerina

Pseudoschwagerina

Paraschwagerina

Parakeyserlingina

FIGURE 8-2.—North American Permian series nomenclature established by Adams et al. (1939), with the general

location of the reference and the stated conceptual basis for each series.

Guadalupian be endorsed as the international standard reference for a formal Middle Permian Series, based on improved

lithostratigraphic and biostratigraphic resolution, stability, and

priority (see Glenister, 1991; Glenister et al., 1992).

Chronostratigraphic Concepts and Nomenclatural History

Girty proposed the Guadalupian Series in a statement

directed primarily toward announcing the unique aspect of

fossils collected from the southern Guadalupe Mountains

(Girty, 1902). The faunas represented an overview of the entire

stratigraphic column (Plate 8-1), ranging from the base of

Guadalupe Pass (the "black limestone" of Shumard, 1860) to

the summit of the range (the "white limestone"). Disparate

collections from across the region were included in his analysis,

along with several fossils from the Guadalupe Mountains

collected by previous workers. Girty's Permian studies

culminated with the publication of his landmark monograph

"The Guadalupian Fauna" (1908). He explicitly included the

black limestone and its faunal components in the Guadalupian

(e.g., Girty, 1908:23). In terms of diversity, more than one-half

of the ammonoid genera that Girty studied were from these

black limestone localities.

Girty's (1908) research material included a small fauna from

the Glass Mountains collected by R.T. Hill. Udden (1917)

published the first broad geologic reconnaissance of that range,

which, along with Bose's (1919) ammonoid studies, established a useful stratigraphic framework. King (1931) conducted

a comprehensive stratigraphic survey based on detailed field

mapping that continues to form the basis of modern research.

Stratigraphic resolution developed further with the extensive

studies of Cooper and Grant (1964, 1966, 1972, 1974, 1975,

1976a,b, 1977). They renamed King's first limestone member

of the Word Formation the Road Canyon Member (Cooper and

Grant, 1964) and later elevated it to a formation (Cooper and

Grant, 1966; Figure 8-3). Cooper and Grant (1966) transferred

the Road Canyon Formation from the basal Guadalupian Series

to the uppermost Leonardian Series to accommodate the

interpreted Leonardian attributes of the Road Canyon brachiopod and ammonoid faunas. Their designated type section for
156 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

King 1931

Third Lst.

Word Fm.

Second Lst.

First Lst.

Leonard

Formation

(top)

Cooper and Grant 1964

Guadalupian Series

Leonardian

Series

Apple Ranch Mbr.

Word Fm.

Willis Ranch Mbr.

Road Canyon Mbr.

Cathedral

Mountain

Formation

Cooper and Grant 1966

Guadalupian Series

I Leonardian Series

Apple Ranch Mbr.

Word Fm.

Willis Ranch Mbr.

Road Canyon Formation

Cathedral

Mountain

Formation

FIGURE 8-3.—History of nomenclature and series assignment for the Road Canyon Formation.

the Road Canyon Formation was included by Cys (1981) in the

Leonardian lectostratotype.

Blanchard and Davis (1929) had previously named the Bone

Spring Limestone for an extensive section of thin-bedded black

limestone exposed along the western escarpment of the

Guadalupe Mountains. They correlated the Bone Spring

Limestone with Shumard's (1860) basal black limestone at the

bottom of Guadalupe Pass. They also equated the Bone Spring

Limestone with the Leonard Formation of the Glass Mountains,

based largely on fossils collected from the black limestone.

King (1934) subsequently adopted their correlations, citing

Girty's (1908:23) remark that, although the black limestone

fauna is "unmistakably related to the overlying faunas, [it] has

an individual fades." These widely accepted correlations

became firmly established following the publication of King's

(1948) monumental Guadalupe Mountains monograph.

Preliminary results from King's Guadalupe Mountains work

decisively influenced the Permian subdivisions of Adams et al.

(1939; Figure 8-2), who placed the Leonardian-Guadalupian

boundary at the Bone Spring-Brushy Canyon contact in the

Guadalupe Mountains. This lithostratigraphic distinction between Leonardian and Guadalupian strata became accepted

dogma; however, correlation between the western escarpment

and more basinward deposits continued to confound stratigraphers. Because the basinal black limestone was considered to

be Bone Spring a priori, the faunas recovered from it had to be

Leonardian, and several contrasting lithostratigraphic correlations were proposed (Figure 8-4). The most often cited are

those of King (1942, 1948) and Newell et al. (1953).

King tentatively correlated the Cutoff Shaly Member

(uppermost Bone Spring Limestone at that time) of the western

escarpment shelf and slope areas with a generally covered

interval south of Bone Canyon that is informally referred to as

the "southern Cutoff" (King, 1948). The southern Cutoff

overlies the black limestone, which King correlated with the

Bone Spring. The nonresistant southern Cutoff interval

included what is now called the Pipeline Shale Member

(Warren, 1955), presently considered to be the basal unit of the

Brushy Canyon Formation. In contrast to King, Newell et al.

(1953) traced the Cutoff Shaly Member into the basin below an

overlying thin-bedded black limestone they informally termed

the "upper Bone Spring," which in turn underlies the Pipeline

Shale (= Waagenoceras Shale of Newell et al., 1953). As a

consequence, they projected the Cutoff shaly strata into the

subsurface below the upper Bone Spring beds.

King differentiated the Cutoff Member as a distinct

formation in a later study on the geology of the Sierra Diablo,

located just southwest of the Guadalupe Mountains (King,

1965). He retained the shelf deposits at Cutoff Mountain in the

northern Guadalupe Mountains as the formation's type section.

King continued to treat the basinal black limestone in

Guadalupe Pass and further south in the Delaware Mountains

as equivalent to the Bone Spring Limestone along the western

escarpment. He may have considered it probable that the

pre-Brushy Canyon erosional event had entirely removed

Cutoff strata from the basin, although no such interpretation

was advanced. King (1965) simply stated that his previous

correlation was untenable, and he left the basinal Cutoff

correlation unresolved.

The correct temporal position of the basinal black limestone

is critical to understanding the proper shelf-to-basin correlations (lithostratigraphic units) and to clarifying the Leonardian-Guadalupian boundary (chronostratigraphic units). Newell

et al. (1953) mapped the rocks accurately but felt compelled to

remain within the established stratigraphic nomenclature. They

had traced the El Centro Member, a diagnostic shale-
NUMBER 32 157

CHERRY CANYON FORMATION

BRUSHY

CANYON

FORMATION

VICTORIO PEAK

GRAY MEMBER

KING 1965

CHERRY CANYON FORMATION

CUTOFF SHALE

VICTORIO PEAK

LIMESTONE X

. RRUSHY CANYON FORMATION

JTOFF SHALE

"PIPELINE SHALE" •>

- "

BONE SPRING LIMESTONE

CHERRY CANYON FORMATION

BRUSHY CANYON FORMATION

MACDANIEL AND PRAY, UNPUBL; HARRIS 1987

CUTOFF

CHERRY CANYON FORMATION

VICTORIO PEAK

FORMATION*

BRUSHY CANYON FORMATION

CUTOFF FM

BONE SPRING LIMESTONE

* WARREN 1955

FIGURE 8-4.—History of nomenclature and correlation for the Cutoff Formation.

VERTICAL

SCALE IN

METERS

300-1

200-

100-

0 -

Girty1902

eries adalupian S

U

Yellow

Quartzose

Sandstone

Basal

Black

Limestone

King 1942,1948

Guad.

Series jian Series Leon

Brushy Canyon Fm.

Bone Spring

Limestone

Newel! etal., 1953

Guad.

Series rdian Series

ro

c Leo

Brushy Canyon Fm.

"Upper Bone

Spring"

Cutoff Member

"Middle Bone

Spring"

Harris 1987

COjpian Serfc Guadak

?

I Leon. Series

Brushy Canyon Fm.

correlation

unit 5

Cutoff Fm.

("upper correlation 4

unit") units 3

2

("lower correlation

unit") unit 1

Bone Spring

Limestone

This paper;

Harris, this volume

CO

CDupian Seri Guadal Series I Leon, i

Brushy Canyon Fm.

Williams Ranch Mbr.

c

To

o El Centra Member

u.

o

Shumard Member

Bone Spring

Limestone

FIGURE 8-5.—Nomenclature, series assignment, and history of subdivision for the strata originally referred to

Shumard's (1860) "black limestone," including members of the Cutoff Formation used in this paper (formally

proposed in Harris, this volume).

limestone-shale triplet, in the Cutoff Formation (Figures 8-4,

8-5; see Harris, this volume) basinwards as the Cutoff Shale in

toto. The thin-bedded black limestone overlying the El Centra

triplet (the Williams Ranch Member) was not recognized as

Cutoff but was correctly interpreted as equivalent to the basinal

black limestone. The basinal Williams Ranch Member-black

limestone thus came to be the upper Bone Spring of Newell et

al. (1953; Figure 8-5).
158 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Harris (1988a) recognized three consistent lithostratigraphic

subdivisions within the Cutoff Formation. He traced the

Williams Ranch Member (correlation unit 5) to the edge of the

basin just south of Bone Canyon, and he suggested that the low

hills of black limestone south and west of El Capitan are

comprised of that member of the Cutoff. Subsequent field work

(Lambert, unpub.) corroborated this hypothesis by tracing the

black limestone-Brushy Canyon contact through those low

hills and into the slope area, working towards the shelf from the

basinal black limestone outcrops. The Pipeline Shale Member

was noted to be discontinuous along this transect, cut out in

many places by later Brushy Canyon sandstones and shales

(Lambert, unpub.). The Pipeline Shale Member pinches out at

the basin edge one-half mile (0.8 km) south of Bone Canyon.

Our collections of ammonoids and conodonts made along this

basin to slope transect confirm that the black limestone is the

basinal Williams Ranch Member of the Cutoff Formation.

The Leonardian-Guadalupian series boundary was delineated by Adams et al. (1939) between the Leonard and Word

formations in the Glass Mountains, and between the Bone

Spring Limestone and Brushy Canyon Formation in the

Guadalupe Mountains (Figure 8-2). This stratigraphic designation was promoted prior to the differentiation of the Cutoff as

a separate formation, and it incorporated the miscorrelation of

the basinal black limestone. These lithostratigraphically derived boundary definitions were based, in part, on the

contemporary interpretations of ammonoid zonal differences.

Indeed, the fauna always cited in the literature as "Bone

Spring" of the southern Guadalupe Mountains is that of the

Cutoff Formation (black limestone). The Leonard and Word

formations and their ammonoid zones (see below) were largely

the basis for the Adams et al. (1939) series concepts.

Wilde has pointed out that fusulinid data strongly suggest the

Road Canyon and Cutoff formations are at least partially

correlative (e.g., Wilde and Todd, 1968; Wilde, 1990).

Furthermore, these fusulinid faunas bear greater similarity to

their Guadalupian descendants than their Leonardian predecessors. Several species range through these formations and into

the overlying strata, but no holdover species from the

underlying strata are known to occur in either the Road Canyon

or Cutoff formations. Because current stratigraphic practice

predicts greater precision by correlating first occurrences,

Wilde has assigned all rocks containing these forms to the basal

Guadalupian. Wilde's age assignments have been adopted by

many Permian basin workers.

The Cutoff Formation, originally a member of the Bone

Spring Limestone, was initially retained in the Leonardian

Series; nevertheless, it has become treated as Guadalupian by

an increasing number of workers. Similarly, the Road Canyon

was once a member of the Word Formation (Guadalupian

Series), but, when elevated to formation status, it was

reassigned to the Leonardian Series (Figures 8-3, 8-4). These

juggled stratigraphic assignments were justifiable at the time

because both the Cutoff (black limestone / Bone Spring) and

Road Canyon formations contain fossil communities comprising elements transitional between typical Leonardian and

Guadalupian forms (Grant and Cooper, 1973:578). Furnish

(1966, 1973) recognized the broad utility of erecting a separate

stage to represent these transitional faunas, and he proposed the

Roadian as the youngest stage of the Leonardian (Artinskian)

Series. The Roadian Stage was readily adopted by many

Permian stratigraphers.

Stratigraphic Framework

The Cutoff Formation forms a drape deposit overlying

eroded Victorio Peak bank sediments and the basinal Bone

Spring Limestone. Shoreward, the Cutoff passes laterally into

shelf deposits of the lower and middle San Andres Formation

(Boyd, 1958; Hayes, 1959; Sarg and Lehmann, 1986a).

Well-exposed outcrops along the western escarpment of the

Guadalupe Mountains expose a dip section cutting across an

essentially complete shelf-to-basin profile (Figures 8-6, 8-7).

The Cutoff is composed predominantly of very fine-grained

basinal carbonate and clastic facies that accumulated under

generally anoxic conditions during a pronounced marine

transgression. Coarse rudstones and megabreccias occur primarily as channel fill in slope and proximal basin positions.

A vertical succession of five internal depositional units used

for field correlation provides a consistent stratigraphic framework for mapping the Cutoff Formation. They are critical for

understanding the formation because of discontinuous exposure along its paleo-slope. These units provide correlation

within the stratigraphically complex slope area, as well as with

more distant exposures both shelfward and basinward. The

discontinuous character of the slope strata and the depositional

topography on which the Cutoff Formation was deposited

resulted from erosional episodes prior, during, and after Cutoff

deposition (Harris, 1988a; Harris et al., this volume).

The Road Canyon Formation overlies slope and basinal

facies of the Cathedral Mountain Formation (Figure 8-8).

Where exposed, the contact of these formations commonly

appears to represent a significant surface of channelling and

scour (Figures 8-9, 8-10). The upper Road Canyon Formation

is gradational with basinal facies of the Word Formation, and

the contact is poorly defined. Most Road Canyon strata can be

grouped into three primary sediment types: (1) fossiliferous

packstones and grainstones, (2) fine-grained radiolarian and

spicule-rich lutites, and (3) coarse sheet or lensoidal conglomerates and channelized megabreccias. Both the conglomerates

and megabreccias are comprised of allochthonous clasts.

Similarly, packstone and grainstone lithologies of the Road

Canyon contain variable amounts of transported material. The

Road Canyon Formation is interpreted to have accumulated in

a distal shelf-to-slope setting (Harris et al., this volume).

The pattern of lithofacies succession and their relative

proportions in the Road Canyon Formation is highly variable,
NUMBER 32 159

EXPLANATION

CHERRY

CANYON FM

BRUSHY

CANYON FM.

EL CENTRO &

WILLIAMS

RANCH MBRS.

SHUMARD

MEMBER

MEGABRECCIA

CONTOUR INTERVAL 200 FT.

Modified from: King, 1948; MacDaniel and Pray, unpubl.; Harris, 1982.

FIGURE 8-6.—General paleoenvironmental setting and distribution of the Cutoff Formation along the western

escarpment of the Guadalupe Mountains. This area represents the paleoslope during Cutoff Formation deposition

(compare with Figure 8-7).

particularly in comparisons between the easternmost and the

westernmost Road Canyon (or Road Canyon equivalent)

exposures. The formation outcrop parallels depositional strike,

rendering the recognition of possible regional discontinuities

corresponding to those of the Cutoff Formation, as well as other

distinctive marker horizons, difficult to recognize. Despite

these complexities, an internal stratigraphic framework can be

established by recognizing a stratigraphic pattern that records

two successive episodes of major down-slope transport, which

are overlain by deposits of a lesser magnitude transport

episode. In the central Glass Mountains, the major transport

episodes are recorded most commonly by megabreccia units.
160 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Shelf H Basin

L

EXPLANATION

Cutoff Formation

[... ...| Cherry Canyon Formation I I El Centra and Williams Ranch Members

^ H Brushy Canyon Formation 1 I Shumard Member

^ ^ | megabreccias

\//\ Victoria Peak Formation

I'l l Bone Spring Limestone

FIGURE 8-7.—North-south cross section of the Cutoff Formation as seen along the western escarpment of the

Guadalupe Mountains. Note that the vertical exaggeration is x2.

TESSEY

LIMESTONE OCHOA

SERIES ?

POST-PERMIAN

r CAPITAN LIMESTONE

GUADALUPIAN

SERIES Apple Ranch Mbr. UNDIFFERENTIATED

Willis Ranch Mbr."~ WORD

FORMATION

SKINNER RANCH

FORMATION

LEONARDIAN

SERIES

WOLFCAMPIAN

SERIES

wsw ENE

FIGURE 8-8.—Schematic cross section of the stratigraphy exposed along the Glass Mountains Front. (Modified

from Ross, 1986.)

The other primary evidence of transport is distribution of the

conglomeratic facies. Deposits of each transport episode are

capped by a lower-energy facies (Harris et al., this volume).

The Road Canyon and Cutoff formations record a major,

relatively rapid increase in sea level. Subdivision of both

formations into smaller lithostratigraphic packages that represent contemporaneous depositional episodes provides the

consistent internal stratigraphy necessary for precise biostratigraphy. A detailed review of the physical stratigraphy and

depositional environment of the Road Canyon and Cutoff

formations is covered in a companion paper (Harris et al., this

volume). Stratigraphic subdivision of the Cutoff Formation

helps resolve the black limestone problem that confounded

previous workers, which in turn clarifies the stratigraphic

assignment of both old and new fossil collections. Recognition

of the temporal sequence of Road Canyon transport episodes

similarly provides for an improved assessment of new and

previously collected faunas.
NUMBER 32 161

103° 16"

FIGURE 8-9.—Index map of Road Canyon Formation sections measured along the Glass Mountains Front, which

were used to construct Figure 8-10. (Modified from Cooper and Grant, 1966.)

Distribution of Faunal Elements

AMMONOIDS

Bose (1919) established the Perrinites Zone for the Leonard

Formation and the Waagenoceras Zone for the Word Formation (Figure 8-2). He correlated these zones with other

previously described Permian ammonoid assemblages. Bose's

pioneering ammonoid studies formed much of the basis for the

series standardized by Adams et al. (1939). Later a conceptual

problem arose when both Perrinites and Waagenoceras were

reported from the first limestone member of the Word

Formation (e.g., Clifton, 1945). Miller (e.g., 1938, 1945; Miller

and Furnish, 1940) had insisted that these genera could not

occur together. He argued that the first limestone member must

be at least partially Leonardian in age because Perrinites is one

of the most abundant taxa recovered from the base of that

member. King (1947) pointed out that both taxa were present in

the basal Word at the limits of their ranges; thus, he concluded

that no real problem existed. However, when Cooper and Grant

(1966) considered Perrinites and Waagenoceras along with

brachiopods bearing a Leonardian aspect, they decided to erect

the Road Canyon Formation for the first limestone member of

the Word, and they reassigned it to the Leonardian Series

(Figure 8-3).

Glassoceras, a rare ammonoid considered at the time of its

discovery to be the stem cyclolobid (and thus the direct

ancestor of Waagenoceras as Stacheoceras normani Miller and

Furnish, 1957), subsequently became an ammonoid index for

the Road Canyon Formation. Although morphologically

similar to the Cyclolobidae (Plate 8-2), Glassoceras is now

classified as representing a distinct subfamily of the Vidrioceratidae (Ruzhentsev, 1960; Glenister and Furnish, 1987). The

taxonomic concept of Demarezites was stabilized by Glenister

and Furnish (1987) to represent ancestral cyclolobins. Its

morphological characters intergrade with those of its descendant, Waagenoceras. Reports of Waagenoceras low in the

Road Canyon Formation most likely represent occurrences of

Demarezites, which is now also regarded as a Roadian

ammonoid index. This possibility is presently being investigated. Transitional forms currently considered to be earliest

Waagenoceras have been recovered from the topmost bed of

the Road Canyon type section. Interestingly, Perrinites and

Demarezites {Waagenoceras of older literature) have yet to be

collected in direct association; however, museum records

indicate that Glassoceras may occur with Perrinites in the Old

Word Ranch area (AMNH Ioc. 503; see Appendix 8-1). It

should be noted that Perrinites largely represents a shelf

biotope, whereas Demarezites and most other cyclolobins

represent basinal water masses. An old report of possible

Perrinites from the black limestone (King, 1934, citing a

footnote on page 160 in Bose, 1919) has not been substantiated.

Scattered ammonoids are present throughout the Road

Canyon Formation. Most have been documented from beds in

which they are especially abundant, but sampling has been

uniquely extensive due in part to the comprehensive acid
162 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Word Formation

S6

wsw

Road Canyon Formation

Base of Mesogondolella serrata s.s.

Cathedral Mountain Formation

ENE

Conglomeratic limestone

Conglomeratic dolomite

Megabreccia

Lime packstone to grainstone

Dark lutite

Orange lutite

Covered interval

Normal grading

Geopetal orientation

FIGURE 8-10.—Schematic of Road Canyon Formation measured sections. Datum is the lowest recovered

Mesogondolella nankingensis s.s (senior synonym of M. serrata). Note widespread channelling at Road

Canyon-Cathedral Mountain Formation contact.

etching program of Cooper and Grant (1972, 1974, 1975,

1976a,b, 1977). Ammonoid diversity is remarkably high in the

Road Canyon, and the spatial distribution of forms is complex.

Both result from the fact that the formation contains a mixture

of taxa representing shelf and basinal paleoenvironments. The

mixing may result primarily from physical depositional

processes, or it may represent overlapping communities at their

intergradational boundary. Table 8-1 lists the ammonoids that

are well-documented from the Road Canyon. This diverse

assemblage comprises much of the Roadian ammonoid fauna

of North America (Plates 8-2, 8-3).

A particularly important Road Canyon ammonoid locality is

USNM loc. 732z. It represents a microcosm of the entire Road

Canyon ammonoid fauna, which contains an admixture of shelf

and basin faunal elements. It is the source of the largest

collection of Permian ammonoids from West Texas, and it

provides the primary data for detailed correlation between the

Glass and Guadalupe mountains (Furnish and Glenister, 1977).

Most of the ammonoids are exquisitely preserved as ferric

molds, showing fine details of ornamentation and sutural

configuration. Paraceltites elegans (Girty), Peritrochia erebus

(Girty), and Texoceras texanum (Girty) are extremely abundant

in both the basinal Cutoff Formation and at loc. 732z but are

uncommon elsewhere. Noteworthy rare ammonoids recovered

from this locality also have their counterparts in the Cutoff

Formation (black limestone) of the Guadalupe Mountains. For

example, Peritrochia n. sp. is represented in the Cutoff

Formation by a single specimen, and the only other known

specimen is from Road Canyon Formation locality USNM loc.

732z. Epithalassoceras (?) n. sp. has only been recovered from
NUMBER 32 163

TABLE 8-1.—Ammonoids documented from the Road Canyon Formation.

Agathiceras girtyi

Agathiceras uralicum

Daubichites cooperi

Epithalassocerasil) n. sp.

Eumedlicottia burckhardti

Glassoceras normani

Neocrimites spp.

Paraceltites elegans

Peritrochia erebus

Peritrochia n. sp.

Perrinites vidriensis

Propinacoceras spp.

Roadoceras roadense

Stachaeoceras spp.

Stenolobulites stenolobulus

Texoceras texanum

Waagenoceras n. sp.

the Glass Mountains (USNM Iocs. 732z and 739d) and the

Guadalupe Mountains (Pipeline Shale Member type section).

Similarly, Stenolobulites stenolobulus Mikesh, Glenister, and

Furnish is present in the basinal Cutoff Formation, and most

Road Canyon specimens are from USNM loc. 732z.

The majority of ammonoids collected from the Cutoff

Formation have been recovered from the Williams Ranch

Member. Scattered specimens are present throughout that

member, but preservation is best and diversity is highest in the

ammonoid-rich horizons near the top. Newell et al. (1953)

noted the presence of ammonoids all along the top of the Cutoff

as they traced the upper Bone Spring basinward from Bone

Canyon. That is still the case, confirmed recently by tracing the

black limestone northward from the basin to Bone Canyon

(Lambert, unpub.). This extensive concentration of ammonoids

may represent a single widespread sedimentological event in

the Delaware basin (sensu Spinosa et al., 1975), or it could have

resulted from accumulation during a brief period of sediment

starvation.

The components of the Cutoff ammonoid fauna form a

diagnostic assemblage that should be immediately recognizable as the Bone Spring (black limestone) fauna of past studies

(Table 8-2). The basinal Cutoff Formation of the southern

Guadalupe Mountains is the type stratum of Texoceras

texanum, Peritrochia erebus, and Paraceltites elegans (Girty,

1908). These taxa are by far the most common ammonoids in

the basinal Cutoff. The first two of these are not known outside

of correlative strata in West Texas. Paraceltites elegans more

typically comprises a widespread but rare component of

Guadalupian ammonoid faunas. Most of the other taxa present

are also comparatively rare. Stenolobulites stenolobulus has a

restricted distribution similar to that of T. texanum and P.

erebus. The single thalassoceratid fragment so far recovered

from the Cutoff represents an advanced form, but it is at such an

early stage of ontogeny that generic assignment is unwarranted.

A few forms (e.g., Agathiceras) represent widespread ammonoid taxa with little biostratigraphic utility.

Ammonoids recovered from other members of the Cutoff

Formation are poorly documented. A possible example is an

incomplete pseudogastrioceratin mold from the base of the

Cutoff (El Centra Member ?) preserved in a fault block west of

Bartlett Peak (Warren, 1955). During the present study, fossils

that may represent poorly preserved ammonoids were occasionally noted in the middle limestone of the El Centro Member

along the western escarpment of the Guadalupe Mountains.

Unfortunately, these specimens are unusually fragile and are

tightly held within the matrix. As a consequence, they typically

break across the fossils rather than crack out of the rock, and

they are not preserved by differential weathering. A specimen

of Perrinites described by Miller and Furnish (1940) from

USGS loc. 7701-PC along the western escarpment south of

Bone Canyon could be either from the Shumard Member of the

Cutoff Formation or from the upper Bone Spring Limestone.

Indeterminate ammonoids were recently noted in the upper

Bone Spring Limestone near that locality.

The San Andres Formation of the northern Guadalupe

Mountains is the updip equivalent of the Cutoff Formation and

is comprised of middle to distal shelf deposits (Boyd, 1958;

Hayes, 1959; Sarg and Lehmann, 1986a). The San Andres

produces rare ammonoids from scattered localities. Perrinites

vidriensis Bose, Paraceltites elegans, and Stenolobulites

stenolobulus have been recorded from the northern Guadalupes, confirming correlation with the Cutoff and Road Canyon

formations (see Wilkerson et al., 1991). Strata assigned to the

Cutoff Formation in the Apache Mountains located to the

southeast (Wood, 1968) are slightly different lithologically

from the Cutoff elsewhere, but they have produced P. elegans,

Stenolobulites aff. S. stenolobulus, and a weathered specimen

of Texoceras texanum. These ammonoid taxa again strongly

support previous fusulinid correlations (Wilde and Todd,

1968). Several poorly preserved specimens from localities

assigned to the Bone Spring Limestone in the Delaware

Mountains to the south and the Sierra Diablo to the

south-southwest (the latter cited in King, 1964) may, in part,

be from the Cutoff Formation or an equivalent, but field

verification is needed for confident stratigraphic assignment.

Immediately overlying the basinal Cutoff Formation (and its

abundant Williams Ranch ammonoid fauna) is the Brushy

Canyon Formation. The lowermost unit of the Brushy Canyon

TABLE 8-2.—Ammonoids documented from the Williams Ranch Member of

the Cutoff Formation.

Agathiceras girtyi

Eumedlicottia burckhardti

Paraceltites elegans

Peritrochia erebus

Peritrochia n. sp.

Stenolobulites stenolobulus

Texoceras texanum

Thalassoceras(J) spp.
164 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

is the discontinuous Pipeline Shale Member (Warren, 1955). In

at least its type locality in the basin, the Pipeline Shale Member

produces another diagnostic and important ammonoid fauna

consisting of the taxa listed in Table 8-3. King (1948) stated

that the Pipeline Shale is continuous in the Delaware

Mountains, but his interpretation appears to have been based on

mapping covered slopes, where typical Brushy Canyon

sandstones and siltstones are indistinguishable from the

nonresistant Pipeline Shale. We could not confirm these

relations because of restricted access to the land. The

Cutoff-Brushy Canyon contact has been traced into Guadalupe

Mountains National Park, where the Pipeline Shale Member

pinches out against the basin edge just south of Bone Canyon.

Referring to Table 8-3, note that the Pipeline Shale Member

duplicates only Eumedlicottia burckhardti Bose (and possibly

the thalassoceratid) from the immediately underlying Cutoff

ammonoid fauna. A cursory examination of the ammonoid taxa

listed on these tables might suggest that the faunal differences

are pronounced; however, cyclolobins have yet to be collected

from strata older than the Pipeline Shale Member in the

Guadalupe Mountains. The Waagenoceras present in the

Pipeline Shale appears to be conspecific with the transitional

Demarezites-Waagenoceras recovered from the uppermost

type Road Canyon. Moreover, all but two ammonoid species

collected from the Cutoff Formation and the Pipeline Shale

Member occur together in the Road Canyon Formation. As

discussed previously, Demarezites is probably present but

misidentified as Waagenoceras and/or Glassoceras. Altudoceras, Daubichites, and Roadoceras are closely related

pseudogastrioceratin genera with overlapping ranges and

similar paleoenvironmental distributions. Consequently, a

faunal comparison with the Road Canyon Formation strongly

suggests that the disconformity separating the Brushy Canyon

(Pipeline Shale Member) and Cutoff formations represents

only a minor hiatus in the Delaware basin.

The ammonoid assemblages recovered from the Pipeline

Shale Member (Brushy Canyon) and the Road Canyon and

Cutoff formations reflect affinities with both Leonardian and

Guadalupian faunas. Perrinites is the most abundant genus

recovered from the Glass Mountains front, on which the type

Road Canyon was established. It represents the last of a family

that characterizes the entire Lower Permian, and it is the index

taxon for the classic Leonardian ammonoid zone. Conversely,

Paraceltites first appears in these strata, and it is the oldest

genus in the suborder Ceratitina. The Ceratitina flourished in

the Upper Permian and eventually gave rise to most Mesozoic

ammonoids (Spinosa et al., 1975). Stenolobulites represents the

earliest Pseudogastrioceratinae, a group that similarly flourished in the Upper Permian. The Pseudogastrioceratinae is the

only subfamily of the Goniatitina that may have extended into

the Triassic, although only briefly. Ammonoid biostratigraphy

and correlations in the middle through Upper Permian are

largely based on evolutionary lineages within the Cyclolobidae

(Furnish and Glenister, 1970; Glenister, 1981). This important

TABLE 8-3.—Ammonoids documented from the Pipeline Shale Member, basal

Brushy Canyon Formation.

Altudoceras altudense

Demarezites n. sp.

Epithalassocerasf?) n. sp.

Eumedlicottia burckhardti

Waagenoceras n. sp.

family evolved during Roadian time and is first represented in

West Texas by Demarezites. A strong case can thus be made

that Roadian ammonoids reflect stronger Guadalupian attributes rather than Leonardian.

A recently discovered locality at the Road Canyon type

section is important because it produces ammonoids in direct

association with a conodont morphotype transitional between

the species Mesogondolella idahoensis and its descendant, M.

nankingensis (see below). The small silicifled ammonoids are

poorly preserved with few external sutures, but conch form and

internal sutures are sufficiently diagnostic to assign many

specimens to the genus level with confidence. Preliminary

study records representatives of Eumedlicottia, Paraceltites,

Peritrochia, and Stenolobulites. Other specimens include very

poorly preserved propinacoceratids, thalassoceratids, and intriguing globular forms that may represent cyclolobids.

Comparison with other specimens recovered from the Road

Canyon Formation suggests some specific assignments (e.g.,

the Peritrochia are probably P. erebus); however, insufficient

data is presently available to determine whether the globular

forms represent Glassoceras or Demarezites. This locality is

significant in that (1) it produces an abundant and diverse fauna

comprised of characteristically Guadalupian ammonoids considered typical of the Roadian, with no representatives of

Perrinites, (2) this Guadalupian ammonoid fauna coincides

with the upper range of a transitional form between the

conodonts M. idahoensis and M. nankingensis, and (3) the

locality is part of the Road Canyon type section. This fauna

further strengthens Road Canyon ammonoid ties with the

Guadalupian rather than the Leonardian Series.

CONODONTS

Conodont faunas from both the Road Canyon and Cutoff

formations are dominated by the genus Mesogondolella. Other

faunal components include Diplognathodus, Hindeodus, Neostreptognathodus, Sweetina, Sweetognathus, and Xaniognathus. Only the Mesogondolella lineage will be considered

in the present discussion because it provides the primary

database for conodont biostratigraphy and correlation in the

middle Permian (Clark and Behnken, 1979; Clark et al., 1979).

The predominance of Mesogondolella along the western

escarpment and in Guadalupe Pass suggests that exclusively

basin-type conditions prevailed for the Cutoff Formation,

following the biofacies distribution model of Wardlaw and
NUMBER 32 165

Collinson (1984). The relative proportions of genera present

(Wardlaw and Grant, 1990), along with a relatively sparse

ramiform element representation (reflecting the degree of

apparatus completeness), support interpreting an offshore

milieu with elevated hydrodynamic energy for the mixed shelf

and basinal components of the Road Canyon Formation.

Geochemical conditions related to the paleoenvironment

resulted in lithologies that are difficult and time-consuming to

process for microfossils. Facies in both formations are

dominated by organic-rich lutites that accumulated under

dysaerobic to anoxic conditions, and samples often require

complex methods of disaggregation. The pervasive organics,

particularly characteristic of the Cutoff Formation, typically

release petroliferous lixivium into solution during acid digestion of carbonate lithologies. This interferes with further

carbonate dissolution. Abundant disseminated argillaceous

material also commonly insulates carbonate samples from

complete acid digestion. A significant portion of insoluble

residues is composed of sponge spicules, radiolarians, and

other siliceous microdetritus. Fissile lithologies are commonly

enriched in silica cements from these sources, and they are

similarly resistant to acid digestion. As a result, multiple

processing methods over a series of runs are needed to

completely break down the rock. Nevertheless, persistence is

rewarded with pristinely preserved specimens. The relative

abundance of conodonts in the Cutoff Formation varies

significantly between samples, but the average is roughly five

elements per kilogram of rock. Samples from the Road Canyon

Formation almost always produce conodonts, but in variable

amounts related to the sample's lithology (Lehrmann, 1988;

Wardlaw and Grant, 1990).

The conodont biostratigraphy of the Road Canyon Formation has been examined recently by Lehrmann (1988) and

Wardlaw and Grant (1987, 1990). Lehrmann (1988) found the

evolutionary succession from Mesogondolella idahoensis

(which largely characterizes the Leonard Formation) to M.

nankingensis to occur low in the Road Canyon, commonly

within the basal beds of the formation. Wardlaw and Grant

(1990) reported the changeover to occur slightly higher, at

various horizons in the lower one-third of the Road Canyon

Formation. They described the changeover to be rapid, often

represented by the co-occurence of both species within a single

sample. The apparent synchroniety of this evolutionary

succession across the North American continent (possibly

worldwide) led them to recommend the first occurrence of M.

nankingensis to mark the base of the Guadalupian. They

recognized that such a boundary definition would closely

match the original Leonardian-Guadalupian boundary in the

Glass Mountains. The rapid conodont changeover within the

Road Canyon Formation, however, also led them to recommend abandoning the Roadian Stage (Grant and Wardlaw,

1984; Wardlaw and Grant, 1990).

The confusion over precisely where the changeover occurs

stems from the way that Mesogondolella idahoensis evolved

into M. nankingensis'. The anterior platform margins of M.

nankingensis have conspicuous serrations that variably extend

toward the posterior of the element. This striking character

serves to distinguish M. nankingensis from M. idahoensis, its

direct ancestor, which has unornamented platform margins.

Basinal deposits of the Cutoff Formation along the western

escarpment of the Guadalupe Mountains preserve a complete

record of the morphological transition from M. idahoensis to

M. nankingensis. Faunal suites representing juvenile through

adult stages of development provide a detailed chronicle of the

clinal pattern by which this transition proceeded. Several

important characters, in addition to platform serration, evolved

at different rates relative to each other, resulting in a mosaic

pattern of transition from one species into the next (Plate 8-4).

The clinal record preserved in the Cutoff Formation can be used

to interpret the complex distribution of morphotypes

characteristic of the lower Road Canyon Formation.

Mesogondolella idahoensis has a Pa element with parallel to

slightly tapering sides through the posterior three-fourths of the

platform. It tapers more markedly, yet evenly, through the

remaining one-fourth to its anterior termination. The platform

is usually widest at its posterior end, but very large individuals

can be slightly wider at mid-platform. The posterior termination is blunt, commonly with squared lateral margins. The

entire element may be gently bowed, arched, or both.

Carina denticles are moderately high in the anterior portion

of M. idahoensis, but they decrease in size toward the posterior

cusp. These denticles are compressed and fused anteriorly,

round and variably discrete posteriorly, and transitional along

the mid-platform. Denticles typically become more fused and

less pronounced in larger elements. Adcarinal furrows are wide,

shallow, and typically well defined. The posterior platform

margins are often thickened around the posterior end of the

adcarinal furrows, which results in a characteristically steep

cul-de-sac posterior termination of the furrows.

The rounded cusp of M. idahoensis is erect and conspicuously large, usually more than twice the size of the adjacent

carinal denticle. It is often fused with this posterior-most

carinal denticle, producing an ellipsoidal cusp cross section. In

large specimens, the cusp is commonly fused to the posterior

lateral margins as well, resulting in a distinctive triangular cross

section. A blade-like secondary carina can be developed by the

incorporation of a small accessory denticle posterior of the

cusp, which is fused to the cusp complex and sometimes to the

adjacent carina denticle. This entire denticle amalgamation is

compressed and is usually oriented toward the inner lateral

terminus.

Viewed from the bottom, the lower attachment surface of M.

idahoensis forms a broad, open V-shaped groove that is

elevated anteriorly to form a short open keel. Posteriorly, this

groove is recessed for three-fourths to four-fifths of the

platform length. It is flat in subadults. The posterior loop

surrounding the basal pit is poorly developed and often

asymmetrical.
166 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Mesogondolella nankingensis is characterized by a Pa

element that tapers through its anterior one-half to one-third,

with distinctively pronounced serrations along the tapering

anterior margins. These serrations cut the lateral margins in the

anterior one-third to one-half of the platform, are subdued to

subtle in the mid-platform, and are absent to subtle in the

posterior one-third of the platform. Mesogondolella serrata

(Clark and Ethington, 1962) is a junior synonym of M.

nankingensis (Ching, 1960).

The anterior platform of M. nankingensis terminates at or,

more characteristically, just short of the anteriormost carina

denticle. Elements may be quadrate or posses a modified

tear-drop shape posteriorly. The former have a blunt posterior

termination and are marginally widest in the posteriormost

one-fourth of the element. Forms with a tear-drop shape are

significantly more common and tend to be widest near the

platform midpoint. Bowing is relatively rare in M. nankingensis. Elements are typically arched gently through the posterior

part of the element. The tapered serration-bearing anterior tends

to be straight, producing a prominent tangential profile in

contrast to the arched posterior platform.

Carina denticles of M. nankingensis are moderately high in

the anterior portion but low in the middle and posterior

platform. Denticles are discrete, round, and pointed. They are

compressed in the anterior and become decreasingly compressed toward the posterior. The denticles become subdued

and sometimes partially fused posteriorly with increasing

specimen size. Adcarinal furrows are commonly well defined

but tend to be moderately thin and shallow. The relative width

and degree of their development is often inversely proportional

to that of the enclosing serrations.

The cusp of M. nankingensis is relatively subdued, often no

larger than the posterior carina denticles. It becomes decreasingly distinct in larger specimens. The cusp is most commonly

circular to elliptical in cross section, and it often comprises the

posteriormost part of the platform. Accessory denticles and

secondary carinae are rare; however, in submature specimens

the cusp may comprise a pair of denticles that are offset by a

gap, but which otherwise are identical with the adjacent

posterior carina denticles. These twinned cusp denticles

coalesce with full maturity and produce a distinctly elliptical

cusp that is, nevertheless, only slightly larger than the adjacent

carina denticles. Although usually erect, the cusp can be

proclined in a small percentage of specimens.

In lower view, the attachment surface of M. nankingensis is

generally narrow, with a very well-defined keel. The keel

usually extends one-fourth (maximum of one-third) of the

length of the lower surface, opposite the tapering portion of the

platform. The keel is characteristically elevated above the rest

of the lower surface, although in very large specimens the

posterior portion may be comparatively flat. The posterior loop

surrounding the basal pit is well defined and conspicuous.

The most striking and consistent character through the

transition from M. idahoensis to M. nankingensis is platform

ornamentation. Serrations first occur in specimens above the

basal shale of the El Centro Member, where they are restricted

to juvenile specimens. Subadult and adult forms mask the

serrations beneath successive laminae. The smoothed serrations

are initially masked at the margins, leaving subdued relict

serrations adjacent to the adcarinal furrows. Slightly higher in

the El Centro Member, subadult specimens display the subdued

serrations, whereas those on juveniles become better defined.

This incrementally expanding pattern of serration is carried

progressively later through ontogeny with increasingly younger faunas. Adult specimens from the middle El Centro

Member attain the pronounced serrations characteristic of M.

nankingensis sensu stricto, which are distinctly visible in side

view as notches in the anterior platform margins. Notches are

not discernable from this perspective on earlier transitional

forms. This type of progressive juvenilization through character development results from the heterochronic process of

neoteny (Alberch et al., 1979; McNamara, 1986).

In lower view, the broad, flat, and often recessed basal

attachment surface of adult M. idahoensis narrows and

develops a consistently elevated keel through the transition.

Correspondingly, the posterior loop becomes increasingly well

developed at all stages of ontogeny. This reflects a reverse

pattern of the ontogenetic development of M. idahoensis. The

fused anteriormost denticles of the carina in adult M.

idahoensis also progressively separate and tend to become

discrete during the transition, a character of both M. nankingensis and juvenile M. idahoensis. The cusp and posterior carina

denticles become less pronounced and less fused. The adcarinal

furrows also become less prominent by continued thinning and

shallowing. The amalgamated cusp complex of M. idahoensis

becomes increasingly rare, and the cusp attains a simplified

circular to elliptical cross section. All of these characters can be

seen to have passed through different stages of ontogeny during

the transition, and together they represent a mosaic heterochronic paedomorphocline (McNamara, 1990).

The temporal pattern of increasingly developed serration

accounts for the discrepancy between where Lehrmann (1988)

and Wardlaw and Grant (1987, 1990) recognized the basal

Mesogondolella nankingensis Zone. Lehrmann placed the

boundary at the first serrated conodont recovered from each

section, whereas Wardlaw and Grant selected the first

occurrence of populations in which serrations were exhibited

by adult specimens. The latter authors referred early transitional forms to M. idahoensis because of the unserrated adult

morphologies. The level within the transition where some

subadults first became serrated accounts for the Road Canyon

samples described by Wardlaw and Grant (1990) as containing

both M. idahoensis and M. nankingensis.

It should be noted that in certain places Lehrmann (1988)

and Wardlaw and Grant (1990) selected the same boundary

horizon, in part because the record of transition in the Road

Canyon Formation is confounded by stratigraphic admixture

and, in most localities, is less complete than in the Cutoff
NUMBER 32 167

Formation. This results from sedimentological complications

related to the predominance of allochthonous carbonate

lithologies in the lower Road Canyon Formation of the eastern

and central Glass Mountains (Figure 8-10). A better record of

the transition is preserved in the western Glass Mountains,

where transportation events were less pervasive and scouring

was less intensive in the subdued energy of a more basinward

setting. Although the species transition preserved in the Glass

Mountains is significantly less straightforward than it is in the

Guadalupe Mountains, enough of the record is present that,

particularly if an early point in the transitional continuum is

selected to define the basal Guadalupian boundary, the majority

of the Road Canyon Formation will be included in the

Guadalupian.

Mesogondolella idahoensis characterizes the Bone Spring

Limestone of the Guadalupe Mountains western escarpment

(Behnken, 1975). It is also present in the Shumard Member of

the Cutoff Formation in the basal rudstone of the type section,

and it has been recovered near the top of the member from

several samples in paleo-slope and basin localities. The

transition from M. idahoensis to M. nankingensis takes place

entirely within the middle El Centro Member. Bruce Wardlaw

has kindly made his conodont collections available for study,

and they include an abundant occurrence of the transitional

form from flank beds associated with the large megabreccia just

south of Bone Canyon. The remainder of the Cutoff Formation

and the lower Brushy Canyon Formation are characterized by

M. nankingensis. Relatively abundant M. nankingensis from

several black limestone localities in the basin confirm that it is

correlative with the upper Cutoff Formation.

Mesogondolella nankingensis was the first in a sequence of

variably serrated species that characterize the Guadalupian

(Clark and Behnken, 1979). This gives the Roadian a distinctly

Guadalupian aspect with respect to conodonts. The authors

concur with Grant and Wardlaw (1984) and Wardlaw and Grant

(1990) that the Leonardian-Guadalupian boundary should be

recognized at the first occurrence of M. nankingensis (i.e.,

somewhere within the morphological continuum between M.

idahoensis and M. nankingensis). With the additional information summarized herein, that level is demonstrated to closely

match the base of the original Guadalupian Series in the

Guadalupe Mountains and the original LeonardianGuadalupian boundary in the Glass Mountains. It would

accordingly settle the continuing confusion that results from

previous miscorrelations. Additionally, the various interrelated

changes in morphology provide a complex pattern on which a

precise definition of the basal Guadalupian boundary can be

established.

FUSULINIDS

Fusulinids are abundant and diverse through most of the

Road Canyon Formation. Ross (1963) was the first specialist to

study the Road Canyon fauna in detail. During the extensive

work of Cooper and Grant (1964, 1966, 1972, 1974, 1975,

1976a,b, 1977), fusulinid specimens were referred to C.A.

Ross, J.W. Skinner, and G.L. Wilde for identification and

biostratigraphic interpretation (Cooper and Grant, 1977). Since

then Wilde has dealt extensively with Road Canyon correlations based on fusulinid data (Wilde and Todd, 1968; Wilde

1975, 1986a,b, 1990, this volume). Other recent fusulinid

studies include those of Yang and Yancey (this volume).

Wilde (1990) assigned the Road Canyon to the Parafusulina

boesi-Skinnerina Zone. Parafusulina boesei Dunbar and

Skinner, P. attenuata Dunbar and Skinner, and P. splendens

Dunbar and Skinner are particularly abundant. Other species of

Parafusulina and Skinnerina are important faunal associates

(notably P. rothi Dunbar and Skinner). Fusulinid workers have

long agreed that this fauna bears a much closer affinity to the

overlying Guadalupian faunas than to the preceding Leonardian ones. Indeed, neither Ross nor Wilde found a single Road

Canyon species in common with those of the Leonard

Formation, although several are shared by the Road Canyon

and younger Guadalupian faunas (Ross, 1963; Wilde, 1975,

1990). An unpublished report by Skinner (mentioned in Wilde,

1975) is sometimes referred to during discussions in support of

a Leonardian affinity for Road Canyon fusulinids. The

discrepancy is probably because of the old dogma: the upper

Bone Spring fusulinids studied by Skinner were probably

collected from basinal flow deposits located in the upper black

limestone—and were considered to be from the Bone Spring

Limestone a priori, rather than the truly correlative Cutoff

Formation.

Fusulinids are relatively rare in the Cutoff Formation along

the western escarpment and in basinal exposures of the

Guadalupe Mountains. Warren (1955) reported fusulinids from

the type Cutoff at Cutoff Mountain, but specific identifications

were not mentioned, nor were the collections successfully

duplicated until recently. Wilde (1988) illustrated two fusulinid

genera and species from approximately the middle of the type

section: Parafusulina splendens Dunbar and Skinner and

Skinnerina rotundata (Dunbar and Skinner). The only other

published fusulinids from the Cutoff Formation proper were

those collected by Harris from the Williams Ranch Member

just west of El Capitan. These specimens were recovered from

two intraclastic rudstone flows near the base of the member.

Wilde (1986b) identified these specimens as P. boesei and P.

maleyi Dunbar and Skinner. All of these taxa consistently

support the correlation and age assignment of the Road Canyon

and Cutoff formations to a Roadian fusulinid Zone of

Parafusulina boesei-Skinnerina (Wilde, 1990), which bears a

distinctly Guadalupian aspect.

Implications and Recommendation for Permian

Chronostratigraphy

Ammonoid, conodont, and fusulinid faunas are accorded

premier importance for Upper Paleozoic biostratigraphy and

correlation. The foregoing discussion illustrates the unique
168 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

character of each of these major taxa in the Road Canyon and

Cutoff formations and demonstrates the excellent correlation

between the Road Canyon and the combined Cutoff-Pipeline

faunas. All three faunal groups are first represented in Roadian

strata by forms considered characteristic of the Guadalupian.

The temporal distribution of biostratigraphically important taxa

and our correlation of Roadian sections in the Guadalupe and

Glass mountains are summarized in Figure 8-11.

The faunal correlations are corroborated by physical depositional evidence that these widely separated sections accumulated during a major marine transgression (Harris et al., this

volume). The magnitude of this event was such that its

correlation potential was recognized before sequence stratigraphy was developed and used in a similar manner (e.g., Wilde in

Wilde and Todd, 1968). If this sea-level rise can be

demonstrated to be eustatic, it will provide an additional

criterion on which correlations outside the Trans-Pecos region

can be based.

The Road Canyon and Cutoff formations have long been part

of the standard reference for the Permian of North America.

This regional reference gained increasing international status as

it became widely recognized that the middle Permian deposits

of the Ural Mountains (type Permian) are comprised largely of

evaporitic and continental strata. When Girty (1902) erected the

Guadalupian it became the first series-level chronostratigraphic

unit for rocks of middle Permian age. The Guadalupian Series,

therefore, has priority as the type for a formal Middle Permian

Series.

Stabilization of the lower Guadalupian Series boundary is

the only remaining step. Recent field studies have clarified

lithostratigraphic relationships in both the Guadalupe and Glass

mountains (Harris et al., this volume). In turn, biostratigraphic

resolution has been greatly increased, and previous miscorrelations have been corrected. Both priority and stability are best

served by restoring Girty's original (1902) Guadalupian Series

concept. The lower portion of the Guadalupian, excluded by

Guadalupe

Mountains

Important Biostratigraphic Ranges

Fusulinids Conodonts Ammonoids

Glass

Mountains

Brushy

Canyon

Fm.

Pipeline Sh,

Williams

Ranch

 cu

-

5

c.u. 4

S * c.u.3

^ Centro

O

c.u. 2

Shumard

Canyon

 C'u

"

Mn

Pa

Te Pr St Gl

i i i I

Ep

Mt

Bone

Spring

Limestone

Word

Formation

Wa

Road

Canyon

Formation

Mi

Pe Cathedral

Mountain

Formation

Fusulinids:

P = Parafusulina boesei, P. maleyi,

P. attenuata and P. rothi

Conodonts:

Mn = Mesogondolella nankingensis

Mt = Mesogondolella transitional forms

Mi = Mesogondolella idahoensis

Ammonoids:

Pe = Pem'nites

Pa = Paraceltites

Te = Texoceras

Pr = Peritrochia

St = Stenolobulites

Ep = Epithalassoceras

Gl = Glassoceras

Wa = Waagenoceras

FIGURE 8-11.—Correlation and faunal range summary for the Cutoff (Guadalupe Mountains) and Road Canyon

(Glass Mountains) Formations. Dashed ranges are those documented only in the Glass Mountains. Note that "P'

includes other species of Parafusulina, and Skinnerina as well (see Wilde, 1990, this volume). "Gl" may include

early species of Demarezites in the Road Canyon; "Wa" includes Demarezites n. sp. in the Pipeline Shale.

Distribution of the Mesogondolella idahoensis-M. nankingensis transitional form strongly suggests that the

discontinuity between the Shumard and El Centro members of the Cutoff Formation corresponds with the basal

Road Canyon channelling event. The uninterrupted faunal record of the upper Road Canyon and its similarity to

the record in the Guadalupe Mountains suggests that the Cutoff-Pipeline discontinuity represents a condensed

section or a minor hiatus, rather than a major unconformity.
NUMBER 32 169

Adams et al. (1939), is retained as the Roadian Stage. The

section in the type Guadalupian that correlates directly to the

Road Canyon Formation is the upper Cutoff Formation (El

Centro and Williams Ranch members) through the Pipeline

Shale Member. Grant and Wardlaw (1984) and Wardlaw and

Grant (1987, 1990) proposed that the Leonardian-Guadalupian

boundary be based on the conodont changeover from Mesogondolella idahoensis to M. nankingensis, which is recognizable

worldwide (e.g., Clark and Wang, 1988). The middle limestone

in the El Centro Member of the Cutoff Formation contains a

complete record of the evolutionary continuum through which

this transition occurred. The transition and the beds from which

it has been recorded meet all criteria for establishing a Global

Stratotype Section and Point.

The authors therefore recommend the following: (1) recognition of the Guadalupian Series as originally proposed (Girty,

1902), with a complete body stratotype to be established along

the western escarpment within Guadalupe Mountains National

Park; (2) the Roadian constitute the basal stage of the

Guadalupian Series; and (3) precise definition of the concurrent

basal Guadalupian Series and Roadian Stage boundary within

the clinal transition from Mesogondolella idahoensis to M.

nankingensis. These results strongly support the Guadalupian

Series as the candidate for the international standard reference

of a formal Middle Permian Series, as proposed by Glenister et

al. (1992).

Acknowledgments

Financial support for field and related expenses were

provided to Lambert by a grant from the Atlantic Richfield

Company (ARCO), the National Geographic Society, and the

Max and Lorraine Littlefield Fund (Department of Geology,

University of Iowa). Additional funding was secured from the

National Science Foundation, U.S.-China Cooperative Research Program administered to Brian F. Glenister. Financial

support for Harris was provided by a grant from the New

Mexico Bureau of Mines and Mineral Resources. A special

thanks is extended to the National Park Service. In addition to

the individuals acknowledged in Harris et al. (this volume),

Roy Mapes provided the septate specimen of E. burckhardti

from the basinal Cutoff Formation, and Bruce Wardlaw

provided access to his extensive Road Canyon and Cutoff

conodont collections. Scott Ritter provided conodont collections from the type Cutoff Formation and supplemental faunas

from the San Andres Formation as part of a previous

collaborative project. Shannon Rudine provided assistance

with land access in the Glass Mountains, and Paul Brenckle

(AMOCO) provided conodont sample bags. Julia Golden

arranged for loans of critical type specimens. This paper was

reviewed by Bruce Wardlaw and Garner Wilde.

All figured specimens are reposited at the University of

Iowa.
170 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Appendix 8-1: Locality Register for Figured Specimens

1. Pipeline Shale Member type section, Brushy Canyon Formation (31°50'5"N, 104°50'

5"W). 3.5 mi (5.8 km) SSW of El Capitan, 0.4 mi (0.7 km) along El Paso Gas

Company right-of-way pipeline road, west of junction with U.S. 62/180, Culberson

County, Texas. Samples from basal phosphatic interval with carbonate concretions

containing abundant ammonoids. Private ranch, permission to collect required.

2. Williams Ranch Member, Cutoff Formation (31°50'2"N, 104°50'6"W). Top beds of

Cutoff Formation, containing abundant large allochthonous clasts; exposed primarily

by road grading and pipeline construction (see Locality 1). Private ranch, permission

to collect required.

3. Williams Ranch Member, Cutoff Formation (31°50'3"N, 104°50'3"W). East wall of

ravine S of Pipeline Shale Member type section (see Locality 1). Sample from

uppermost resistant bed without allochthonous clasts. Private ranch, permission to

collect required.

4. Williams Ranch Member, Cutoff Formation (31°49'7"N, 104°49'42"W). Quarry along

right-of-way on NW side of U.S. 62/180, 1.8 mi (3 km) NE of junction with Hwy 54,

Culberson County, Texas.

5. El Centra Member, Cutoff Formation (31°52'58"N, 104°52'48"W). Along westward

facing scarp, south wall of Bone Canyon. Sample from upper-middle of carbonate unit

as exposed. Guadalupe Mountains National Park, permission to collect required.

6. El Centro Member, Cutoff Formation (31°53'25"N, 104°52'33"W). South wall of

southern branch of Shumard Canyon, directly over channel filled with Shumard

Member. Sample from basal bed of middle carbonate unit. Guadalupe Mountains

National Park, permission to collect required.

7. Road Canyon Formation type section (30°20'53"N, 103°15'2"W). SE face of spur 0.5

mi (0.8 km) SE of Peak 5779, 2.4 mi (4 km) due N of Skinner Ranch, Altuda

quadrangle, Brewster County, Texas. (Description from Cooper and Grant, 1964.)

Samples from 10 ft (3 m) above top of drape beds overlying uppermost megabreccia

(within unit 8 of Cys, 1981). Private ranch, permission to collect required.

8. Leonardian Lectostratotype, Cathedral Mountain Formation (30°20'52"N, 103° 15'

2"W). Sample from uppermost bed underlying large Road Canyon megabreccia block

that is sunk into the top of the Cathedral Mountain Formation, just E of Cys (1981)

section (see Locality 7). Private ranch, permission to collect required.

9. Victorio Peak Limestone (31°11'42"N, 104°36T'W). Hills W of Old Jones Ranch

house and Ranch Road 2185, western Apache Mountains, Culberson County, Texas.

Sample from uppermost bed of Victorio Peak Limestone, in gully just S of Wood's

(1968) Measured Section I. Private ranch, permission to collect required.

USNM Loc. 732z. Road Canyon Formation (30°14'24"N, 103°27'0"W). 1.36 mi (2.3 km)

N50°W of Old Payne Ranch site, 1.2 mi (2 km) N2°W of hill 4806, Monument Spring

quadrangle. (Description from Cooper and Grant, 1977.) Private ranch, permission to

collect required.

AMNH Loc. 503. Road Canyon Formation (30°23'28"N, 103°8'47"W). Near top of slope

3.5 mi (5.8 km) S75°W of Old Word Ranch, 1.15 mi (1.9 km) S37°E of hill 5507, and

0.65 mi (1.1 km) SW of road fork to Appel Ranch house, Hess Canyon quadrangle.

(Description from Cooper and Grant, 1972.) Private ranch, permission to collect

required.
NUMBER 32 171

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Wisconsin.

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1988. Sedimentology and Conodont Biostratigraphy of the Road Canyon

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1938. Comparison of Permian Ammonoid Zones of Soviet Russia with

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Plates 8-1-8-4
176 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 8-1

Exposures in the Guadalupe Pass area of the Guadalupe Mountains (type Guadalupian), showing Shumard's

(1860) lithostratigraphic units: 1 = black limestone, 2 = yellow sandstone, 3 = dark limestone, and 4 = white

limestone. Note depositional dip.
NUMBER 32 177
178 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 8-2

Index ammonoids from the Roadian Stage, West Texas.

FIGURES 1-3.—Demarezitesn. sp.: apertural, lateral, and ventral views, xl, hypotype, SUI 32402. Pipeline Shale

Member type section, Brushy Canyon Formation, Loc. 1. (Reduced to 84% of original for publication.)

FIGURES 4-6.—Waagenoceras n. sp.: ventral view, xl, at whorl diameter of 58 mm (estimated), and lateral and

ventral views, xl.5, at whorl diameter of 35 mm (estimated), hypotype, SUI 32407. Note that ontogenetic

changes occur rapidly in cyclolobins, and distinction between minor sutural differences and phyletic

modification requires detailed analysis. Study of additional specimens will be required to confidently resolve

whether the forms illustrated in Figures 1-6 actually represent separate genera. Pipeline Shale Member type

section, Brushy Canyon Formation, Loc. 1. (Reduced to 84% of original for publication.)

FIGURES 7, 8.—Perrinites vidriensis Bose, 1919: apertural and lateral views, xl.5, hypotype, SUI 5976. Road

Canyon Formation, AMNH Loc. 503. (Reduced to 84% of original for publication.)

FIGURES 9, 10.—Glassoceras normani (Miller and Furnish, 1957): lateral and apertural views, xl.25, holotype,

AMNH 28022. Road Canyon Formation, AMNH Loc. 503. (Reduced to 84% of original for publication.)
NUMBER 32 179
180 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 8-3

Ammonoids of the Roadian Stage, West Texas.

FIGURES 1, 2.—Texoceras texanum (Girty, 1908): 1, lateral view, x2, well-preserved conch showing shell and

mature modification, hypotype, SUI 64702, Williams Ranch Member, Cutoff Formation, Loc. 2; 2, apertural

view, x2, phragmacone without shell, hypotype, SUI 64703, Williams Ranch Member, Cutoff Formation, Loc.

4. (Reduced to 84% of original for publication.)

FIGURES 3, 4, 9.—Peritrochia n. sp.: ventral, lateral, and apertural views, x2.5, SUI 64700, Road Canyon

Formation, USNM Loc. 732z. (Reduced to 84% of original for publication.)

FIGURE 5.—Peritrochia erebus Girty, 1908: lateral view, x2.3, well-preserved conch showing shell and mature

modification, hypotype, SUI 64701, Williams Ranch Member, Cutoff Formation, Loc. 2. (Reduced to 84% of

original for publication.)

FIGURES 6-8.—Paraceltites elegans Girty, 1908: 6, 7, lateral and ventral views, x2, well-preserved

phragmacone, hypotype, SUI 31925A, Williams Ranch Member, Cutoff Formation, Loc. 4; 8, lateral view, x2,

conch with well-preserved shell, hypotype, SUI 64705, Williams Ranch Member, Cutoff Formation, Loc. 2.

(Reduced to 84% of original for publication.)

FIGURES 10-12.—Stenolobulites stenolobulus Mikesh, Glenister, and Furnish, 1988: lateral, apertural, and

ventral views, x2, hypotype, SUI 52583, Williams Ranch Member, Cutoff Formation, Loc. 4. (Reduced to 84%

of original for publication.)

FIGURES 13, 16, 17.—Epithalassoceras (?) n. sp.: apertural, ventral, and lateral views, x2, SUI 64704, Pipeline

Shale Member type section, Brushy Canyon Formation, Loc. 1. (Reduced to 84% of original for publication.)

FIGURES 14, 15.—Eumedlicottia burckhardti (Bose, 1919): lateral and apertural views, xl.3, hypotype, SUI

64699, Pipeline Shale Member type section, Brushy Canyon Formation, Loc. 1. (Reduced to 84% of original

for publication.)
NUMBER 32 181
182 SMITHSONIAN CONTRIBUTIONS TO TH E EARTH SCIENCES

PLATE 8-4

Conodonts from the basal Guadalupian and the Roadian-Wordian boundary strata, West

Texas. (All figures are of Pa elements at x50 magnification.)

FIGURES 1-9, 15, 16.—Mesogondolella nankingensis (Ching, 1960): 1, upper view, quadrate form, hypotype,

SUI 64521; 2-4, 16, upper oblique, upper, lower, and right lateral views, specimen with atypically large

rounded cusp, hypotype, SUI 64522; 5, upper view, hypotype, SUI 64523; 6, 1, 15, upper, lower, and right

lateral views, subadult with abundant serrations, hypotype, SUI 64524; 8, upper view, subadult of earliest M.

nankingensis s.s., exhibiting several characters of the transitional form, hypotype, SUI 64525; 9, upper view,

quadrate form less serrated than Figure 1, hypotype, SUI 64526. 1-5, 9, 16, Pipeline Shale Member type

section, Brushy Canyon Formation, Loc. 1 (type stratum of M. nankingensis); 6, 7, 15, Williams Ranch

Member, Cutoff Formation, Loc. 3; 8, Road Canyon Formation type section, Loc. 7. (Reduced to 84% of

original for publication.)

FIGURES 10-14, 17, 18, 20, 21.—Forms transitional between M. idahoensis and M. nankingensis: 10, 12, 18,

upper, lower, and left lateral views, transitional form with primarily M. idahoensis-like characters, hypotype,

SUI 64527; 11, 13, upper and lower views, form with approximately equal mix of ancestral and descendant

characters, hypotype, SUI 64528; 14, upper view, specimen with incipient serrations but otherwise more

reminiscent of M. idahoensis, hypotype, SUI 64529; 17, 20, 21, right lateral, upper, and lower views,

transitional form dominated by many M. nankingensis-Mke characters, hypotype, SUI 64530. 10-13, 18, El

Centro Member, Cutoff Formation, Loc. 5; 14, 17, 20, 21, El Centro Member, Cutoff Formation, Loc. 6.

(Reduced to 84% of original for publication.)

FIGURES 19, 22-29.—Mesogondolella idahoensis (Youngquist, Hawley, and Miller, 1951): 19, 27, left lateral

and upper views, note posterior termination of adcarinal furrows, hypotype, SUI 64531; 22, 23, upper and

lower views, very large specimen with characteristic lower view, hypotype, SUI 64532; 24-26, upper, upper

oblique, and lower views, very large specimen with characteristic carina, hypotype, SUI 64533; 28, 29, upper

and lower views, note triangular cusp complex, hypotype, SUI 64534. 19, 27-29, Leonardian lectostratotype,

Loc. 8; 22-26, Victorio Peak Limestone, Loc. 9. (Reduced to 84% of original for publication.)
NUMBER 32 183
9. Fusulinid Biostratigraphy and Paleontology

of the Middle Permian (Guadalupian) Strata of the

Glass Mountains and Del Norte Mountains, West Texas

Zhendong Yang and Thomas E. Yancey

ABSTRACT

A study of new collections of fusulinids from the Guadalupian

Series in the Glass Mountains and Del Norte Mountains, West Texas,

documents the presence of 44 species (in 10 genera) of fusulinids in

the middle Permian strata. One species of Rauserella Dunbar, 1944,

three species of Reichelina Erk, 1942, and six species of Parafusulina

Dunbar and Skinner, 1931, are described as new. The Guadalupian

fusulinid-bearing sequence of strata in the Glass Mountains and Del

Norte Mountains area contains abundant fusulinid faunas, with

especially diverse fusulinid faunas present in the Road Canyon

Formation and the Altuda Formation, primarily in sediments of shelf

margin and slope-to-basin depositional environments. The Mesogondolella nankingensis (conodont) first appearance datum lies between

the Parafusulina boesei first appearance datum and the Parafusulina

rothi first appearance datum, within the Road Canyon Formation.

Nine fusulinid zones are recognized. Of these zones, the Parafusulina durhami Zone is placed in the Leonardian Stage, the Parafusulina

boesei Zone spans the boundary of the Leonardian and Guadalupian

(as defined by the Mesogondolella nankingensis first appearance

datum), and the Parafusulina rothi Zone, Parafusulina trumpyi Zone

(Roadian Stage), Parafusulina sellardsi Zone, Parafusulina antimonioensis Zone (Wordian Stage), Polydiexodina shumardi Zone,

Reichelina lamarensis Zone, and Lantschichites splendens Zone

(Capitanian Stage) are placed in the Guadalupian Series.

Zhendong Yang, Amoco Production Company, 501 West Lake Park

Blvd., P.O. Box 3092, Houston, Texas 77253-3092. Thomas E. Yancey,

Department of Geology, Texas A&M University, College Station,

Texas 77843-3115.

Introduction

During the Permian, the geographic position of continents

(spanning a wide range of paleolatitudes) and the occurrence of

pronounced climatic gradients combined to produce much

paleobiogeographic isolation and the associated appearance of

many endemic taxa. With many biotic provinces present during

most of the Permian, biotas are not easily correlated from one

region to another. The result has been lower accuracy for

interregional correlation and slow progress toward establishing

standard global chronostratigraphic units for the Permian. No

single region has a complete sequence of fossiliferous Permian

strata, so the proposed global stratotype of the Permian is based

on three series-level subdivisions located in different biogeographic provinces. Organisms with pelagic and nektobenthic

life habits (conodonts and ammonoids) are being used to

develop interregional correlations, whereas benthic fusulinids

are being used for detailed zonation on a regional level.

The middle Permian is best known and documented from

strata in the western part of North America, along the margins

of the Delaware basin, which is exposed in the Glass Mountains

of western Texas and the Guadalupe Mountains of southeastern

New Mexico. Guadalupian strata in the Glass and Guadalupe

Mountains contain richly fossiliferous marine deposits from

reef, shelf, slope, and basin environments. Strata in the

Guadalupe Mountains are accepted as the standard for the

Guadalupian Series of North America (Adams et al, 1939).

This interval is proposed as the basis of the global stratotype for

the Middle Permian (Glenister et al., 1992), based on the type

section of the Guadalupian located at the south end of the

Guadalupe Mountains.

This study was undertaken to improve the documentation of

middle Permian fusulinid zones and to provide data on the

ranges of fusulinid species that could be compared directly with

the ranges of conodonts and ammonoids. Wolfcampian and

185
186 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Leonardian fusulinids in the Glass and Del Norte mountains

have been well monographed, whereas the Guadalupian

fiisulinid fauna, especially in the intervals near the lower and

upper limits of the Guadalupian rocks, have not received

detailed study. This study was carried out in the Glass and Del

Norte mountains, along the south margin of the Delaware

basin, because of the availability of diverse and abundant

fusulinids in outcrop sections. It also allowed the authors the

opportunity to work with persons studying the lithostratigraphy

and conodont biostratigraphy in the same area, usually on the

same stratigraphic sections. This study has shown that the

Glass and Del Norte mountains area contains a complete

sequence of fusulinid-bearing strata for the Guadalupian,

including an especially good sequence of late Guadalupian

fusulinids. This fusulinid-bearing interval is as complete as that

present in the Guadalupe Mountains area, and it contains a

fusulinid diversity greater than that documented for the

Guadalupe Mountains area, as is true for many groups of

Guadalupian fossils. In a comparison of the two areas, the Glass

and Del Norte mountains area would be as good for

documenting Guadalupian zones and establishing stratotypes

as the Guadalupe Mountains.

Previous Fusulinid Work

Previous major reports on the geology and biostratigraphic

zonation of this area include Udden (1917), King (1931),

Cooper and Grant (1964, 1972, 1977), Ross (1960, 1962,

1963a,b), and Rohr et al. (1991). Systematic research on

fusulinid biostratigraphy in the Glass and Del Norte mountains

began with Dunbar and Skinner (1931, 1937), who studied 66

samples from Permian strata and established three fusulinid

zones for the North American Permian (Figure 9-1): the

Pseudoschwagerina Zone, the Parafusulina Zone, and the

Polydiexodina Zone (Dunbar and Skinner, 1937). The next

major work was the study of fusulinids in the Glass Mountains

area by Ross (1959, 1960, 1962, 1963a), who established

fusulinid zones for the Early Permian. Ross (1963b) also

reported on fusulinids of the Word Formation (as defined by

King, 1931), recognizing two fusulinid zones for this interval

DU \DAI-1 i& SKINNER

1937

Cap 5T

T|

3Word Fr 3

r~

o

3

£D

Q.

T |

d

Poly Q. jxodin CD

TJ

CD•afusuli CD

Dela\ | | -

CD CD

TJ

D f->wer & N slaware r ** Q.

O —

"D CD

CD

O

3

T| CD

3 03

TJ

3 '

ROSS

1962,1963

O

cidalijpian r.eo —

n w'

3

O

CD

"D

3

T l

3ord Fr Z3 athe

O

Q.

Parafusuling1

antimonioensis

Parafusulina

seliardsi

Parafusulina

ironensis

Parafusulina

lineata

co TarafusuliJ

r

ullivanen!

1 CT

= : CO

Q. CD

CD —

Parafusulina

durhami

1986

O

CD

Q.

ClupiaD

n 1eonardi —

. 3

1975

c

Q_

C

•>ia n

n .eo p -

n CD

Q,

Cu

3

CD" di n'

e marly

Yabeina

Paradoxiella

Polydiexodina

Parafusulina

deliciasensis

- lineata

Parafusulina

rnthi -

maleyi -

boesei

&

Skinnerina

Parafusulina

Schwagerina

WILDE

1990

D

araboultonia

splendens

Polydiexodina

latest

Parafusulina

Parafusulina

lineatadeliciasensis

Parafusulina

rothimaleyi

Parafusulina

boeseiSkinnerina

Middle Zone

of

Parafusulina

TJ

0 _-

r-3

0 ) CDpre-L Bell Cherry C CD

3

O

3

Brus

Cany §*<

Outoff on

CD

e 03

TJ

3 '

CO

0

CD

TJtaniar 0

ZT

CryaD

n Brush CD

3

TJ:>ad ian CD

0

CD

CD"

3

niuadalupi CD

3

This study

(no fusulinids

discovered)

Lantschichites

splendens

Reichelina

lamarensis

Polydiexodina

shumardi

Parafusulina

antimonioensis

Parafusulina

seliardsi

Parafusulina

trumpyi

Parafusulina

rothi

Parafusulina

boesei

Parafusulina

durhami

H

CDse in

y apitan

0

/ >uda |^ ^»

d

5

0

T|

q

TJ

O

CD

Q.

O

3

3

T|

O

Si

CD

Q.

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0

-rUB

O

O

mpitanian Wordian TJ

0

CD

nian ona

CD

r Q .

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3

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TJ

CDiddl

e 0

CD

TJ

CDrmiai

FIGURE 9-1.—Comparison of fusulinid zonations of middle Permian strata in West Texas and adjacent areas.
NUMBER 32 187

(Figure 9-1), of which the lower one (the Parafusulina

sullivanensis-boesei-wildei Zone) was divided into three

subzones {Parafusulina lineata Subzone at the base, Parafusulina ironensis Subzone in the middle, and Parafusulina

sellardsi Subzone at the top). This was the most detailed study

available on middle Permian fusulinids in the Glass Mountains

until the present study. Wilde (in Cooper and Grant,

1977:3309-3318) identified 229 fusulinid samples collected in

the Glass and Del Norte mountains by Cooper and Grant, 90 of

which are from the middle Permian (Road Canyon Formation,

Word Formation, and Capitan Limestone). Although only a list

of species and short comments were provided, the work added

valuable information on fusulinid occurrences in the Glass

Mountains.

With the continuing documentation of Permian biotas in the

Glass Mountains, controversy arose over the placement of the

Leonardian-Guadalupian boundary. The series boundary had

been set at the top of the "Leonard Formation" by Adams et al.

(1939), a horizon that corresponds to the base of the Word

Formation (at the base of the Road Canyon Formation of

current usage), but the Road Canyon Formation contains

ammonoids and brachiopods of Leonardian aspect along with

fusulinids of Guadalupian aspect. Ross and Ross (1985) and

Ross (1986) accepted a Leonardian age for the Road Canyon

Formation (which includes the Parafusulina boesei Zone), but

in a later publication (Ross and Ross, 1987) they put the

Roadian Stage (regarded as essentially equivalent with the

limits of the Road Canyon Formation) in an intermediate

position between the Leonardian and Guadalupian. In contrast,

Wilde (1975, 1986a,b, 1990) consistently held that fusulinids

from the Road Canyon Formation mark the beginning of the

Guadalupian. In 1990 he designated Roadian, Brushyan,

Cherryan, and Capitanian stages for the Guadalupian with the

Parafusulina boesei-Skinnerina Zone for the Roadian Stage,

Parafusulina rothi-maleyi Zone for the Brushyan Stage, and

Parafusulina lineata-deliciasensis Zone as the basal zone of

his Cherryan Stage (Figure 9-1). Yang and Yancey (1990)

proposed that the Parafusulina rothi Zone be used as the

earliest fusulinid zone of the Guadalupian. The base of this

zone occurs a short distance above the base of the Road Canyon

Formation, indicating that the boundary horizon between the

Leonardian and the Guadalupian is located within the Road

Canyon Formation.

The biggest difference between the fusulinid zonations for

the lower and middle parts of the Guadalupian, as proposed by

Ross (1963b) and Wilde (1975, 1990), is the placement of a

zone defined on Parafusulina lineata Dunbar and Skinner,

1937. In both proposals, P. lineata is shown confined to a

single zone, but Ross (1963b) placed this zone in the lowest

part of the Guadalupian, whereas Wilde (1990) placed this zone

in the middle part of the Guadalupian. Material collected for

this study shows that P. lineata is an uncommon species with

a longer range than either worker indicated, accounting for the

confusion about its zonal status. The species ranges through the

lower and middle portions of the Guadalupian, through three

fusulinid zones (Parafusulina rothi Zone, Parafusulina

trumpyi Zone, and Parafusulina sellardsi Zone).

Middle Permian Stratigraphy of the Glass and

Del Norte Mountains

Strata of middle Permian age in the Glass and Del Norte

mountains include most of the Road Canyon Formation, the

Word Formation, the Vidrio Formation, the Capitan Limestone, the Altuda Formation, and the Gilliam Limestone.

Recent study (Rohr et al., 1991; Haneef, 1993) of the

Capitanian formations has greatly clarified the stratigraphic

relations of these units, which are similar in many ways to the

Guadalupian strata in the Guadalupe Mountains. The present

study follows the stratigraphic framework of Rohr et al. (1991),

except that the Vidrio Formation (at least the upper part)

belongs in the Capitanian.

The fusulinid genus Polydiexodina occurs in the Vidrio

Formation in both the eastern and western parts of the study

area, providing evidence that it is of Capitanian age based on

fusulinids. As Polydiexodina is a diagnostic indicator of the

Capitanian, its first appearance separates the Wordian below

from the Capitanian above. Therefore, the Vidrio Formation

includes reef or shelf margin deposits of lower Capitanian age,

and the Capitan Limestone includes reef deposits of upper

Capitanian age. The Gilliam Limestone includes coeval

deposits from the inner shelf, and the Altuda Formation

includes coeval deposits from the slope and basin settings. The

position of the shelf margin shifted during this time, so

formational units intertongue.

MEASURED SECTIONS

Fusulinid samples were collected from 10 stratigraphic

sections in the middle Permian of the Glass and Del Norte

mountains (Figures 9-2,9-3). The sections cover a stratigraphic

interval extending upward from the top of the Cathedral

Mountain Formation to the top of the Capitan Limestone and

Altuda Formation, and they include reef, shelf, shelf margin,

and basin depositional settings. Many samples come from

sections that cover the lowest and highest intervals of the

Guadalupian Series (see Yang, 1992, which contains detailed

descriptions of stratigraphic sections). A comparison of the

environmental settings of the Glass and Del Norte mountains

with the Guadalupe Mountains areas suggests that the same

fusulinid fauna should occur in both areas, and the sampling

strategies were set to test this hypothesis as well as to complete

the fusulinid biostratigraphy in this classic area of Permian

studies. The youngest Guadalupian fusulinid fauna (previously

described by Skinner and Wilde, 1954, 1955, in the Guadalupe
188 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

6-145\

6-BR4\

6-140, S1-

6-138-

6-135-

6-125v.

6-120^

6-1

6-97

6-BA22

6-BA19,BA20,BA21-

6-BA18-

6-BA15,BA16,BA17^

6-BA12,BA13,BA14-

Siltstone

Sandstone

10-201

10-202

10-A1

10-204

10-A2

10-203

10-205

10-A3

10-A4

10-A5

10-A6

GILLIAM conglomerate

Fm

10-208

10-207

10-206

10-344

8-42,43

8-41

8-39,40

8-36

8-35

8-34-

2-75.R17

2-R16

2-R15

2-R14

2-R13

2-72.R12

2-Rid,R11

2-R9

2-R7.R8

ROAD CANYON

7-56,58-

7-53,55"

8-29,30\

8-25,26,27\

8-23,24A

8-18,20N

8-15,16\\

8-1314^

,

8-13,14

8-11.12-

CATHEDRAL MOUNTAIN Fm

FlGURE 9-2.—Measured sections and stratigraphic positions of samples.

Mountains area, but unknown in the Glass and Del Norte

mountains) was sampled in two stratigraphic sections.

Fossil preservation is best in intervals of interbedded

carbonate and noncarbonate sediments deposited in deep-water

environments located in the lowest and highest parts of the

Guadalupian section, whereas preservation is poor in the thick,

dolomitized carbonates of the Vidrio Formation and Capitan

Limestone and the shoal-water facies of the Word Formation

where rocks are commonly recrystallized and dolomitized.

FUSULINID SPECIES AND FUSULINID ZONES

A total of 44 fusulinid species (in 10 genera) is documented

in samples collected from the Glass and Del Norte mountains,

of which 10 species are new. The ranges of fusulinid species

collected from the stratigraphic sections are shown in Figure

9-4, and all species are illustrated in Plates 1-17. The

illustrations presented in the plates provide the documentation

of the fusulinid species used to establish the zonation. It is
NUMBER 32 189

BREWSTER COUNTY

in

MOUNTAINSi

FIGURE 9-3.—Sketch map of the Glass and Del Norte mountains showing the locations of the measured sections.

noteworthy that some species of Parafusulina (P. biturbinata

Kling, 1960, P. guatemalaensis Dunbar, 1939, P. trumpyi

Thompson and Miller, 1949, and P. durhami Thompson and

Miller, 1949) previously reported from Latin America (Guatemala, Colombia) have been identified in samples from the

Glass and Del Norte mountains area. This suggests a close

relationship of Permian deposits presently located in central

America and northern South America with the Delaware basin,

which was positioned along the southern margin of North

America during the Permian. The genus Yangchienia, previously reported only in the Tethyan realm, is also identified in

these samples.

Based on the stratigraphic ranges of fusulinid species, nine

fusulinid zones have been recognized in the sampled interval

(Figures 9-4, 9-5). The Parafusulina durhami Zone is placed in

the Leonardian Stage; the Parafusulina boesei Zone is placed

partly in the Leonardian stage and partly in the Roadian Stage

(straddling the Mesogondolella nankingensis first appearance

datum, which defines the stage boundary); the Parafusulina

rothi Zone and Parafusulina trumpyi Zone are placed in the

Roadian Stage; the Parafusulina sellardsi Zone and Parafusulina antimonioensis Zone are placed in the Wordian Stage; and

the Polydiexodina shumardi Zone, Reichelina lamarensis

Zone, and Lantschichites splendens Zone are placed in the

Capitanian Stage. The lower boundary corresponds with the

first appearance datum of the species for which the zone is

named, and the upper boundary corresponds with the base of

the overlying zone, which is defined on the first appearance

datum of the zone-naming species. The highest zone in the

sequence is defined on the total range of the defining species of

that zone. Zones used previously are of several different types,

some of which were provisional or not formally defined. These

include assemblage zones, range zones, concurrent range

zones, and even acme zones. The different manner in which

zones were defined and the failure to acknowledge these

differences has caused confusion when comparing zonations.

Discrepancies between previously proposed zonations have

been resolved with additional documentation of fusulinid

species.

Parafusulina durhami Zone

The base of this zone corresponds with the first appearance

datum of Parafusulina durhami, and the upper boundary

corresponds with the first appearance datum of P. boesei

Dunbar and Skinner, 1937. The zone was first defined by Ross

(1962). Other fusulinid species occurring in this zone include

Parafusulina cf. P. biturbinata. This zone occurs in the upper

part of the Cathedral Mountain Formation, which consists

mostly of fine-grained siliciclastic sediments containing a few

fusulinid-bearing limestone interbeds.
190 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Cathedral

— Mtn

Road Canyon Word Vidriol Capitan/Altuda FORMATION rafu rot

«; g.

3' 3

o c

3 W

5' £.

diexc

uman

Reichelin

lamarens

ZONE

Lantschichites splendens

L. haneefi n. sp.

Codonofusiella extensa

C. paradoxica

Reichelina lamarensis

R. bengensis n. sp.

R. birdensis n. sp.

R. inflata n. sp.

R. sp.

R. delawarensis

Rauserella erratica

R. minima n. sp.

Paradoxiella pratti

Polydiexodina shumardi

P. capitanensis

P. oregonensis

P. sp.

Parafusulina virga

P. antimonioensis

P. cf. P. wordensis

P. sellardsi

P. rohri n. sp.

P. trumpyi

P. rothi

P. maleyi

P. alpinensis n. sp.

P. marathonensis n. sp.

P. faliskiei n. sp.

P. lineata

P. sullivanensis

P. glassensis n. sp.

P. rudinei n. sp.

P. splendens

P. boesei

Staffella lacunosa

Parafusulina ironensis

P. fountaini

P. cf. P. bakeri

P. cf. P. guatemalaensis

Yangchienia iniqua

Schubertella sp.

S. cf. S. melonica

Parafusulina durhami

P. cf. P. biturbinata

FIGURE 9-4.—Stratigraphic ranges of fusulinid species.

Parafusulina boesei Zone

The base of this zone corresponds with the first appearance

datum of Parafusulina boesei Dunbar and Skinner, 1937, and

the upper boundary corresponds with the first appearance

datum of P. rothi Dunbar and Skinner, 1936. Other fusulinid

species occurring in this zone include P. cf. P. bakeri Dunbar

and Skinner, 1937, P. fountaini Dunbar and Skinner, 1937, P.

cf. P. guatemalaensis, P. maleyi Dunbar and Skinner, 1937, P.

splendens Dunbar and Skinner, 1937, P. sullivanensis Ross,

1963, Yangchienia iniqua Lee, 1934, Schubertella cf. S.

melonica Dunbar and Skinner, 1937, S. sp., Rauserella erratica

Dunbar, 1944, andi?. minima, new species. This zone occurs in

the lower part of the Road Canyon Formation, in grainstones

and conglomeratic debris flow deposits. The Mesogondolella

nankingensis first appearance datum occurs within this zone,

showing that it spans the Leonardian-Guadalupian boundary.
NUMBER 32 191 PERMIA

N

Upper Middl

e Lower

Ochoan Capitanian Wordian Roadian Leonardian

FUSULINID ZONE

(No fusulinids discovered)

Lantschichites splendens

Reichelina lamarensis

Polydiexodina shumardi

Parafusulina antimonioensis

Parafusulina sellardsi

Parafusulina trumpyi

Parafusulina rothi

Parafusulina boesei

Parafusulina durhami

FORMATION

"Tessey"

V -

1

\ Q-

\°

Altuda \ |

/

Gilliam

\

Vidrio

Word

Road Carlyon

Cathedral Mtn

FIGURE 9-5.—Fusulinid zonation proposed in this study.

Parafusulina rothi Zone

The base of this zone corresponds with the first appearance

datum of Parafusulina rothi, and the upper boundary corresponds with the first appearance datum of Parafusulina

trumpyi. Other fusulinid species occurring in this zone include

Parafusulina boesei, P. faliskiei, new species, P. ironensis

Ross, 1963, P. lineata, P. maleyi Dunbar and Skinner, 1937, P.

splendens, P. sullivanensis, P. glassensis, new species, P.

rudinei, new species, Rauserella erratica, and R. minima, new

species. The fusulinid P. ironensis, used by Ross (1963b:22) to

define the P. ironensis Subzone, is confined to the P. rothi

Zone and the P. trumpyi Zone in the sample set studied.

However, it is rare compared with other species, and it is less

useful as a zonal species than P. rothi. This zone occurs in the

middle part of the Road Canyon Formation.

Parafusulina trumpyi Zone

The base of this zone corresponds with the first appearance

datum of Parafusulina trumpyi, and the upper boundary

corresponds with the first appearance datum of Parafusulina

sellardsi Dunbar and Skinner, 1937. Other fusulinid species

occurring in this zone include Parafusulina boesei, P. lineata,

P. maleyi, P. rothi, P. sullivanensis, P. glassensis, new species,

P. rudinei, new species, P. alpinensis, new species, P. virga

Thompson and Wheeler, 1946, P. marathonensis, new species,

P. splendens, P. faliskiei, new species, P. ironensis, Rauserella

erratica, and R. minima, new species. This zone occurs at the

top of Road Canyon Formation at the type and nearby sections

(Cooper and Grant, 1966) in the Glass Mountains and at the top

of the Road Canyon Formation of nearby sections.

Parafusulina sellardsi Zone

The base of this zone corresponds with the first appearance

datum of Parafusulina sellardsi, and the upper boundary

corresponds with the first appearance datum of Parafusulina

antimonioensis Dunbar, 1953. Other fusulinid species occurring in this zone include Parafusulina lineata, P. rothi, P.

maleyi, P. rudinei, new species, P. sullivanensis, P. trumpyi, P.

virga, P. cf. P. wordensis Dunbar and Skinner, 1931, P. rohri,

new species, P. glassensis, new species, Rauserella erratica, R.

minima, new species, and Staffella lacunosa Dunbar and

Skinner, 1937. This zone occurs in the lower part of the Word

Formation, in the Willis Ranch Member (i.e., King's No. 3

limestone member).
192 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Parafusulina antimonioensis Zone

The base of this zone corresponds with the first appearance

datum of Parafusulina antimonioensis, and the upper boundary

corresponds with the first appearance datum of Polydiexodina

shumardi Dunbar and Skinner, 1931. Parafusulina antimonioensis, which has a very large and elongate test, has an axis that

is commonly arched or sharply bent at the middle, making

exact orientation necessary for accurate comparison of the axial

section of this and related species. Slightly oblique orientation

may cause considerable foreshortening of the poles. The P.

antimonioensis Zone occurs in the upper part of the Word

Formation, which is commonly dolomitized.

Polydiexodina shumardi Zone

The base of this zone corresponds with the first appearance

datum of Polydiexodina shumardi, and the upper boundary

corresponds with the first appearance datum of Reichelina

lamarensis Skinner and Wilde, 1955. Other fusulinid species

occurring in this zone include Polydiexodina capitanensis

Dunbar and Skinner, 1931, P. oregonensis Bostwick and

Nestell, 1965, P. sp., Rauserella erratica, R. minima, new

species, Reichelina delawarensis (Dunbar and Skinner, 1937),

R. birdensis, new species, and Codonofusiella paradoxica

Dunbar and Skinner, 1937. Strata of this zone in the Glass and

Del Norte mountains, as well as in the Guadalupe Mountains,

contain a great abundance of Polydiexodina, reflecting the

proliferation of this genus in shallow marine environments.

Polydiexodina occurs in the Vidrio Formation, Gilliam

Limestone, the lower part of the Altuda Formation, and the

lower part of the Capitan Limestone. This is the lowest

fusulinid zone of the Capitanian Stage.

Reichelina lamarensis Zone

The base of this zone corresponds with the first appearance

datum of Reichelina lamarensis Skinner and Wilde, 1955, and

the upper boundary corresponds with the first appearance

datum of Lantschichites splendens (Skinner and Wilde, 1954).

Other fusulinid species occurring in this zone include

Codonofusiella extensa Skinner and Wilde, 1955, C. paradoxica, Reichelina bengensis, new species, R. haneefi, new

species, R. birdensis, new species, R. sp., Rauserella erratica,

R. minima, new species, and Paradoxiella pratti Skinner and

Wilde, 1955. This zone occurs in the middle part of the Altuda

Formation in the Glass Mountains and the upper part of the

Altuda Formation in the Del Norte Mountains, which consists

of sediments deposited in deep-water slope and basin environments. The Reichelina lamarensis Zone contains tiny fusulinids that tend to have an irregular last whorl or become

uncoiled in the adult growth stage.

Lantschichites splendens Zone

This is the only zone in the present fusulinid zonation based

on the full range of a species. The base of this zone corresponds

with the first appearance datum of Lantschichites splendens,

and the upper boundary of this zone corresponds with its last

appearance. Associated fusulinid species include Lantschichites sp., Codonofusiella extensa, C. paradoxica, Reichelina

lamarensis, R. bengensis, new species, R. birdensis, new

species, Rauserella erratica, and R. minima, new species. The

lower part of this zone is characterized by a high diversity of

species from different genera; however, the upper part of this

zone is dominated by species of Lantschichites in the absence

of Reichelina. The Lantschichites splendens Zone contains

small, diaphanotheca-walled fusulinids that tend to have an

irregular last whorl or become uncoiled in the adult growth

stage.

LOWER BOUNDARY OF THE GUADALUPIAN SERIES

When the Guadalupian Series was formally defined by

Adams et al. (1939), the lower boundary was placed at the

contact of the Brushy Canyon Formation with the underlying

Bone Spring Formation (which included the Cutoff Shale). Of

two zones recognized in the Guadalupian, the lower was

defined as containing the ammonoid Waagenoceras and

evolutionarily advanced species of the fusulinid genus Parafusulina. The criterion for determining the lower boundary was

the first appearance datum of Waagenoceras; however, with

the development of detailed zonations based exclusively on

fusulinids or ammonoids, a long-standing disagreement arose

over the proper placement of this boundary. This disagreement

came from trying to position the Leonardian-Guadalupian

boundary on a horizon that best separates a "Leonardian" biota

(corresponding to the Perrinites Zone) from a "Guadalupian"

biota (containing the Waagenoceras Zone). In the Glass

Mountains this boundary was first drawn at the base of King's

(1931) first limestone member (now named the Road Canyon

Formation) of the Word Formation (Adams et al., 1939).

Ross (1962, 1963b) adhered to this placement of the series

boundary, but Cooper and Grant (1966) suggested that the

Road Canyon Formation should be included in the Leonardian

Series because of the presence of the ammonoid Perrinites and

because the brachiopods present in the formation are more

similar to those of the underlying Leonardian than to the

Guadalupian. Furnish (1966, 1973) proposed the Roadian

Stage between the Leonardian Stage (a part of the Leonardian

Series) and the Wordian Stage, based on a stratigraphically

distinct assemblage of ammonoids in these strata, and he

advocated placement of the Roadian Stage in the Leonardian

Series. However, Wilde and Todd (1968) and Wilde (1986a,b)

correlated the Road Canyon Formation of the Glass Mountains

with the Cutoff Formation and with the lower and middle parts

of the San Andres Formation in the Guadalupe Mountains,

suggesting that they are best placed in the Guadalupian Series.

This interval contains the Parafusulina boesei Zone, which has

usually been assigned (Ross, 1963b; Wilde, 1975, 1990) to the

lowest part of the Guadalupian Series in fusulinid zonations.

Following the erection of the Roadian Stage, the opinion that
NUMBER 32 193

the Roadian Stage forms the top of the Leonardian (Series)

gained some acceptance (e.g., Cys, 1981; Ross, 1986).

Because of this debate, different criteria have been used in

establishing the base of the Guadalupian Series in the Glass

Mountains area, resulting in five different horizons being

proposed as the base of the Guadalupian. The first proposed

horizon is at the base of the Road Canyon Formation, which is

coincident with the boundary between the Leonard Formation

(of Udden, 1917) and the Word Formation that was selected by

Adams et al. (1939) as the top of the Leonardian Series. (The

type section of the Road Canyon Formation, which is the basal

portion of the Word Formation of Udden, 1917, and King,

1931, directly overlies the type section of the Leonard

Formation of Udden, 1917, along the sides of Leonard

Mountain. An exact placement for this boundary can be

determined on the basis of lithologic change.) The second

proposed horizon is at the base of the Parafusulina boeseiSkinnerina Zone of Wilde (1990). This horizon lies at or near

the base of the Road Canyon Formation. The third horizon is

coincident with the boundary between the Neostreptognathodus sulcoplicatus Zone and the Mesogondolella nankingensis

Zone. This horizon lies within the lower part of the Road

Canyon Formation. The fourth horizon is at the base of the

Parafusulina rothi Zone. This horizon lies within the lower part

of the Road Canyon Formation, a short distance above the

Mesogondolella nankingensis first appearance datum. The fifth

proposed horizon is coincident with the mutual boundary

between the Perrinites Zone and the Waagenoceras Zone,

which is similar to the definition of Adams et al. (1939) that

Furnish (1973) described as being the horizon marking the

concurrent extinction of Perrinites and appearance of

Waagenoceras. However, both Newell et al. (1953) and

Furnish (1973) used the first appearance datum of Waagenoceras to place the boundary. This horizon lies roughly at the

base of the China Tank Member of the Word Formation in the

Glass Mountains.

The debate over placement of the Leonardian-Guadalupian

boundary was reduced with the acceptance among participants

of the March, 1991, Guadalupian Symposium to use the

Mesogondolella nankingensis first appearance datum as the

base of the Roadian Stage (and Guadalupian Series). In a

stratigraphic study of conodonts in the Road Canyon Formation, Wardlaw and Grant (1987) found that the Mesogondolella

nankingensis first appearance datum (which defines the

Mesogondolella idahoensis-M. nankingensis zonal boundary)

lies in the lower part of the formation. They suggested that this

datum provides an excellent marker for the boundary between

the Leonardian and Guadalupian.

In the Glass and Del Norte mountains area the Mesogondolella nankingensis first appearance datum occurs within the

Parafusulina boesei Zone, which spans the LeonardianGuadalupian boundary (Yang and Yancey, 1990). The position

of the Mesogondolella nankingensis first appearance datum

relative to the Parafusulina boesei and Parafusulina rothi first

appearance datums has been determined within two stratigraphic sections of the Road Canyon Formation (Figure 9-6). The

position of the Mesogondolella nankingensis first appearance

datum in the Road Canyon Formation type section (section 2)

is based on determinations by Lance Lambert (pers. comm.,

1991), and the position of the Mesogondolella nankingensis

first appearance datum in section 7 is based on determinations

by Bruce Wardlaw (pers. comm., 1991). The position of

fusulinid first occurrence data are compiled from samples

collected for this study.

The Parafusulina rothi first appearance datum is a good

fusulinid indicator of (but does not define) the base of the

Guadalupian. This horizon coincides with an evolutionary

change in the genus Parafusulina, in which species having a

more advanced stage of evolutionary development appear.

Evolutionary development is indicated by several features in

the species of Parafusulina, including test size, intensity and

regularity of septal fluting, and especially by the degree of

development of the cuniculi. Cuniculi are not fully developed

in any Leonardian species of Parafusulina. In primitive

species, such as Parafusulina spissisepta Ross, 1960, P.

allisonensis Ross, 1960, P. brookensis Ross, 1960, P. deltoides

Ross, 1960, P. vidrioensis Ross, 1960, and others, cuniculi

appear first in the outer whorls and are limited to the middle

part of the test. These openings are so low and narrow that they

can only be observed in tangential slices cut very close to the

floor of a whorl. With further evolutionary development,

cuniculi appear earlier and earlier in ontogeny and spread

progressively toward the poles, and the septal flutings that form

cuniculi become wider and higher. Species of Parafusulina

with moderately developed cuniculi, such as Parafusulina

durhami, P. biturbinata, P. fountaini, P. boesei, and P.

splendens, are common in the upper part of the Leonardian and

range up into the basal part of the Guadalupian. In advanced

species of Parafusulina, such as P. rothi, P. trumpyi, P.

sellardsi, P. wordensis, and P. antimonioensis, although

development of cuniculi varies from species to species,

cuniculi may occupy a large portion of a septal fold and up to

one-half the height of the septum. Species with this grade of

development appear in the Parafusulina rothi Zone and are

present in Guadalupian strata. Parafusulina rothi, with its large

size, intensive and regular fluting, and well-developed cuniculi,

is a good marker for the beginning of the advanced

evolutionary stage of Parafusulina and the base of the

Guadalupian.

UPPER BOUNDARY OF THE GUADALUPIAN SERIES

The upper limit of the Guadalupian Series was originally

defined on the basis of lithologic change from fossiliferous

marine strata of the Delaware Group to evaporitic strata of the

overlying section (Adams et al., 1939). This corresponds with

a geologically sudden change from normal marine environments to hypersaline environments throughout the Delaware

basin and occurs within an interval represented by continuous

sedimentation in the deeper parts of the basin (King, 1948). The
194 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Section 2

( Glass Mts )

sample # Legend

Section 7

( Del Norte Mts )

sample #

conglomerate

covered

2-R1T\j

2-72-H Parafusulina rothi FAD

Mesogondolella nankingensis FAD

Parafusulina boesei FAD

2-67

FIGURE 9-6.—Relative positions of first appearance datum (FAD) levels of Parafusulina boesei, P. rothi, and

Mesogondolella nankingensis in the Road Canyon Formation in the Glass and Del Norte mountains.

stratotype section for the Guadalupian Series at the south end of

the Guadalupe Mountains is incomplete at the top, so it was

supplemented with a subsurface section located near Carlsbad,

New Mexico. This designation by Adams et al. (1939) places

the boundary stratotype in a subsurface section, but the interval

is exposed in surface outcrops in the vicinity of the reef

escarpment near the New Mexico-Texas state line.

Dunbar and Skinner (1937) established the Polydiexodina

Zone as the highest fusulinid zone in the Delaware Mountain

Group and Capitan Limestone, and Adams et al. (1939)

reported that the fusulinid Polydiexodina and the ammonoid

Timorites co-occur in the youngest zone of the Guadalupian

Series. On the basis of new records of fusulinids in the Lamar

Limestone Member of the Bell Canyon Formation (Skinner and

Wilde, 1954, 1955), Wilde (1975) designated a YabeinaParadoxiella Zone as the highest zone of the Guadalupian,

which he (Wilde, 1990) later renamed as the Paraboultonia

splendens Zone. This zone occurs in the Lamar Member and

post-Lamar interval of the Delaware Mountain Group and is

part of the Capitanian Stage of the Guadalupian Series. Furnish
NUMBER 32 195

(1973) suggested that the ammonoid and fusulinid assemblages

in the Lamar Limestone Member be placed in an overlying

Amarassian Stage rather than the Capitanian Stage, but this

suggestion was not followed by subsequent workers because

the Capitanian had been established for the stratigraphic

interval extending to the top of the Bell Canyon Formation.

Strata of the Ochoan Series lack normal marine fossils, so the

upper boundary of the Guadalupian Series is indistinct in a

biostratigraphic sense and useless for accurate chronostratigraphic correlation.

Work on fusulinids from Guadalupian strata in the Glass and

Del Norte mountains provides data that can help solve

problems associated with the upper boundary of the Guadalupian Series. A major change in fusulinid assemblages takes

place in the upper part of the Altuda Formation, in which

large-size fusulinids having a keriotheca in their test walls

disappear and are replaced upward with assemblages dominated by tiny fusulinids having a diaphanotheca in their test

walls. A similar changeover in fusulinid faunas occurs in

Permian strata in other parts of the Delaware basin (at the top of

the Lamar Limestone Member of the Bell Canyon Formation)

and other parts of the world, suggesting that the lowest portion

of the Late Permian may be present in the highest parts of the

Guadalupian interval (of Adams et al., 1939). Two fusulinid

zones, the Reichelina lamarensis Zone and the Lantschichites

splendens Zone, occur above the highest occurrences of

keriotheca-walled fusulinids in the Altuda Formation. Several

genera of small fusulinids with numerous species occur in these

zones, providing the potential for additional zones to be

defined.

Correlation of Fusulinid Zones with South China

Although fusulinid faunas are quite different in the tropical

regions of North America and Tethys during the Permian,

similar evolutionary trends and the co-occurrence of some

species allow for the correlation of fusulinid zones between the

two regions. A chart showing the suggested correlation of

middle Permian fusulinid zones between the Delaware basin

region of North America and the South China region of the

Tethyan province is shown in Figure 9-7.

The Mesogondolella nankingensis first appearance datum

provides a standard for correlating the base of the middle

Permian in the two areas. Clark and Wang (1988) showed that

the Mesogondolella nankingensis first appearance datum

occurs in the middle part of the Qixia (previously transliterated

as Chihsia) Formation in South China. Despite the difference in

fusulinid faunas between North America and the Tethyan

province, three fusulinid species {Parafusulina boesei, P.

splendens, Yangchienia iniqua) present in the lower part of the

Road Canyon Formation also occur in the Maklaya-Shengella

Zone in the middle of the Qixia Stage of South China

{Parafusulina boesei, Sheng, 1963:72; P. splendens, Sheng,

1963:71; Yang, 1985:309; Yangchienia iniqua, Sheng,

1963:38; Yang, 1985:310; Xiao et al., 1986:38; Zhang et al.,

1988:271). Therefore, the Parafusulina boesei Zone of this

study may be correlated with the Maklaya-Shengella Zone.

The Parafusulina boesei first appearance datum appears to be

contemporaneous in the two regions.

Parafusulina rothi has been reported from a few localities in

China (Zhang, 1957; Yang, 1985), where it occurs in the

Neoschwagerina simplex Zone, immediately above the CancelUna liuzhiensis Zone. The Neoschwagerina simplex Zone

appears to correlate with the Parafusulina rothi and P. trumpyi

zones.

Fusulinids of the middle and late Guadalupian are more

difficult to correlate with those in South China. Leella Dunbar

and Skinner, 1937, which occurs in middle and upper

Guadalupian strata of the Delaware basin (Dunbar and Skinner,

1937; Wilde and Todd, 1968), occurs in the Afghanella

schencki-Neoschwagerina craticulifera Zone (Xiao et al.,

1986) in South China. This suggests a correlation of the middle

Guadalupian with the lower part of the Maokouan. The

evolutionary development of polydiexodinids also provides a

basis for correlating the Parafusulina sellardsi and P.

antimonioensis zones with the Afghanella schenckiNeoschwagerina craticulifera Zone and the Polydiexodina

shumardi Zone with the Yabeina gubleri Zone. Primitive

species of polydiexodinids (such as Polydiexodina afghanensis

Thompson, 1946, P. craticula Da, 1983, and P. regularis Da,

1986) referable to Eopolydiexodina Wilde, which lack a

well-defined median tunnel and bear irregularly distributed

supplementary tunnels, occur in strata of Afghanella schenckiNeoschwagerina craticulifera Zone in the Maokou Formation

of Gansu, the Yiesanggang Formation and Qipan Formation of

Xinjiang, and the Bayinhe Formation of Qinghai. These are less

evolutionarily advanced than species of Polydiexodina (P.

capitanensis, P. shumardi, etc.) that occur in the Polydiexodina

shumardi Zone of North America.

The highest two zones of the Guadalupian (the Reichelina

lamarensis Zone and the Lantschichites splendens Zone) can be

correlated with the highest zone of the Maokouan in South

China, which also contains assemblages of small, diaphanotheca-walled, last-whorl-uncoiled fusulinids. Within the Tethyan

realm there is a trend of disappearance of large, keriothecawalled fusulinids and subsequent replacement with assemblages containing tiny, diaphanotheca-walled ones similar to

those seen in the Delaware basin. Lantschichites splendens, L.

minima (Chen, 1956), and species of Reichelina occur in the

Neomisellina multivoluta Zone, and Codonofusiella paradoxica occurs in the underlying Yabeina gubleri Zone in South

China (Sheng, 1963; Yang, 1985; Xiao et al., 1986), suggesting

a correlation with the Lantschichites splendens, Reichelina

lamarensis, and Polydiexodina shumardi zones in the Glass and

Del Norte mountains.

Yabeina texana Skinner and Wilde, 1955, does not provide

direct evidence for correlation to the Tethyan province.

Although it has been described as a primitive species of the
196 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

NORTH AMERICA

This study

SOUTH CHINA

Yang

(1985)

Xiao et al.

(1986)

Sheng et al.

(1982)

c

to

o

o

O

(No fusulinids found) Codonofusiella

II

c

CO

'Q.

_ 3

CO

•D

CO

(D

c

CO

'c

CO

co

o

Lantschichites

splendens

Reichelina

lamarensis

Polydiexodina

shumardi

Parafusulina

antimonioensis

Parafusulina

sellardsi

Parafusulina

trumpyi

Parafusulina

rothi

Parafusulina

boesei

Parafusulina

durhami

CD

c

o

N

<D

O)

c

CO

CC

co

c

<D

CO

i

0) co

Neomisellina

multivoluta

Yabeina -

Neomisellina

(Polydiexodina

- Neomisellina)

Yabeina

gubleri

Afghanella

schencki

Neoschwagerina

craticulifera

Neoschwagerina

(Chusenella

conicocylindrica)

Neoschwagerina

simplex

Parafusulina

Cancellina

Cancellina

liuzhiensis

Maklaya -

Shengella

c

CO

X

b

Misellina

claudiae

Misellina

claudiae

FIGURE 9-7.—Correlation of fusulinid zones between North America and South China.

genus (implying a correlation with the lower part of the

Yabeina gubleri Zone), it is probably an aberrant form adapted

to unusual environmental conditions. Similar malformation of

neoschwagerinids occurs in the top of the Maokou Formation

in South China (Yang, 1985). Similarly, stratigraphically high

occurrences of species of Polydiexodina (P. chekiangensis

Sheng, 1962; P. tungluensis Sheng, 1962, and P. altilis Lin,

1982) from the Neomisellina-Polydiexodina-Codonofusiella

Zone of Zhang (1984) (equivalent to the Neomisellina

multivoluta Zone) of southeast China are quite different from

other species of polydiexodinids and cannot be correlated with

the range zone of Polydiexodina in North America. These

species of Polydiexodina reported in the southeastern part of

China have a poorly developed median tunnel and sporadic

supplementary tunnels, and, unlike earlier species of

polydiexodinids, they are very small in size (for the genus),

with few volutions, a short axial length, and a small proloculus.

Systematic Descriptions

For specimen measurements and description of fusulinid

species, this study adopts the measurement methodology and

terminology employed by Dunbar and Skinner (1937), Thompson (1948), and Kling (1960). All specimens studied and
NUMBER 32 197

illustrated were collected from the Glass Mountains and Del

Norte mountains of West Texas. All figures on the plates are

unretouched photographs. All type specimens, illustrated

specimens, and study materials are housed in the Department of

Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, D.C.

Family OZAWAINELLIDAE Thompson and Foster, 1937

Rauserella Dunbar, 1944

TYPE SPECIES.—Rauserella erratica Dunbar, 1944.

Rauserella erratica Dunbar, 1944

PLATE 9-1: FIGURES 1-7

Rauserella erratica Dunbar, 1944:37-38, pi. 9: figs. 1-8.—Ross, 1964:315,

pi. 50: figs. 1,2.

TYPES.—Hypotypes: USNM 482975-482981; from the

Road Canyon Formation and Altuda Formation of the Glass

and Del Norte mountains, Texas.

MATERIAL STUDIED.—Samples from the Road Canyon

Formation, Word Formation, Vidrio Formation, and Altuda

Formation in the Glass and Del Norte mountains, Texas: 2-68,

2-R6, 2-77; 6-BA3, 6-BA13; 7-49; 8-19, 8-28, 8-41, 8-45; 9-6,

9-10; 10-202, 10-206.

AGE AND DISTRIBUTION.—Parafusulina boesei Zone to

Lantschichites splendens Zone of the Guadalupian Series,

Glass and Del Norte mountains; Apache Mountains and

Guadalupe Mountains of West Texas (Dunbar, 1944); Las

TABLE 9-1.—Measurements of Rauserella erratica Dunbar.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

(mm)

Tunnel

angle (°)

Volution

0

1

2

3

4

5

1

2

3

4

5

1

2

3

1

2

3

4

1

2

USNM

482975

0.03

0.085

0.13

0.25

-

0.065

0.12

0.22

-

-

0.76

0.81

0.88

0.012

0.018

0.020

0.035

_

-

USNM

482976

0.03

0.08

0.14

0.24

-

0.05

0.08

0.15

0.65

1.35

0.63

0.57

0.63

0.010

0.015

0.020

0.030

12

18

USNM

482977

0.03

_

_

_

(0.22)

(0.38)

0.04

0.08

0.15

-

-

-

-

-

0.010

0.015

0.020

-

_

-

USNM

482978

0.035

0.07

0.12

0.22

-

0.05

0.09

0.14

-

-

0.71

0.75

0.64

0.010

0.020

0.022

0.030

16

22

Delicias area of Coahuila, Mexico (Dunbar, 1944). Lower part

of Maokou Formation in Datieguan, Guizhou Province, China

(Yang, 1985), and the upper part of Qixia Formation in

Dalianshan, Jiangsu Province, China (Zhang et al., 1988).

REMARKS.—Rauserella is characterized by having an abrupt

change in the orientation of the axis of coiling during growth,

which occurs after forming nautiliform, symmetrically coiled

inner volutions. This juvenile nautiliform shell usually has

three to four volutions. Rauserella erratica is larger than other

species associated with it. The specimens studied resemble the

type specimens of Rauserella erratica Dunbar in all respects.

Measurement data of specimens are given in Table 9-1.

Rauserella minima, new species

PLATE 9-1: FIGURES 8-16

TYPES.—Holotype: USNM 482987; Paratypes: USNM

482982-482986, 482988-482990; from the Road Canyon

Formation and Altuda Formation of the Glass and Del Norte

mountains, Texas.

MATERIAL STUDIED.—Samples from the Road Canyon

Formation and the Altuda Formation in the Glass and Del Norte

mountains, Texas: 1-62; 2-68, 2-R5, 2-R6; 6-BA3, 6-BA10,

6-BA11; 8-18,8-24; 10-202.

DIAGNOSIS.—Test minute, irregularly ellipsoidal; 3 to 3V2

volutions; inner two volutions planispiral and discoidal; outer

volutions expanding abruptly and aberrant in form, with axis of

coiling askew at high angle or right angle to axis of inner

volutions; chomata small, weak, and present only in inner

volutions.

AGE AND DISTRIBUTION.—Parafusulina boesei Zone to

Lantschichites splendens Zone of the Guadalupian Series,

Glass and Del Norte mountains, Texas.

DESCRIPTION.—Minute size; irregularly ellipsoidal form; 3

to 3V2 volutions; attaining a maximum length of 1.12 mm and

maximum diameter of 0.58 mm; first two volutions planispiral

and discoidal in shape, with narrowly rounded periphery and

short axis of coiling, forming a nautiliform juvenile; outer

volutions irregularly coiled and expanded, abruptly elongated,

with axis of coiling askew at large angle (even at right angle) to

axis of inner volutions; proloculus small and spherical, 0.04 to

0.07 mm in outside diameter; spirotheca thin, consisting of

tectum and diaphanotheca; spirotheca about 0.01 mm in inner

volutions and about 2.0 mm in outer ones; septa planar in inner

volutions, but irregularly arched without obvious fluting in

outer volutions; chomata small and weakly developed, present

only in inner volutions; tunnel narrow and not well marked;

tunnel angle averaging 15° in first volution. Measurement data

of specimens given in Table 9-2.

REMARKS.—This species differs from Rauserella erratica

Dunbar, 1944, in having a smaller and shorter test, a thinner

spirotheca, and only two volutions in the inner nautiloid

juvenile portion compared to three to four volutions. It is

somewhat similar to Rauserella fujimotoi Kobayashi, 1956, but
198 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 9-2.—Measurements of Rauserella minima, new species. TABLE 9-3.—Measurements of Reichelina bengensis, new species.

Radius

vector

(mm)

Half

length (mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle (°)

Volution

0

1

2

1

2

1

2

1

2

3

1

2

USNM

482983

0.020

0.050

0.110

0.030

0.060

0.60

0.55

0.010

0.012

0.020

13

-

USNM

482984

0.030

0.050

0.130

0.040

0.060

0.66

0.46

0.018

0.015

0.025

14

-

USNM

482982

0.025

0.050

0.090

0.040

0.055

0.80

0.61

0.010

0.015

0.025

_

-

USNM

482987

0.035

0.060

0.130

0.040

0.060

0.66

0.46

0.010

0.010

0.020

15

16

USNM

482985

0.035

0.060

0.120

0.050

0.070

0.83

0.58

0.010

0.012

0.015

11

18

differs in having a smaller size, fewer volutions, and less

angular periphery on the inner volutions. Some specimens

reported as Rauserella sp. from the Road Canyon Formation

and Willis Ranch Member of the Word Formation in the Glass

Mountains (Wilde in Cooper and Grant, 1977) and from the

San Andres Formation in the northern Guadalupe Mountains

(Wilde, 1986a) might be conspecific with the new species.

ETYMOLOGY.—The species name is derived from the Latin

word minimus, meaning small; an important feature of this

species compared with other species of the genus.

Reichelina Erk, 1942

TYPE SPECIES.—Reichelina cribroseptata Erk, 1942.

Reichelina bengensis, new species

PLATE 9-2: FIGURES 17-20

TYPES.—Holotype: USNM 482992; Paratypes: USNM

482991, 482993-482994; from the Altuda Formation of the

Glass and Del Norte mountains, Texas.

MATERIAL STUDIED.—Samples from the middle part of the

Altuda Formation at Benge Ranch in the Glass Mountains and

the upper part of the Altuda Formation near Bird Mountain in

the Del Norte Mountains, Texas: 6-BA8, 6-BA10; 10-202,

10-205.

DIAGNOSIS.—Test minute, lenticular; axis of coiling extremely short; umbilical areas slightly depressed; periphery

subangular; spirotheca very thin, consisting of tectum and

diaphanotheca; septa unfluted; proloculus very small.

AGE AND DISTRIBUTION.—Reichelina lamarensis Zone to

Lantschichites splendens Zone of the Guadalupian Series,

Glass and Del Norte mountains, Texas.

DESCRIPTION.—Minute size; lenticular form; 5 volutions,

with the last one-half volution uncoiled; coiled part ~0.20 mm

long and 0.58 mm in diameter, resulting in a form ratio of 0.35;

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°\

\ )

Volution

0

1

2

3

4

1

2

3

4

1

2

3

4

1

2

3

4

5

1

2

3

4

USNM

482992

0.012

0.030

0.070

0.120

0.180

0.020

0.040

0.060

0.080

0.67

0.57

0.50

0.44

0.010

0.012

0.015

0.010

-

-

12

14

-

USNM

482993

0.011

0.035

0.060

0.110

0.180

0.025

0.040

0.060

0.085

0.63

0.66

0.54

0.47

0.010

0.015

0.015

0.020

0.010

-

8

11

10

USNM

482991

0.014

0.035

0.060

0.100

0.150

0.024

0.040

0.060

0.080

0.68

0.66

0.60

0.53

0.010

0.012

0.015

0.015

0.010

-

10

12

15

axis of coiling extremely short with gently depressed umbilical

areas; first two volutions subdiscoidal, with relatively rounded

periphery; subsequent volutions lenticular, with angular periphery; proloculus very small, averaging 0.028 mm in outside

diameter, and spherical in shape; spirotheca of tectum and

diaphanotheca, about 0.010 to 0.018 mm thick; septa thin and

closely spaced, almost planar but broadly sinuous in the

uncoiled part; chomata low and broad, extending laterally to

the poles; tunnel low and narrow; tunnel angle averaging 11°,

13°, and 10° in the second to the fourth volutions, respectively.

Measurement data of specimens given in Table 9-3.

REMARKS.—This species differs from Reichelina lamarensis

Skinner and Wilde, 1955, in being much smaller, having a

more sharply lenticular shape, a smaller proloculus, and a much

shorter axis of coiling. The specimens studied mostly resemble

the type specimens of Reichelina changhsingensis Sheng,

1963, but differ in having a smaller size, a shorter axis of

coiling, more volutions, lower chamber height in corresponding volutions, and more rounded periphery of the inner

volutions.

ETYMOLOGY.—The species is named for the Benge Ranch,

on the northwest side of the Glass Mountains, Texas, where the

type specimens were collected.

Reichelina birdensis, new species

PLATE 9-2: FIGURES 21-27

TYPES.—Holotype: USNM 482998; Paratypes: USNM
NUMBER 32 199

482995-482997, 482999-483001; from the Altuda Formation

of the Glass and Del Norte mountains, Texas.

MATERIAL STUDIED.—Samples from the upper part of the

Altuda Formation near Bird Mountain in the Del Norte

Mountains and from the middle part of the Altuda Formation at

Benge Ranch in the Glass Mountains, Texas: 6-BA5, 6-BA10,

6-BA11; 10-202, 10-205, 10-208.

DIAGNOSIS.—Test minute; first volution subdiscoidal; later

volutions lenticular; uncoiled last one-half volution is rather

large; spirotheca consists of two layers; septa unfluted; small

and broad chomata border a low tunnel; proloculus very small.

AGE AND DISTRIBUTION.—Polydiexodina shumardi Zone to

Lantschichites splendens Zone of the Guadalupian Series,

Glass and Del Norte mountains, Texas.

DESCRIPTION.—Minute size; lenticular form; 4V2 to 5

volutions; attaining length of 0.26-0.30 mm and diameter of

0.70-0.90 mm; first volution subdiscoidal, with a narrowly

rounded periphery; second to fourth volutions lenticular, with

angular periphery; last one-half volution uncoiled; proloculus

small, 0.03 to 0.04 mm in outside diameter; spirotheca thin,

consisting of tectum and diaphanotheca, the thickest part about

0.02 mm; septa planar; chomata low and narrow; tunnel low

and narrow, with tunnel angle about 10° and 20° in the first and

fourth volutions, respectively. Measurement data of specimens

given in Table 9-4.

REMARKS.—This species is very similar to Reichelina media

TABLE 9-4.—Measurements of Reichelina birdensis, new species.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

t°\

\ )

Volution

0

1

2

3

4

5

1

2

3

4

5

1

2

3

4

5

1

2

3

4

5

1

2

3

4

USNM

482998

0.015

0.05

0.08

0.13

0.24

0.47

0.03

0.05

0.07

0.10

0.14

0.60

0.63

0.54

0.42

0.30

0.010

0.014

0.018

0.015

0.010

-

10

13

USNM

482999

0.015

0.04

0.07

0.12

0.22

0.40

0.02

0.04

0.07

0.12

0.15

0.63

0.57

0.58

0.55

0.38

_

-

-

0.020

0.010

-

10

12

18

USNM

483000

0.020

0.04

0.08

0.12

0.22

-

0.03

0.05

0.08

0.11

0.14

0.75

0.64

0.66

0.50

-

_

-

-

-

0.015

-

10

22

-

USNM

482996

0.020

0.04

0.06

0.11

0.20

0.41

0.03

0.05

0.09

0.12

0.16

0.75

0.83

0.82

0.60

0.39

0.012

0.018

0.020

0.015

-

12

18

19

-

Miklukho-Maklay, 1954, but R. media is more slender in shape,

is slightly smaller, and has a higher form ratio in corresponding

volutions. It differs from Reichelina lamarensis Skinner and

Wilde in having a smaller size, more slender shape, and fewer

volutions. It can be easily distinguished from Reichelina

bengensis, new species, in having a larger size, a longer axis of

coiling, and a higher form ratio.

ETYMOLOGY.—The species is named for Bird Mountain, a

large hill in the northern Del Norte Mountains, Texas, where

the holotype specimen was collected.

Reichelina delawarensis (Dunbar and Skinner, 1937),

new combination

PLATE 9-4: FIGURES 15, 16; PLATE 9-9: FIGURES 1-3

Ozawainella delawarensis Dunbar and Skinner, 1937:602, pi. 46: figs. 21-26.

TYPES.—Hypotypes: USNM 483002, 483003, 483132-

483134; from the Altuda Formation of the Del Norte

Mountains, Texas.

MATERIAL STUDIED.—Samples from the Altuda Formation

and the upper part of the Vidrio Formation in the Del Norte

Mountains, Texas: 9-5, 9-6, 9-10; 10-204, 10-206, 10-208,

10-344.

AGE AND DISTRIBUTION.—Polydiexodina shumardi Zone of

the Guadalupian Series, Del Norte Mountains, Texas; Guadalupe Mountains, Texas (Dunbar and Skinner, 1937).

REMARKS.—The specimens studied resemble the type

specimens of Ozawainella delawarensis Dunbar and Skinner,

1937, in major respects. An assignment to the genus Reichelina

is warranted by the sharply expanded or uncoiled character of

the last one-half volution and by the presence of well-preserved

wall structure with distinct layers. Skinner and Wilde

(1955:930) were correct in stating that the species is not a

member of the genus Ozawainella. Reichelina delawarensis is

characterized by a larger test, a smaller uncoiled part, and

thicker spirotheca than other species of Reichelina. Measurement data of specimens are given in Table 9-5.

Reichelina haneefi, new species

PLATE 9-4: FIGURES 9-13

TYPES.—Holotype: USNM 483005; Paratypes: USNM

483004, 483006-483008; from the Altuda Formation of the

Glass Mountains, Texas.

MATERIAL STUDIED.—Samples from the middle part of the

Altuda Formation at Benge Ranch in the Glass Mountains,

Texas: 6-BA2, 6-BA3, 6-BA10, 6-BA11.

DIAGNOSIS.—Test minute; lenticular, with highly inflated

polar regions; last one-half volution uncoiled; spirotheca thick

for genus, consisting of tectum and diaphanotheca; septa

unfluted; chomata low, broad, and extending to the poles;

proloculus small, with a spherical form.
200 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 9-5.—Measurements of Reichelina delawarensis (Dunbar and Skinner). TABLE 9-6.—Measurements of Reichelina haneefl, new species.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°)

Volution

0

1

2

3

4

1

2

3

4

5

1

2

3

4

1

2

3

4

5

1

2

3

USNM

483134

0.03

0.09

0.18

0.30

0.50

0.06

0.12

0.20

0.34

0.50

0.67

0.67

0.67

0.68

0.02

0.03

0.04

0.05

0.03

18

20

35

USNM

483133

0.04

-

-

-

-

0.06

0.11

0.21

0.32

0.42

_

-

-

-

_

0.02

-

-

-

_

-

-

USNM

483002

0.035

0.08

0.15

0.27

-

0.06

0.10

0.17

0.28

-

0.75

0.67

0.63

-

0.02

0.02

0.03

-

-

-

24

38

AGE AND DISTRIBUTION.—Reichelina lamarensis Zone of

the Guadalupian Series, Glass Mountains, Texas.

DESCRIPTION.—Minute size; thickly lenticular form; 5

volutions in maturity; attaining a length of 0.5 to 0.6 mm and

diameter of 1.0 to 1.6 mm; axis of coiling short and straight;

first volution subdiscoidal, with narrowly rounded periphery;

remaining volutions lenticular, with bluntly angular periphery;

polar regions distinctly inflated, resulting in an extraordinarily

great length and high form ratio for the genus; proloculus small

and spherical, 0.3 to 0.4 mm in outside diameter; spirotheca

consisting of tectum and diaphanotheca; thickness averaging

0.010, 0.018, 0.029, 0.030, and 0.018 mm in first to fifth

volutions, respectively; septa unfluted, counting 10, 14, 15, 17,

and 28 in first to fifth volutions, respectively; chomata low,

broad, and extending to the poles, looking like a thick outer

tectorium; tunnel low and slit-shaped; tunnel angle averaging

9°, 11°, 16°, and 22° in the first to fourth volutions, respectively.

Measurement data of specimens given in Table 9-6.

REMARKS.—This species is similar in several features to

Reichelina turgida Sheng, 1963; however, the longer axis of

coiling, higher form ratio, and more inflated polar regions

distinguish it from the latter species. It is also similar to

Reichelina lamarensis Skinner and Wilde but differs in having

fewer volutions, larger size, higher form ratio, inflated poles,

and broader and heavier chomata. Reichelina delawarensis

(Dunbar and Skinner) has a larger test, lower form ratio, and

less inflated poles than R. haneefi. Reichelina haneefi is

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

Volution

0

1

2

3

4

5

1

2

3

4

5

1

2

3

4

5

1

2

3

4

5

1

2

3

4

USNM

483005

0.015

0.06

0.11

0.18

0.29

0.50

0.04

0.08

0.14

0.21

0.28

0.66

0.73

0.78

0.72

0.60

0.010

0.020

0.030

0.030

0.020

-

10

12

17

USNM

483007

0.018

0.05

0.10

0.17

0.26

0.52

0.035

0.07

0.11

0.18

0.23

0.70

0.70

0.65

0.69

0.49

0.010

0.015

0.028

0.030

0.015

8

9

14

19

USNM

483008

0.020

0.05

0.09

0.15

0.25

0.42

0.03

0.07

0.13

0.22

-

0.60

0.78

0.86

0.88

-

0.010

0.020

0.030

0.030

0.020

10

13

20

30

USNM

483004

0.016

0.06

0.11

0.20

0.33

0.80

_

-

-

-

-

_

_

_

-

-

0.010

0.015

0.020

0.030

-

-

:

-

characterized by its inflated polar regions and thereby is easily

distinguished from other species of the genus.

ETYMOLOGY.—The species is named for Mohamed Haneef,

a graduate student at Sul Ross State University, who helped

with the field work of this study.

Reichelina lamarensis Skinner and Wilde, 1955

PLATE 9-2: FIGURES 1-16

Reichelina lamarensis Skinner and Wilde, 1955:929-930, pi. 89: figs. 1-9.

TYPES.—Hypotypes: USNM 483009-483024; from the

Altuda Formation of the Glass and Del Norte mountains,

Texas.

MATERIAL STUDIED.—Samples from the Altuda Formation

at Benge Ranch in the Glass Mountains and near Bird

Mountain in the Del Norte Mountains, Texas. Localities:

6-BA1, 6-BA2, 6-BA3, 6-BA4, 6-BA7, 6-BA8, 6-BA10,

6-BAll,6-BA12, 6-BA17; 10-202, 10-204, 10-205.

AGE AND DISTRIBUTION.—Reichelina lamarensis Zone, to

Lantschichites splendens Zone of the Guadalupian Series,

Glass and Del Norte mountains, Texas; Guadalupe Mountains,

Texas (Skinner and Wilde, 1955).

REMARKS.—The specimens studied resemble the type

specimens of Reichelina lamarensis Skinner and Wilde in all

respects. Measurement data of specimens are given in Table

9-7.
NUMBER 32 201

TABLE 9-7.—Measurements of Reichelina lamarensis Skinner and Wilde. TABLE 9-8.—Measurements of Reichelina sp.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°\

\ )

Volution

0

1

2

3

4

5

6

1

2

3

4

5

6

1

2

3

4

5

6

1

2

3

4

5

6

1

2

3

4

USNM

483016

0.020

0.05

0.09

0.15

0.23

0.51

-

0.03

0.05

0.08

0.13

0.19

-

0.60

0.56

0.53

0.56

0.37

-

0.008

0.010

0.012

0.015

0.015

-

-

16

22

-

USNM

483013

0.023

0.05

0.08

0.15

0.24

0.54

-

0.03

0.05

0.08

0.13

0.21

-

0.60

0.63

0.53

0.54

0.33

-

0.007

0.010

0.010

0.015

-

-

-

15

17

-

USNM

483014

0.025

0.06

0.09

0.15

0.28

0.60

-

0.03

0.05

0.08

0.14

0.22

-

0.50

0.56

0.53

0.50

0.37

-

0.008

0.010

0.010

0.010

0.015

-

14

16

17

24

USNM

483011

0.030

0.05

0.10

0.16

0.23

0.70

-

0.03

0.05

0.09

0.15

0.21

-

0.60

0.50

0.56

0.65

0.30

-

0.010

0.010

0.015

0.015

0.020

-

15

16

24

-

USNM

483010

0.021

0.04

0.07

0.11

0.20

0.30

0.78

0.03

0.05

0.08

0.14

0.20

0.26

0.75

0.71

0.73

0.70

0.67

0.33

0.008

0.010

0.010

0.015

0.020

0.020

-

16

18

22

Reichelina sp.

PLATE 9-4: FIGURE 14

MATERIAL STUDIED.—Sample from the middle part of the

Altuda Formation at Benge Ranch in the Glass Mountains,

Texas: 6-BA3; specimen: USNM 483025.

AGE AND DISTRIBUTION.—Reichelina lamarensis Zone of

the Guadalupian Series, Glass Mountains, Texas.

DESCRIPTION.—Minute size; slender and lenticular form;

3

 xli volutions, attaining a length of 0.27 mm and a diameter of

0.71 mm; form ratio of about 0.38; first volution subdiscoidal,

with narrowly rounded periphery; outer volutions lenticular,

with sharply angular periphery; proloculus small, about 0.08

mm in outside diameter; spirotheca very thin, consisting of

tecrum and diaphanotheca; thickest part of spirotheca about

0.015 mm; septa planar; chomata low, occurring only in the

inner two volutions, and extending to polar areas; tunnel low

and narrow; tunnel angle 10° and 20° in the first and second

volutions, respectively. Measurement data of the specimen

given in Table 9-8.

REMARKS.—This is a distinct species, but there is inadequate

material to justify naming a new species. It is similar to

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle (°)

Volution

0

1

2

3

4

1

2

3

4

1

2

3

4

5

1

2

3

4

1

2

USNM

483025

0.04

0.08

0.15

0.25

0.43

0.04

0.07

0.10

0.14

0.67

1.50

1.43

1.45

1.40

0.010

0.010

0.010

0.015

12

16

Reichelina birdensis, new species, but it is more slender in

shape, has a lower form ratio, and has sharper angular periphery

in corresponding volutions. It differs from Reichelina bengensis, new species, in being larger but having fewer volutions. It

can be easily distinguished from Reichelina lamarensis in that

the latter has a much larger size, a longer axis of coiling, and a

higher form ratio.

Family STAFFELLIDAE Miklukho-Maklay, 1949

Staffella Ozawa, 1925

TYPE SPECIES.—Fusulina sphaerica Abich, 1859.

Staffella lacunosa Dunbar and Skinner, 1937

PLATE 9-1: FIGURE 17

Staffella lacunosa Dunbar and Skinner, 1937:598-599, pi. 52: figs. 9-13.

TYPES.—Hypotype: USNM 483026; from the Word Formation of the Del Norte Mountains, Texas.

MATERIAL STUDIED.—Sample from the lower part of the

Word Formation in the Del Norte Mountains, Texas: 8-32.

AGE AND DISTRIBUTION.—Leonardian (Dunbar and Skinner,

1937) and Guadalupian Series, Glass and Del Norte mountains,

Texas. Found only in the Parafusulina sellardsi Zone of the

Guadalupian Series in this study.

REMARKS.—The illustrated specimen is an immature individual, but it resembles the type specimens of Staffella

lacunosa Dunbar and Skinner in all respects. Measurement data

of the specimen are given in Table 9-9.
202 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 9-9-

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°)

—Measurements of Staffella lacunosa Dunbar and Skinner.

Volution

0

1

2

3

4

5

6

1

2

3

4

5

6

1

2

3

4

5

6

1

2

3

4

5

6

1

2

3

4

5

USNM

483026

0.06

0.06

0.11

0.20

0.30

0.43

0.64

0.04

0.08

0.15

0.24

0.35

0.51

0.67

0.73

0.75

0.80

0.81

0.78

0.02

0.03

0.03

0.04

0.04

0.03

12

17

19

34

51

Family FUSULINIDAE von Moller, 1878

Subfamily SCHUBERTELLINAE Skinner, 1931

Codonofusiella Dunbar and Skinner, 1937

TYPE SPECIES.—Codonofusiella paradoxica Dunbar and

Skinner, 1937.

Codonofusiella extensa Skinner and Wilde, 1955

PLATE 9-3: FIGURE 10

Codonofusiella extensa Skinner and Wilde, 1955:930, pi. 89: fig. 10, pi. 90:

figs. 1-5, pi. 91: figs. 1-6.

TYPES.—Hypotype: USNM 483027; from the Altuda Formation of the Glass Mountains, Texas.

MATERIAL STUDIED.—Samples from the upper part of the

Altuda Formation at Benge Ranch in the Glass Mountains and

near Bird Mountain in the Del Norte Mountains, Texas: 6-S2,

6-110,6-120; 10-204.

AGE AND DISTRIBUTION.—Reichelina lamarensis Zone to

Lantschichites splendens Zone of the Guadalupian Series,

Glass and Del Norte mountains, Texas; Guadalupe Mountains,

Texas (Skinner and Wilde, 1955).

REMARKS.—The specimens studied resemble the type

specimens of Codonofusiella extensa Skinner and Wilde in all

respects.

Codonofusiella paradoxica Dunbar and Skinner, 1937

PLATE 9-3: FIGURES 7-9

Codonofusiella paradoxica Dunbar and Skinner, 1937:607-609, pi. 45: figs.

1-9.—Sheng, 1963:47, pi. 6: figs. 21-24.

TYPES.—Hypotypes: USNM 483029-483031; from the

Altuda Formation of the Glass and Del Norte mountains,

Texas.

MATERIAL STUDIED.—Samples from the Altuda Formation

at Benge Ranch in the Glass Mountains and near Bird

Mountain in the Del Norte Mountains, Texas: 6-110; 10-202,

10-208.

AGE AND DISTRIBUTION.—Polydiexodina shumardi Zone to

Lantschichites splendens Zone of the Guadalupian Series,

Glass and Del Norte mountains, Texas; Guadalupe Mountains,

Texas (Dunbar and Skinner, 1937; Skinner and Wilde, 1955);

Chinati Mountains, Texas (Skinner, 1940). Wujiaping Limestone near Zisongzhen of Wangmo, Guizhou Province, China

(Sheng, 1963).

REMARKS.—The specimens studied resemble the type

specimens of Codonofusiella paradoxica Dunbar and Skinner

in all respects.

Lantschichites Toumanskaya, 1953

TYPE SPECIES.—Codonofusiella {Lantschichites) maslennikovi Toumanskaya, 1953.

Lantschichites splendens (Skinner and Wilde, 1954)

PLATE 9-3: FIGURES 1-6,11

Paraboultonia splendens Skinner and Wilde, 1954:441, pi. 44: figs. 1-7, pi.

45: figs. 1-4.

Lantschichites splendens (Skinner and Wilde).—Sheng, 1963:42, pi. 12: figs.

16-22.

TYPES.—Hypotypes: USNM 483028, 483032-483037;

from the Altuda Formation of the Glass and Del Norte

mountains, Texas.

MATERIAL STUDIED.—Samples from the upper part of the

Altuda Formation at Benge Ranch in the Glass Mountains and

near Bird Mountain in the Del Norte Mountains, Texas:

6-BA12, 6-BA13, 6-BA14, 6-BA15, 6-BA16, 6-BA17, 6-

BA18, 6-BA19, 6-BA20, 6-BA21, 6-BA22, 6-110, 6-120,

6-125, 6-135, 6-138, 6-140, 6-S1, 6-S2, 6-BR4, 6-145; 10-204.

AGE AND DISTRIBUTION.—Lantschichites splendens Zone of

the Guadalupian Series, Glass and Del Norte mountains, Texas;

Apache Mountains and Guadalupe Mountains, Texas (Skinner
NUMBER 32

203

and Wilde, 1954). Upper part of the Maokou Limestone in

Yishan, Guangxi Province, China (Sheng, 1963).

REMARKS.—Lantschichites splendens is characterized by its

small size and slender, cylindrical test with bluntly rounded

poles. It is the largest species in this genus and has the most

volutions at maturity; however, the expansion of its last

one-half volution is commonly not as great as that of other

species. The specimens studied resemble the type specimens of

Paraboultonia splendens Skinner and Wilde in all respects.

Measurement data of specimens are given in Table 9-10.

The genus Lantschichites was originally established as a

subgenus of Codonofusiella by Toumanskaya (1953) and later

was raised to full genus level (Sheng, 1963). It differs from

Codonofusiella in having a larger test size, a cylindrical form,

more numerous volutions, and more intensely fluted septa.

However, the wall structure and coiling features of the inner

and outer volutions are quite similar in the two genera.

Regarding the relationship between Lantschichites and Paraboultonia, the authors agree with Sheng (1963) and Xiao et al.

(1986) that Paraboultonia Skinner and Wilde is a junior

synonym of Lantschichites Toumanskaya. This conclusion is

based on the observation that characters of the type specimens

of both Lantschichites maslennikovi Toumanskaya and Paraboultonia splendens Skinner and Wilde are essentially the

TABLE 9-10.—Measurements of Lantschichites splendens (Skinner and Wilde).

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle (°)

Volution

0

1

2

3

4

5

6

1

2

3

4

5

6

1

2

3

4

5

6

1

2

3

4

5

6

1

2

USNM

483032

0.026

0.05

0.07

0.12

0.20

0.31

0.65

0.03

0.08

0.25

0.62

1.31

1.95

0.60

1.14

2.08

3.10

4.23

3.00

0.01

0.01

0.015

0.02

0.025

0.025

_

18

USNM

483035

0.025

0.06

0.09

0.15

0.27

0.44

-

0.06

0.12

0.31

0.80

1.71

-

1.00

1.33

2.07

2.96

3.89

-

0.01

0.15

0.15

0.20

0.25

-

_

15

USNM

483034

0.022

0.05

0.08 .

0.11

0.18

0.26

0.55

0.05

0.07

0.24

0.55

1.16

1.84

1.00

0.88

2.18

3.05

4.46

3.35

0.008

0.008

0.01

0.015

0.02

0.02

_

17

USNM

483033

0.030

0.05

0.08

0.10

0.19

0.32

-

0.04

0.06

0.34

0.89

1.40

-

0.80

0.75

3.40

4.68

4.38

-

0.01

0.01

0.015

0.025

0.02

-

_

-

same, including rapid expansion or uncoiling of the last

one-half volution. Because thin sections cut through different

positions of the uncoiled part may show different dimension of

expansion, it is difficult to define limits of scope between

"expansion" and "uncoiling" for species of these nominal

genera.

Lantschichites splendens is an important zonal species of the

latest Guadalupian, and it commonly occurs in deeper water

deposits. Discovery of it in the Glass Mountains area extends

its range from the northwestern shelf of the Delaware basin,

where it occurs in the Lamar Limestone Member of the Bell

Canyon Formation (Skinner and Wilde, 1954), to the southern

shelf of the basin.

Lantschichites sp.

PLATE 9-4: FIGURES 1-8

MATERIAL STUDIED.—Samples from the Altuda Formation

at Benge Ranch in the Glass Mountains and near Bird

Mountain in the Del Norte Mountains, Texas: 6-120, 6-145,

6-BA12, 6-BA14, 6-BA15, 6-BA18, 6-BA20, 6-BA22, 6-BR4,

6-S2, 10-204; specimens: USNM 483038-483045.

DIAGNOSIS.—Small size; ellipsoidal to shortly cylindrical

form; 4V2 to 5 volutions; inner two volutions discoidal and

coiled askew to the outer volutions, with weak chomata

present; last one-half volution expanding rapidly and greatly;

cuniculi well developed.

AGE AND DISTRIBUTION.—Lantschichites splendens Zone of

the Guadalupian Series, Glass Mountains, Texas.

DESCRIPTION.—Test small; ellipsoidal to short cylindrical

form; 472 to 5 volutions in maturity; first two volutions

endothyroidal and coiled askew or at right angle to outer

volutions; third and fourth volutions thickly fusiform to

fusiform in shape, with bluntly pointed poles; last one-half

volution abruptly expanded or uncoiled, resulting in elliptical

to rectangular shape on axial section; proloculus very small,

0.05 to 0.06 mm in outside diameter; spirotheca very thin,

consisting of tectum and diaphanotheca; spirotheca thickness

averaging 0.010, 0.010, 0.015, 0.022, and 0.021 mm in the first

to fifth volutions, respectively; septa intensely and regularly

fluted throughout length of test; cuniculi well developed in

outer volutions; chomata very weak and only present in the

endothyroidal inner volutions; tunnel low, narrow, and indistinct; thin axial fillings sometimes present in the inner four

volutions. Measurement data of specimens given in Table 9-11.

REMARKS.—This species differs from Lantschichites splendens (Skinner and Wilde) in having a smaller and shorter test,

less numerous volutions, and a larger uncoiled portion of the

test. An elliptical to rectangular shape is characteristic of this

species on a properly cut axial section, thus readily distinguishing these two species from each other. It closely resembles

Lantschichites minima (Chen, 1956), but the latter has a more

slender coiled part of the test, more sharply pointed poles, and

a larger uncoiled portion.
204 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 9-11.—Measurements of Lantschichites sp.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle (°)

Volution

0

1

2

3

4

5

1

2

3

4

5

1

2

3

4

5

1

2

3

4

5

1

2

USNM

483041

0.030

0.06

0.08

0.11

0.20

0.34

0.03

0.05

0.23

0.63

1.06

0.50

0.63

2.09

3.15

3.12

0.01

0.01

0.015

0.02

0.025

_

20

USNM

483040

0.025

0.05

0.08

0.10

0.19

0.32

0.04

0.06

0.34

0.89

1.40

0.80

0.75

3.40

4.68

4.37

0.01

0.01

0.015

0.025

0.02

-

-

USNM

483038

0.024

0.07

0.10

0.15

0.24

0.58

0.06

0.16

0.43

1.05

1.48

0.86

1.60

2.87

4.38

2.55

0.01

0.01

0.015

0.02

0.02

_

-

USNM

483039

0.025

0.04

0.07

0.11

0.19

0.31

0.07

0.24

0.45

0.82

1.60

_

3.43

4.09

4.31

5.16

0.01

0.01

0.016

0.02

0.024

_

-

This species is being formally named in a companion paper

in this volume. (See Wilde and Rudine, this volume.)

Paradoxiella Skinner and Wilde, 1955

TYPE SPECIES.—Paradoxiella pratti Skinner and Wilde,

1955.

Paradoxiella pratti Skinner and Wilde, 1955

PLATE 9-3: FIGURES 12-15

Paradoxiella pratti Skinner and Wilde, 1955:935, pi. 91: figs. 7-9, pi. 92: figs.

1-10, pi. 93: fig. 1.

TYPES—Hypotypes: USNM 483046-483049; from the

Altuda Formation of the Del Norte Mountains, Texas.

MATERIAL STUDIED.—Sample from the upper part of the

Altuda Formation near Bird Mountain in the Del Norte

Mountains, Texas: 10-204.

AGE AND DISTRIBUTION.—Reichelina lamarensis Zone of

the Guadalupian Series, Del Norte Mountains, Texas; Guadalupe Mountains, Texas (Skinner and Wilde, 1955).

REMARKS.—The specimens illustrated herein are fragmentary, showing either the inner coiled portion or the uncoiled

flare of the test. The shape and distribution pattern of the septal

folds are exactly the same as those of the type specimens of

Paradoxiella pratti Skinner and Wilde.

Schubertella Staff and Wedekind, 1910

TYPE SPECIES.—Schubertella transitoria Staff and Wedekind, 1910.

Schubertella cf. S. melonica Dunbar and Skinner, 1937

PLATE 9-1: FIGURE 18

Schubertella melonica Dunbar and Skinner, 1937:611-613, pi. 57: figs. 10-14.

MATERIAL STUDIED.—Sample from the lower part of the

Road Canyon Formation in the Glass Mountains, Texas: 2-68;

specimen: USNM 483050.

AGE AND DISTRIBUTION.—Found only in the Leonardian

Series portion of the Parafusulina boesei Zone, Glass

Mountains, Texas, in this study.

REMARKS.—Although the proloculus and the first juvenile

volution are not visible, the specimens studied resemble the

type specimens of Schubertella melonica Dunbar and Skinner

in major respects. Schubertella melonica is characterized by a

shorter and thicker test and a lower form ratio than the similar

species, Schubertella kingi Dunbar and Skinner, 1937.

Schubertella sp.

PLATE 9-1: FIGURE 19

MATERIAL STUDIED.—Sample from the lower part of the

Road Canyon Formation in the Glass Mountains, Texas: 2-R2;

specimen: USNM 483051.

AGE AND DISTRIBUTION.—Leonardian Series portion of the

Parafusulina boesei Zone, Glass Mountains, Texas.

DESCRIPTION.—Minute size; fusiform test; vaulted in the

median part and bluntly pointed at poles; 5 volutions, attaining

a length of 0.68 mm and a diameter of 0.34 mm; first volution

short and coiled at a large angle to outer volutions; form ratio

0.56, 1.60, 1.63, 1.67, and 2.00 in first to fifth volutions,

respectively; proloculus small, 0.06 mm in outside diameter;

spirotheca very thin, consisting of tectum and diaphanotheca,

about 0.010 to 0.020 mm thick; septa planar; chomata small

and low, extending laterally to the polar regions; tunnel

distinct, narrow, and high; tunnel angle 24° in third volution.

Measurement data of the specimen given in Table 9-12.

REMARKS.—This specimen differs from Schubertella melonica Dunbar and Skinner and Schubertella pseudogiraudi

Sheng, 1963, in having a smaller, more tightly coiled test and

more expanded chomata. Schubertella compacta Sheng, 1963,

is also tightly coiled, but it has a smaller test, thinner

spirotheca, and smaller chomata than the studied specimen.

Family FUSULINIDAE von Moller, 1878

Subfamily FUSULININAE von Moller, 1878

Yangchienia Lee, 1934

TYPE SPECIES.—Yangchienia iniqua Lee, 1934.
NUMBER 32 205

TABLE 9-12.—Measurements of Schubertella sp. TABLE 9-13.—Measurements of Yangchienia iniqua Lee.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

O

Volution

0

1

2

3

4

5

1

2

3

4

5

1

2

3

4

5

1

2

3

1

2

3

USNM

483051

0.03

0.045

0.05

0.08

0.12

0.17

0.025

0.08

0.13

0.20

0.34

0.56

1.60

1.63

1.67

2.00

-

-

0.02

_

18

24

Yangchienia iniqua Lee, 1934

PLATE 9-6: FIGURES 7, 8

Yangchienia iniqua Lee, 1934:14, pi. 1: figs. 1, la.—Sheng, 1963:38, pi. 4:

figs. 30-35.—Xiao et al., 1986:79, pi. 2: figs. 3, 4.—Zhang et al., 1988:276,

pi. 5: fig. 9.

TYPES.—Hypotypes: USNM 483052, 483053; from the

Road Canyon Formation of the Glass Mountains, Texas.

MATERIAL STUDIED.—Samples from the lower part of the

Road Canyon Formation in the Glass Mountains, Texas: 2-68,

2-R6.

AGE AND DISTRIBUTION.—Leonardian Series portion of the

Parafusulina boesei Zone, Glass Mountains, Texas. Upper

portion of the Qixian Stage at the top of the Qixia Formation,

Ningzhen Mountains, southern Jiangsu Province, China (Lee,

1934), the lower part of the Maokou Formation in Guangxi

Province (Sheng, 1963) and Guizhou Province, China (Yang,

1985), and the Qixia Formation in the Qixia Mountains,

Nanjing, Jiangsu Province, China (Zhang et al., 1988).

REMARKS.—Yangchienia iniqua is characterized by its very

small size, fusiform test, few volutions, planar septa, axis of

coiling of inner volutions perpendicular to that of the outer

volutions, and massive chomata extending to the polar

extremities. The specimens studied are juveniles, but they

resemble the type specimens of Yangchienia iniqua in all

respects. This species differs from Yangchienia compressa

(Ozawa, 1927) in having a shorter but more inflated test and a

lower form ratio. Compared with Yangchienia minuta Xiao et

al. (1986), it has a slightly larger and more inflated test, more

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

\ )

Volution

0

1

2

3

4

5

1

2

3

4

5

1

2

3

4

5

1

2

3

4

5

1

2

3

4

USNM

483053

0.05

0.06

0.08

0.14

0.20

0.28

0.04

0.12

0.20

0.29

0.39

0.67

1.50

1.43

1.45

1.40

_

-

-

-

0.03

21

23

25

volutions in maturity, and more extended chomata. Some

species of Neofusulinella Deprat look similar to species of

Yangchienia in size, form, and presence of massive chomata;

however, Neofusulinella does not change coiling direction

during ontogeny, and it has polar extremities with slightly

fluted septa but with no chomata deposits. Measurement data of

one specimen are given in Table 9-13.

Yangchienia is a common and important genus of Permian

fusulinid fauna in the Tethyan realm. This is the first time it has

been reported in North America.

Family FUSULINIDAE von Moller, 1878

Subfamily SCHWAGERININAE Dunbar and Henbest, 1930

Parafusulina Dunbar and Skinner, 1931

TYPE SPECIES.—Parafusulina wordensis Dunbar and Skinner, 1931.

Parafusulina alpinensis, new species

PLATE 9-10: FIGURES 6, 7

TYPES.—Holotype: USNM 483054; Paratype: USNM

483055; from the Road Canyon Formation of the Del Norte

Mountains, Texas.
206 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

MATERIAL STUDIED.—Samples from the upper part of the

Road Canyon Formation in the Del Norte Mountains, Texas:

7-53; 8-24.

DIAGNOSIS.—Ellipsoidal outline; low, narrow, and crowded

septal folds; very thin spirotheca; distinctive secondary

deposits distributed throughout length along axis, narrow near

proloculus but gradually wider and heavier toward poles.

AGE AND DISTRIBUTION.—Parafusulina trumpyi Zone of the

Guadalupian Series, Del Norte Mountains, Texas.

DESCRIPTION.—Large size; ellipsoidal form; 6V2 to 7V2

volutions; attaining a length of about 10 mm and a diameter of

about 3 mm; chamber height and length increase gradually,

resulting in average form ratio changing from 2.25 in first

volution to 3.85 in sixth volution; proloculus ranging between

0.28 to 0.36 mm in outside diameter, subspherical or slightly

depressed on one side; spirotheca very thin, consisting of

TABLE 9-14.—Measurements of Parafusulina alpinensis, new species.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

O

Volution

0

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

8

1

2

3

4

5

USNM

483054

0.18

0.24

0.32

0.46

0.60

0.80

1.04

1.30

1.52

0.58

1.06

1.58

2.32

3.08

3.92

5.00

2.42

3.31

3.43

3.86

3.85

3.77

3.85

0.02

0.02

0.03

0.04

0.04

0.04

0.05

0.04

30

36

-

-

43

USNM

483055

0.14

0.24

0.36

0.48

0.67

0.86

1.08

1.32

-

0.50

0.92

1.40

2.08

2.84

3.68

-

2.08

2.56

2.92

3.10

3.30

3.41

-

0.02

0.02

0.03

0.03

0.04

0.06

-

-

_

-

35

38

48

tectum and keriotheca, thickness averaging 0.020, 0.020,

0.030, 0.035, 0.040, 0.050, and 0.050 mm from first to seventh

volutions, respectively; septa intensely and regularly fluted;

septal folds low, narrow, and crowded; cuniculi well developed; chomata lacking; secondary deposits occur along axis

throughout length of test, narrow near proloculus but gradually

wider and heavier toward poles; tunnel narrow and not well

marked; tunnel angle averaging 30° and 45° in first and fifth

volutions, respectively. Measurement data of specimens given

in Table 9-14.

REMARKS.—This species differs from other species of the

genus Parafusulina in having an ellipsoidal test, extraordinarily thin spirotheca, and a unique pattern of secondary deposits

that extend along the entire axis and become gradually wider

and heavier toward the poles.

ETYMOLOGY.—The species is named for the town of Alpine,

Texas, located west of the Glass and Del Norte mountains.

Parafusulina antimonioensis Dunbar, 1953

PLATE 9-15: FIGURES 1-4

Parafusulina antimonioensis Dunbar, 1953:15, pi. 2: figs. 1-8, pi. 3: figs.

1-3.—Ross, 1963b:28, pi. 5: figs. 2, 3.

TYPES.—Hypotypes: USNM 483056-483059; from the

Word Formation of the Del Norte Mountains, Texas.

MATERIAL STUDIED.—Samples from the upper part of the

Word Formation in the Del Norte Mountains, Texas: 9-7, 9-8.

AGE AND DISTRIBUTION.—Parafusulina antimonioensis

Zone of the Guadalupian Series, Glass and Del Norte

mountains, Texas; Sonora, Mexico.

REMARKS.—The specimens studied resemble the type

specimens of Parafusulina antimonioensis in these major

features: a very large and elongate, subcylindrical test, large

proloculus, highly developed cuniculi, and secondary deposits

heavily filling the septal folds in the polar extremities along the

axis. Because this species has an exceptionally long, slender,

and irregular test, it is very difficult to obtain thin sections cut

through the entire length of the test. Even a slightly oblique

axial section distorts the apparent length of the test, such that

the specimens obtained look shorter than the type specimens.

Measurement data of specimens are given in Table 9-15.

Parafusulina cf. P. bakeri Dunbar and Skinner, 1937

PLATE 9-6: FIGURE 6

Parafusulina bakeri Dunbar and Skinner, 1937:677-679, pi. 71: figs. 1-10.

MATERIAL STUDIED.—Sample from the lower part of the

Road Canyon Formation in the Glass Mountains, Texas: 2-68;

specimen: USNM 483060.

AGE AND DISTRIBUTION.—Leonardian Series, Glass Mountains, Texas. Found only in the Leonardian portion of the

Parafusulina boesei Zone.
NUMBER 32 207

TABLE 9-15.—Measurements of Parafusulina antimonioensis Dunbar.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(O\

\ )

Volution

0

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

USNM

483058

0.24

0.30

0.44

0.52

0.64

0.76

0.96

1.16

1.36

0.48

1.52

2.28

3.60

4.84

6.68

8.32

10.00

1.60

3.45

4.38

5.63

6.37

6.96

7.17

7.35

0.03

0.03

0.03

0.04

0.04

0.05

0.06

0.06

_

30

32

-

-

USNM

483057

0.28

0.32

0.40

0.56

0.72

0.84

1.04

1.28

1.52

0.68

1.20

2.04

3.40

4.28

5.44

7.00

8.20

2.13

3.00

3.64

4.72

5.10

5.23

5.78

5.39

0.03

0.04

0.04

0.04

0.05

0.05

0.06

0.07

_

25

33

36

40

36

USNM

483059

0.30

0.36

0.52

0.66

0.78

0.93

1.12

1.35

-

0.48

1.34

2.00

3.16

4.20

5.24

7.00

-

1.33

2.58

3.03

4.05

4.52

4.68

5.20

-

0.03

0.03

0.04

0.04

0.05

0.06

-

-

_

28

-

-

USNM

483056

0.38

0.44

0.56

0.70

0.88

1.04

1.22

1.52

-

0.78

1.44

2.24

3.48

4.72

6.08

8.40

-

1.77

2.57

3.20

3.59

4.54

4.98

5.53

-

0.03

0.03

0.04

0.05

0.05

0.06

0.06

-

24

28

28

46

35

-

Parafusulina cf. P. biturbinata Kling, 1960

PLATE 9-5: FIGURES 3-5

Parafusulina biturbinata Kling, 1960:653, pi. 81: figs. 4, 5, 7-9.

MATERIAL STUDIED.—Sample from the upper part of the

Cathedral Mountain Formation in the Glass Mountains, Texas:

1-60; specimens: USNM 483061-483063.

AGE AND DISTRIBUTION.—Parafusulina durhami Zone of

the Leonardian Series, Glass Mountains, Texas; Guatemala

(Kling, 1960).

REMARKS.—Parafusulina biturbinata is characterized by

having a small, fusiform test with convex slopes and sharply

pointed poles, large proloculus, and narrow axial fillings. The

specimens studied resemble the type specimens of P. biturbinata in major respects, but they differ slightly from them in

having less pointed poles and lighter secondary deposits.

Parafusulina boesei Dunbar and Skinner, 1937

PLATE 9-13: FIGURES 1-5

Parafusulina boesei Dunbar and Skinner, 1937:679, pi. 73: figs. 1-9.—Ross,

1963b:26, pi. 3: figs. 1-10.—Sheng, 1963:72, pi. 20: figs. 6, 7, pi. 21: fig. 1.

Parafusulina boesei var. attenuata Dunbar and Skinner, 1937:680, pi. 74: figs.

5-13.

TYPES.—Hypotypes: USNM 483064-483068; from the

Road Canyon Formation of the Glass and Del Norte mountains,

Texas.

MATERIAL STUDIED.—Samples from the Road Canyon

Formation in the Glass and Del Norte mountains, Texas: 2-68,

2-70, 2-73, 2-R1; 7-56, 7-58; 8-13, 8-20, 8-24, 8-29.

AGE AND DISTRIBUTION.—Parafusulina boesei Zone to

Parafusulina trumpyi Zone of the Leonardian and Guadalupian

series, Glass and Del Norte mountains, Texas; Guadalupe

Mountains, Texas (Wilde, 1986a); Chinati Mountains, Texas

(Skinner, 1940). Lower part of the Maokou Formation, China

(Sheng, 1963; Yang 1985).

REMARKS.—Parafusulina boesei is a species of moderate

size and is characterized by a variable fusiform shape, lower

and less closely crowded septal folds, and light secondary

deposits. Ross (1963b) considered this species to have wider

morphological limits than those suggested by Dunbar and

Skinner (1937), who erected the variety name attenuata for

more elongate forms. Ross held that P. boesei is most

comparable to late Leonardian species, such as Parafusulina

durhami and P. leonardensis Ross, 1962. The present study

agrees with Ross and adopts the same practice in dealing with

the scope of this species. Measurement data of specimens are

given in Table 9-16.

This species was collected only from the Road Canyon

Formation during this study (in three sections), but it has been

reported from a stratigraphic interval ranging from the Road

Canyon Formation through the Willis Ranch Member of the

Word Formation in the Glass Mountains (Dunbar and Skinner,

1937; Ross 1963b; Wilde in Cooper and Grant, 1977).

Parafusulina durhami Thompson and Miller, 1949

PLATE 9-5: FIGURES 1,2

Parafusulina durhami Thompson and Miller, 1949:15, pi. 3: figs. 3-7, pi. 5:

figs. 9, 11, 12.—Ross, 1962:15, pi. 6: figs. 1-7.

TYPES.—Hypotypes: USNM 483069, 483070; from the

Cathedral Mountain Formation of the Glass Mountains, Texas.

MATERIAL STUDIED.—Samples from the upper part of the

Cathedral Mountain Formation in the Glass Mountains, Texas:

1-60; 2-67.
208 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 9-16.—Measurements of Parafusulina boesei Dunbar and Skinner. TABLE 9-17.—Measurements of Parafusulina durhami Thompson and Miller.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°)

Volution

0

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

USNM

483064

0.20

0.27

0.39

0.54

0.78

1.05

1.31

1.74

0.84

1.27

2.16

3.23

4.24

5.47

6.01

3.11

3.26

4.00

4.14

4.04

4.18

3.45

0.03

0.04

0.04

0.06

0.07

0.08

0.10

_

-

-

-

-

USNM

483065

0.19

0.26

0.38

0.50

0.69

0.94

1.20

1.48

0.77

1.23

1.85

2.70

3.62

4.73

5.90

2.96

3.24

3.70

3.91

3.85

3.94

3.98

0.03

0.04

0.05

0.06

0.08

0.09

-

_

-

-

-

-

USNM

483067

0.24

0.36

0.52

0.72

0.96

1.24

1.56

-

0.72

1.20

1.96

2.95

4.36

5.44

-

2.00

2.31

2.72

3.08

3.52

3.49

-

0.03

0.04

0.04

0.06

0.07

0.07

-

30

31

37

46

42

USNM

483066

0.20

0.28

0.44

0.64

0.88

1.12

1.36

-

0.64

1.12

1.72

2.56

3.40

4.42

-

2.29

2.55

2.69

2.91

3.04

3.25

-

0.03

0.03

0.04

0.05

0.05

0.07

-

29

30

44

48

-

USNM

483068

0.20

0.28

0.40

0.64

0.76

1.06

1.34

-

0.68

1.08

1.72

2.36

3.20

4.44

-

2.43

2.70

2.89

3.11

3.02

3.31

-

0.03

0.03

0.04

0.06

0.07

0.08

-

_

-

41

46

-

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°\

\ )

Volution

0

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

1

2

3

4

5

6

USNM

483070

0.15

0.20

0.28

0.40

0.56

0.76

1.04

1.32

0.44

0.86

1.30

2.08

3.24

4.82

4.16

2.20

3.07

3.25

3.71

4.26

4.63

4.67

0.03

0.03

0.04

0.05

0.07

0.07

33

42

48

54

50

47

USNM

483069

0.16

0.32

0.44

0.60

0.78

1.00

1.28

-

0.64

1.12

1.68

2.48

3.64

4.80

-

2.00

2.55

2.80

3.18

3.64

3.75

-

0.03

0.03

0.04

0.04

0.06

0.08

25

36

:

45

-

AGE AND DISTRIBUTION.—Parafusulina durhami Zone of

the Leonardian Series, Glass Mountains, Texas; Colombia

(Thompson and Miller, 1949).

REMARKS.—Measurement data of specimens are given in

Table 9-17.

Parafusulina faliskiei, new species

PLATE 9-11: FIGURES 5-7

TYPES.—Holotype: USNM 483072; Paratypes: USNM

483071, 483073; from the Road Canyon Formation of the

Glass Mountains, Texas.

MATERIAL STUDIED.—Samples from the lower and middle

parts of the Road Canyon Formation in the Glass Mountains,

Texas: 1-63; 2-68, 2-73, 2-R14.

DIAGNOSIS.—Test large; elongated ellipsoidal, with bluntly

rounded poles; septal fluting very strong and regular; septal

folds commonly low, with rounded crests; tunnel path

irregular; tunnel angle rather high.

AGE AND DISTRIBUTION.—Parafusulina rothi Zone to

Parafusulina trumpyi Zone of the Guadalupian Series, Glass

Mountains, Texas.

DESCRIPTION.—Large size; elongate ellipsoidal to shortly

subcylindrical form; 7 72 volutions in maturity; commonly

attaining a length of 10.0 to 13.0 mm and a diameter of 3.3 to

3.7 mm; lateral slopes of volutions nearly parallel and ending in

bluntly rounded poles; form ratio increasing gradually from

first to sixth volutions, but decreasing in last 1V2 volutions,

giving a final form ratio about 3.0; proloculus of medium size,

averaging 0.28 to 0.34 mm in outside diameter; spirotheca

consisting of tectum and keriotheca; spirotheca thickness

averaging 0.023, 0.030, 0.040, 0.056, 0.070, 0.080, and 0.083

mm in first to seventh volutions, respectively; septa intensely

and regularly fluted; cuniculi well developed; septal folds

commonly low, in small, slim arches with rounded crests;
NUMBER 32 209

chomata completely lacking; secondary deposits very light;

tunnel path irregularly present; tunnel angle averaging 35° and

56° in first and fourth volutions, respectively. Measurement

data of specimens given in Table 9-18.

REMARKS.—This species is characterized by its elongate

ellipsoidal shape, bluntly rounded poles, and low, slim septal

folds with rounded crests. It may be distinguished from

Parafusulina wildei Ross, 1963, in having a less slender shape,

more bluntly rounded poles, and lower form ratio, as well as

lower and less crowded septal folds and less developed

secondary deposits. The present species is somewhat similar in

shape to Parafusulina elliptica Sheng, 1963, but differs in

having a larger and much longer test, different fluting style, and

much more developed secondary deposits.

ETYMOLOGY.—This species is named for Ray Faliskie, a

TABLE 9-18.—Measurements of Parafusulina faliskiei, new species.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°)

Volution

0

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

USNM

483071

0.16

0.24

0.36

0.48

0.64

0.84

1.08

1.36

1.64

0.50

0.80

1.38

2.12

2.88

3.64

4.36

4.92

2.08

2.22

2.88

3.31

3.43

3.37

3.21

3.00

0.02

0.02

0.03

0.04

0.04

0.06

0.08

0.06

31

38

43

56

46

USNM

483072

0.23

0.28

0.38

0.57

0.79

1.04

1.42

1.72

-

0.78

1.32

2.00

2.76

3.60

4.85

6.20

-

1.73

3.47

3.51

3.49

3.46

3.42

3.60

-

0.03

0.04

0.05

0.06

0.06

0.06

0.05

-

_

45

44

40

47

USNM

483073

0.17

0.26

0.38

0.50

0.68

0.90

1.16

1.52

1.88

0.65

1.04

1.68

2.42

3.46

5.00

5.84

-

2.50

2.74

3.36

3.56

3.85

4.31

3.61

-

0.03

0.04

0.05

0.07

0.08

0.09

0.07

-

38

46

60

62

-

graduate student at Sul Ross State University, who helped with

the field work of this study.

Parafusulinia fountaini Dunbar and Skinner, 1937

PLATE 9-10: FIGURES 1, 2

Parafusulina fountaini Dunbar and Skinner, 1937:675-677, pi. 70: figs. 1-10.

TYPES.—Hypotypes: USNM 483074, 483075; from the

Road Canyon Formation of the Glass Mountains, Texas.

MATERIAL STUDIED.—Samples from the lower part of the

Road Canyon Formation in the Glass Mountains, Texas: 2-70,

2-R3.

AGE AND DISTRIBUTION.—Leonardian Series portion of the

Parafusulina boesei Zone, Glass Mountains, Texas; Guadalupe

Mountains, Texas (Dunbar and Skinner, 1937).

REMARKS.—The specimens studied resemble the type specimens of Parafusulina fountaini Dunbar and Skinner in all respects. Measurement data of specimens are given in Table 9-19.

TABLE 9-19.—Measurements of Parafusulina fountaini Dunbar and Skinner.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°\ \ }

Volution

0

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

USNM

483074

0.20

0.25

0.38

0.55

0.76

1.04

1.40

1.82

0.88

1.42

2.00

2.68

3.92

5.48

8.00

3.52

3.74

3.64

3.50

3.77

3.91

4.40

0.03

0.04

0.05

0.06

0.10

0.10

0.09

29

35

44

46

43

22

USNM

483075

0.23

0.30

0.42

0.56

0.78

1.02

1.32

1.64

0.68

1.20

1.76

2.36

4.00

5.20

6.96

2.27

2.86

3.14

3.03

3.92

3.94

4.24

0.03

0.04

0.04

0.06

0.08

0.09

0.07

26

41

32

48

56

-
210 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Parafusulina glassensis, new species

PLATE 9-8: FIGURES 1-3

Parafusulina rothi Dunbar and Skinner, 1937:684, pi. 76: fig. 10 [in part, not

figs. 1-9].

TYPES.—Holotype: USNM 483076; Paratypes: USNM

483077, 483078; from the Road Canyon Formation of the

Glass Mountains, Texas.

MATERIAL STUDIED.—Samples from the middle and upper

part of the Road Canyon Formation and Willis Ranch Member

of the Word Formation in the Glass and Del Norte mountains,

Texas: 1-62; 2-72, 2-R8, 2-R10; 8-39.

DIAGNOSIS.—Very large size; almost cylindrical form, with

bluntly rounded poles; septa numerous and strongly fluted;

septal folds high, narrow, closely spaced, and very regular;

tunnel low and not well defined; secondary deposits light.

AGE AND DISTRIBUTION.—Parafusulina rothi Zone to

Parafusulina sellardsi Zone of the Guadalupian Series, Glass

and Del Norte mountains, Texas; Guadalupe Mountains, Texas

(Dunbar and Skinner, 1937).

DESCRIPTION.—Very large size; subcylindrical to almost

cylindrical form; 8 to 9 volutions, attaining a length of 18 to 21

mm and a diameter of 3.5 to 4.2 mm; axis of coiling irregular,

but slightly curved; slopes of volutions nearly parallel, tapering

slightly near the bluntly rounded ends; chamber height

increasing very slowly as length increases rapidly, resulting in

a nearly cylindrical test; form ratio averaging from 2.4 in first

volution to 4.20 and 5.00 in fifth and eighth volutions,

respectively; proloculus ranging between 0.36 to 0.44 mm in

outside diameter, and spherical or subspherical in shape;

spirotheca consisting of tectum and keriotheca; spirotheca

thickness averaging 0.030, 0.035, 0.045, 0.060, 0.075, 0.090,

0.093, 0.100, and 0.080 mm from first to ninth volutions,

respectively; septa numerous and intensely fluted; septal folds

narrow, regular, and closely spaced; cuniculi very well

developed; chomata completely lacking; secondary deposits

scarcely or very slightly developed, filling septal loops in the

inner volutions; tunnel low and not well defined; tunnel angle

may reach 55° to 60° in outer volutions. Measurement data of

specimens given in Table 9-20.

REMARKS.—This species differs from Parafusulina wordensis Dunbar and Skinner in having a smaller test and less

developed cuniculi. It differs from Parafusulina trumpyi

Thompson and Miller in having an almost cylindrical test, more

numerous and regular septal folds, and a low and not

well-defined tunnel. Parafusulina antimonioensis Dunbar and

Parafusulina deliciasensis Dunbar and Skinner, 1936, somewhat resemble the present species, but they differ in having a

much larger proloculus and denser secondary deposits. The

present species also differs from Parafusulina rohri, new

species, in having a slender test and lighter secondary deposits.

TABLE 9-20.—Measurements of Parafusulina glassensis, new species.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°)

Volution

0

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

USNM

483078

0.18

0.21

0.31

0.43

0.58

0.78

1.04

1.27

1.51

1.75

0.58

1.01

1.54

2.28

3.39

4.66

6.52

8.22

8.90

2.76

3.26

3.58

3.93

4.35

4.48

5.13

5.44

5.29

0.03

0.03

0.04

0.05

0.08

0.10

0.10

0.10

0.08

31

26

28

32

34

USNM

483076

0.18

0.24

0.32

0.48

0.64

0.85

1.12

1.46

1.84

-

0.60

1.10

1.92

2.40

4.00

5.12

6.72

8.12

-

2.50

3.44

4.00

4.38

4.70

4.57

4.60

4.41

-

0.03

0.03

0.05

0.07

0.07

0.08

0.10

0.10

-

28

34

46

40

45

USNM

483077

0.22

0.28

0.40

0.56

0.72

0.94

1.24

1.52

-

-

0.64

1.00

1.68

2.72

3.80

5.84

7.12

-

-

2.29

2.50

3.00

3.78

4.04

4.71

4.68

-

-

0.04

0.04

0.05

0.06

0.07

0.08

0.06

-

-

28

44

54

60

-

Furthermore, the large, almost cylindrical test, more numerous,

narrower, and more regular septal folds, and denser secondary

deposits may distinguish this species from Parafusulina rothi

Dunbar and Skinner. The exceptionally large individual

referred with some uncertainty to Parafusulina rothi by Dunbar

and Skinner (1937), and illustrated by them (pi. 76: fig. 10),

resembles P. glassensis in all respects, and thus is considered to

be conspecific.

ETYMOLOGY.—This species is named for the Glass Mountains, located in West Texas.
NUMBER 32 211

Parafusulina cf. P. guatemalaensis Dunbar, 1939

PLATE 9-5: FIGURES 6, 7

Parafusulina guatemalaensis Dunbar. 1939:347, pi. 36: figs. 1-10.

MATERIAL STUDIED.—Samples from the lower part of the

Road Canyon Formation in the Glass Mountains, Texas: 2-R5,

2-R6; specimens: USNM 483079, 483080.

AGE AND DISTRIBUTION.—Leonardian Series portion of the

Parafusulina boesei Zone, Glass Mountains, Texas; Guatemala

(Dunbar, 1939).

REMARKS.—The specimens studied resemble the type

specimens of Parafusulina guatemalaensis Dunbar in most

respects, but they differ in having a smaller test and slightly

lower form ratio, probably because the thin sections obtained

are slightly oblique.

Parafusulina ironensis Ross, 1963

PLATE 9-7: FIGURES 5-7

Parafusulina ironensis Ross, 1963b:25, pi. 4: figs. 13-15.

TYPES.—Hypotypes: USNM 483081-483083; from the

Road Canyon Formation of the Glass and Del Norte mountains,

Texas.

MATERIAL STUDIED.—Samples from the middle part of the

Road Canyon Formation in the Glass and Del Norte mountains,

Texas: 1-62, 1-63; 7-55.

AGE AND DISTRIBUTION.—Parafusulina rothi Zone to

Parafusulina trumpyi Zone of the Guadalupian Series, Glass

Mountains, Texas.

REMARKS.—The specimens studied resemble the type

specimens of Parafusulina ironensis Ross in all respects.

Measurement data of specimens are given in Table 9-21.

Parafusulina lineata Dunbar and Skinner, 1937

PLATE 9-12: FIGURES 2-5

Parafusulina lineata Dunbar and Skinner, 1937:681-682, pi. 74: figs.

1_4._R OSS ? I963b:29, pi. 3: figs. 12, 13.

TYPES.—Hypotypes: USNM 483084-483087; from the

Road Canyon Formation and the Word Formation of the Glass

and Del Norte mountains, Texas.

MATERIAL STUDIED.—Samples from the Road Canyon

Formation and lower part of the Word Formation in the Glass

and Del Norte mountains, Texas: 2-R12, 2-R16; 8-38.

AGE AND DISTRIBUTION.—Parafusulina rothi Zone to

Parafusulina sellardsi Zone of the Guadalupian Series, Glass

and Del Norte mountains, Texas; Guadalupe Mountains, Texas

(Dunbar and Skinner, 1937; Wilde, 1990).

REMARKS.—Parafusulina lineata is characterized by its

small size, extremely slender, subcylindrical form, compact

TABLE 9-21.—Measurements of Parafusulina ironensis Ross.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°\

y )

Volution

0

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

USNM

483082

0.09

0.15

0.22

0.32

0.45

0.60

0.84

1.12

1.40

0.33

0.66

1.08

1.52

2.76

4.08

5.56

6.16

2.20

3.00

3.38

3.38

4.60

4.85

4.96

4.46

0.020

0.030

0.030

0.040

0.040

0.060

0.070

0.080

28

29

30

35

48

44

USNM

483083

0.12

0.18

0.25

0.34

0.48

0.67

0.90

1.21

1.52

0.36

0.68

1.04

1.56

2.64

3.60

4.92

5.90

2.00

2.72

3.05

3.25

3.94

4.00

4.07

3.88

0.020

0.020

0.030

0.040

0.060

0.070

0.080

0.080

25

28

26

42

49

-

coiling, and poorly developed axial filling. The specimens

studied resemble the type specimens of Parafusulina lineata in

nearly all respects. It resembles Monodiexodina linearis

(Dunbar and Skinner, 1937), in test size, wall thickness, and

external form, but M. linearis differs greatly in having low,

irregular, and loose septal folds, a poorly defined tunnel, and

very heavily developed axial filling. Measurement data of

specimens are given in Table 9-22.

Parafusulina lineata is an uncommon species in the

Delaware basin and has a relatively long stratigraphic range.

Ross (1963b) and Wilde (1990) both recognized a zone defined

on P. lineata, which Ross placed in the lower part of the
212 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 9-22.—Measurements of Parafusulina lineata Dunbar and Skinner.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°)

Volution

0

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

USNM

483085

0.15

0.18

0.24

0.32

0.44

0.56

0.76

1.01

0.36

0.70

1.24

1.84

2.80

3.60

4.20

2.00

2.92

3.88

4.18

5.00

4.74

4.16

0.02

0.02

0.02

0.03

0.03

0.05

0.07

24

-

-

-

40

USNM

483087

0.14

0.18

0.28

0.44

0.60

0.84

1.04

-

0.54

1.20

1.96

3.04

4.52

6.24

-

3.00

4.28

4.45

5.06

5.38

6.00

-

0.03

0.04

0.04

0.05

0.07

0.08

-

38

36

56

57

-

USNM

483086

0.14

0.22

0.32

0.44

0.62

0.82

1.04

-

0.44

1.10

1.68

2.48

3.96

5.20

-

2.00

3.44

3.82

4.00

4.83

5.00

-

0.03

0.03

0.04

0.06

0.06

0.05

-

20

47

41

45

-

Guadalupian, whereas Wilde placed it in the middle part of the

Guadalupian. Material collected for this study shows that P.

lineata has a longer range than either worker indicated,

accounting for the confusion about its zonal status. The species

also has been reported from the China Tank Member of the

Word Formation in the Glass Mountains (Wilde in Cooper and

Grant, 1977) and the Grayburg Formation in the northern

Guadalupe Mountains (Wilde, 1986a). Wilde (1990) pointed

out that there were some unfortunate errors in locality

numbering in Dunbar and Skinner (1937), contending that the

type specimens of P. lineata came from locality 171, in the

Cherry Canyon Formation in Trew Canyon, southern Delaware

Mountains, not from locality 157 as published.

Parafusulina maleyi Dunbar and Skinner, 1937

PLATE 9-13: FIGURES 7, 8

Parafusulina maleyi Dunbar and Skinner, 1937:686-687, pi. 77: figs. 1-12.

TYPES.—Hypotypes: USNM 483088, 483089; from the

Word Formation of the Glass and Del Norte mountains, Texas.

MATERIAL STUDIED.—Samples from the Road Canyon

Formation and the lower part of the Word Formation in the

Glass and Del Norte mountains, Texas: 1-64; 2-R12; 3-24;

7-53; 8-14, 8-18, 8-24, 8-27, 8-39.

AGE AND DISTRIBUTION.—Parafusulina boesei Zone to

Parafusulina sellardsi Zone of the Guadalupian Series, Glass

and Del Norte mountains, Texas.

REMARKS.—Parafusulina maleyi is characterized by a large,

elongate, fusiform test, a slowly increasing diameter, and

scarcely or very lightly developed secondary deposits. Ross

(1963b) included Parafusulina maleyi and P. maleyi var.

referta Dunbar and Skinner, 1937, in Parafusulina deliciasensis Dunbar and Skinner, 1936. On the basis of the rather

prominent axial filling from pole to pole and the narrow and

more closely crowded septal folds, P. deliciasensis (which

includes P. maleyi var. referta) and P. maleyi are considered to

be separate species in this study. The specimens studied closely

resemble the type specimens of Parafusulina maleyi. The only

difference is that some specimens having light secondary

deposits are included in this species. Measurement data of

specimens are given in Table 9-23.

Parafusulina marathonensis, new species

PLATE 9-8: FIGURES 4, 5; PLATE 9-10: FIGURE 8

TYPES.—Holotype: USNM 483091; Paratypes: USNM

483090, 483092; from the Road Canyon Formation and the

Word Formation of the Glass and Del Norte mountains, Texas.

MATERIAL STUDIED.—Samples from the upper part of the

Road Canyon Formation and the lower part of the Word

Formation in the Glass and Del Norte mountains, Texas: 3-23;

8-26.

DIAGNOSIS.—Test large; elongate fusiform shape; slightly

curved axis of coiling and bluntly pointed poles; septal fluting

very strong and regular; septal folds commonly low and very

narrow; cuniculi highly developed; on axial section, foramina

are numerous, subcircular in shape, and present on the septal

folds of all volutions except those filled with secondary

deposits; secondary deposits usually occupy the inner 2 to 3

volutions.

AGE AND DISTRIBUTION.—Parafusulina trumpyi Zone of the

Guadalupian Series, Glass and Del Norte mountains, Texas.

DESCRIPTION.—Large size; elongate, fusiform test; 8 to 8V2

volutions, attaining a length of 18.0 mm and a diameter of 3.6

mm, giving a form ratio of about 5; axis of coiling slightly

curved; lateral slopes of volutions taper to bluntly pointed

poles; proloculus ranging between 0.24 and 0.32 mm in outside

diameter; spirotheca consisting of tectum and keriotheca;

spirotheca thickness averaging 0.027, 0.030, 0.037, 0.043,

0.050, 0.067, 0.083, and 0.070 mm in first to eighth volutions,

respectively; septa intensely and regularly fluted; septal folds
NUMBER 32 213

TABLE 9-23.—Measurements of Parafusulina maleyi Dunbar and Skinner. TABLE 9-24.—Measurements of Parafusulina marathonemis, new species.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

o

Volution

0

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

USNM

483089

0.20

0.28

0.45

0.60

0.78

1.00

1.28

1.50

-

0.68

1.20

2.04

3.20

4.36

5.72

6.88

-

2.43

2.67

3.40

4.10

4.36

4.47

4.59

-

0.02

0.03

0.04

0.05

0.05

0.07

0.08

-

21

35

49

_-

_

-

USNM

483088

0.20

0.25

0.34

0.41

0.52

0.72

0.98

1.20

1.52

0.48

0.80

1.08

1.68

2.64

4.20

5.96

7.40

1.92

2.35

2.63

3.23

3.67

4.29

4.97

4.87

0.02

0.03

0.03

0.03

0.04

0.06

0.07

0.08

_

_

_

_

-

52

commonly low and very narrow; cuniculi highly developed; on

axial section, basal foramina numerous, subspherical in shape,

and present in volutions without axial filling; chomata

completely lacking; secondary deposits fill the inner 2 to 3

volutions; tunnel singular and well marked; tunnel angle

averaging 24° and 48° in first and fifth volutions, respectively.

Measurement data of specimens given in Table 9-24.

REMARKS.—This species is characterized by its shape and

highly developed foramina, which distinguishes it from most

species of the genus. It is somewhat similar to Parafusulina

glassensis, new species, but differs in that it is smaller, elongate

in form, has a smaller proloculus, narrower septal folds, and

more developed foramina.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°)

Volution

0

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

USNM

483090

0.14

0.20

0.26

0.35

0.45

0.66

0.94

1.28

1.68

1.96?

0.40

0.76

1.08

1.60

2.60

3.88

6.72

8.64

-

2.00

2.92

3.08

3.33

3.94

4.13

5.25

5.14

-

0.03

0.03

0.04

0.04

0.05

0.07

0.09

0.10

0.06

_

-

36

52

44

USNM

483092

0.16

0.19

0.25

0.36

0.50

0.72

0.96

1.24

-

-

0.44

0.86

1.32

1.82

2.70

3.86

6.08

-

-

2.31

3.44

3.66

3.64

3.75

4.02

4.90

-

-

0.03

0.03

0.04

0.05

0.05

0.07

0.09

0.06

-

24

40

54

-

-

USNM

483091

_

0.26

0.32

0.44

0.56

0.78

1.04

1.28

1.64

2.00

0.72

1.04

1.40

1.96

2.84

3.88

5.76

7.44

9.28

2.76

3.25

3.18

3.50

3.64

3.73

4.50

4.53

4.64

0.03

0.04

0.04

0.05

0.07

0.08

0.09

0.10

0.08

_

-

-

-

-

ETYMOLOGY.—This species is named for Marathon, a small

town located about 10 miles south of the Glass Mountains and

35 miles southeast of Alpine, Texas. Many geologists and

students of the Permian have stayed in Marathon while doing

field work in the Glass Mountains area.

Parafusulina rohri, new species

PLATE 9-14: FIGURES 1-3

TYPES.—Holotype: USNM 483093; Paratypes: USNM
214 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

483094, 483095; from the Word Formation of the Glass

Mountains, Texas.

MATERIAL STUDIED.—Samples from the Willis Ranch

Member of the Word Formation in the Glass Mountains, Texas:

3-21, 3-23, 3-24.

DIAGNOSIS.—Very large and subcylindrical; rather small

proloculus; septal folds closely spaced, narrow, high, and

regular; tunnel narrow; secondary deposits dense along axis.

AGE AND DISTRIBUTION.—Parafusulina sellardsi Zone of

the Guadalupian Series, Glass Mountains, Texas.

DESCRIPTION.—Very large size; subcylindrical form; 9 to 10

volutions; attaining a length of 20 to 22 mm and a diameter of

3.5 to 5.0 mm; lateral slopes of volutions end in bluntly

rounded poles; chamber height increasing very slowly as length

increases rapidly, resulting in average form ratio changing from

2.28 in first volution to 5 or 6 at maturity; proloculus ranging

between 0.30 to 0.40 mm in outside diameter and commonly

subspherical; spirotheca consisting of tectum and keriotheca;

spirotheca thickness averaging 0.030 to 0.040 mm in inner two

volutions, but 0.10 to 0.11 mm in outer volutions; septa

intensely and regularly fluted; septal folds narrow, high, and

closely spaced; cuniculi very well developed; chomata completely lacking; dense secondary deposits largely fill the

chambers of most inner volutions; tunnel narrow and well

marked; tunnel angle averaging 16° and 43° in first and sixth

volutions, respectively. Measurement data of specimens given

in Table 9-25.

REMARKS.—This species is most similar to Parafusulina

trumpyi Thompson and Miller, but it differs in having a larger

test, more highly folded septa, and denser secondary deposits.

It differs from Parafusulina sellardsi Dunbar and Skinner in

having a rather small proloculus, higher form ratio of inner

volutions, and heavier secondary deposits. Compared with

Parafusulina deliciasensis Dunbar and Skinner, the present

species has more volutions, smaller proloculus, thicker spirotheca, and lower form ratio.

ETYMOLOGY.—This species is named for David Rohr,

professor of geology at Sul Ross State University, Alpine,

Texas, in appreciation for his great help in field work and

discussions of stratigraphy.

Parafusulina rothi Dunbar and Skinner, 1936

PLATE 9-7: FIGURES 1-4

Parafusulina rothi Dunbar and Skinner, 1936:181-183, pi. 2: figs. 1-8.—

Dunbar and Skinner, 1937:684-686, pi. 76: figs. 1-9 [in part, not fig. 10].

TYPES.—Hypotypes: USNM 483096-483099; from the

Road Canyon Formation of the Glass Mountains, Texas.

MATERIAL STUDIED.—Samples from the Road Canyon

Formation and the lower part of the Word Formation in the

Glass and Del Norte mountains, Texas: 1-62, 1-63; 2-R8, 2-76,

2-R11, 2-R19; 7-49, 7-52; 8-14, 8-20, 8-23, 8-29, 8-42.

TABLE 9-25.—Measurements of Parafusulina rohri, new species.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall .

thickness

(mm)

Tunnel

angle

O

Volution

0

1

2

3

4

5

6

7

8

9

10

1

2

3

4

5

6

7

8

9

10

1

2

3

4

5

6

7

8

9

10

1

2

3

4

5

6

7

8

9

10

1

2

3

4

5

6

7

8

USNM

483094

0.14

0.20

0.25

0.33

0.42

0.52

0.65

0.83

1.05

1.39

1.73

0.56

0.96

1.38

1.96

2.68

3.86

5.28

6.82

8.44

9.76

2.80

3.84

4.18

4.66

4.12

5.94

6.36

6.50

6.07

5.64

0.02

0.03

0.03

0.04

0.05

0.05

0.07

0.07

0.08

0.10

16

35

25

36

48

43

58

54

USNM

483093

0.18

0.26

0.41

0.60

0.80

1.10

1.24

1.46

1.78

2.12

-

0.44

0.96

1.56

2.28

2.82

3.90

5.88

7.92

9.64

-

1.70

2.34

2.60

2.85

2.56

3.15

4.03

4.45

4.55

-

0.03

0.03

0.03

0.05

0.07

0.08

0.09

0.11

0.11

-

_

-

-

-

-

USNM

483095

0.20

0.34

0.46

0.68

0.88

1.12

1.40

1.72

2.08

2.50

-

0.64

0.96

1.60

2.40

3.68

5.20

6.80

8.32

11.72

-

1.88

2.09

2.35

2.73

3.28

3.71

3.95

4.00

4.70

-

0.03

0.03

0.04

0.05

0.06

0.08

0.10

0.10

0.09

-

_

-

31

37

-

-

AGE AND DISTRIBUTION.—Parafusulina rothi Zone to

Parafusulina sellardsi Zone of the Guadalupian Series, Glass

and Del Norte mountains, Texas; Guadalupe Mountains, Texas

(Dunbar and Skinner, 1937). Upper Qixia Formation and lower

Maokou Formation, China (Zhang, 1957; Yang, 1985).
NUMBER 32 215

REMARKS.—The specimens studied resemble the type

specimens of Parafusulina rothi in all respects; however, the

specimen illustrated in pi. 76: fig. 10 by Dunbar and Skinner

(1937) has an elongate test, more intensive and regular fluting,

and more extensive and heavier secondary deposits in the septal

folds than the other specimens, and it is not included in

Parafusulina rothi in this report. That specimen is included

within the range of Parafusulina glassensis, new species.

Measurement data of specimens are given in Table 9-26.

Ross (1963b) included this species within his concept of

Parafusulina deliciasensis, which he reported as having a

stratigraphic range from the upper part of the Road Canyon

Formation to the top of the Appel Ranch Member of the Word

Formation. It also has been reported (Wilde in Cooper and

Grant, 1977) from the China Tank Member of the Word

Formation in the Glass Mountains, Texas.

TABLE 9-26.—Measurements of Parafusulina rothi Dunbar and Skinner.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°\

\ )

Volution

0

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

USNM

483096

0.18

0.24

0.38

0.56

0.88

1.32

1.68

2.12

0.42

0.86

1.60

2.36

3.28

5.84

7.28

1.75

2.20

2.85

2.68

2.48

3.48

3.43

0.04

0.04

0.05

0.07

0.10

0.11

0.10

_

-

52

40

56

USNM

483098

0.23

0.31

0.44

0.64

0.92

1.26

1.56

2.04

0.68

1.2

2.24

3.32

4.80

6.24

7.36

2.19

2.72

3.50

3.61

3.80

4.00

3.61

0.03

0.04

0.06

0.08

0.09

0.11

0.08

38

51

60

66

71

-

USNM

483099

0.22

0.28

0.40

0.58

0.82

1.08

1.40

-

0.64

0.98

1.56

2.86

4.04

5.60

-

2.28

2.45

2.68

3.48

3.74

4.00

-

0.03

0.04

0.04

0.06

0.08

0.10

-

27

30

:

24

-

Parafusulina rudinei, new species

PLATE 9-10: FIGURES 3-5

TYPES.—Holotype: USNM 483100; Paratypes: USNM

483101, 483102; from the Road Canyon Formation of the

Glass and Del Norte mountains, Texas.

MATERIAL STUDIED.—Samples from the upper part of the

Road Canyon Formation in the Glass and Del Norte mountains,

Texas: 1-64, 1-66; 7-59; 8-28.

DIAGNOSIS.—Stout, fusiform test; very large proloculus;

thin spirotheca; septal folds low and not very crowded;

secondary deposits commonly filling septal loops along the

outsides of the tunnel in the inner 2 to 3 volutions.

AGE AND DISTRIBUTION.—Parafusulina rothi Zone to

Parafusulina sellardsi Zone of the Guadalupian Series, Glass

and Del Norte mountains, Texas.

DESCRIPTION.—Large size; stubby, fusiform test; 6 to 7

volutions; attaining a length of 9 to 11 mm and a diameter of

3.2 to 3.4 mm; convex lateral slopes of volutions end in bluntly

pointed poles; chamber height and length increasing slowly and

gradually, resulting in average form ratio changing from about

2.0 in first volution to about 3.0 or 3.5 at maturity; proloculus

very large, averaging 0.60 mm in outside diameter and usually

subspherical in shape; spirotheca quite thin, consisting of

tectum and keriotheca; spirotheca thickness averaging 0.030,

0.035, 0.044, 0.052, 0.063, and 0.065 mm from first to sixth

volutions, respectively; septa intensely fluted; septal folds fine,

low, and not crowded; cuniculi well developed; chomata

lacking; secondary deposits irregularly distributed along

outsides of runnel in first 2 to 3 volutions; tunnel broad but not

well defined; tunnel angle averaging 34° and 67° in first and

sixth volutions, respectively. Measurement data of specimens

given in Table 9-27.

REMARKS.—This species somewhat resembles Parafusulina

boesei Dunbar and Skinner and Parafusulina biturbinata

Kling, but it differs in having a stouter test, a larger proloculus,

less regular folds, and thinner spirotheca.

ETYMOLOGY.—This species is named for Shannon F.

Rudine, a graduate student at Sul Ross State University, who

helped with the field work of this study.

Parafusulina sellardsi Dunbar and Skinner, 1937

PLATE 9-12: FIGURES 1, 6; PLATE 9-13: FIGURE 6

Parafusulina sellardsi Dunbar and Skinner, 1937:688-689, pi. 78: figs.

1-11.—Dunbar, 1944:44, pi. 11: fig. 2, pi. 14: figs. 1-4.—Ross, 1963b:26,

pi. 4: fig. 8, pi. 5: figs. 9-12, 16.

TYPES.—Hypotypes: USNM 483103-483105; from the

Word Formation of the Glass Mountains, Texas.

MATERIAL STUDIED.—Samples from the lower part of the

Word Formation in the Glass and Del Norte mountains, Texas:

3-21, 3-22, 3-23, 3-24; 8-39, 8-45.
216 SMYTHSOWXN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 9-27.—Measurements of Parafusulina rudinei, new species. TABLE 9-28.—Measurements of Parafusulina sellardsi Dunbar and Skinner.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wal Wall

l

thickness

(mm)

Tunnel

angle

v )

Volution

0

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

1

2

3

4

5

6

USNM

483100

0.22

0.38

0.52

0.68

0.89

1.16

1.44

1.70

0.74

1.08

1.44

1.84

2.40

3.28

4.20

1.95

2.08

2.12

2.07

2.07

2.28

2.47

0.03

0.03

0.03

0.05

0.05

0.06

_

28

36

-

-

USNM

483102

0.28

0.45

0.64

0.80

1.02

1.28

1.60

-

0.96

1.61

2.40

3.28

4.56

-

-

2.13

2.52

3.00

3.22

3.56

-

-

0.03

0.03

0.04

0.05

0.06

0.05

30

45

46

32

-

-

USNM

483101

0.30

0.40

0.52

0.68

0.88

1.12

1.40

1.68

0.98

1.45

1.92

2.52

3.36

4.68

5.52

2.45

2.79

2.82

2.86

3.00

3.34

3.29

0.03

0.04

0.05

0.06

0.07

0.08

34

41

50

42

62

67

AGE AND DISTRIBUTION.—Parafusulina sellardsi Zone of

the Guadalupian Series, Glass and Del Norte mountains, Texas;

Guadalupe Mountains, Texas (Dunbar and Skinner, 1937);

Chinati Mountains, Texas (Skinner, 1940).

REMARKS.—The specimens studied resemble the type

specimens of Parafusulina sellardsi in all respects. Some

specimens have a test that is larger than any reported specimens

of this species. Measurement data of specimens are given in

Table 9-28.

Parafusulina splendens Dunbar and Skinner, 1937

PLATE 9-6: FIGURES 1-5

Parafusulina splendens Dunbar and Skinner, 1937:682-684, pi. 75: figs. 1-11,

pi. 73: fig. 10.—Sheng, 1963:71, pi. 17: figs. 1-6, pi. 21: figs. 6-8.—Ross,

1963b:29, pi. 4: figs. 14, 16, 17, pi. 5: fig. 1.—Xiao et al., 1986:108, pi. 14:

figs. 1,4,6.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(O\

V )

Volution

0

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

USNM

483103

0.39

0.54

0.72

0.96

1.20

1.54

1.92

2.34

2.83

-

1.08

1.52

3.08

4.20

6.00

7.90

9.62

11.40

-

2.00

2.11

3.21

3.50

3.90

4.11

4.11

4.03

-

0.03

0.04

0.06

0.06

0.10

0.12

0.09

0.10

-

28

-

32

47

48

58

USNM

483104

0.25

0.38

0.48

0.60

0.78

1.00

1.32

1.68

2.04

2.52

0.78

1.52

2.36

3.08

4.00

5.64

7.16

8.87

11.04

2.05

3.17

3.93

3.95

4.00

4.27

4.26

4.35

4.38

0.04

0.04

0.05

0.06

0.07

0.08

0.09

0.10

0.11

24

27

38

41

52

-

USNM

483105

0.36

0.43

0.56

0.70

0.92

1.16

1.44

1.84

-

-

0.88

1.46

2.24

3.36

5.30

7.00

7.60

-

-

2.05

2.61

3.20

3.65

4.57

4.86

4.13

-

-

0.04

0.05

0.06

0.07

0.08

0.10

0.12

-

-

_

-

40

41

50

-

TYPES.—Hypotypes: USNM 483106-483110; from the

Road Canyon Formation of the Glass Mountains, Texas.

MATERIAL STUDIED.—Samples from the Road Canyon

Formation in the Glass and Del Norte mountains, Texas: 1-63;

2-R3, 2-R16, 2-77; 7-52; 8-13, 8-15.

AGE AND DISTRIBUTION.—Leonardian Series portion of the

Parafusulina boesei Zone to Parafusulina trumpyi Zone of the

Guadalupian Series, Glass and Del Norte mountains, Texas;

Guadalupe Mountains, Texas (Wilde, 1986a). Upper part of the

Qixia Formation and the lower part of the Maokou Formation,

China (Sheng, 1963; Yang, 1985; Xiao et al., 1986).
NUMBER 32 217

TABLE 9-29.—Measurements of Parafusulina splendens Dunbar and Skinner. TABLE 9-30.—Measurements of Parafusulina sullivanensis Ross.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

Volution

0

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

USNM

483106

0.24

0.26

0.40

0.58

0.80

1.08

1.34

1.68

2.00

0.54

0.88

1.26

1.84

2.60

3.72

5.14

6.86

2.08

2.20

2.17

2.30

2.41

2.78

3.06

3.43

0.02

0.03

0.04

0.06

0.07

0.08

0.08

0.06

28

32

32

27

31

34

USNM

483110

0.24

0.32

0.44

0.58

0.79

1.06

1.34

1.65

-

0.44

1.02

1.68

2.24

3.26

4.42

6.40

7.04

1.38

2.31

2.90

2.84

3.08

3.30

3.88

-

0.03

0.03

0.04

0.05

0.06

0.08

0.06

-

30

38

37

46

38

-

USNM

483108

0.14

0.36

0.52

0.72

0.96

1.24

1.60

-

-

0.64

1.04

1.84

2.76

4.20

5.42

-

-

1.78

2.00

2.56

2.88

3.39

3.39

-

-

0.03

0.03

0.04

0.06

0.07

0.08

-

-

_

36

36

45

-

-

USNM

483109

0.26

0.34

0.46

0.64

0.88

1.12

1.36

_

-

0.52

1.00

1.46

2.20

3.36

4.68

-

-

1.53

2.17

2.28

2.50

3.00

3.44

-

-

0.03

0.04

0.06

0.07

0.08

-

-

-

26

30

35

40

42

-

USNM

483107

0.23

0.36

0.51

0.74

1.04

1.32

1.68

2.12

-

0.90

1.44

2.02

3.04

4.60

6.20

7.48

-

2.50

2.82

2.73

2.92

3.48

3.69

3.53

-

0.03

0.03

0.04

0.06

0.07

0.08

0.07

-

25

37

34

33

42

-

REMARKS.—The specimens studied resemble the type

specimens of Parafusulina splendens Dunbar and Skinner in all

respects. Measurement data of specimens are given in Table

9-29.

This species is widely distributed in the Delaware basin and

is also widely distributed in South China.

Parafusulina sullivanensis Ross, 1963

PLATE 9-11: FIGURES 1-4

Parafusulina sullivanensis Ross, 1963b:23, pi. 4: figs. 9, 12, pi. 5: figs. 13-15,

17-22.

TYPES.—Hypotypes: USNM 483111-483114; from the

Road Canyon Formation and the Word Formation of the Del

Norte Mountains, Texas.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

O

Volution

0

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

8

1

2

3

4

5

USNM

483112

0.18

0.26

0.40

0.56

0.74

0.99

1.26

1.44

-

0.60

1.08

1.68

2.60

3.92

5.52

-

2.31

2.70

3.00

3.51

3.95

4.38

-

0.03

0.04

0.04

0.04

0.06

0.07

0.06

-

29

50

43

37

37

USNM

483111

0.21

0.32

0.44

0.61

0.78

1.01

-

-

-

0.80

1.32

2.24

3.28

4.52

-

-

2.50

3.00

3.67

4.21

4.48

-

-

0.03

0.04

0.04

0.06

0.06

_

-

-

_

30

-

-

-

USNM

483113

0.17

0.25

0.36

0.52

0.74

0.92

1.24

1.52

1.90

0.68

1.08

1.80

2.60

3.55

4.84

5.78

2.72

3.00

3.46

3.51

3.86

3.90

3.80

0.03

0.03

0.05

0.05

0.06

0.08

0.06

0.05

24

35

41

40

47

USNM

483114

0.20

0.25

0.36

0.49

0.68

0.92

1.20

1.56

-

0.60

1.04

1.72

2.64

3.92

5.56

-

2.40

2.89

3.51

3.88

4.26

4.63

-

0.03

0.04

0.04

0.06

0.06

0.07

0.08

-

24

35

44

41

-

MATERIAL STUDIED.—Samples from the Road Canyon

Formation and the lower part of the Word Formation in the

Glass and Del Norte mountains, Texas: 1-62; 2-R11, 2-R16;

7-53; 8-15, 8-24, 8-32, 8-38.

AGE AND DISTRIBUTION.—Parafusulina boesei Zone to

Parafusulina sellardsi Zone of the Guadalupian Series, Glass

and Del Norte mountains, Texas.

REMARKS.—The specimens studied resemble the type

specimens of Parafusulina sullivanensis in all respects.

Measurement data of specimens are given in Table 9-30.

Parafusulina trumpyi Thompson and Miller, 1949

PLATE 9-9: FIGURES 4-7

Parafusulina trumpyi Thompson and Miller, 1949:18-21, pi. 4: figs. 1-3, pi.

5: figs. 7, 8, 10.
218 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TYPES.—Hypotypes: USNM 483115-483118; from the

Road Canyon Formation of the Glass and Del Norte mountains,

Texas.

MATERIAL STUDIED.—Samples from the Road Canyon

Formation and the lower part of the Word Formation in the

Glass and Del Norte mountains, Texas: 1-66; 2-R19, 2-R20;

3-21; 7-53; 8-25.

AGE AND DISTRIBUTION.—Parafusulina trumpyi Zone to

Parafusulina sellardsi Zone of the Guadalupian Series, Glass

and Del Norte mountains, Texas; Colombia (Thompson and

Miller, 1949).

TABLE 9-31.—Measurements of Parafusulina trumpyi Thompson and Miller.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(°)

Volution

0

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

8

9

1

2

3

4

5

6

7

USNM

483116

0.16

0.26

0.38

0.54

0.76

0.96

1.28

1.60

1.97

2.26

0.64

0.98

1.42

2.04

2.92

4.20

5.96

7.64

9.40

2.46

2.58

2.63

2.68

3.04

3.28

3.03

3.88

4.16

0.02

0.03

0.04

0.04

0.05

0.06

0.08

0.09

0.07

28

37

31

40

50

59

-

USNM

483117

0.22

0.24

0.34

0.46

0.68

0.92

1.22

1.56

1.96

2.24

0.72

1.04

1.68

2.52

3.92

6.12

7.76

9.12

9.72

3.00

3.06

3.65

3.70

4.08

5.01

4.97

4.65

4.34

0.03

0.04

0.04

0.06

0.07

0.08

0.09

0.09

0.08

28

28

32

39

40

32

-

USNM

483115

0.16

0.23

0.35

0.50

0.72

0.96

1.24

1.50

1.80

-

0.50

0.78

1.20

1.96

2.92

4.24

5.68

6.92

-

2.17

2.51

2.40

2.72

3.04

3.42

3.79

3.84

-

0.02

0.03

0.03

0.05

0.05

0.06

0.06

0.07

-

32

36

42

40

42

49

62

USNM

483118

0.15

0.24

0.42

0.60

0.78

1.04

1.36

1.76

2.16

2.48

0.64

1.00

1.40

2.00

2.88

4.00

4.84

7.04

9.04

2.67

2.38

2.33

3.69

2.77

2.94

3.56

3.26

3.65

0.03

0.03

0.04

0.04

0.07

0.09

.0.10

0.08

0.07

27

31

30

34

40

45

52

REMARKS.—The specimens studied resemble the type

specimens of Parafusulina trumpyi Thompson and Miller in all

respects. Thompson and Miller (1949) assigned an age of

Leonardian or early Guadalupian for this species in Colombia.

This is the first time it has been reported in North America.

Measurement data of specimens are given in Table 9-31.

Parafusulina virga Thompson and Wheeler, 1946

PLATE 9-15: FIGURES 5, 6

Parafusulina virga Thompson and Wheeler, 1946:32, pi. 9: figs. 1-7 [in part,

not pi. 6: figs. 1-3].

TYPES.—Hypotypes: USNM 483119, 483120; from the

Word Formation of the Del Norte Mountains, Texas.

MATERIAL STUDIED.—Samples from the upper part of the

Road Canyon Formation and the lower part of the Word

Formation in the Glass and Del Norte mountains, Texas: 2-75,

2-77; 8-45.

AGE AND DISTRIBUTION.—Parafusulina trumpyi Zone to

Parafusulina sellardsi Zone of the Guadalupian Series, Glass

and Del Norte mountains, Texas; Klamath Mountains, California (Thompson and Wheeler, 1946).

REMARKS.—Parafusulina virga is characterized by a large,

elongate-fusiform to subcylindrical test with very low lateral

slopes and broadly rounded poles, thick spirotheca, broad

tunnel, and light discontinuous axial fillings through the length

of the test. The specimens studied differ from the type

specimens of Parafusulina virga (pi. 9: figs. 1-7) only in

having a slightly lower form ratio and thicker spirotheca in

outer volutions. When Parafusulina virga was named by

Thompson and Wheeler in 1946, no holotype was designated.

Among all specimens illustrated as syntypes, only pi. 6: fig. 1

and pi. 9: fig. 3 are axial sections; however, they are so different

in shape, form ratio, size of proloculus, and shape and

arrangement of septal folds that they probably belong to

different species. The specimen shown in pi. 6: fig. 1 has a

slender test, low and loosely spaced septal folds, and virtually

no axial fillings, thus resembling Parafusulina nosonensis

Thompson and Wheeler, 1946. The specimen illustrated in pi.

9: fig. 3 bears the characteristics of Parafusulina virga as

described by the authors, and thereby it is herein designated as

the lectotype of this species. This is the first time this species

has been reported in the Glass and Del Norte mountains area.

Measurement data of specimens are given in Table 9-32.

Parafusulina cf. P. wordensis Dunbar and Skinner, 1931

Parafusulina wordensis Dunbar and Skinner, 1931:261, pi. 2: figs. 1-4;

1937:690-691, pi. 72: figs. 1-8.

MATERIAL STUDIED.—Sample from the upper part of the

Word Formation in the Del Norte Mountains, Texas: 8-45.

AGE AND DISTRIBUTION.—Parafusulina sellardsi Zone of

the Guadalupian Series, Glass and Del Norte mountains, Texas.
NUMBER 32 219

TABLE 9-32.—

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

y )

-Measurements of Parafusulina virga Thompson and Wheeler.

Volution

0

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

1

2

3

4

5

6

USNM

483119

0.30

0.33

0.44

0.60

0.82

1.05

1.42

1.80

2.28

0.74

1.24

1.92

2.96

4.52

5.96

7.16

8.00

2.24

2.82

3.20

3.61

4.30

4.20

3.98

3.51

0.03

0.04

0.04

0.06

0.07

0.10

0.11

0.10

_

25

38

49

58

65

USNM

483120

0.26

0.36

0.46

0.64

0.85

1.14

1.51

1.84

-

0.80

1.40

2.08

3.12

5.40

7.40

9.00

-

2.22

3.04

3.25

3.67

4.74

4.90

4.89

-

0.03

0.03

0.04

0.06

0.08

0.09

0.11

-

21

36

46

48

55

65

REMARKS.—Parafusulina wordensis is characterized by an

exceptionally large, subcylindrical test, very numerous septa,

highly developed cuniculi and basal foramina, very thick

spirotheca, and a well-marked tunnel. Size and shape will

normally distinguish this species from any other species of the

genus Parafusulina. The major features of the specimens

studied resemble those of the type specimens of Parafusulina

wordensis Dunbar and Skinner, although no good axial

sections were observed. The sample material available is too

heavily dolomitized to produce reasonable illustrations of the

species.

Polydiexodina Dunbar and Skinner, 1931

TYPE SPECIES.—Polydiexodina capitanensis Dunbar and

Skinner, 1931.

Polydiexodina capitanensis Dunbar and Skinner, 1931

PLATE 9-17: FIGURES l, 2

Polydiexodina capitanensis Dunbar and Skinner, 1931:264, pi. 3: figs. 7-11;

1937:693-695, pi. 80: figs. 2, 4-11.

TYPES.—Hypotypes: USNM 483121, 483122; from the

Gilliam Limestone of the Glass Mountains, Texas.

MATERIAL STUDIED.—Samples from the upper part of the

Vidrio Formation, the Gilliam Limestone, the lower part of the

Capitan Limestone, and the lower part of the Altuda Formation

in the Glass and Del Norte mountains, Texas: 4-88, 4-210,

4-211, 4-212, 4-213; 5-79, 5-85; 9-6, 9-10F; 10-206, 10-208,

10-344. Most samples are heavily dolomitized.

AGE AND DISTRIBUTION.—Polydiexodina shumardi Zone of

the Guadalupian Series, Glass and Del Norte mountains, Texas;

Guadalupe Mountains, Texas (Dunbar and Skinner, 1937); Las

Delicias area of Coahuila, Mexico (Dunbar, 1944).

REMARKS.—The specimens studied resemble the type

specimens of Polydiexodina capitanensis Dunbar and Skinner

in all respects. Measurement data of specimens are given in

Table 9-33.

Polydiexodina oregonensis Bostwick and Nestell, 1965

PLATE 9-17: FIGURES 3,4

Polydiexodina oregonensis Bostwick and Nestell, 1965:612, pi. 74: figs. 1-10.

TYPES.—Hypotypes: USNM 483123, 483124; from the

Vidrio Formation and the Altuda Formation of the Del Norte

Mountains, Texas.

MATERIAL STUDIED.—Samples from the upper part of the

Vidrio Formation and the lower part of the Altuda Formation in

the Del Norte Mountains, Texas: 9-10, 9-1 OF; 10-206, 10-344.

AGE AND DISTRIBUTION.—Polydiexodina shumardi Zone of

the Guadalupian Series, Del Norte Mountains, Texas; Oregon

(Bostwick and Nestell, 1965).

REMARKS.—Polydiexodina oregonensis is characterized by

a very elongate and slender test, relatively low septal folds,

broad median tunnel, and rather weak supplementary tunnels.

Bostwick and Nestell (1965) considered this species to be an

early form of the lineage. On the basis of rather close

similarities of this species to Polydiexodina shumardi, its

moderately developed characters for the genus, and its

occurrence in the lowest level of all collections of this study

that yield Polydiexodina, the authors suggest that P. oregonensis may be the immediate ancestor of P. shumardi. The

specimens studied resemble the type specimens of P. oregonensis in all respects except they are not well oriented;
220 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 9-33.—Measurements of Polydiexodina capitanensis Dunbar and

Skinner.

TABLE 9-34.—Measurements of Polydiexodina oregonensis Bostwick and

Nestell.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Volution

0

1

2

3

4

5

6

7

8

9

10

11

12

13

1

2

3

4

5

6

7

8

9

10

11

12

13

1

2

3

4

5

6

7

8

9

10

11

12

13

1

2

3

4

5

6

7

8

9

10

11

12

USNM

483121

0.30

0.44

0.52

0.64

0.78

0.94

1.10

1.27

1.44

1.66

1.90

2.14

2.40

2.68

0.84

1.44

2.28

3.04

4.32

5.76

7.04

8.08

9.48

11.24

13.12

14.60

15.76

1.91

2.77

3.56

3.90

4.60

5.24

5.54

5.61

5.71

5.92

6.13

6.08

5.88

0.03

0.04

0.04

0.04

0.05

0.05

0.06

0.07

0.06

0.07

0.07

0.06

USNM

483122

0.26

0.32

0.40

0.52

0.64

0.79

0.96

1.20

1.42

1.60

1.84

-

-

-

0.72

1.58

2.52

3.80

5.60

6.80

8.60

10.40

11.48

12.60

-

-

-

2.25

3.95

4.85

5.94

7.08

7.08

7.20

7.32

7.18

6.85

-

-

-

0.03

0.03

0.04

0.04

0.05

0.06

0.06

0.07

0.07

-

-

-

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

i

m m )

Volution

0

1

2

3

4

5

6

1

2

3

4

5

6

7

1

2

3

4

5

6

1

2

3

4

5

6

7

USNM

483124

0.16

0.32

0.44

0.54

0.64

0.78

0.94

0.60

1.12

1.80

3.08

4.40

6.92

9.60

1.88

2.55

3.33

4.81

5.64

7.36

0.03

0.04

0.04

0.04

0.05

0.05

0.06

therefore, they appear somewhat shorter than their actual

lengths. Measurement data of one specimen are given in Table

9-34.

Polydiexodina shumardi Dunbar and Skinner, 1931

PLATE 9-16: FIGURES 1-4

Polydiexodina shumardi Dunbar and Skinner, 1931:267, pi. 3: figs. 1-6;

1937:695-697, pi. 81: figs. 3-10.

TYPES.—Hypotypes: USNM 483125-483128; from the

Altuda Formation of the Del Norte Mountains, Texas.

MATERIAL STUDIED.—Samples from the upper part of the

Vidrio Formation, the Gilliam Limestone, the lower part of the

Capitan Limestone, and the lower part of the Altuda Formation

in the Glass and Del Norte mountains, Texas: 4-88, 4-210,

4-212, 4-213; 5-79, 5-86; 9-5, 9-6, 9-10, 9-1 OF; 10-206,

10-207, 10-208, 10-344.

AGE AND DISTRIBUTION.—Polydiexodina shumardi Zone of

the Guadalupian Series, Glass and Del Norte mountains, Texas;

Guadalupe Mountains, Texas (Dunbar and Skinner, 1937).

REMARKS.—The specimens studied resemble the type

specimens of Polydiexodina shumardi Dunbar and Skinner in

all respects. Measurement data of specimens are given in Table

9-35.
NUMBER 32 221

TABLE 9-35.—Measurements of Polydiexodina shumardi Dunbar and Skinner. TABLE 9-36.—Measurements of Polydiexodina sp.

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Volution

0

1

2

3

4

5

6

7

8

9

10

11

1

2

3

4

5

6

7

8

9

10

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

9

10

USNM

483128

0.24

0.28

0.40

0.53

0.67

0.82

1.09

1.35

1.58

-

-

-

0.88

1.37

2.15

3.28

4.92

7.10

-

-

-

-

3.14

3.43

4.06

4.90

6.00

6.51

-

-

0.03

0.03

0.04

0.05

0.05

0.06

0.06

0.05

-

-

USNM

483127

0.25

0.31

0.43

0.59

0.66

0.81

0.97

1.16

1.35

1.64

-

-

1.04

1.81

2.78

4.00

5.04

6.02

7.58

9.45

-

-

3.35

4.21

4.71

6.06

6.22

6.21

6.53

7.00

0.03

0.03

0.04

0.04

0.05

0.05

0.05

0.06

0.05

-

USNM

483126

0.23

0.28

0.42

0.54

0.68

0.86

1.02

1.25

1.46

1.24

1.40

1.60

0.84

1.42

2.00

2.77

3.59

5.89

8.58

10.10

-

-

3.00

3.38

3.70

4.07

4.17

5.77

6.87

6.91

0.03

0.03

0.04

0.04

0.05

0.05

0.05

0.06

0.06

0.04

USNM

483125

0.17

0.24

0.32

0.40

0.52

0.68

0.80

0.92

1.08

-

-

-

0.72

1.24

1.64

2.18

2.96

4.45

5.78

6.83

8.90

10.84

3.00

3.88

4.10

4.19

4.35

5.56

6.28

6.42

0.03

0.03

0.03

0.03

0.04

0.04

0.05

0.06

-

-

Polydiexodina sp.

PLATE 9-17: FIGURES 5-7

MATERIAL STUDIED.—Samples from the upper part of the

Vidrio Formation and the lower part of the Altuda Formation in

the Del Norte Mountains, Texas: 9-10, 9-1 OF; 10-208;

specimens: USNM 483129-483131.

AGE AND DISTRIBUTION.—Polydiexodina shumardi Zone of

the Guadalupian Series, Del Norte Mountains, Texas.

DESCRIPTION.—Large size; elongate, fusiform test; 6V2

volutions; attaining a length of 14.2 mm and a diameter of 3.2

mm; axis of coiling commonly curved, so that measurements of

length probably inaccurate; lateral slopes of volutions taper to

broadly rounded poles; average form ratio increasing from 2.20

Radius

vector

(mm)

Half

length

(mm)

Form

ratio

Wall

thickness

(mm)

Tunnel

angle

(O\

\ )

Volution

0

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

7

1

2

3

4

5

6

1

2

3

4

USNM

483131

0.36

0.44

0.60

0.72

0.92

1.12

1.36

1.60

0.98

1.60

2.48

3.64

4.76

5.28

7.10

2.23

2.67

3.44

3.96

4.25

3.88

4.44

0.03

0.04

0.04

0.05

0.05

0.06

21

25

40

22

USNM

483129

0.20

0.44

0.56

0.68

0.80

0.94

1.12

1.26

0.92

1.56

2.56

-

-

-

-

2.09

2.79

3.76

-

-

0.03

0.03

0.04

0.04

0.05

0.05

20

32

-

USNM

483130

0.40

0.42

0.56

0.70

0.88

1.04

-

-

0.96

1.58

2.28

3.48

4.72

-

-

2.28

2.82

3.26

3.95

4.54

-

-

0.03

0.03

0.03

0.04

0.04

-

28

42

-

in first volution to 4.44 in sixth volution; proloculus very large,

0.40 to 0.80 mm in outside diameter, and subspherical or

irregular in shape; spirotheca very thin and consisting of tectum

and keriotheca; spirotheca thickness averaging 0.030, 0.033,

0.036, 0.043, 0.047, and 0.055 mm from first to sixth volutions,

respectively; septa intensely and regularly fluted; cuniculi

highly developed; chomata completely lacking; secondary

deposits fill extremities along axis; median tunnel relatively

well marked; tunnel angle averaging 23° and 40° in first and

third volutions, respectively; supplementary tunnels occurring

in outer volutions. Measurement data of specimens given in

Table 9-36.

REMARKS.—The specimens studied resemble the type

specimen of Polydiexodina praecursor Lloyd, 1963, in having

a small size for the genus, a short coiling axis, few volutions,

and a large and irregular proloculus, but they differ from that

species in bearing a well-marked median tunnel and better

developed supplementary tunnels. Evolutionarily, the present

specimens seem more primitive than Polydiexodina capitanensis and P. shumardi, which are characterized by the presence of
222 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

a well-defined median tunnel and supplementary tunnels, but

more advanced than Polydiexodina praecursor and P. afghanensis Thompson, which lack a well-defined median tunnel

and have sporadic supplementary tunnels. More specimens

with better orientation of thin sections are needed before a new

species name can be given.

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Plates 9-1-9-17
226 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-1

FIGURES 1-7.—Rauserella erratica Dunbar: 1, axial section, x25, hypotype, USNM 482975, Road Canyon

Formation, sample 8-28; 2, axial section, x25, hypotype, USNM 482976, Road Canyon Formation, sample

2-68; 3, tangential section, x25, hypotype, USNM 482977, Road Canyon Formation, sample 2-R6; 4, broken

axial section, x40, hypotype, USNM 482978, Altuda Formation, sample 6-BA13; 5, axial section, x40,

hypotype, USNM 482979, Road Canyon Formation, sample 2-R6; 6, tangential section near proloculus, x40,

hypotype, USNM 482980, Road Canyon Formation, sample 2-68; 7, tangential section near proloculus, x40,

hypotype, USNM 482981, Road Canyon Formation, sample 2-R6.

FIGURES 8-16.—Rauserella minima, new species: 8, oblique section, x25, paratype, USNM 482982, Road

Canyon Formation, sample 2-68; 9, axial section, x40, paratype, USNM 482983, Altuda Formation, sample

6-BA11; 10, axial section, x25, paratype, USNM 482984, Road Canyon Formation, sample 2-R5; 11, oblique

section, x25, paratype, USNM 482985, Road Canyon Formation, sample 2-R6; 12, axial section, x25,

paratype, USNM 482986, Road Canyon Formation, sample 2-68; 13, axial section, x40, holotype, USNM

482987, Road Canyon Formation, sample 2-R6; 14, partial axial section, x40, paratype, USNM 482988, Road

Canyon Formation, sample 6-BA3; 15, partial axial section showing inner volutions, x60, paratype, USNM

482989, Road Canyon Formation, sample 2-68; 16, axial section showing inner volutions, x60, paratype,

USNM 482990, Road Canyon Formation, sample 2-68.

FIGURE 17.—Staffella lacunosa Dunbar and Skinner: 17, axial section, x30, hypotype, USNM 483026, Word

Formation, sample 8-32.

FIGURE 18.—Schubertella cf. S. melonica Dunbar and Skinner: 18, tangential section near proloculus, x40,

hypotype, USNM 483050, Road Canyon Formation, sample 2-68.

FIGURE 19.—Schubertella sp.: 19, slightly oblique axial section near proloculus, x40, USNM 483051, Road

Canyon Formation, sample 2-R2.
NUMBER 32 227

14

18

10

19
228 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-2

FIGURES 1-16.—Reickelina lamarensis Skinner and Wilde: 1-5, axial sections, x40, hypotypes, USNM

483009-483013, Altuda Formation, sample 10-204; 6, tangential section near proloculus, x40, hypotype,

USNM 483014, Altuda Formation, sample 10-204; 7, 8, axial sections, x40, hypotypes, USNM 483015,

483016, Altuda Formation, sample 10-205; 9, axial section, x40, hypotype, USNM 483017, Altuda Formation,

sample 10-205; 10, axial section, x40, hypotype, USNM 483018, Altuda Formation, sample 6-BA10; 11, axial

section, x40, hypotype, USNM 483019, Altuda Formation, sample 6-BA11; 12, oblique section through

proloculus, x40, hypotype, USNM 483020, Altuda Formation, sample 10-205; 13, axial section, x40,

hypotype, USNM 483021, Altuda Formation, sample 6-BA11; 14, 15, parallel sections near proloculus, x40,

hypotypes, USNM 483022, 483023, Altuda Formation, sample 6-BA3; 16, sagittal section, x40, hypotype,

USNM 483024, Altuda Formation, sample 10-204.

FIGURES 17-20.—Reichelina bengensis, new species: 17, axial section, x40, paratype, USNM 482991, Altuda

Formation, sample 6-BA8; 18, axial section, x40, holotype, USNM 482992, Altuda Formation, sample 10-202;

19, axial section, x40, paratype, USNM 482993, Altuda Formation, sample 6-BA 10; 20, sagittal section, x40,

paratype, USNM 482994, Altuda Formation, sample 10-202.

FIGURES 21-27.—Reichelina birdensis, new species: 21, axial section, x40, paratype, USNM 482995, Altuda

Formation, sample 10-205; 22, axial section, x40, paratype, USNM 482996, Altuda Formation, sample

6-BA10; 23, slightly oblique parallel section near proloculus, x40, paratype, USNM 482997, Altuda

Formation, sample 10-202; 24, axial section, x40, holotype, USNM 482998, Altuda Formation, sample

10-205; 25, sagittal section, x40, paratype, USNM 482999, Altuda Formation, sample 6-BA10; 26, axial

section, x40, paratype, USNM 483000, Altuda Formation, sample 10-202; 27, sagittal section, x40, paratype,

USNM 483001, Altuda Formation, sample 6-BA5.
NUMBER 32 229
230 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-3

FIGURES 1-6, 11.—Lantschichites splendens (Skinner and Wilde): 1, axial section, x30, hypotype, USNM

483032, Altuda Formation, sample 6-110; 2, axial section, x30, hypotype, USNM 483033, Altuda Formation,

sample 6-S2; 3, slightly oblique axial section, x30, hypotype, USNM 483034, Altuda Formation, sample

6-BR4; 4, axial section, x30, hypotype, USNM 483035, Altuda Formation, sample 6-S2; 5, parallel section

near proloculus, x30, hypotype, USNM 483036, Altuda Formation, sample 10-204; 6, sagittal section, x30,

hypotype, USNM 483037, Altuda Formation, sample 10-204; 11, parallel section, x50, hypotype, USNM

483028, Altuda Formation, sample 6-BR4.

FIGURES 7-9.—Codonofusiellaparadoxica Dunbar and Skinner: 7, axial section, x30, hypotype, USNM 483029,

Altuda Formation, sample 6-110; 8, parallel section near proloculus, x40, hypotype, USNM 483030, Altuda

Formation, sample 10-202; 9, tangential section near proloculus, x30, hypotype, USNM 483031, Altuda

Formation, sample 10-208.

FIGURE 10.—Codonofusiella extensa Skinner and Wilde: 10, axial section, x30, hypotype, USNM 483027,

Altuda Formation, sample 6-120.

FIGURES 12-15.—Paradoxiella pratti Skinner and Wilde: 12, fragment of uncoiled final whorl, x60, hypotype,

USNM 483046, Altuda Formation, sample 10-204; 13, partial sagittal section, x40, hypotype, USNM 483047,

Altuda Formation, sample 10-204; 14, partial tangential section, x40, hypotype, USNM 483048, Altuda

Formation, sample 10-204; 15, tangential section, x40, hypotype, USNM 483049, Altuda Formation, sample

10-204.
NUMBER 32 231

15
232 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-4

FIGURES 1-8.—Lantschichites sp.: 1, axial section, x30, USNM 483038, Altuda Formation, sample 10-204; 2,

axial section, x30, USNM 483039, Altuda Formation, sample 6-BR4; 3, axial section, x30, USNM 483040,

Altuda Formation, sample 6-145; 4, tangential section near proloculus, x30, USNM 483041, Altuda

Formation, sample 6-145; 5, axial section, x30, USNM 483042, Altuda Formation, sample 6-BR4; 6, axial

section, x30, USNM 483043, Altuda Formation, sample 6-120; 7, parallel section, x30, USNM 483044, Altuda

Formation, sample 10-204; 8, parallel section, x30, USNM 483045, Altuda Formation, sample 10-204.

FIGURES 9-13.—Reichelina haneefi, new species: 9, sagittal section, x50, paratype, USNM 483004, Altuda

Formation, sample 6-BA3; 10, axial section, x50, holotype, USNM 483005, Altuda Formation, sample 6-BA2;

11, axial section, x50, paratype, USNM 483006, Altuda Formation, sample 6-BA10; 12, tangential section near

proloculus, x50, paratype, USNM 483007, Altuda Formation, sample 6-BA10; 13, axial section, x50, paratype,

USNM 483008, Altuda Formation, sample 6-BA11.

FIGURE 14.—Reichelina sp.: 14, axial section, x45, USNM 483025, Altuda Formation, sample 6-BA3.

FIGURES 15, 16.—Reichelina delawarensis (Dunbar and Skinner): 15, axial section of immature individual

showing inner volutions, x40, hypotype, USNM 483002, Altuda Formation, sample 10-206; 16, oblique

parallel section, x40, hypotype, USNM 483003, Altuda Formation, sample 9-6.
NUMBER 32

233

16
234 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-5

FIGURES 1, 2.—Parafusulina durhami Thompson and Miller: 1, 2, axial sections, xlO, hypotypes, USNM

483069, 483070, Cathedral Mountain Formation, sample 1-60.

FIGURES 3-5.—Parafusulina cf. P. biturbinata Kling: 3, oblique axial section, xlO, USNM 483061, Cathedral

Mountain Formation, sample 1-60; 4, axial section, xlO, USNM 483062, Cathedral Mountain Formation,

sample 1-60; 5, oblique axial section, xlO, USNM 483063, Cathedral Mountain Formation, sample 1-60.

FIGURES 6, 7.—Parafusulina cf. P. guatemalaensis Dunbar: 6, slightly oblique axial section, xlO, USNM

483079, Road Canyon Formation, sample 2-R6; 7, axial section, xlO, USNM 483080, Road Canyon

Formation, sample 2-R5.
NUMBE

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235
236 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-6

FIGURES 1-5.—Parafusulina splendens Dunbar and Skinner: 1-3, axial sections, xlO, hypotypes, USNM

483106-483108, Road Canyon Formation, sample 2-R3; 4, axial section, xlO, hypotype, USNM 483109,

Road Canyon Formation, sample 2-R16; 5, axial section partially obscured by dolomitization, xlO, hypotype,

USNM 483110, Road Canyon Formation, sample 2-R3.

FIGURE 6.—Parafusulina cf. P. bakeri Dunbar and Skinner: 6, axial section, xlO, USNM 483060, Road Canyon

Formation, sample 2-68.

FIGURES 7, 8.—Yangchienia iniqua Lee: 7, tangential section showing massive chomata, x40, hypotype, USNM

483052, Road Canyon Formation, sample 2-68; 8, axial section, x40, hypotype, USNM 483053, Road Canyon

Formation, sample 2-68.
NUMBE

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237
238 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-7

FIGURES 1-4.—Parafusulina rothi Dunbar and Skinner: 1, 2, axial sections, xlO, hypotypes, USNM 483096,

483097, Road Canyon Formation, sample 2-76; 3, slightly oblique axial section, xlO, hypotype, USNM

483098, Road Canyon Formation, sample 2-R11; 4, axial section of immature individual, xlO, hypotype,

USNM 483099, Road Canyon Formation, sample 2-76.

FIGURES 5-7.—Parafusulina ironensis Ross: 5, partial axial section of immature individual, xlO, hypotype,

USNM 483081, Road Canyon Formation, sample 7-55; 6, axial section, xlO, hypotype, USNM 483082, Road

Canyon Formation, sample 1-62; 7, slightly oblique axial section, xlO, hypotype, USNM 483083, Road

Canyon Formation, sample 1-63.
NUMBER 32

239
240 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-8

FIGURES 1-3.—Parafusulina glassensis, new species: 1, axial section, xlO, holotype, USNM 483076, Road

Canyon Formation, sample 2-72; 2, axial section, xlO, paratype, USNM 483077, Road Canyon Formation,

sample 2-R10; 3, partial axial section, xlO, paratype, USNM 483078, Road Canyon Formation, sample 2-R8.

FIGURES 4, 5.—Parafusulina marathonensis, new species: 4, slightly oblique axial section, x 10, paratype, USNM

483090, Road Canyon Formation, sample 8-26; 5, axial section, xlO, holotype, USNM 483091, Word

Formation, sample 3-23.
NUMBER 32 241
242 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-9

FIGURES 1-3.—Reichelina delawarensis (Dunbar and Skinner): 1, tangential section, x40, hypotype, USNM

483132, Altuda Formation, sample 9-6; 2, partial, slightly oblique axial section, x40, hypotype, USNM

483133, Altuda Formation, sample 9-6; 3, slightly oblique axial section, x40, hypotype, USNM 483134,

Altuda Formation, sample 9-6.

FIGURES 4-7.—Parafusulina trumpyi Thompson and Miller: 4, axial section of immature individual, xlO,

hypotype, USNM 483115, Road Canyon Formation, sample 7-53; 5, partial axial section, xlO, hypotype,

USNM 483116, Road Canyon Formation, sample 2-R19; 6, slightly oblique axial section, xlO, hypotype,

USNM 483117, Road Canyon Formation, sample 2-R20; 7, axial section, xlO, hypotype, USNM 483118,

Road Canyon Formation, sample 1 -66.
NUMBER 32 243
244 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-10

FIGURES 1, 2.—Parafusulina fountaini Dunbar and Skinner: 1, axial section, xlO, hypotype, USNM 483074,

Road Canyon Formation, sample 2-70; 2, axial section, xlO, hypotype, USNM 483075, Road Canyon

Formation, sample 2-R3.

FIGURES 3-5.—Parafusulina rudinei, new species: 3, axial section, x 10, holotype, USNM 483100, Road Canyon

Formation, sample 7-59; 4, axial section, xlO, paratype, USNM 483101, Road Canyon Formation, sample

1-66; 5, slightly oblique axial section, xlO, paratype, USNM 483102, Road Canyon Formation, sample 8-28.

FIGURES 6, 7.—Parafusulina alpinensis, new species: 6, axial section, xlO, holotype, USNM 483054, Road

Canyon Formation, sample 8-24; 7, axial section, xlO, paratype, USNM 483055, Road Canyon Formation,

sample 8-24.

FIGURE 8.—Parafusulina marathonensis, new species: 8, axial section, xlO, paratype, USNM 483092, Road

Canyon Formation, sample 8-26.
NUMBER 32

245

8
246 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-11

FIGURES 1-4.—Parafusulina sullivanensis Ross: 1, slightly oblique axial section, xlO, hypotype, USNM

483111, Road Canyon Formation, sample 7-53; 2, axial section, xlO, hypotype, USNM 483112, Word

Formation, sample 8-38; 3, 4, axial sections of individuals with partial dolomitization of interior, xlO,

hypotypes, USNM 483113, 483114, Road Canyon Formation, sample 8-15.

FIGURES 5-7.—Parafusulina faliskiei, new species: 5, axial section, xlO, paratype, USNM 483071, Road

Canyon Formation, sample 2-68; 6, axial section, xlO, holotype, USNM 483072, Road Canyon Formation,

sample 2-73; 7, slightly oblique axial section, xlO, paratype, USNM 483073, Road Canyon Formation, sample

2-R14.
NUMBE

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247
248 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-12

FIGURES 1, 6.—Parafusulina sellardsi Dunbar and Skinner: 1, axial section, xlO, hypotype, USNM 483103,

Word Formation, sample 3-21; 6, slightly oblique axial section, xlO, hypotype, USNM 483104, Word

Formation, sample 3-21.

FIGURES 2-5.—Parafusulina lineata Dunbar and Skinner: 2, tangential section near proloculus, xlO, hypotype,

USNM 483084, Road Canyon Formation, sample 2-R16; 3, slightly oblique axial section, xlO, hypotype,

USNM 483085, Road Canyon Formation, sample 2-R12; 4, axial section, xlO, hypotype, USNM 483086,

Word Formation, sample 8-38; 5, axial section, xlO, hypotype, USNM 483087, Road Canyon Formation,

sample 2-R16.
NUMBE

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249
250 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-13

FIGURES 1-5.—Pamfusulina boesei Dunbar and Skinner: 1, axial section, xlO, hypotype, USNM 483064, Road

Canyon Formation, sample 2-R1; 2, axial section, xlO, hypotype, USNM 483065, Road Canyon Formation,

sample 2-68; 3, slightly oblique axial section, x 10, hypotype, USNM 483066, Road Canyon Formation, sample

8-13; 4, slightly oblique axial section, xlO, hypotype, USNM 483067, Road Canyon Formation, sample 7-58;

5, slightly oblique axial section, xlO, hypotype, USNM 483068, Road Canyon Formation, sample 8-24.

FIGURE 6.—Parafusulina sellardsi Dunbar and Skinner: 6, axial section of individual with partial dolomitization

of interior, xlO, hypotype, USNM 483105, Word Formation, sample 3-22.

FIGURES 7, 8.—Parafusulina maleyi Dunbar and Skinner: 7, axial section, xlO, hypotype, USNM 483088, Word

Formation, sample 3-24; 8, axial section, xlO, hypotype, USNM 483089, Word Formation, sample 8-39.
NUMBER 32

251

8
252 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-14

FIGURES 1-3.—Parafusulina rohri, new species: 1, axial section, xlO, holotype, USNM 483093, Word

Formation, sample 3-24; 2, axial section, xlO, paratype, USNM 483094, Word Formation, sample 3-23; 3,

axial section, xlO, paratype, USNM 483095, Word Formation, sample 3-24.
NUMBER 32 253

\ • •
254 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-15

FIGURES 1-4.—Parafusulina antimonioensis Dunbar: 1, 2, axial sections, xlO, hypotypes, USNM 483056,

483057, Word Formation, sample 9-8; 3, axial section, xlO, hypotype, USNM 483058, Word Formation,

sample 9-7; 4, partial axial section, xlO, hypotype, USNM 483059, Word Formation, sample 9-8.

FIGURES 5, 6.—Parafusulina virga Thompson and Wheeler: 5, slightly oblique axial section, xlO, hypotype,

USNM 483119, Word Formation, sample 8-45; 6, axial section, xlO, hypotype, USNM 483120, Word

Formation, sample 8-45.
NUMBER 32 255
256 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-16

FIGURES 1-4.—Polydiexodina shumardi Dunbar and Skinner: 1, 2, axial sections, xlO, hypotypes, USNM

483125, 483126, Altuda Formation, sample 9-6; 3, oblique axial section, xlO, hypotype, USNM 483127,

Altuda Formation, sample 9-6; 4, axial section, xlO, hypotype, USNM 483128, Altuda Formation, sample

10-206.
NUMBER 32 257

.*>*• • $mL
258 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 9-17

FIGURES 1, 2.—Polydiexodina capitanensis Dunbar and Skinner: 1, axial section of individual with heavily

dolomitized outer volutions, x8, hypotype, USNM 483121, Gilliam Limestone, sample 4-212; 2, axial section,

x8, hypotype, USNM 483122, Gilliam Limestone, sample 4-213.

FIGURES 3, 4.—Polydiexodina oregonensis Bostwick and Nestell: 3, tangential section showing cuniculi and

supplemental tunnels, x8, hypotype, USNM 483123, Altuda Formation, sample 10-206; 4, slightly oblique

tangential section near proloculus, xlO, hypotype, USNM 483124, Vidrio Formation, sample 9-10.

FIGURES 5-7.—Polydiexodina sp.: 5, axial section of immature individual, xlO, USNM 483129, Vidrio

Formation, sample 9-1 OF; 6, oblique axial section, xlO, USNM 483130, Vidrio Formation, sample 9-10; 7,

partial axial section, xlO, USNM 483131, Vidrio Formation, sample 9-1 OF.
NUMBER 32 259
10. Carbonate Deposition of the Permian

Word Formation, Glass Mountains, West Texas

James D. Rathjen, Bruce R. Wardlaw, David M. Rohr,

and Richard E. Grant

ABSTRACT

The carbonates of the Word Formation are restricted to the Word,

undifferentiated, China Tank, Willis Ranch, and Appel Ranch

members, and to the thin lens between the Willis Ranch and Appel

Ranch members. The sediments of the Word can be divided into five

mappable lithofacies in the central Glass Mountains: mudstone,

peloidal packstone, skeletal wackestone/packstone, fusulinid-crinoid

grainstone/bioturbated wackestone, and recrystallized limestone/

dolostone. The mudstone lithofacies grades into sandstone and siltsone

to the west.

The Word Formation represents deposition in a shallow shoal to

backbay environment. Dolostones, recrystallized grainstones and

wackestones, and fusulinid-crinoid packstones/grainstones mixed

with bioturbated wackestones represent transitional deposition between the shoal and backbay. Peloidal packstones, mudstones,

sandstones, and siltstones represent backbay deposition.

Introduction

The Word Formation was named by Udden, Baker, and Bose

(1916) and was expanded by Udden (1917). King (1931)

redescribed the formation, establishing a western shale facies,

an eastern carbonate facies, and a zone of transition (transitional facies) between Hess Canyon and Gilliland Canyon.

James D. Rathjen, 214 W. Texas, Midland, Texas 79701. Bruce R.

Wardlaw, U.S. Geological Survey, 926A National Center, Reston,

Virginia 20192. David M. Rohr, Geology Department, Sul Ross State

University, Alpine, Texas 79832. Richard E. Grant {deceased),

Department of Paleobiology, National Museum of Natural History,

Smithsonian Institution, Washington, D.C. 20560-0121.

King (1931) designated numbered limestone members in the

transitional facies. Cooper and Grant (1964) named the

numbered members of King (1931). Cooper and Grant (1966)

removed the Road Canyon Member from the Word Formation

and raised the Road Canyon to formation rank. The brachiopod

faunas of the Road Canyon Formation supported this revision

as they indicated strong Leonardian affinities to Cooper and

Grant (1966). Grant and Wardlaw (1984), Wardlaw and Grant

(1990), and Wardlaw, Ross, and Grant (this volume) strongly

suggest that the Road Canyon Formation belongs in the

Wordian than in the Leonardian. The proper placement of the

Road Canyon is dealt with by Lambert, Lehrman, and Harris

(this volume). The Vidrio Limestone Member at the top of the

Word Formation is unconformably bounded and highly

recrystallized and dolomitized and is not dealt with here.

The regional stratigraphy of the Word Formation in the Glass

Mountains and the Del Norte Mountains is described in Rohr et

al. (this volume). In that paper, Rohr et al. raised the Vidrio to

formation rank, thereby removing it from the Word Formation.

The members of the Word (as revised) consist of the China

Tank, the Willis Ranch, the Appel Ranch, and the lens between

the Willis Ranch and Appel Ranch members. The eastern

carbonate facies is generally referred to as the Word,

undifferentiated (King, 1931). The transitional facies of the

Word Formation crops out along Hess Canyon in the central

part of the Glass Mountains (Figure 10-1). The limestone

members of the Word in the transitional facies and their

gradation into the eastern carbonate facies is described in detail

in this study.

General Stratigraphy

The generally perceived stratigraphic relationships of the

Word Formation (Figure 10-2) do show the general facies of

King (1931). The Word changes from sandstone and "shale"

(western) to "shale" and carbonate (transitional) to carbonate

261
262 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

WORD

FORMATION (385

FIGURE 10-1.—Location of the Word Formation in the Glass Mountains, showing map area of Figure 10-3.

(eastern). The Word in the study area (Figure 10-1) is largely

made up of mudstones ("shales") and carbonates. Figure 10-3

shows the distribution of Word "shales," Word undifferentiated, and the Word members along with the location of the

sections used for facies analysis in the study area. The

stratigraphic relationships of mudstones and carbonates of the

Word are shown in Figure 10-4. This figure is plotted as a true

distance diagram, with the distance measured from the

easternmost section, 12PW. Conodont biostratigraphy (Wardlaw, this volume) provides a sharp datum at the top of the

Willis Ranch Member. Here, faunas dominated by Mesogondolella nankingensis below are replaced by faunas dominated by

Mesogondolella aserrata above.

WORD "SHALES" (MUDSTONES)

The "shales" (King, 1931) of the Word Formation are rarely

fissile and are better described as mudstones and some
NUMBER 32 263

WESTERN FACIES TRANSITIONAL i EASTERN FACIES

SW

DUGOUT

MOUNTAIN

LENOX

HILLS

LEONARD

MOUNTAIN

LENOX HILLS FORMATION

FROM COOPER AND GRANT (1972)

FIGURE 10-2.—General relationship of the Word Formation to the regional Permian stratigraphy defining eastern,

transitional, and western facies of the formation. (From Cooper and Grant, 1972.)

clay stones. The mudstones of the Word Formation are

characteristically yellow and form thin platy beds averaging 10

cm (4 in.) in thickness and occur in scattered blocky and platy

outcrops (Figure 10-5). The rocks weather to red or pink hues

that form unusual geometric patterns. The mudstones are

largely siliceous and contain silicified calcispheres, radiolarians?, and sponge spicules in a dull, earthy, clay matrix. The

rocks display scattered traces and burrows and sparse brachiopods and fusulinids. Thin limestone stringers and laterally

discontinuous limestone channels are common to the mudstones within the transitional facies.

CHINA TANK MEMBER

The China Tank Member has the most limited extent of the

Word Formation members. The China Tank is a thin- to

medium-bedded, gray skeletal packstone and wackestone with

thin, interbedded yellow mudstone. Packstone generally forms

thicker, more prominent ledges and is more common in the

lower and middle parts of the unit than wackestone. In addition,

packstone is more common to the unit in the northeast and

becomes less abundant to the southwest. Limestones contain

abundant silicified brachiopods, crinoids, fusulinids, and

bryozoans. Most fossils are broken, abraded, and poorly sorted.

Complete fossils are rare but more common in the wackestones.

In many places, fossils are concentrated into thin fossiliferous

chert layers with no appreciable lime-mud matrix. In general,

limestones are roughly parallel-bedded, laterally continuous,

poorly sorted, and lack any large-scale sedimentary structures

or depositional relief suggesting level bottom conditions at the

time of deposition. Thicknesses remain relatively constant and

contacts between strata are distinct.

WILLIS RANCH MEMBER

Over most of the study area the Willis Ranch Member is

clearly divisible into two carbonate units that are divided by a

persistent mudstone (Figure 10-4). The limestones are generally medium-bedded, and the upper part of the units are

massive in places. Southwestern sections of the Willis Ranch

are dominated by peloidal packstone, which is easily recognized by its concentrations of silicified peloids. Central and

eastern sections contain many more fossils and typically

consist of alternating packstone and wackestone with dolostone

comprising the uppermost parts of these sections. The Willis

Ranch is sandy in all parts, but the sand increases in abundance

to the southwest. The sand grains are primarily subangular to

angular and relatively fine grained. Sections remain relatively

uniform in thickness, averaging 38 m (125 ft). Like the China

Tank Member, large-scale sedimentary structures and depositional relief are minimal, and contacts between beds are sharp.
264 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

1 - 12PW

2 - SEC.26

3-WORD I

4-9AR

5-WRII

6-7CT

7-8AR

8-2TL

9 - 706e

10-RCX

11 -CTI

12-5CT

14-4AR

15-10AR

16 - AR II

17-WRI

18-1WR

19 -WR III

Word Foramtion

(Undifferentiated)

Appel Ranch Member

China Tank Member

Road Canyon Formation Willis Ranch Member

30°20'

FIGURE 10-3.—Geology of the Word Formation in the Hess Canyon and the Glass Mountains, with the locations

of the measured sections. Word Formation (undifferentiated) is largely represented by mudstone in the west and

dolostone in the northeast.

APPEL RANCH MEMBER

The Appel Ranch Member is also clearly divisible into two

carbonate units, which are divided by a persistent mudstone/

claystone unit. The Appel Ranch is composed of limestone and

mudstone that is thinly bedded to the southwest but increases in

thickness and fossil abundance toward the central and eastern

sections. Fusulinid/crinoid packstones and grainstones and

bioturbated wackestones and lime mudstones occur in the

Appel Ranch, in addition to the skeletal packstones and

wackestones typical of the lower part of the Word. In the

southwestern sections, the Appel Ranch is composed of

peloidal packstones (containing fusulinids and crinoids),

skeletal wackestones, and thin interbedded mudstones and

claystones. These mudstones and claystones are darker than the

typical mudstones found in the lower part of the Word. The

darker color of the mudstones is probably due to a much higher

clay content. Current-orientated fusulinids and brachiopod

spines are not uncommon in the mudstones.

Section 9AR (the easternmost section) consists of mediumbedded, highly pitted, gray dolostone at its base that contains

chert nodules and very few silicified fossils. The dolostone is

vuggy and silty in parts with some biomoldic (leached fossil)

porosity. Above the dolostones are thinner, medium beds of

skeletal packstone with current-aligned fusulinids in many

places. Fusulinid grainstone near the top of the section contains

small black and brown carbonate pebbles, which are possibly

authogenic sediments (Flugel, 1982). The top of the section

terminates where the strata become massive and largely

unfossiliferous, which is presumably at the base of the Vidrio

Foramtion.

THIN LENS BETWEEN THE WILLIS RANCH AND

APPEL RANCH MEMBERS

This lens has a very limited lateral extent along the southern

extension of Hess Canyon to the junction of the west-trending

and north-trending Hess canyons. The lens is clean (lacking a
NUMBER 32 265

19 18

I

17

I

10 1114

16 15 12V/13 9 86 7 5

_ | I I III I I II I I

800-

700-

-200

600-

500-

400-

300-

200-

100-

0 •

FT

•100

VIDRIO FORMATION

APPEL RANCH MEMBER

WILLIS RANCH MEMBER

FIGURE 10-4.—Stratigraphy of the Word Formation in the study area of Hess Canyon and the Glass Mountains.

Each section is compiled into the cross section by true distance from the easternmost section, 12PW. (Numbers

across the top refer back to sections in Figure 10-3.)

significant terrigenous clastic component), and allochems

consist primarily of peloids and skeletal debris. Fusulinids,

brachiopods, and crinoids are common near the top at USNM

Loc. 706b. Small ammonoids and rare trilobites also are

present. Matrix at this locality is primarily lime-mud with a

trace of sparry calcite in places. Chert nodules are common and

are similar to the lower part of the Word, consisting of

concentrated masses of fusulinids and brachiopods or other

silicified fossils in small layers or pockets.

WORD FORMATION, UNDIFFERENTIATED

In the northeast of the study area, the three carbonate

members were not differentiated by King (1931) or Cooper and

Grant (1964, 1966) as the sections consist of medium-tomassive, gray crystalline dolostone. Differentiation between

different members is difficult because of the similarity of the

strata. Only a few fossils are recognizable, primarily crinoids

and fusulinids. The outcrops generally are highly pitted and

vuggy on fresh surfaces. The eastern facies are laterally

continuous and lack major sedimentary structures. This forms

a regular monotonous sequence of dolostones. The members

are only differentiable when the major siltstone/mudstone

breaks are present.

Carbonate Microfacies of the Word Formation

Five major microfacies are recognized from thin sections,
266

SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 10-5.—Word Formation siltstones and mudstones. A, typical outcrop of yellow, platy-bedded mudstone

(just below base of section 7CT; Jacob's staff is 1.5 m long). B, photomicrograph of mudstone to siltstone. Note

calcispheres and clotted distribution of clays (section 7CT, 12.2 m; long axis of photomicrograph represents 0.5

mm).

polished slabs, etched samples, and field observations. These

are peloidal packstone, skeletal wackestone/packstone, bioturbated wackestone/lime mudstone, fusulinid-crinoid packstone/grainstone, and recrystallized limestone/dolostone. One

major microfacies, skeletal wackestone/packstone, is divided

into skeletal and whole fossil subfacies.

PELOIDAL PACKSTONE

This microfacies is common in the southwest portion of the

study area and is very common to the Willis Ranch Member

(Figures 10-6, 10-7). Texturally, this microfacies contains

peloids and a few fossil fragments in a lime-mud matrix. Sparry

calcite is rare and primarily occurs in intrabiotic cavities and

along secondary fractures. Detrital quartz sand is mixed

throughout the matrix and in places is a major rock constituent.

Dolomite is rare in this microfacies. Matrix material appears

homogeneous and consists of a mixture of micrite and

microspar. Crystals are uniform in size and shape, generally

ranging from less than 4 microns (micrite) and up to 20 microns

(microspar). The micrite probably represents lithification of the

original lime-mud (orthomicrites of Wolf, 1965), whereas the

microspars are commonly recrystallized micrites (Folk, 1965).

A tight, interlocking network is formed by the crystal

boundaries, with the boundaries appearing darker than the

crystals. This probably results from a high percentage of clays

or other inorganic substances concentrated around the perimeters of individual crystals (Folk, 1959). It is very difficult to

distinguish between the micrite and microspar because of the

small crystal sizes. Micrite, however, generally appears much

darker than the microspar (due to the individual crystals

stacked on each other), whereas microspar forms lighter,

equant subhedral calcite crystals. Skeletal grains are rare in this

microfacies, although isolated seams or pockets of richly

fossiliferous beds do occur.

Typically, fossils occur scattered throughout the finecrystalline matrix. Skeletal grains consist of disarticulated,

fragmented, and abraded remains of brachiopods and brachiopod spines, bryozoans, fusulinids, and crinoids. Fossil grains

are angular and poorly sorted, ranging in size from a few

millimeters to several centimeters. Fossil morphologies suggest

contrasting depositional environments with delicate branching

bryozoans, thick shelled brachiopods, and fusulinids commonly found in the same rock. Because of these differing

morphologies and their fragmentary nature, many of the fossils
NUMBER 32 267

FIGURE 10-6.—Photomicrographs of peloidal packstone microfacies from the Willis Ranch Member (bottom of

each photomicrograph represents 0.5 mm). A, fecal pellets appear as well-rounded, dark, structureless grains.

Elongate grains are micritized skeletal debris (section 1WR, 11.4 m). B, algal-coated quartz grains (light colored).

Note micritized and algal-coated skeletal grains, matrix consists of fine crystalline microspar (section 1 WR, 36.3

m). C, characteristic sandy nature of the Willis Ranch Member. Many sand grains are algal encrusted. Fecal pellets

and micritized skeletal grains are scattered throughout matrix (section 1WR, 53.4 m). D, various skeletal grains

are shown. The grain at the center is partially micritized, other grains have micrite envelopes. The matrix is fine

crystalline microspar, and some spar is in intrabiotic cavities (section 1 WR, 53.4 m).

probably represent faunal mixing of nearby skeletal microfacies.

Brachiopods, bryozoans, and crinoids are commonly silicified, but fusulinids are very rarely silicified. Silicification of

original fossil parts to length-slow chalcedony is the most

common type of replacement. Many different stages of

silicification can be seen in thin sections and hand samples;

these stages range from only partial replacement along the

exteriors of fossils (thin coatings) to complete silicification of

the entire skeleton. Generally, thinly coated fossils have much

more detail preserved, whereas totally silicified fossils are

coarsely replaced and noticeably lacking in detail. In some

places the fossils are so coarsely silicified that identification of

the fossil type is virtually impossible. Skeletal debris commonly have micrite envelopes or algal encrustations. Peloids

are the common type of framework grain in this microfacies

and are of two types: fecal pellets and algal peloids. Fecal

pellets are spherical, sand-sized particles that average between

0.1-0.2 mm in diameter (Figure 10-7). Most commonly, these

particles are well-rounded and appear dark with no internal

structure discernible. The dark color of the pellets commonly

results from a combination of high organic content and the

extremely fine-crystalline nature of the pellets. Peloids in this

group are characterized by good "sorting." No sedimentary

features, such as bedding or laminations, can be recognized,

probably due to thorough homogenization of the sediments by
268 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 10-7.—Photomicrographs of pellets from the Willis Ranch Member. A, intraclast of pelleted sediment.

Note lighter color of matrix in the intraclast, truncated pellets along the margin of the grain, and elongate shape.

Pellets are probably fecal because of their uniform size and "good sorting" (section 1WR, 2.9 m; bottom of

photomicrograph represents 0.5 mm). B, close-up of pellet from matrix. The grain has no internal structure, is

composed of micrite and terrigenous mud, and is in a fine crystalline matrix (section 1WR, 25.9 m; bottom of

photomicrograph represents 0.05 mm).

the organisms responsible for the pellets. Common producers

of fecal pellets are brachiopods, amphineura, gastropods,

worms, ostracodes, echinoderms, and tunicates (Fliigel,

1982:133). Fecal pellets are also produced by other deposit

feeders and herbivorous animals as well as plankton feeders,

such as copopods and fishes.

In Recent carbonate sediments, fecal pellets are probably the

most common type of allochem. They dominate subtidal and
NUMBER 32 269

shallow intertidal environments and occur preferentially in low

energy zones. In these shallow water, low energy environments, rapid cementation is possible because these areas are

commonly supersaturated with calcium carbonate (Bathurst,

1971). This seems to be the general case in the peloidal

microfacies, with early, rapid cementation followed by very

little subsequent diagenetic alteration. With rapid cementation,

pore throats become sealed-off and do not permit later fluids to

pass through the sediments, which might diagenetically alter

the sediments.

The second group of peloids is formed by the interaction of

algae with various particles. Types included in this group are

algal-coated grains and micritized grains. Almost all of the

bioclasts and other allochems are coated by some type of

micrite envelope. These coatings range from thin superficial

films around the margins of the allochems to thick crusts of

micrite that obscure the original particle. Coated grains with

skeletal debris as nuclei probably form as a result of boring

micro-organisms, most likely endolithic algae. Nuclei for these

micrite-coated grains most commonly are brachiopod, bryozoan, fusulinid, and coral fragments. Micritized echinoderm

fragments are rare but do occur sporadically. Micritized

coatings appear much darker than the surrounding matrix,

probably as a result of the "stacking effect" of the micrite plus

some organic and terrigenous material mixed in with the

sediments.

These micrite envelopes form by micro-organisms that

attack and bore into the surfaces of the skeletal debris creating

tiny holes, which are subsequently filled with micrite (bacterially produced?) after the death of the organism. Other sources

of micrite possibly include the very fine carbonate needles

produced after the death and decomposition of certain types of

algae that fill in the small voids. If the process of boring and

infilling (micritization) continues over a prolonged period of

time, micrite replacement of the entire grain is possible.

Micritization can be seen in various stages of maturity in this

microfacies. Many particles are enclosed by thin micrite

envelopes, whereas other grains have been thoroughly micritized and are classified as peloids because the grains are totally

unrecognizable.

Quartz sand grains are common in this microfacies. Sand

primarily occurs disseminated throughout the matrix, but small

sand stringers and thin layers are common in the field and in

hand samples. Sand grains are typically subangular to

subrounded, well sorted, and fine (0.1-0.2 mm) in size. Like

many of the carbonate allochems, sand grains form the "nuclei"

of many coated grains. Many dark algal-coated grains

commonly have a quartz "nucleus" still visible in the center.

Intraclasts occur in this microfacies, although they are rare.

Intraclasts are very similar to the surrounding matrix, consisting of pelleted or peloidal sediments. Identification of these

lithoclasts is based on truncated peloids along the margins and

the flat, well-rounded nature of the clasts. These lithoclasts

probably represent small rip-ups or the products of biologic

activity. The limited number of the intraclasts indicates that

these formed in sporadic, rare events.

SKELETAL WACKESTONE/PACKSTONE

Skeletal wackestone/packstone represents the most common

microfacies type in the transition facies of the Word Formation

(Figure 10-8). This microfacies is truly "transitional" in a strict

sense because it represents the transition between normal open

marine conditions and a semirestricted lagoonal environment.

This microfacies represents most of the China Tank Member,

the central part of the Willis Ranch Member, and some parts of

the Appel Ranch Member. The microfacies is divided into two

subfacies, skeletal and whole fossil.

SKELETAL SUBFACIES.—These rocks consist of very coarse

grains of broken or whole brachiopods, crinoids, fusulinids,

and bryozoans. This subfacies also contains abundant peloids

and minor amounts of silt-sized quartz grains. Most samples

are at least partially washed and moderate-to-well sorted but

contain varying amounts of lime-mud and terrigenous mud

mixed throughout the matrix. Some coarse sparry calcitecemented sediments are common in places, and dolomite is a

locally abundant accessory in many intervals.

Matrix types are highly variable, even in a single thin section

or polished slab. Portions may contain areas that are largely

spar-cemented, whereas other adjacent areas are rich in lime or

terrigenous mud, probably resulting from incomplete winnowing of the sediments. Micrite and microspar are common in the

wackestones, whereas sparry calcite occurs only in the

well-sorted, fossil-rich, packstones. Sparry calcite also occurs

as void-filling cement in many intrabiotic cavities, sheltered

voids, and along secondary fractures.

Peloids (fecal and algal) are a common framework grain.

Peloids occur in both wackestones and packstones, though they

are more common in the wackestones. In the wackestones,

most of the peloids are probably fecal pellets produced by some

type of detritus feeder. Many peloids in the packstones are

algal-coated grains or micritized grains that were probably

formed by some type of boring or encrusting algae. Fecal

pellets are also common in the packstones. Most fecal pellets

are much smaller than the algal-coated grains and are typically

better sorted. Algal-coated grains include brachiopod fragments, fusulinids, and bryozoan fragments. Crinoid columnals

scattered throughout the matrix have either a thick algal coating

or thin micrite envelopes.

Fossils are very common in this subfacies. The most

common fossil types include brachiopods, fusulinids, crinoids,

and rarely ammonoids and straight nautiloids. Packstones

generally contain large amounts of skeletal debris and

relatively few complete fossils, whereas the wackestones

consist largely of whole fossils that are relatively complete,

mixed in with lesser amounts of skeletal debris. Most of the

complete fossils are robust forms of brachiopods and bryozoans, which were adapted to higher energy environments,
270 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 10-8.—Skeletal wackestone/packstone microfacies. A, photograph of the skeletal packstone from the

lower part of the Appel Ranch Member (section 8AR, 60.4 m; lens cover is 55 mm wide). B, thin section from the

Willis Ranch Member showing the cross section of a brachiopod shell that contains internal sediments and

perched sediments, which appear dark and consist of pelleted material. The brachiopod is also filled with micrite

and sparry calcite (section RC X, 29.3 m). C, thin section of skeletal packstone showing broken and abraded

grains. Many grains are micritized or have algal coatings. Intrabiotic cavities are filled with clear microspar

(section 5CT, 25 m). D, thin section of skeletal and intraclastic packstone. Many clasts and grains have dark

micritic algal encrustations or coatings (section 7CT, 8.5 m). (Bottoms of photomicrographs represent 0.5 mm).

including lytonnid brachiopods and encrusting bryozoans.

Crinoids are rarely found as more than three articulated

columnals. Most of these fossils are randomly oriented but

locally are current orientated. The fossils and skeletal debris are

commonly well sorted and angular to subangular depending on

the size of the particles.

Geopetal structures common in this subfacies include

sheltered voids, partially-filled brachiopods or ammonoids, and

perched sediments. Many brachiopods and ammonoids are

filled with internal sediment that most commonly consists of

pelleted material. The upper portion of the voids are filled with

coarse crystalline calcite or silica. Sheltered voids (which

commonly form underneath brachiopod valves) contain areas

of coarse crystalline calcite and little matrix of skeletal debris,

whereas the "roof" or "umbrella" has large amounts of pelleted

or skeletal material perched on the upper portion of the valve.

Sheltered voids with perched sediments indicate that sedimentation occurred fairly rapidly and possibly periodically. The

contacts between the internal sediment and void-filling cement

in oriented samples indicate that the surfaces have not been

significantly tilted since the time of deposition. Intrabiotic

cavities of brachiopods, fusulinids, bryozoans, and corals

contain multiple layers of cements.

Brachiopod shells are commonly replaced by length-slow,

fibrous chalcedony. Other fossils, such as corals and bryozoans, are also commonly silicified. Fusulinids are silicified in

isolated beds, but generally their tests remain as calcite.

Generally, silicified and calcite fossils contain a thin inner

micritic rim along the interior of the shells. These micritic rims

grade into an outer, thinly bladed, terminated calcite rim along

the interiors of the intrabiotic cavities. The remaining portions

of the interiors of the cavities are filled with clear, coarse,
NUMBER 32

271

blocky, sparry calcite or, less frequently, with quartz or

megaquartz (Figure 10-9). These types of interior cements

indicate that the sediments have been subjected to some

subaerial exposure. Terminated calcite crystals will only begin

to crystallize in open void spaces. Subaerial exposure was also

probably "short" in duration because if the sediments were

exposed for a prolonged period of time, the calcite crystals

would have continued to grow until they interfered with each

other and formed interlocking, compromise boundaries. Also,

if these sediments were exposed for any extended period of

FIGURE 10-9.—Photomicrographs of preserved cements. A, fusulinid intrabiotic cavity is lined by calcite needles

and filled with blocky calcite and quartz from the Willis Ranch Member (section 1WR, 70.4 m; bottom of

photomicrograph represents 0.5 mm). B, brachiopod shell at lower right is replaced by length-slow chalcedony

and calcite needles line the inside of the cavity, which is filled with megaquartz from the China Tank Member

(section 5CT, 73.2 m; bottom of photomicrograph represents 0.05 mm).
272 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

time, more and better porosity and different types of cements

would be expected to be found. Megaquartz occurs as a

replacement of carbonates in shallow marine to intertidal

environments (Flores et al., 1977:1619), which further supports

an environment of deposition in which short-lived exposure

can occur.

Most of the fossils in this subfacies probably represent death

assemblages (thanatocoenoses) that were piled up into low

lying areas or depressions by storms or bottom currents (shell

heaps). The majority of these fossils were probably disarticulated, broken, and abraded before they were buried. A few

fossils, however, are articulated and well preserved and likely

lived in the area attached to the dead, disarticulated brachiopods.

Skeletal wackestones and packstones are intimately related,

and micrograding is a common feature in polished slabs.

Commonly, a poorly fossiliferous wackestone makes up the

lower portion of these units and grades upward into a more

fossiliferous packstone. The poorly fossiliferous wackestone

contains peloids, the majority of which are probably fecal in

origin. Algal-coated grains do occur in this portion, but they are

not very common. Fossils are also not common in the

wackestone, but they are generally complete specimens.

The packstone contains many more fossils than the

underlying wackestone. Generally the packstone matrix consists of lime-mud and peloids, although many areas are sparry

calcite cemented. Many of these fossils represent skeletal

debris. Commonly this packstone grades into a thin chert layer

that consists entirely of silicified fossils. The chert layer

probably represents a high energy grainstone phase that has

been subsequently silicified. Fossils in these thin chert layers

most commonly are brachiopods, but fusulinids and crinoids

are also common. These chert layers are overlain by thin

mudstone layers or dirty wackestones that represent a return to

low energy, semirestricted conditions.

The sequence of wackestone-packstone-chert is the pattern

found in this subfacies, although the grainstone (skeletal chert)

or thin shale unit is not always present. In this subfacies, the

wackestone grading into a more fossiliferous packstone

probably represents a change from relatively low energy

(wackestone) to higher energy (packstone) environments.

Many portions of the higher energy phase (packstones and

grainstones) are slightly dolomitic. Dolomite occurs in many

intrabiotic cavities and portions of the matrix. Areas that are

dolomitic commonly are slightly vuggy and have some

biomoldic (leached fossils) and intercrystalline porosity developed. These dolomite units represent areas that were intermittently subaerially exposed, thus slightly dolomitizing the

sediments and leaching out some of the fossils at the same time.

Subaerial exposure was probably only brief and sporadic,

limiting the amount of dolomitization and leaching.

WHOLE FOSSIL SUBFACIES.—This subfacies is identified by

a large percentage of whole fossils and the presence of

organically stabilized buildups. This subfacies is located

generally to the northeast of the skeletal subfacies. Texturally,

this subfacies consists of whole fossils in a lime-mud matrix.

Major fossils include brachiopods, crinoids, bryozoans, and

small ammonoids. Skeletal debris is common in this subfacies.

Matrix material is most commonly a very fine to fine

crystalline mixture of micrite and microspar. Microspar

generally forms a tight, interlocking hypidiotopic fabric with

no visible pore space. Most crystals are uniform in size and

shape. The matrix contains little terrigenous material.

Peloids are a common framework grain in this subfacies.

Included in this group of peloids are fecal pellets and

algal-coated grains. Fecal pellets represent approximately 60

percent of the nonfossil allochems and are well sorted and

uniform in size and shape. Algal-coated grains generally

consist of partially micritized skeletal debris. Although not

very abundant, this skeletal debris varies in size and shape, with

coatings ranging from thin micrite envelopes to thick algal

crusts.

Peloids and algal-coated grains appear much darker than the

enclosing cement. This is probably due to the fine crystalline

nature of the micrite that makes up the peloids and possibly to

some organic matter incorporated into the grains. Because of

the fine crystalline nature of these sediments, identification of

the different cements was difficult. It appears that only one

generation of cement is present between the peloids. Much of

this cement probably represents very early diagenetic recrystallization of the original lime-mud to microspar shortly after the

sediments were deposited. This recrystallization effectively

sealed off the pores so the sediments were subjected to little

subsequent diagenetic alteration.

Fossils are the most important key in defining this subfacies.

Many of the fossils are whole and show little evidence of being

transported any appreciable distance. Brachiopods are the most

common type of fossil found in the China Tank and Willis

Ranch members in the lower part of this subfacies. Other fossils

commonly found in association with the brachiopods are

bryozoans and ammonoids. Bryozoans include both delicate

branching forms as well as massive encrusting types. Bryozoans occur inbetween richthofenids or other brachiopods.

Ammonoids occur primarily in seams or clusters, but individuals are commonly found throughout the matrix. Ammonoids

are fairly small in size and are complete specimens. Most of the

ammonoids appear to have been juvenile forms that probably

died and sank to the bottom of the shallow sea floor or were

washed in from adjacent areas. A few rare straight nautiloids

also were found in this subfacies.

A nearly complete crinoid was discovered in this subfacies

by Karen Quick. Most of the crinoids are more complete than

the adjoining skeletal subfacies, are commonly silicified, and

occur in groups of several (5-10) columnals.

Fossils commonly contain abundant internal sediment

consisting of pelleted material and little skeletal debris. Pellets

probably are fecal in origin and are well sorted and not graded.

Other intrabiotic cavities are either partially or totally filled

with blocky sparry calcite.
NUMBER 32 273

Stropoli et al. (1991) computer modeled the brachiopod

assemblages of the Word Formation and identified organically

stabilized shell buildups and shell heaps that correspond

exactly with the whole fossil and skeletal subfacies, respectively.

FUSULINID-CRINOIDPACKSTONE/GRAINSTONE

Fusulinid-crinoid packstone and grainstone have varying

matrix types depending on the outcrop locality (Figures

10-10-10-12). The southwest sections (10AR and 4AR)

" ^ '%zm>*h,.v • " "'" ' -*v .-,••• •'•"•

FIGURE 10-10.—Massively bedded channels of fusulinid-crinoid packstone cutting through thinly bedded

bioturbated wackestones in the Appel Ranch Member. A, photograph of outcrop. B, sketch of outcrop. (Top of

outcrop is 61 m (200 ft.) in section 8AR.)
274 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

f- ' M

FIGURE 10-11.—Fusulinid-crinoid packstone/grainstone microfacies from the Appel Ranch Member. A,

photograph of packed bedding plane (section 8AR, 36.3 m; pen cap is 2 cm long). B, photomicrograph of fusulinid

grainstone showing intrabiotic cavities filled with sparry calcite and microspar (section 9AR, 116.6 m). C,

photomicrograph of fusulinid packstone. Many fusulinids are micritized along the margins of their tests (section

8AR, 83.8 m). D, photomicrograph of crinoid-fusulinid packstone showing broken up fusulinids and crinoids.

Matrix consists of sparry calcite. Scattered peloids are mixed in the matrix (section 8AR, 54.9 m). (Bottoms of

photomicrographs represent 0.5 mm.)

generally consist of fine-crystalline micrites and microspars,

and the central and northeast sections (8AR and 9AR) are

sparry calcite dominated. Sparry calcite is rare in the southwest

section, occurring only as void-filling cement. Dominant

carbonate allochems are fusulinids and crinoids with lesser

numbers of brachiopods and bryozoans. Detrital quartz sand

and terrigenous muds (clays) are common in the southwest

sections, whereas the central and eastern sections typically are

much cleaner and lack appreciable terrigenous clastic material.

Dolomite is rare in the southwest sections but becomes an

important constituent in the central area and dominates part of

the eastern sections. Matrix material is uniform and homogenous at each outcrop, although it varies between different

outcrops. Southwest sections contain matrix of micrite,

microspar, sand grains, and clay-sized material. The matrix is

considered to be "dirty" in these sections, with a large

percentage of detrital quartz sand and clay-sized particles. The

mixture of lime-mud and terrigenous mud gives the slabs and

thin sections a brownish color.

The central and northeastern sections contain sparry calcite.

Microspar and micrite do occur in these sections, although they

represent a smaller percentage. Clastic material is also present

in the central locality, but it is widely scattered throughout the

matrix. In many thin sections and slabs micrite and sparry

calcite are found together, which suggests incomplete winnowing of the sediments. Intrabiotic cavities are calcite filled.

Fossils fall into two different assemblages: mixed assemblages and group dominated assemblages (fusulinids and
NUMBER 32 275

FIGURE 10-12.—Photomicrographs of the fusulinid-crinoid packstone/

grainstone microfacies from the Appel Ranch Member. A, fusulinid packstone

showing replacement dolomite in matrix and intrabiotic cavities (section 9AR,

127.1 m). B, fusulinid-crinoid packstone showing a fusulinid on the right

containing ropey micrite encrustations that are interpreted as the remains of

blue-green algae (section 8AR, 38.1 m). (Bottoms of photomicrographs

represent 0.5 mm.)

crinoids). The southwest sections contain fusulinids and

crinoids mixed with brachiopods, brachiopod spines, and

bryozoans. These fossils are poorly sorted and are typically

broken, fragmented, and abraded. Fossils are scattered throughout a micrite and terrigenous mud matrix with little or no

grading evident. Fusulinids are preferentially aligned, although

the directions are somewhat variable.

Fossils in the central and northeastern sections are dominated by fusulinids (Parafusulina). Spectacular numbers of

Parafusulina typically are tightly packed into the rocks (Figure

10-1 1A). Most fusulinids are complete, although many are

broken, crushed, or distorted due to compaction. Brachiopods

and bryozoans are rarely seen in the grainstones and occur only

as scattered fossil fragments. Cement most commonly is clear

sparry calcite, with the intrabiotic cavities also filled with

sparite. Crinoid columnals are found mixed in with the

fusulinids, but other thin sections and slabs commonly have the

reverse situation, with crinoids being the dominant allochem

and fusulinids as the accessory. Crinoids are more abundant in

the northeast section (9AR), probably reflecting more stenohaline conditions. Fusulinids still remain a very important

contributor to the sediments at this locality.

Silicified fossils occur throughout the different sections.

Brachiopods and bryozoans are the most commonly silicified

fossils, but fusulinids and crinoids are also replaced. In the

northeast section (9AR), only scattered brachiopods are

silicified and fusulinids are not altered. Replacement by

length-slow chalcedony is the most common type of silicification. Replacement is good, with many skeletal details faithfully

mimicked.

Peloids (fecal and algal-coated grains) are important framework contributors in the central and northeast sections, and

especially in the southwest sections. These peloids are very

similar to those described from the peloid packstone microfacies common to the China Tank and Willis Ranch members.

Most commonly, fusulinids and crinoids are coated by micrite

envelopes and thick algal encrustations. Areas between

fusulinids contain ropy micrite rinds or calcareous tubes, which

possibly are blue-green algal remains. Peloids appear to be

coated with layered micritic films, which probably are also

blue-green algal remains. These films might form in semiagitated water, similar to that in which modern ooids or oncoids

form, with micrite added on to the exteriors of the grains layer

by layer.

Intraclasts occur in the southwest and central portions of the

Appel Ranch but are absent in the sections in the northeast.

Lithoclasts primarily consist of pellet and peloidal material

with few fossil inclusions. Lithoclasts are flat, rounded, and

relatively small (several millimeters to a few centimeters) and

probably represent small rip-ups or the results of biologic

activity because these lithoclasts are very similar to the

surrounding sediments. Peloids and fossil fragments are

truncated along the margins. Small, brown, round terrigenous

intraclasts are also common in the southwest portion of the

Appel Ranch.

Dolostone is primarily limited to the central and northeast

sections of the Appel Ranch (8AR and 9AR) where it occurs in

both the fusulinid-crinoid packstone/grainstone as well as the

bioturbated wackestone microfacies. Dolomite in the fusulinidrich beds occurs mostly as replacement dolomite in isolated

intrabiotic cavities and scattered throughout the matrix. The

replacement dolomite is composed of coarse crystals (0.2-1.0

mm), most of which are euhedral, and is primarily limited to the

fusulinid-crinoid packstone/grainstone microfacies. In contrast, penecontemporaneous dolomite is made up of finer

crystals (< 0.25 mm) and commonly forms a hypidiotopic

fabric. Pervasive dolomitization of the wackestones and

packstones has destroyed most of the original textures, but

some relict textures and allochems are still recognizable as

"ghosts."
276 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

BlOTURBATED WACKESTONE/LlME MUDSTONE

Interbedded with the fusulinid-crinoid packstone and

grainstone is sparsely fossiliferous, bioturbated, and burrowed

wackestone and lime mudstone (Figure 10-13). This microfacies typically contains few fossils and is uniquely recognized

by the large number of chertified burrows. This microfacies

occurs throughout the Appel Ranch Member, but it is best

developed in the central portions of the field area (sections 8AR

and AR III).

A variety of different matrix types occurs in this microfacies.

Some are very argillaceous and can be considered to be marls,

whereas others are considered to be clean lime mudstones. Still

others have been dolomitized and lack any original texture.

These dolostones are most commonly finely crystalline and

probably represent diagenetic dolostones that formed during or

shortly after deposition. Except for being bioturbated, this

microfacies lacks any other primary sedimentary structure.

Rare articulated brachiopods occur in this microfacies and

show little evidence of being transported. Brachiopods are

concentrated along the margins of the burrows and occur very

rarely inside the burrows. These fossils probably were pushed

aside by the burrowing infauna.

In the sediments that have not been dolomitized, pellets and

peloids are the most common allochems. Most of these pellets

probably represent fecal pellets because of their uniform sizes

and shapes. The large number of burrows also supports a fecal

origin for these pellets, which are products of mud ingestors.

Micritized grains are rare, although some algal-coated grains

are present.

Burrows are randomly oriented and typically form "spaghetti

noodle" patterns in vertical and horizontal directions. These

probably represent fodinichnal, or randomly oriented, feeding

burrows. The burrows are a much darker brown than the

surrounding sediments because they contain a much higher

content of terrigenous and organic matter. The high organic

content and the fact that the burrows were probably more

porous than the surrounding sediments helps explain why only

the burrows were chertified and not the surrounding sediments.

RECRYSTALLIZEDLIMESTONE/DOLOSTONE

Dolostone makes up the majority of the rocks in the eastern

facies of the Word Formation of King (1931). This microfacies

is identified by the presence of 20 percent or more of the

mineral dolomite in the rock. The primary texture has been

largely destroyed, and the dolomite consists mainly of

replacement dolomite in which relict textures, such as fossils,

peloids, and crude bedding, are preserved (Figures 10-14,

10-15). Other dolomite probably represents penecontemporaneous dolomite as identified by small crystal size and no relict

features.

Texturally, this microfacies consists of two different sizes of

dolomite crystals. Most replacement dolomite is composed of

•tw

C %

FIGURE 10-13.—Bioturbated wackestone/lime mudstone microfacies. A,

photograph of chertified burrows in the Appel Ranch Member (section 8AR,

2.1 m; hammer is 0.46 m long). B, photomicrograph of skeletal wackestone

from the Appel Ranch Member (section 8AR, 2.1 m; bottom of photomicrograph represents 0.5 mm).

coarse (0.25-1.0 mm) crystals that typically form a tight,

interlocking, xenotopic fabric. In contrast, the penecontemporaneous dolomite is made up of finer crystalline (generally less

than 0.25 mm) dolomite. Many of these dolomite crystals are

euhedral and, in part, form a sucrosic texture. Most of the fine

crystalline dolomite is restricted between framework grains and

is considered to be recrystallized matrix material.

Fossils in this microfacies generally consist of fusulinids and

crinoids. Fusulinids are fairly common, and most are unbroken

and are rarely dolomitized. Disarticulated crinoid columnals

are dark in thin sections and remain relatively unaffected by

dolomitization. Many of the crinoids have been epitaxially

cemented by coarse crystalline calcite, which occurs as

optically continuous overgrowths along the margins of crinoid

columnals. Some of this calcite can be considered to be
NUMBER 32 277

FIGURE 10-14.—Photomicrographs of the recrystallized limestone/dolostone microfacies from the undifferentiated Word Formation (eastern facies). A, coarse crystalline dolomite destroying a fusulinid (section 12PW, 30.8

m). B, various stages of the recrystallization of fusulinids from a "ghost" at the lower left to a fairly well-preserved

large fusulinid with coarse crystalline dolomite in the intrabiotic cavities at the lower right (section 12PW, 30.8

m). (Bottoms of photomicrographs represent 0.5 mm.)

poikilotopic, enclosing several grains. This cement probably

was deposited during the leaching and dolomitization of the

sediments, or it could have occurred during a void-filling late

stage of diagenesis. Brachiopods, bryozoans, and other fossils

that have been silicified are recognizable, but these are rare.

Pervasive dolomitization and recrystallization of this microfacies has destroyed most of the original texture; however,

some relict features of the original limestone are commonly

preserved as "ghosts," including peloids (fecal and algal),

crinoids, fusulinids, and bryozoans. Another relict feature
278 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 10-15.—Photomicrographs of the recrystallized limestone/dolostone

microfacies from the undifferentiated Word Formation (eastern facies). A,

complete dolomitization has left no recognizable skeletal grains (section 12PW,

55.3 m). B, recognizable crinoid debris. Note the pore at center right, which

probably represents a fossil that has been leached out (section 12PW, 78.7 m).

(Bottoms of photomicrographs represent 0.5 mm.)

commonly found in this microfacies are leached fossils. The

most common leached fossils are brachiopods and less

commonly crinoids and fusulinids. Other areas of the sediment

contain irregular vugs whose specific origin is unknown. These

vugs are irregular in size and shape and possibly are the result

of the dissolution of sulfates or are enlarged fossil molds.

Lithofacies

The carbonate microfacies and Word mudstones define five

mappable lithofacies: (1) mudstone, (2) peloidal packstone, (3)

skeletal wackestone/packstone, (4) fusulinid-crinoid grainstone/bioturbated wackestone, and (5) recrystallized limestone/

dolostone. The distribution of these lithofacies is shown in

Figure 10-16. All lithofacies intergrade and are identified by

the dominant rock type. Beds of an identifiable facies thicker

than 1 m are identified as that lithofacies.

1. Mudstone: The mudstone lithofacies consists of mudstone, claystone, and fine sandstone with scattered thin beds of

peloidal packstone and scattered lenses that represent channel

deposits of skeletal to conglomeratic wackestone and peloidal

packstone. Carbonates thicker than 1 m were classified in the

appropriate carbonate lithofacies. Thin beds and interbeds of

mudstone are common to all the carbonate lithofacies.

2. Peloidal Packstone: The peloidal packstone lithofacies

consists of peloidal packstone, skeletal peloidal packstone, and

thin beds of mudstone, fine sandstone, and skeletal wackestone/packstone.

3. Skeletal Wackestone/Packstone: The skeletal wackestone/packstone lithofacies consists of two intimately related

subfacies, skeletal and whole fossil. Even though the whole

fossil subfacies is restricted to the eastern part of the

distribution of this lithofacies (Figure 10-16), persistent

interbeds of the skeletal subfacies makes it impossible to

separate it as a mappable lithofacies. Thin interbeds of

mudstone, peloidal packstone, bioturbated wackestone, and

fusulinid-crinoid packstone are common.

4. Fusulinid-Crinoid Packstone/Bioturbated Wackestone: The fusulinid-crinoid packstone/bioturbated wackestone lithofacies consists of two intimately related carbonate

microfacies. Typically, fusulinid-crinoid packstone and grainstone form channel deposits that cut the bioturbated wackestone. Thin beds of mudstone and skeletal wackestone and

packstone are common. This lithofacies grades laterally into

the recrystallized limestone/dolostone lithofacies.

5. Recrystallized Limestone/Dolostone: This lithofacies

consists of the carbonate microfacies of the same name. Most

of the rock appears to be recrystallized and dolomitized

fusulinid-crinoid packstone and grainstone and bioturbated

wackestone.

Depositional Environments

The various microfacies types and their mutual relationship

in space, as well as their sedimentary structures and paleontology, define the depositional environments of the Word

Formation more precisely than has been previously reported. In

general, the lower portion of the Word (China Tank and Willis

Ranch members) represents a shallow-water lagoonal or

back-reef environment, whereas the upper portion of the Word

(Appel Ranch Member) represents higher energy shoals or tidal

flat deposits.

The peloidal packstone microfacies in the lower part of the

Word is interpreted to have been formed in a shallow-water

lagoonal environment with varying degrees of water circulation

and energy levels, especially toward the northeast. A lagoonal

environment is identified by the abundance of pelleted

sediments, which comprise nearly all the sand-size grains in the

southwestern part of the Willis Ranch. Here the Willis Ranch is

very argillaceous and sandy, indicating that this area was

relatively close to a clastic source area. Quartz sand grains are

angular to subangular, suggesting that they have not been
NUMBER 32 279

900

800

700

19

L_

18

_J

17

10 11 14

12 \ 1/13 9

I HI I I

FUSULINID-CRINOIDGRAINSTONE/

BIOTURBATED WACKESTONE

-200

600-

500-

400-

300 -

200-

WORD FORMATION

MUDSTONES

PELOIDAL PACKSTONE

RECRYSTALIZED LIMESTONE/DOLOSTONE

SKELETAL WACKESTONE/PACKSTONE

100-

FlGURE 10-16.—Facies analysis of the Word Formation displayed as a true distance cross section (as in Figure

10-4; numbers across the top refer back to sections in Figure 10-3).

transported any appreciable distance. This was a low-energy

environment as indicated by the fine textures of the mudstones,

siltstones, and lime mudstones deposited here. This type of

environment was an ideal habitat for infaunal deposit feeders,

such as worms, gastropods, or other mud ingestors. Conversely, this environment was not suitable for filter feeding

organisms, such as brachiopods or crinoids, whose respiratory

and feeding organs do not function well in a muddy, turbid

environment. Thus, only a relatively few broken and transported fossils are found in this microfacies. Primary sedimentary structures, such as laminations or small-scale bedding, are

also lacking probably as a result of bioturbation. The peloidal

packstones have not been winnowed, which also contributes to

the lack of small-scale sedimentary structures. The finely

crystalline nature (micrite and clay-sized particles) and the

absence of any sparry calcite within this microfacies again

suggest deposition in a quiet, low energy environment. This

was a shallow water environment as indicated by the

abundance of algal-coated grains and small intraclasts. The

conodont Hindeodus, which is indicative of near-shore conodont biofacies, is common to this microfacies. This environment was probably semirestricted, with little epifauna as

indicated by the scarcity of fossils. Most of the fossils that are

found in this microfacies represent allochthonous debris. Tidal

currents and periodic storms, or other high energy events

brought in fossil debris from a nearby, more normal marine
280 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

environment. This microfacies is interpreted to represent a low

energy, shallow water lagoon between a normal marine

environment but still near a positive land area from which the

detrital quartz sand was derived. This microfacies is similar to

the "Restricted Marine Shelf Lagoons (Facies Belts 7 and 8)" of

Wilson (1975:68), which are characterized as being bioturbated

pelleted lime-mud wackestones that occasionally grade into

higher energy fabrics. The fauna is somewhat reduced and

represents deposition in quiet, restricted bays and ponds.

The peloidal packstone microfacies grades into a much more

fossiliferous skeletal wackestone/packstone subfacies of the

wackestone/packstone microfacies that also represents a shallow-water lagoonal or back-reef environment. This part of the

lagoon was further from land, and much cleaner carbonates

were deposited. The subfacies represents more normal marine

conditions as indicated by the greater abundance of stenohaline

organisms (crinoids and other echinoderms). Most commonly,

low energy conditions existed, which allowed the lime-mud to

settle out without affecting the brachiopods or other filter

feeding organisms. The abundance of fecal pellets suggests

mud-ingesting infaunal organisms thrived in this environment.

This low energy environment persisted during most of the

time of deposition; however, sporadic higher energy conditions

occurred probably as the result of storms or unusually strong

tides. These higher energy events are recognized by heaps of

shells. Shell heaps appear to be represented by two types:

moderately large heaps, which were colonized by hard

substrate-loving organisms exemplified by some of the

productid brachiopod localities of Cooper and Grant (1972),

and packed thin beds and seams that are commonly chertified.

Many outcrops show a relationship of alternating high and low

energy deposits. Sparsely fossiliferous and pellet-rich sediments represent the low energy deposits, which are commonly

overlain by a mixture of more abundant fossils with pelleted

sediments that reflect a change to higher energy conditions.

Commonly this unit is capped by thin fossiliferous cherts

containing nothing but tightly packed fossils with little or no

matrix material. This represents the highest energy phase with

all of the lime-mud being winnowed out of the sediments.

These high energy chert layers are relatively thin and sporadic,

indicating they were possibly storm events and not normal for

this microfacies.

The skeletal wackestone/packstone subfacies was deposited

in very shallow water as indicated by the abundance of

algal-coated grains. Many of these encrustations are interpreted

to be the product of blue-green algae, which thrives only in

very shallow water. The conodont faunas also support a

shallow water environment of deposition. This subfacies

corresponds to the "Open Platform (Facies Belt 7)" of Wilson

(1975), which is a shallow water environment with moderate

circulation just below the wave base and with common

bioturbation of the sediments.

The skeletal wackestone/packstone subfacies is intimately

associated with the whole-fossil wackestone/packstone subfacies. This whole-fossil subfacies is identified by abundant

whole, or relatively complete fossils, many of which are

interpreted to be in life position. Skeletal debris does occur in

this subfacies, but it is not as abundant as in the adjacent,

skeletal subfacies. The carbonates in this subfacies are very

clean of terrigenous material compared to those to the

southwest, indicating that they were deposited further from the

clastic source area. Carbonates in this subfacies were also

deposited in a low energy environment as indicated by the high

percentage of lime-mud and fine crystalline carbonates. Many

of the brachiopods contain internal sediment, which generally

is a mixture of pellets and lime-mud. Very little sparry calcite

was found in this subfacies, suggesting that this area was not

subjected to high energy conditions. This subfacies corresponds to the "Open Platform or Shelf (Facies Belt 7)" of

Wilson (1975), which forms in quiet water below the wave base

and generally preserves some infauna and epi fauna.

The fusulinid-crinoid packstone/grainstone microfacies is

commonly interbedded with the sparsely fossiliferous, bioturbated wackestone/lime mudstone microfacies. Packstone and

grainstone contain abundant current-aligned fossils and are

commonly spar-cemented indicating high energy conditions.

Most of the lime-mud has been winnowed out of these

sediments. Of course, the lime-mud is abundant in the adjacent

bioturbated wackestone/lime mudstone. A shallow-water environment is recognized by the abundance of algal-coated and

encrusted grains. The abundance of stenohaline organisms,

such as crinoids, also indicates normal marine conditions. The

large sedimentary feature (Figure 10-10), which is interpreted

to be a tidal channel, consists of fusulinid-crinoid packstone

that cuts into the underlying bioturbated wackestone. The

channel is slightly dolomitic, probably due to its original high

permeability and porosity and to its subsequent flushing with

meteoric waters. This dolomitization suggests near-surface

conditions. The intimately intermixed high and low energy

depositional environments and the abundant shallow-water

indicators of these two microfacies represent tidal mud flats cut

by tidal channels.

The most common type of organisms present in the

bioturbated wackestone/lime mudstone microfacies were burrowing organisms and other mud ingestors. Burrows within

this microfacies became chertified because of their originally

high organic content and high permeability. Little skeletal

material was washed into this microfacies, and the majority of

that present represents allochthonous debris.

The upper portion of the Word Formation (Appel Ranch

Member) represents high energy platform sands in the central

part and grades into adjacent lower energy tidal or lagoon

environments. The high energy environment is represented by

fusulinid-crinoid grainstone. Fusulinids are current-oriented in

a roughly north-south direction. Further southwest, the

samples become more shaly and sandy, and the fusulinids have

more varied orientations but still indicate north-south current

directions. The lower velocity orientation (Futterer, 1978) was

used because the samples contain abundant mud, indicating a

lower energy environment than in other portions of the Appel
NUMBER 32 281

Ranch. The Appel Ranch represents the fusulinid-crinoid

packstone/bioturbated wackestone lithofacies and is similar to

the "Open Platform Sands (Facies Belt 6)" of Wilson (1975).

The eastern facies still remains somewhat of an enigma.

Dolomitization and recrystallization has destroyed most of the

fabric and texture, which makes identification of the depositional environment difficult. The few recognizable crinoids and

fusulinids in this microfacies indicate that this was a normal

marine environment. This was a very shallow water environment that was probably subaerially exposed at times, thereby

dolomitizing the sediments and causing the vuggy nature of the

sediments. Because of the abundance of crinoids and fusulinids

in places and the general lack of fossils in others, this

microfacies is thought to have been very similar to the

fusulinid-crinoid packstone/grainstone microfacies interbedded with the bioturbated wackestone/lime mudstone microfacies, but it was shallower and commonly exposed. This

microfacies is similar to Wilson's "Organic Reef or Platform

Sands (Facies Belts 5 and 6)." These microfacies are described

as being massive limestones and dolomites, which may be

vuggy due to periodic subaerial exposure (Wilson, 1975).

The sediments of the Word Formation suggest very shallow

deposition in the area studied, probably along a shoal

developed on the seaward rim or geantiform of a foreland basin

(Rohr et al., this volume; Wardlaw, this volume) and deposition

into the foreland basin. The eastern facies represents a shoal

facies, and the remaining facies represent shallow foreland

basin facies. The distribution of facies and flow directions

appear to be directly opposite of those hypothesized by Harris

et al. (this volume) for the underlying Road Canyon Formation.

It appears that by Word time most of the foreland basin was

filled in yielding backbay depositional settings.
282 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Appendix 10-1: Measured Sections

Locations of the sections measured for this study are shown in Figure 10-3, and the

sections are graphically displayed in Figures 10-17-10-22. (The latitude and longitude is

for the base of the section.)

Section

WRIII

1WR

WRI

5CT

RCX

CTI

706e

7CT

WRII

WORD I

Above 7CT

2TL

ARII

10AR

4AR

ARIII

8AR

9AR

12PW

Figure

Figure 10-17

Figure 10-17

Figure 10-17

Figure 10-18

Figure 10-18

Figure 10-18

Figure 10-18

CT II, Figure 10-19

Figure 10-19

Figure 10-19

CT II, Figure 10-20

Figure 10-20

Figure 10-21

Figure 10-21

Figure 10-21

Figure 10-21

AR I, Figure 10-22

Figure 10-22

Figure 10-22

Measured by

Wardlaw and Grant

Rathjen

Wardlaw and Grant

Rathjen

Wardlaw, Grant, Rohr, and Rathjen

Wardlaw and Grant

Wardlaw and Grant

Wardlaw, Grant, and Rathjen

Wardlaw and Grant

Wardlaw and Grant

Wardlaw, Grant, and Rathjen

Wardlaw and Rohr

Wardlaw and Grant

Rathjen

Rathjen

Wardlaw and Grant

Rathjen, Wardlaw, and Grant

Rathjen

Rathjen

Location

30°21.42'N, 103°14.06'W

30°22.48'N, 103°13.79'W

30°22.80'N, 103°13.41'W

3O°23.35'N, 103°10.70'W

30°23.23'N, 103°10.43'W

30°23.53'N, 103°10.58'W

30°23.75'N, 103°10.45'W

30°23.74'N, 103°09.81'W

30°23.92'N, 103°09.53'W

30°24.05'N, 103°07.85'W

30°23.74'N, 103°09.81'W

30°24.16'N, 103°10.18'W

30°23.56'N, 103°12.08'W

30°23.51'N, 103°11.42'W

30°23.97'N, 103°10.80'W

30°24.01'N, 103°10.67'W

30°24.27'N, 103°09.84'W

30°24.43'N, 103°09.33'W

30°25.35'N, 103°06.98'W
NUMBER 32 283

WR III

200-,

- 5 0

100-

0-

FT

APPENDIX 10-1.—Continued.

• SK. SLS.

MS.

P. PS.

- ir[; • s. p. PS.

UZL rz

U-L

T T l

L_l

• SK. P. PS.

• P. PS.

r , i

m

• SK. P. PS.

• AM. P. PS.

T~ I

1 . T I ,„- LT

I. T

T ~T

. P. PS.

• P. PS.

• SK. P. PS.

I . T -L-TJ

t • . i

V •. \ •

; TT

LZI

LJ.

i, r

TTTT

EZI

L .1

1 1 7

• S. SK. P. PS.

• SK. P. PS.

• SK. P. GS.

• S. SK. P. PS.

• SK. P. PS.

• S. SK. P. WS.

P.WS.

• S. P. WS.

S. SK. WS.

WR1

•• \ • SK. SLS.

H Z X

T 7 T

t .1

I 71

i, r i r

r r

• SK. P. PS.

• L. SS.

• S. SK. P. PS.

• S. SK. P. PS.

FIGURE 10-17.—Measured sections of the Willis Ranch Member from the western part of the study area showing

the petrographic sample location and identification. (Petrographic abbreviations: AM, ammonoid; GS,

grainstone; L, limy; MS, mudstone; P, peloidal; PS, packstone; S, sandy; SK, skeletal; SLS, siltstone; SS,

sandstone; WS, wackestone.)
284 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

5CT 5CT

APPENDIX 10-1.—Continued.

RC X RC X

200 -i

-50

100-

0-L0

FT M

LZI

•SK. P. PS.

• P. PS.

.SK.WS-PS.

*SK. PS.

•SK. MS.

T— \ «SK. MS.

•-M

£-4

JLJL

'SK. PS.

•SK. PS.

• SK. PS.

•SK.WS.

>SK. P.WS-PS.

NE. DUS.

• P. PS.

•SK.WS.

•SK.WS.

WILLIS

•SK. PS.

CT l/706e

S. SK.WS-PS.

FIGURE 10-18.—Measured sections of the China Tank and Willis Ranch members from the central part of the

study area. (Petrographic abbreviations: AM, ammonoid; DS, dolostone; FUS, fusulinid; GS, grainstone; MS,

mudstone; NE, neomorphic; P, peloidal; PS, packstone; RE, recrystallized; SI, silty; SK, skeletal; WS,

wackestone.)
NUMBER 32 285

APPENDIX 10-1.—Continued.

7CT

200 -i

-50

100-

O-LO

FT M

SK. PS.

SK. PS-WS.

SK. PS.

WRII

• SK. P. PS.

/SK . PS-GS.

•-SK. P. PS.

^ . P. FUS. PS

• MS.

• SK. P. PS.

WORD I

f T

T /

7 7

J / g

TTT

•SK. DS.

•RE. SK. LMS.

•RE.SK.WS-PS.

XT V, •RE. SK. FUS.WS-PS.

•SI. LMS.

•SK.FUS.PS.

• FUS. SK. PS.

• ROAD CANYON

FORMATION

FIGURE 10-19.—Measured sections of the China Tank and Willis Ranch members from the eastern part of the

study area. (Petrographic abbreviations: FUS, fusulinid; GS, grainstone; LMS, lime mudstone; M, muddy; MS,

mudstone; P, peloidal; PS, packstone; RE, recrystallized; SK, skeletal; WS, wackestone.)
286 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

APPENDIX 10-1.—Continued.

ABOVE

7CT

5 0 -

10

0-L0

FT M

• P. PS.

200 FT

7CT

2TL

SK. FUS. PS-GS.

L J->( • SK. P. PS.

l I \ • P. PS.

• SK. P. PS.

• SK. P. PS.

FIGURE 10-20.—Measured section of the lens between the Willis Ranch

Member and the Appel Ranch Member. (Petrographic abbreviations: FUS,

fusulinid; GS, grainstone; P, peloidal; PS, packstone; SK, skeletal.)
NUMBER 32 287

APPENDIX 10-1.—Continued.

200 -|

-50

100-

ARII

• SLS. &

L SI. SS.

•P. PS.

i r

.P. SK. PS.

t-SK. WS.

•-P. SK. PS.

=^H «L SLS.

•L SLS.

FT M

10 AR

TTT

•SK. P. PS.

•SK. P. PS.

•SK. WS-PS.

•SK. PS.

•SK. MS.

• SK. P. PS.

•SK. PS.

•SK. P. PS.

i »SK. WS.

•SK. P. PS.

•SK. WS.

•SK. P. PS.

•SK. PS.

4AR

IT I

•SK. PS.

•SK. PS.

•SK. PS-WS.

7.1 ~ A • MS.

•SK. P. PS.

•SK. PS.

- - 1 «MS.

'SK. WS-PS.

•SK. WS.

1 ^1 1 •

IT IBl. LMS.

I T T

• p. PS.

•SK. P. PS.

•SK. P. PS.

•SK. P. PS.

7 7

)»L. DS.

•DS.

I I I -RE. SK. PS.

/ r S

-r r ( «SK. p. SLS.

— •--i

-SK.FUS.PS.

•FUS. PS.

•Bl. SI. P. LMS.

^m »BI. si. P. LMS.

•SK. PS.

•Bl. LMS.

•SK. PS.

±Ti •Bl. LMS.

•SK. PS.

T-=- -I

•Bl. SI. P. LMS.

•P. SK. PS.

FIGURE 10-21.—Measured sections of the Appel Ranch Member in the central part of the study area.

(Petrographic abbreviations: Bl, bioturbated; DS, dolostone; FUS, fusulinid; L, limy; LMS, lime mudstone; MS,

mudstone; P, peloidal; PS, packstone; RE, recrystallized; SI, silty; SK, skeletal; SLS, siltstone; SS, sandstone;

WS, wackestone.)
288 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

8AR

200-,

-50

100-

0 -

FT

I I) »CR. FUS. GS-PS.

-CR. FUS. GS.

•BI.SK.WS.

>CR. FUS.GS.

8AR

J-T-L

• SK. P. PS.

SK. FUS.

GS.

'SK. FUS.

• P. PS.

).SK. P.

PS-WS.

BI.SK.WS

- I -\ 'SLUMS.

• SK. P.

PS-WS.

T-,1

•SI.WS.

•SI.BI.WS.

•BI.SK.WS,

•BI.SK.PS.

•BI.SK.WS.

If

If.

If

\

[

L

\

I

L

I

i

_lr

•V)

\

V

i

m

I

I

I

.BI.SK.WS.

• BI.SK.WS.

SK. FUS.

PS-GS.

'BI.SK.WS.

-SK.WS-PS.

• SK. PS-GS.

APPENDIX 10-1.—Continued.

9 AR 9 AR

'SK.PS.

• SK.GS.

• SK.PS.

• SK.

P. PS.

."I.1 I -MS.

L-I

- S i

7/

7 /

7

• SK.DS.

•SK.DS.

• SK.DS.

• SK.DS.

• NE.DS.

t-E

i^-k

I Z I

T , I

>SK. LMS.

Iu

r rnr

tr-ta

• SK.GS.

' SK. PS.

-S. SK.GS.

12 PW

/

/

/

/

/

/

/

/

/

/

/

//

7

/

/

/

/

7

/

/

/

/

/ i

/

/

/

/

/

/

/

/

/

/

/

/

/

/

/

/

/

/

/

/

r

/

1

t 1

I

1

I

/

1

1

i

1

I

I

/

)

1

/

/

/

/

1

1

1

1

/

/,

/

/

/

/

(I

I

1

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/

1

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1

I

• P. DS.

• NE.DS.

«NE. DS.

12 PW

'NE.DS.

.NE.DS.

•SK.DS.

NE.P?

DS.

L

• NE. P. DS.

• SK.DS.

'SK.DS.

_ZJ #S K. DS.

FIGURE 10-22.—Measured sections of the Appel Ranch Member from the eastern part of the study area.

(Petrographic abbreviations: BI, bioturbated; CR, crinoid; DS, dolostone; FUS, fusulinid; GS, grainstone; LMS,

lime mudstone; MS, mudstone; NE, neomorphic; P, peloidal; PS, packstone; S, sandy; SI, silty; SK, skeletal; WS,

wackestone.)
NUMBER 32 289

Literature Cited

Bathurst, R.G.C.

1971. Carbonate Sediments and Their Diagenesis {Developments in

Sedimentology, 12), 658 pages. Amsterdam: Elsevier Publishing

Company.

Cooper, G.A., and R.E. Grant

1964. New Permian Stratigraphic Units in Glass Mountains, West Texas.

Bulletin of the American Association of Petroleum Geologists,

48(9):1581-1588.

1966. Permian Rock Units in the Glass Mountains, West Texas. United

States Geological Survey Bulletin, 1244-E:E1-E9, plates 1, 2.

1972. Permian Brachiopods of West Texas, I. Smithsonian Contributions

to Paleobiology, 14:1-231, plates 1-23.

Flores, R.M., T.L. McMillan, and G.E. Watters

1977. Lithofacies and Sedimentation of Lower Permian Carbonate of the

Leonard Mountain Area, Glass Mountains, Western Texas. Journal

of Sedimentary Petrology, 47(4): 1610-1622.

Flugel, E.

1982. Microfacies Analysis of Limestones. 633 pages. Berlin: SpringerVerlag.

Folk, R.L.

1959. Practical Petrographic Classification of Limestone. Bulletin of the

American Association of Petroleum Geologists, 43(1): 1-38.

1965. Some Aspects of Recrystallization in Ancient Limestones. In L.C.

Pray and R.C. Murray, editors, Dolomitization and Limestone

Diagensis: A Symposium. Society of Economic Paleontologist and

Mineralogists, Special Publication, 13:14-48.

Futterer, Elke

1978. Hydrodynamic Behaviour of Biogenic Particles. In A. Seilacher and

F. Westphal, editors, Paleoecology; Constructions, Sedimentology,

Diagenesis and Association of Fossils. Neus Jahrbuchfur Geologie

und Palaeontologie, Abhandlungen, 157:37-42.

Grant, R.E., and B.R. Wardlaw

1984. Redefinition of Leonardian-Guadalupian Boundary in Regional

Stratotype for the Permian of North America. 27th International

Geological Congress, Moscow, USSR, Abstracts, 1:58.

Harris, M.T., D.J. Lehrmann, and L.L. Lambert

2000. Comparison of the Depositional Environments and Physical Stratigraphy of the Cutoff Formation (Guadalupe Mountains) and the

Road Canyon Formation (Glass Mountains): Lowermost Guadalupian (Permian) of West Texas. In B.R. Wardlaw, R.E. Grant, and the

D.M. Rohr, editors, The Guadalupian Symposium. Smithsonian

Contributions to the Earth Sciences, 32:127-152, 25 figures.

King, P.B.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part I:

Descriptive Geology. University of Texas Bulletin, 3038: 167 pages,

15 plates. [Date on title page is 1930; actually published in 1931.]

Lambert, L.L., D.J. Lehrman, and M.T. Harris

2000. Correlation of the Road Canyon and Cutoff Formations, West Texas,

and Its Relevance to Establishing an International Middle Permian

(Guadalupian) Series. In B.R. Wardlaw, R.E. Grant, and D.M. Rohr,

editors, The Guadalupian Symposium. Smithsonian Contributions to

the Earth Sciences, 32:153-183, 11 figures, 4 plates, 3 tables.

Rohr, D.M., B.R. Wardlaw, S.F. Rudine, M. Haneef, A.J. Hall, and R.E. Grant

2000. Guidebook to the Guadalupian Symposium. In B.R. Wardlaw, R.E.

Grant, and D.M. Rohr, editors, The Guadalupian Symposium.

Smithsonian Contributions to the Earth Sciences, 32:5-36, 31

figures.

Stropoli, C.K., R.E. Grant, and B.R. Wardlaw

1991. Wordian (Permian) Brachiopod Assemblages, Western USA. In D.I.

MacKinnon, D.E. Lee, and J.D. Campbell, editors, Brachiopods

through Time. Proceedings of the Second International Brachiopod

Congress, University of Otago, Dunedin, New Zealand, 5-9

February 1990, pages 227-232. Rotterdam: A.A. Balkema.

Udden, J.A.

1917. Notes on the Geology of the Glass Mountains. University of Texas

Bulletin, 1753: 59 pages.

Udden, J.A., C.L. Baker, and E. Bose

1916. Review of the Geology of Texas. University of Texas Bulletin, 44:

164 pages.

Wardlaw, B.R.

2000. Guadalupian Conodont Biostratigraphy of the Glass and Del Norte

Mountains. In B.R. Wardlaw, R.E. Grant, and D.M. Rohr, editors,

The Guadalupian Symposium. Smithsonian Contributions to the

Earth Sciences, 32:37-87, 3 figures, 12 plates, 1 table.

Wardlaw, B.R., and R.E. Grant

1990. Conodont Biostratigraphy of the Permian Road Canyon Formation,

Glass Mountains, Texas. United States Geological Survey Bulletin,

1895-A:A1-A18, plates 1-4.

Wardlaw, B.R., C.A. Ross, and R.E. Grant

2000. Cyclic Deposition of the Permian Road Canyon Formation, Glass

Mountains, West Texas. In B.R. Wardlaw, R.E. Grant, and D.M.

Rohr, editors, The Guadalupian Symposium. Smithsonian Contributions to the Earth Sciences, 32:121-126, 3 figures.

Wilson, J.L.

1975. Carbonate Fades in Geologic History. 471 pages. Berlin: SpringerVerlag.

Wolf, K.H.

1965. Petrogenesis and Paleoenvironment of Devonian Algal Limestones

of New South Wales. Sedimentology, 4:113-178.
11. Geology and Depositional Environments

of the Guadalupian Rocks of the Northern

Del Norte Mountains, West Texas

Shannon F. Rudine, Bruce R. Wardlaw, David M. Rohr,

and Richard E. Grant

ABSTRACT

The Guadalupian rocks of the northern Del Norte Mountains were

deposited in a foreland basin between land of the Marathon orogen and

a carbonate shoal established on the geanticline separating the foreland

basin from the Delaware basin. Deposition was alternately influenced

by coarse clastic input from the orogen and carbonate input from the

shoal, which interrupted shallow basinal siltstone deposition. Relatively deeper-water deposition is characterized by carbonate input

from the shoal, and relatively shallow-water deposition is characterized by sandstone input from the orogen. Deposition was in five

general transgressive-regressive packages that include (1) the Road

Canyon Formation and the first siltstone member and first sandstone

member of the Word Formation, (2) the second siltstone member,

Appel Ranch Member, and limy sandy siltstone member of the Word

Formation, (3) the Vidrio Formation, (4) the lower and part of the

middle members of the Altuda Formation, and (5) part of the middle

and upper members of the Altuda Formation.

Introduction

The northern Del Norte Mountains have received little

attention since King mapped (1931) and interpreted (1937) the

Shannon F. Rudine, Geology Department, Sul Ross State University,

Alpine, Texas 79832. Bruce R. Wardlaw, U.S. Geological Survey,

926A National Center, Reston, Virginia 20192. David M. Rohr,

Geology Department, Sul Ross State University, Alpine, Texas 79832.

Richard E. Grant (deceased), Department of Paleobiology, National

Museum of Natural History, Smithsonian Institution, Washington,

D.C. 20560-0121.

section, other than the intensive fossil collecting of Cooper and

Grant (1972) and others. Wardlaw et al. (1990) initiated an

interpretative study and revised the map of the northern part of

the northern Del Norte Mountains (Figure 11-1). The current

study maps a more southern part of the northern Del Norte

Mountains and attempts to build upon the work of Wardlaw et

al. (1990) and to refine and improve it. The area between the

two mapped areas has been visited by the authors, but general

access has commonly been denied, so our work in this area is

based solely on one measured section (section 6). The bulk of

the mapping was carried out by Rudine in 1985-1987.

Wardlaw and Grant, commonly accompanied by the other

authors, measured and described sections throughout the

northern Del Norte Mountains from 1983 to 1990. Rudine has,

subsequently to 1987, measured additional sections throughout

the area.

General Stratigraphy

The stratigraphy of the northern Del Norte Mountains is

complex because many units are laterally discontinuous. Much

of this problem was clarified with the identification of King's

(1931) lower massive member of the Capitan Limestone to be

the Vidrio Formation (Rudine et al., 1987; Rohr et al., this

volume) and the collapse breccias King (1931) assigned to the

upper massive member of the Capitan to be the Tessey

Formation (Haneef et al., 1990; Rohr et al., this volume). Still,

the Word Formation displays a great deal of lateral variation,

which is the focus of this paper.

The general relationships of the Road Canyon, Word, Vidrio,

Altuda, and Tessey formations are those of unconformably

bounded units containing lateral facies changing from shoal

and basin in the north to shallow foreland basin and shore to the

south (Figure 11-2). Detailed relations of the upper part of the

291
292 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Road Canyon Formation

WARDLAW ET AL. (1990)

MAP AREA

Northern

Del Norte

Mountains

a—Vidrio Formation

30° 15'-

FlGURE 11-1.—General geologic map of the northern Del Norte Mountains showing section locations, the study

area (enlarged in Figure 11-4), and the area mapped by Wardlaw et al. (1990) (square).

Cathedral Mountain Formation (uppermost Leonardian), the

Road Canyon Formation, the many members of the Word

Formation, the Vidrio Formation, the members of the Altuda

Formation (see Wardlaw and Rudine, this volume), and the

Tessey Formation are displayed in Figure 11-3. The Capitan

Limestone, so pervasive in the northern part of the Glass

Mountains, is completely missing from the Del Norte Mountains. The Capitan may not have been deposited in the Del

Norte region, suggesting a platform did not develop but that

ramp deposition persisted through the late Guadalupian as

represented by the Altuda Formation. The three lower members

of the Altuda are certainly deposited over most of the area

(Figure 11-3; sections 3, 6, D3), suggesting persistent ramp

deposition, as opposed to the Glass Mountains, where only the

first member of the Altuda is widespread as a ramp deposit

before the development of the Capitan platform (Haneef et al.,

1990). If the Capitan was deposited at all, it was much more

limited than in the Glass Mountains, and it has been completely

removed by pre-Tessey or pre-Cretaceous erosion.

Stratigraphic Units

The Road Canyon Formation, the members of the Word

Formation, the Vidrio Formation, and the Altuda Formation in

the study area (Figure 11-4) are described in detail below.
NUMBER 32 293

FIGURE 11-2.—Stratigraphic relationships on a general south to north trend through the northern Del Norte

Mountains for the upper part of the Cathedral Mountain Formation (Leonardian), Guadalupian units, and the

Tessey Formation (Ochoan), and also showing the conodont zonation of Mesogondolella species.

ROAD CANYON FORMATION

The Road Canyon Formation consists of interbedded

limestones and siltstones forming moderately steep slopes,

broken in part by small ledges of limestone. Grayish orange

siltstones form slightly recessive slopes. Siltstones are commonly thin- to very thin-bedded, platy, or flaggy, and appear

similar to basal Word siltstones. Limestones are medium- to

thick-bedded with minor thin beds. Limestone beds frequently

exhibit marked lateral thickness variations; all are laterally

discontinuous. The uppermost limestone bed appears to have

the largest lateral extent.

Skeletal packstones in channel bedforms characterize most

of the formation. Carbonates range from muddy, poorly sorted

wackestones to well-sorted grainstones. Minor beds of limy

siltstones and silty lime mudstones are rare. Scattered,

subrounded grains of quartz silt and fine sand are present in

many thin sections. Well-rounded, chert pebble channel lags

are present at the base of several limestone lenses.

Carbonates commonly consist of silty, peloid, lithoclastic,

skeletal wackestones and packstones (Figure 11-5). Lenses of

winnowed, skeletal grainstone are locally developed in

channels. Microspar cements prevail over coarser interparticle

blocky calcite. Dolomite and ankerite rarely replace the spar

cements. Spar cements and skeletal fabrics are sporadically

replaced by chalcedony. Sedimentary structures include graded

bedding, cross-bedding, planar and stromatolitic laminations,

load deformation structures, and channel lag deposits.

Carbonate allochem percentages vary substantially from bed

to bed. Peloid allochem distribution is erratic. Peloids appear to

be of fecal origin based on their uniform size and degree of

sorting. Intraclasts of lime mudstone are commonly angular,

ranging in size from fine sand- to pebble-sized clasts. Finely

divided planar laminations are present in many pebble-sized

clasts.

Skeletal elements are dominant constituents in all of the

Road Canyon carbonates. Skeletal grains are generally partially

micritized or recrystallized. Silicification is sporadic and

commonly incomplete. Fusulinids, ostracodes, sponge spicules, and dasycladacean algae are common in the channels.

Other elements include uniserial and biserial foraminifers,

brachiopod valves and spines, echinoderm plates, bryozoans,

codiacean and solenoporacean algae, and rare cephalopods,

gastropods, trilobites, and plant material. Calcispheres and

cortoids are minor accessories. Kerogen-filled skeletal chambers and finely comminuted plant debris occur in thin sections

from the top of the Road Canyon.

The Cathedral Mountain-Road Canyon contact is generally

covered, but it appears gradational based on observed field

relations. The Road Cany on-Word contact appears to be

conformable throughout the study area. The contact is difficult

to map in areas where limestone channels are not abundant. In

areas where limestones of the Road Canyon are overlain by

lower Word limestone channels, the two can be separated on

the basis of lateral extent and faunal content. Generally, the

highest Road Canyon limestone has a greater lateral extent than
294 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

r 3 0 0

800-

-200

600-

400-

200-

- 100

FT M

SECOND LIMESTONE AND

CLASTIC MBER

Cathedral Mountain Format!

FIGURE 11-3.—Columnar sections showing the stratigraphic units. (The location of the sections is shown in

Figure 11-1.)

the overlying Word limestones, which rarely exceed 91 m (300

ft) in lateral extent. The lytonnid brachiopod Coscinophora

distinguishes beds of the Road Canyon Formation.

The Road Canyon Formation in the northern Del Norte

Mountains is characterized by marked variation in thickness,

ranging from 1 m (3.3 ft.) of limestone to 32.6 m (107 ft.) of

interbedded limestone and siltstone in the south. In the north,

the unit varies from 6.1 m (20 ft.) of limestone to 61 m (200 ft.)

of interbedded limestone, sandstone, and siltstone.

WORD FORMATION

Eight Word lithostratigraphic units were delimited in the

northern Del Norte Mountains. A southern succession (Figure

11-3) consists of, in ascending order, the first siltstone member,

the first sandstone member, the second siltstone member, the

Appel Ranch Member, and the limy, sandy siltstone member. A

northern succession consists of, in ascending order, the first

sandstone member, the Willis Ranch Member, and the second

sandstone member. Wardlaw et al. (1990) described the

northern succession in detail; the southern succession is

described in detail herein (Figure 11-3).

FIRST SILTSTONE MEMBER.—The first siltstone member is

largely characterized by siltstone, but it also contains common

limestone lenses and channels near its base. Fresh and

weathered surfaces of the siltstone are consistently grayish
NUMBER 32 295

Quaternary (Q), Tertiary (T), Cretaceous (K) deposits

— PERMIAN —

^ B Altuda Formation

/A Vidrio Formation

^ | Limy sandy siltstone member

iJ\ Appel Ranch Member '

I ||| Second siltstone member '

First sandstone member '

First siltstone member '

Road Canyon Formation

Cathedral Mountain Formation

1

 of the Word Formation

FIGURE 11-4.—Geologic map of the area shown in Figure 11-1 of the southern part of the northern Del Norte

Mountains. The topographic base is from the SW part of Altuda, SE part of Bird Mountain, NW part of Dugout

Mountain, and NE part of Mount Ord 7.5 min. quadrangles.

orange. Fresh surfaces of the limestone in the lower portion of

the member vary from yellowish gray and brown, to brownish

gray; weathered surfaces are commonly of a lighter color than

that of the fresh surface. Fresh surfaces of the limy siltstone

lenses are of a moderate yellowish gray color; weathered

surfaces are pale yellowish gray.

Gentle, rounded hills are formed by the siltstones and

limestones of this unit. Excellent exposures of strata are

provided by the arroyos that cut deeply into the siltstones. The

siltstones occur as platy, thin beds, generally less than 1 cm

thick (Figure 11-6).

The limestones display a wide variety of bedding styles.

Peloid packstone/grainstone lenses are commonly dispersed in

thin, featureless beds, generally less than 15.3 cm (6 in.) thick

(Figure 11-6A). Channel bedforms of wackestones, packstones,

and grainstones are massive and medium- to thick-bedded, with

beds ranging from 0.3 m (1 ft.) to 2.4 m (8 ft.) thick, but

generally less than 0.9 m (3 ft.) thick (Figure 1 1-6B). Lenses of

limy siltstone are similar to those of the peloid packstone/

grainstone, except that they are commonly thicker, not

exceeding 0.9 m (3 ft.) in thickness.

The siltstones are composed of fine, angular grains of quartz

silt and fine sand (Figure 11-6C). Other constituents include

skeletal grains and ferroan opaque minerals. Planar and wavy

laminations are subordinate to massive, possibly bioturbated,

beds. Trough cross-bedded, sandy siltstones were observed in

one locality above a limestone channel sequence. Thin sections

reveal a fine ferroan-stained chert cement with vague, distorted,

planar laminations. Chalcedony replacements of skeletal grains

are present. Calcareous cements are present in many thin

sections.

Thin-bedded, peloid packstones and grainstones are characterized by well-sorted coarse silt and fine sand-sized carbonate

grains. Skeletal grains commonly constitute the largest sedimentary particles. Coarse sand-sized carbonate lithoclasts are

not common. Peloids appear as featureless, ovoid- to angularshaped grains of coarse silt-sized micrite, and many appear to

be a product of sediment-ingesting organisms, based on their

shape, size, and structureless interior. Rare angular peloids may

represent finely comminuted lime-mud lithoclasts derived from

a nearby source. Micritization of skeletal debris by boring algae

and sponges would produce similar featureless silt-sized

micrite clasts.

Channel-form wackestones and packstones represent the

most common type of carbonate developed in the first siltstone

member. Carbonate allochems are moderately sorted and
296 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 11-5.—Photomicrographs of the Road Canyon Formation. A, silty, skeletal, lithoclastic packstone

(sample 2-302). B, lithoclastic, skeletal packstone to grainstone (sample 313A). c, silty, skeletal wackestone

(sample 2-300). D, silty, pelletal, skeletal packstone with Epimastopora and sponge spicules (sample 2-302).

Scale of the long axis in the photomicrographs equals 2.9 cm. (Further information on thin-section locations can

be found in Rudine (1988); generally the measured section number is followed by the footage in the section.)

coarser grained in comparison with peloid packstones/

grainstones. Allochem constituents exhibit large bed-by-bed

variations. Most grains are sand sized; however, some beds

contain a significant percentage of granule- to pebble-sized

clasts. Peloids and quartz sand are commonly subordinate to

carbonate lithoclasts and skeletal debris. Numerous small

pebbles of chert, novaculite, and sandstone occur in coarse

channel lags. These "exotic" grains were probably derived from

nearby pre-Permian formations of the uplifted rocks of the

Marathon basin.

Fusulinids are the dominant allochem in many of the lower

carbonate channels. In many channels, they occur almost to the

exclusion of all other allochems. The highest channels in the

sequence contain fewer fusulinids and are marked by a more

diverse, normal marine fauna. Allochems in thin section are

cemented by varying amounts of microspar and blocky spar.

Chert replacement of skeletal grains and cements is common.

Dolomite rhombs and cements are not common. Sedimentary

structures include graded bedding, cross-bedding, cut-and-fill,

and current aligned skeletal tests; imbricated clasts are rare.

Sporadic lenses of argillaceous lime mudstone and limy,

skeletal siltstone occur, respectively, below and above the main

carbonate channel sequence in the lower part of the member.

Lime mudstones contain minor amounts of clay, quartz, silt,

and sand-sized particles of lime-mud, and are interbedded with

many thin beds of shale and siltstone. Load-deformed bases are

common where lime mudstones overlie shale interbeds. In

many areas, bedding planes are covered by numerous ammonoid shells.

Scattered lenses of limy, skeletal siltstone occur above the

channel sequence. Beds are locally replete with sponge spicules

and brachiopod spines. Large concretions of sandy, limy

siltstone, several feet across, are found in close association with

the limy, skeletal siltstone. Pebble- to cobble-sized concretions

are present near the top of the member in section 4.

Fossils in the first siltstone member are largely confined to
NUMBER 32 297

FIGURE 11-6.—The first siltstone member of the Word Formation. A, view of thin beds of peloidal packstone

(below hammer) separated by thin-bedded siltstones, located south of section 4. These are interpreted as overbank

deposits. B, view of a limestone channel, south of section 4. Note sandy cross-beds to the left of hammer and

multiple reactivation surfaces to the right of hammer. (Hammer is 39.5 cm long.) c, photomicrograph of siltstone

containing calcispheres and sponge spicules (sample 4-85). D, photomicrograph of peloidal skeletal packstone

(sample 299B). Scale of the long axis in the photomicrographs equals 2.9 cm.

the carbonate beds. No fossils were observed in the shale

interbeds. Horizontal burrows are present in many of the

siltstone beds. Featureless siltstones may represent beds that

were extensively burrowed by infaunal organisms. Marine

megafossils (other than sporadic beds of spicule-rich siltstone)

are absent.

Ammonoids are rare but occur abundantly on some bedding

planes of lime mudstones. The rich ammonoid fauna described

by Furnish and Glenister (in Cooper and Grant, 1977, USNM

Loc. 732z) occurs in a channel carbonate equivalent to the top

of section 1 (Figures 11-1, 11-3) a few hundred meters around

the hill to the northeast. Fusulinids dominate the fauna in most

of the channel bedforms. Brachiopods are present in moderate

numbers and diversity, but most are broken and unidentifiable.

Whole specimens are generally not silicified. Cryptostome

bryozoans, such as Fenestella, and ramose forms are also

present in small numbers. Crinoid columns and ostracodes are

frequent accessories in the channel deposits. Chambered

calcareous sponges, trilobites, corals, and echinoid tests are

rare.

Algal remains were observed in many carbonate thin

sections. Packstones and grainstones contain sporadic occurrences of dasycladacean and solenoporacean algae (Mizzia and

Epimastopora; Solenpora and Parachaetetesl', respectively).

Algal? filaments of undetermined origin are also present.

The upper contact of the first siltstone member with the

overlying first sandstone member is poorly exposed and is

probably gradational in nature. The uppermost beds of the first

siltstone are more sandy in comparison with beds below. The

lowest beds of the overlying first sandstone member consist of

fine- to medium-grained, moderately sorted, quartz sands with

flakes of muscovite. Sands of the first sandstone member are

rusty, reddish orange. The contact is generally marked by a

small increase in slope.

FIRST SANDSTONE MEMBER.—The first sandstone member

divides the first siltstone member from the second siltstone
298 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

member and also helps to the define structural features in the

study area (Figure 11-4). The sandstones of this unit form

smooth, nondescript slopes, somewhat steeper in comparison

with those of the siltstone units above and below. Two

prominent ledges are present in the upper part of the member

near sections 2 and 4. The highest ledge was traced out by King

(1931:132) on his geologic map.

Medium- to thick-bedded sandstones are common with

subordinate very thin- to thin-bedded intervals. Sandstones are

sublitharenites (Dott, 1964). The sandstones in the lower

two-thirds of the member are poorly sorted, very fine- to

medium-grained, with dominantly angular grains of quartz

sand. Quartz and strained quartz compose the sand-sized

grains. Accessory grains of chert prevail over sand-sized grains

of siltstone, shale, and spicular chert. Grain boundaries are

sharp. Many grains display the effects of corrosion by

surrounding calcite and dolomite cements. Identification of

cement(s) proved difficult due to pervasive ferroan staining.

Point contact dissolution features are present in some thin

sections; sutured contacts are rare. Flakes of muscovite are

common at the base of the member.

Sandstones in the upper one-third of the member exhibit a

greater textural maturity in comparison with those below.

Sandstones in the upper portion are well-sorted, mediumgrained, subround to subangular quartz sands. Quartz sands

significantly outnumber the other detrital grains common in the

beds below. The detrital constituents are bound together by

multiple cements. The cement texture is dominated by an

equigranular, medium silt-sized, ankeritic cement bounded by

minor amounts of nonferroan calcite microspar. Siliceous

syntaxial cements and overgrowths are present. Quartz grains

commonly occur as sutured aggregate (polycrystalline) grains.

Sutures are straight or slightly crenulate. Stylolites were not

observed. Strained quartz grains are common. No feldspar

grains were observed.

Minor beds of coarse siltstone occur at irregular intervals.

The siltstone beds are commonly covered and form recessive

benches between beds of sandstone.

Sedimentary structures include uncommon low-angle crossstratification, trough cross-bedding, and normally graded beds.

Thin conglomeratic intervals are present at a few locations.

Clasts in the conglomeratic interval are composed of flattened

pebbles of siltstone and silicified wood (Figure 11-7A).

Abundant Skolithos-type burrows are found in the upper 1.25 m

(4 ft.) of the member (Figure 11-7B). Limy siltstone concretions, 1.3 cm (0.5-1.5 in.) in diameter, are locally abundant.

Fossils are rare in the first sandstone member. Silicified

wood fragments were found in the conglomeratic interval at the

base of section 5. Abraded fragments of crinoids, brachiopod

spines and valves, bryozoans, and cephalopods are rare. One

reworked concretion bed contained abundant, poorly preserved

crinoids, bryozoans, brachiopods, fusulinids, trilobites, and

possible algae.

The upper contact with the overlying second siltstone

member is marked by an abrupt decrease in grain size, bed

thickness, and weathering resistance. The highest bed in the

first sandstone member is commonly thick-bedded and heavily

bioturbated. Burrows are common to (if not diagnostic of) the

top surface of the first sandstone member, apparently indicating

a preserved surface (nondepositional or erosional). In contrast,

the beds of the overlying second siltstone are very thin-bedded

and lack abundant burrows. Concretions are rare in the second

siltstone, whereas they are fairly abundant in the siltier intervals

in the first sandstone member.

This unit is found in the northern part of the northern Del

Norte Mountains (Wardlaw et al., 1990) where it is similar.

There it is composed largely of angular quartz grains with some

chert, sparse mica, and sedimentary rock fragments. Bioturbation is not apparent, but discontinuous pebble beds and

low-angle cross-bedding is common in the upper part of the

unit. The member is reported to be very thick south of the study

area (King, 1937), reaching a thickness in excess of 152 m (500

ft.). The upper beds of the member can be traced along

discontinuous outcrops from the study area to Bird Mountain;

however, thickness variations cannot be determined because of

insufficient exposure.

SECOND SILTSTONE MEMBER.—The siltstones and fine

sandstones that make up the majority of this unit form smooth,

featureless slopes (Figure 11-8); benches and ledges are rarely

developed. The majority of exposures are covered with a thin

veneer of talus or regolith. Bedding habits are varied in the

study area, but very thin beds are commonly found at the base

of the unit (Figure 11-9A). AS a whole, the member is

thin-bedded with subordinate medium beds. The unit is largely

represented by a medium to coarse siltstone. Beds of fine sandy

siltstone, silty fine sandstone, and minor beds of sandy and silty

lime mudstone are locally present. Sedimentary structures

include flaser bedding, planar laminated beds, wavy laminations, and abundant horizontal burrows. Structureless beds may

represent rapid deposition and/or extensive bioturbation.

The siltstones are immature, poorly sorted, and fine- to

coarse-grained. The majority of the quartz silt grains are

angular. Ferroan-stained siliceous and/or ankeritic cements are

common. Calcareous cements, frequently noted in the field,

appear to be rare in thin section. Ferroan masking of the

cements could explain this apparent discrepancy. Skeletal

elements are frequently replaced with chalcedony.

Limestones are commonly represented by thin lenses of silty,

skeletal lime mudstones and frequently lack any well-defined

sedimentary structures. Wackestones are rare. Graded bedding

and burrow infilling are present in a few beds, and stringers of

off-white and reddish orange chert are present. Fossils are

generally rare; however, sponge spicules and ammonoids are

present in many beds, and brachiopods, bryozoans, crinoids,

ostracodes, and fusulinids are rare accessories. Abundant algal

remains, peloids, and a mixed normal marine fauna were

observed in thin section. One collected bed from section 2
NUMBER 32 299

FIGURE 11 -7.—-The first sandstone member of the Word Formation. A, view of conglomeratic sandstone with

clasts of siltstone and silicified wood, Red Haw Spring Canyon. B, view of Skolithos-type burrows at the top of

unit. C, photomicrograph of argillaceous sandstone (sample 4-380). D, photomicrograph of lithoclastic sandstone

(sample 4-290). Scale of the long axis in the photomicrographs equals 2.9 cm.

contained an abundant silicified ammonoid fauna. The limestone beds appear to represent the lateral extension (although

not mappable) of the Willis Ranch Member of the Word

Formation (Figure 11-3) from the northern part of the northern

Del Norte Mountains described by Wardlaw et al. (1990).

The contact of the second siltstone member with the Appel

Ranch Member is gradational. Beds belonging to the overlying

Appel Ranch consist largely of silty, skeletal lime mudstones

and wackestones. In the western half of the study area (Figure

11-4), the boundary is consistently difficult to discern due to a

significant increase of silt in the lower carbonates of the Appel

Ranch. In Red Haw Spring Canyon, approximately 23 m (75

ft.) of Appel Ranch limestones grade laterally, over a distance

of 0.8 km (0.5 mi.), into very limy siltstones. In this gradational

interval, thin-bedded siltstones were assigned to the second

siltstone member, and medium-bedded, limy siltstones and

silty lime mudstones were assigned to the overlying Appel

Ranch Member. The second siltstone member becomes more

sandy in its northern extent (Figures 11-1, 11-3; section 6),

apparently grading laterally into the second sandstone member

described by Wardlaw et al. (1990) in the northern part of the

northern Del Norte Mountains.

APPEL RANCH MEMBER.—Carbonates and elastics of the

Appel Ranch Member form a variety of slope types in the study

area (Figures 11-8,11-10). Carbonates in the lower one-third of

the unit form moderately inclined slopes of greater declivity

than in adjacent beds. Middle beds form nondescript convex

slopes, broken in part by random, mound-shaped carbonate

masses. The upper one-third of the Appel Ranch forms slopes

similar in appearance to the middle beds except they lack the

abundant carbonate masses.

The Appel Ranch carbonates are medium-bedded with

subordinate thick beds (excluding carbonate masses). Thinbedded intervals are abundant in the upper one-third of the

member. Interbeds of siltstone and sandstone are thin- to

medium-bedded. Clastics are either featureless or finely
300 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 11-8.—View of the Word and Vidrio formations in the central portion

of "Split Canyon." The top of the second siltstone member of the Word forms

the smooth slope at the extreme lower right corner of the photograph. The first

resistant bench above the slope marks the base of the Appel Ranch Member.

Note that the lighter colored layer above this bench contains a large channel

(left and slightly below center). Uniform, even beds of limestone at the top of

the Appel Ranch Member and the recrystallized peloidal wackestone bench

(poorly defined in this photograph) form the interval below the nonbedded

carbonates of the Vidrio Formation (upper part of the photograph). Cretaceous

limestones form the top of the hill above the Vidrio Formation.

FIGURE 11-9.—The second siltstone member of the Word Formation. A, view

of the characteristic bedding habit; hammer point points to an irregular lens of

poorly graded, lithoclastic and dolomitic wackestone. (Hammer is 39.5 cm

long.) B, photomicrograph of siltstone (sample 4-394). Scale of the long axis in

the photomicrographs equals 2.9 cm.

FIGURE 11-10 (left).—View of two carbonate masses in the Appel Ranch

Member. The carbonate masses form resistant, nonbedded bodies of limestone

that occur at the same stratigraphic horizon (in the middle of the Appel Ranch

Member). Typical Appel Ranch limestones are seen above and below the

masses. Cretaceous limestones cap the hill above the masses. Tertiary volcanics

form the hill seen in the upper left corner of the photograph (Mount Ord).
NUMBER 32 301

laminated. Wavy laminations are present in the lower one-third

of the Appel Ranch carbonates, whereas planar, wispy, and

cross-laminations are locally abundant in higher carbonate

beds. Carbonate masses are uniformly massive and thickbedded. Thick beds also occur in channel bedforms (Figure

11-8).

Appel Ranch lithologies consist primarily of silty, lithoclastic, skeletal lime mudstones and wackestones. Packstones,

grainstones, and dolostones are not common, constituting just

15 percent of the Appel Ranch carbonates. The lime mudstones

and wackestones are sparsely sandy and pelletal. Peloidal

limestones are very common in the upper one-third of the

member. Siltstone and sandstone interbeds contain variable

amounts of skeletal and carbonate lithoclastic debris. Gradational sequences of siltstone, limy siltstone, and silty lime

mudstone or wackestone are common in the interbedded

intervals.

Sedimentary structures include low angle crossstratification, normal- and reverse-graded bedding, currentaligned fossils, clastic dikes, penecontemporaneous and postlithification load deformation structures, penecontemporaneous slumping, and trace fossils. Channel bedforms are common

in the middle and upper portions of the Appel Ranch. Channels

were not observed in the lower part of the member. The

majority of the channels are small, rarely exceeding 6 m (20 ft.)

in width. Depth-to-width ratios are estimated to range from

1:4 to 1:10 or greater. The greatest channel widths and

depths are 15-20 m (50-70 ft.) and 6 m (20 ft.), respectively.

The carbonates of the Appel Ranch Member are described as

lower, middle, upper, and carbonate masses. The lower Appel

Ranch carbonates are characterized by sparsely sandy and

dolomitic, peloid, lithoclastic, skeletal, silty lime mudstones

and wackestones. Recrystallization and dolomitization are

generally uncommon; however, some dolomitization is fabric

selective, replacing micrite particles. Ferroan microspar cements are common. Ostracodes, crinoids, and sponge spicules

are abundant, but algal traces are absent.

The middle Appel Ranch carbonates are characterized by

sparsely sandy and pelletal, dolomitic, lithoclastic, skeletal,

silty lime mudstones. Wackestones, packstones, and grainstones are uncommon. Recrystallization is slight, with rare

matrix inversion. Dolomitization is slight to moderate and is

matrix selective. The majority of samples (86 percent) contain

some dolomite. Ankerite is present in 45 percent of the

samples, and nonferroan dolomite is present in 60 percent of

the samples. Microspar and coarse calcite cements are

dominantly ferroan. Calcite void-fills may exhibit up to 20

subtle generations of cement. Faunal constituents consist of

crinoids and fusulinids and minor bryozoans, sponge spicules,

ostracodes, and algal traces. Prelithification, sediment stabilization features are present.

The upper Appel Ranch carbonates are characterized by

sparsely sandy, pelletal, and lithoclastic, dolomitic, skeletal,

silty, peloid lime mudstones and wackestones. Packstones are

rare. Samples are generally slightly recrystallized, but the

recrystallization varies from minor to extensive. Dolomite is

present in 75 percent of the samples. Microspar cements prevail

over coarser calcite. One-half of the calcitic cements are

ferroan. Calcite and dolomite void-fills commonly display

several dozen generations of cement. Moldic porosity is

common. Ostracodes, crinoids, bryozoans, foraminifers, calcispheres, sponges, and sponge spicules are common.

The middle beds of the Appel Ranch are frequently

interrupted by massive mound-shaped carbonate accumulations, referred to herein as "masses." These structures are

limited to the upper half of the Appel Ranch Member.

Sixty-four mound-shaped masses were observed (Figure

11-11), with the majority occuring in the middle portion of the

member. Low altitude aerial reconnaissance suggests several

such occurrences also may be present in the southwestern Glass

Mountains, due east of Altuda siding. The masses range in size

from inconspicuous structures 61 cm high and 93 cm long (2 x

3 ft.) to immense structures 12.2-15.2 m high (40-50 ft.) and

76.2 m (250 ft.) in length. The large mass at the top of section

2 was originally interpreted by King (1931:132, section 7, bed

1) as an isolated remnant of the lower massive member of the

Capitan Limestone (= Vidrio Formation).

The masses commonly form resistant mounds of massive,

nonbedded carbonate that stand in sharp contrast with the

adjacent bedding. Weathered surfaces frequently mask internal

textures, but occasional "windows" reveal much of the hidden

features. The mass sequences are characterized by recurrent

vertical and lateral facies successions. These facies are

subdivided into underlying, mass, mass flank, and overlying

beds.

The underlying lithologies vary considerably from mass to

mass. Underlying beds include siltstones, fine sandstones, lime

mudstones, and wackestones. All underlying lithologies appear

to contain skeletal debris and/or lime-mud lithoclasts. The

contact relationships are frequently poorly exposed. Partially

winnowed lags were observed below a few of the masses;

however, it is uncertain whether all masses overlie such

deposits. Underlying bedforms are generally undulatory and

lack definable sedimentary structures. The examined carbonates are characterized by sparsely sandy and lithoclastic, silty,

skeletal, peloid lime mudstones, and they are rarely dolomitic.

Bryozoans, crinoids, and algal structures are present. Sparry

patches are not present.

The composition of the carbonate mass facies varies from

mass to mass. These mass facies include massive skeletal lime

mudstones and skeletal and/or lithoclastic wackestones. Intramass facies can be subdivided into basal, middle mass or

mass core, and upper mass regimes. Intramass facies are

gradational and may be difficult to define in each mass. Flank

facies are marked by variations in thickness, lateral extent, and

overall texture. Flank beds exhibit both symmetric and

asymmetric development. Mass and mass flank facies may be
302 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

103° 30'

-30c17'30"

-30° 15"

3 KM

FIGURE 11-11.—Map showing the distribution of carbonate masses in the Appel Ranch Member. The masses are

designated by the solid black areas.
NUMBER 32 303

overlain by draping beds that thin proximal to the mass. Some

masses do not have discernable draping beds.

The transition from underlying bed to basal mass is abrupt

and apparently rarely gradational. The underlying beds-basal

mass contacts are generally undulatory with a thin lithoclastrich underlying horizon. Underlying Iithoclasts are ordinarily

composed of angular, granule- to cobble-sized clasts of lime

mudstone. Underlying and lateral beds rarely interfinger with

the basal portion of the mass. Basal mass beds consist of

growth assemblages of crinoids, bryozoans, and/or sponges.

Basal mass beds also may contain recrystallized, angular

lime-mud Iithoclasts cemented in a darker lime mudstone.

Similar lithoclast-rich deposits occur in the flank breccia beds;

however, the flank breccia deposits are cemented in a markedly

siltier lime-mud matrix. Clastic dikes are occasionally injected

into the basal and middle portions of the mass, indicating

moderate lithoclastic loading of the underlying strata. The

clastic dikes are composed of lithic-rich, silty lime mudstone

with common flow-line features.

The basal mass carbonates consist of a partially dolomitized,

moderate to heavily recrystallized, sparsely silty and pelletal,

lithoclastic, peloid, skeletal wackestone. Microspar cements

outnumber pseudospar and blocky spar cements. Peripheral

enlargement of microspar cement indicates an inversion of

fine-grained cements to coarser pseudospar. Dolomite and

ankerite occur at random in 60 percent of the samples

examined. One dedolomitized sample was noted. Ostracodes

and sponge spicules are background accessories to crinoids,

bryozoans, and algal structures. Sediment stabilization structures, such as algal overgrowths and encrustations of sediment,

are present in 25 percent of the thin sections.

The mass core sediments are similar to the basal facies

sediments; they primarily differ in the degree of substrate

modification. Prolific crinoid and bryozoan bafflestones and

framestones are developed in many of the smaller masses

(Figure 11-12). Calcareous sponges are found commonly in

association with the crinoids and bryozoans. In many cases,

sponges appear to be the primary sediment contributor because

of the abundance of spicules in thin section. The mass core

facies appear to vary depending on the size and orientation of

the structure. Masses with widths greater than 12 m (40 ft.)

commonly lack abundant skeletal remains in the central

portions of the structure. In larger masses, skeletal accumulations tend to concentrate along the outer margins of the mass

core.

The mass core sediments differ from the basal sediments in

that they possess sheltered voids and early marine cements

(Figure 11-13). The mass core sediments consist of dolomitic

and moderately recrystallized, lithoclastic, skeletal, peloid

wackestone. Peloid packstones and grainstones are rare.

Cements vary from microspar to blocky spar. Primary sheltered

void spaces are commonly lined with a fibrous, early marine

cement. Sheltered voids are filled with spar-cemented peloidal

FIGURE 11-12.—View of abundant well-preserved crinoids in a carbonate

mass.

sediments, blocky calcite, or a combination of the two.

Algal-stabilized sediments and numerous Tubiphytes occur in

thin sections containing early marine cements (Figure 11-14).

The occurrence of these structures suggests initial cementation

in shallow marine waters.

Voids formed during exposure to a freshwater phreatic

environment are found in mass core sediments. Evidence

suggests that these voids formed via selective solution and

replacement of several precursor grain types and textures. Thin

section and field observations support the interpretation that

many voids represent extensively recrystallized molds after

sponges. Other voids appear to have formed as a result of

dissolution of recrystallized peloid lime mudstones, particularly in areas where fractures and coarser inverted microspar

cements are present. Fracturing events are difficult to date in

thin section. Cathodoluminescence analysis of mass carbonates

revealed several generations of fracture fillings and secondary

mineralization. The voids are generally lined with zone-free

ankerite surrounded by multiple zones of dolomite and

nonluminescent dolomite and ferroan calcite. Dolomite growth

is terminated by a thin, highly luminescent, nonferroan calcite.

Blocky calcite void fillings consist of alternating luminescent
304

SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 11-13.—Photomicrographs of the Appel Ranch Member carbonate mass from sample 147M. A, skeletal,

peloid packstone. B, void lined with recrystallized fibrous cement, partially filled with sediment and spar. C,

skeletal and lithoclast grains in recrystallized fibrous cement. D, skeletal, peloid wackestone showing

recrystallized fibrous cement. Scale of the long axis in the photomicrographs equals 2.9 cm.

marine (?) calcite and nonluminescent, ferroan, freshwater

phreatic calcite. A majority of void fillings exhibit crystal

coarsening toward the void center. Loucks (1977) believed

such a trend to be distinctive of freshwater phreatic cementation. Individual calcite crystals may contain several dozen

zoned cement generations. Peloid lime mudstones may be

partially or completely replaced with rhombs of ankerite

rimmed with dolomite. Dolomitic replacements possibly

represent transitions between marine phreatic and freshwater

phreatic diagenetic environments.

The sediments of the upper mass facies are lithologically

similar to the mass core sediments, only they differ slightly in

the degree of dolomitization and character of the highest

horizon. The upper mass sediments exhibit greater variations in

dolomite content than the facies below. Extensively dolomitized zones were observed in many thin sections. The

observation of syntaxial overgrowths on echinoderm fragments

further strengthens the arguments for freshwater phreatic

cementation (Loucks, 1977).

The character of the upper mass horizon varies from

structure to structure. Many masses possess a crinoidal

limestone cap replete with current-aligned, disarticulated

crinoid columnals. Crinoid accumulations are absent from a

majority of masses. The abundance of algae and the lack of

coarse skeletal debris in thin sections of the mass sediments

may suggest either a restricted water chemistry or perhaps algal

stabilization, if present, inhibited the attachment of other

marine fauna.

The mass flank facies demonstrate a wide developmental

range. Flank beds consist of moderately to poorly sorted

mass-derived breccias admixed with skeletal debris. Flank

sediments vary from granule-sized particles of lime mudstone

to boulders of lithified mass material, several 10s of cm (1-3

ft.) across (Figure 11-15B). Flank breccia development may be

symmetric, asymmetric, or absent. Breccia beds extend from

the mass core for a few meters (10s of ft.) to 30 m (100 ft.) or

more. Moderately sorted flank breccias are cemented in blocky

calcite and silty micrite matrix. Poorly sorted flank breccias
NUMBER 32 305

FIGURE 11-14.—Photomicrographs of the Appel Ranch Member carbonate mass from sample 253. A, Tubiphytes

in peloid wackestone. B, skeletal, peloid packstone containing Tubiphytes. C, skeletal fragments in isopachous

cement. D, partially recrystallized skeletal, peloid wackestone containing recrystallized mollusk shell and

Tubiphytes with isopachous cement above. Scale of the long axis in the photomicrographs equals 2.9 cm.

commonly consist of chaotic boulder- to pebble-sized clasts

floating in a massive, thick-bedded silty lime mudstone matrix.

Distal portions of these beds grade laterally into the typical

medium-bedded, slightly lithoclastic silty lime mudstones of

the Appel Ranch. Flank breccias "lime up" proximal to the

mass, grading laterally into massive carbonates. No apparent

relationship exists between the extent of the flank breccias and

the size of the mass.

The masses that display well-developed flank facies generally display an overlying facies. The overlying facies are

characterized by a sequence of graded beds that drape over the

mass and mass flank facies (Figure 11-1 5A). These drape beds

thin proximal to the mass and thicken distally off mass where

they may interfinger with upper portions of the flank facies.

The lower drape beds consist of skeletal packstones and

grainstones that grade upward into skeletal wackestones and

lime mudstones. The highest drape beds consist of crosslaminated, silty lime mudstones with well-defined silty

laminations. The highest drape beds can be traced for great

distances away from the mass, thus indicating an even

post-mass topography. Drape-bed development appears to be

limited to the highest mass horizon. Vertically stacked masses

were observed at several locations. In each case, the mass(es)

positioned below the uppermost structure(s) lacked a definable

overlying facies. Beds of the overlying facies grade upward

into medium- and thin-bedded Appel Ranch siltstones and

carbonates.

The contact between the Appel Ranch Member and the

overlying limy sandy siltstone member is gradational in the

majority of exposures; however, at many locations, carbonates

of the Vidrio Formation directly overlie carbonates and

siltstone of the Appel Ranch. This suggests the presence of an

unconformity beneath the Vidrio that cut out the limy, sandy

siltstone member. North of the study area, in section 6, the

upper Appel Ranch consists of interbedded, sandy, channel

carbonates and sandstones that, in turn, are overlain by

recrystallized carbonates of the Vidrio Formation. The more
306 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 11-15.—Views of the Appel Ranch Member carbonate masses. A,

carbonate mass and draping bed; hammer rests on mass. Note the steeply

inclined, thin-bedded limestones above and to the right of the hammer. B,

flanking bed of a mass. Note the angular character of the mass-derived breccia

clasts. The clasts range from pebble to boulder size and "float" in a featureless

silty lime-mudstone matrix.

sandy interval in the upper portion of the Appel Ranch may

represent a condensed limy, sandy siltstone interval separating

the two units.

Western exposures of the upper Appel Ranch are characterized by rapid vertical and lateral lithologic changes, and they

contain a variety of carbonate lithologies interbedded with limy

siltstones. Silty, skeletal, and lithoclastic wackestones common

to the eastern part of the study area are replaced westward by

extensively recrystallized, partially dolomitized, skeletal wackestones. Dissolution voids filled with coarse, milky calcite spar

and cherty patches dominate the surface texture. Recrystallized

sparry and cherty wackestones commonly occur as massive

channel-fill deposits, some of which produce load deformation

structures in the underlying limy siltstone. Another common

lithology found in the western outcrops consists of thinbedded, recrystallized, cherty, peloid, and silty mudstones.

Bedforms common in the eastern outcrops also are found in the

western area. Channel intervals appear to occur with higher

frequency in the western area. Along the south wall of Red Haw

Spring Canyon, silty carbonates of the Appel Ranch are

successively replaced up section, in a westward direction, by

limy siltstones. Carbonate mass numbers drop off substantially

in the western portions of the canyon.

LIMY, SANDY SILTSTONE MEMBER.—In the western half of

the study area, carbonates of the Appel Ranch Member and the

Vidrio Formation are separated by a thin wedge of elastics and

dolomitic carbonates. This unit is best exposed in the

south-facing slopes of Red Haw Spring Canyon, due east of

section 5. Exposures in the low, east-facing foothills are not as

easily defined as are those in the deep western canyons. The

unit apparently pinches out to the north of the study area.

Cretaceous limestones unconformably overlie the unit to the

south of hill 6129 (Figure 11-4).

Interbedded limy, sandy siltstones and skeletal, peloid

wackestones characterize the unit. Most of the unit is

thin-bedded, but minor medium beds may be locally abundant.

The lower beds of the unit form a prominent bench of

dolomitized, skeletal, peloid wackestones with subordinate

sand and silt-rich beds. Channel bedforms are common in the

wackestone/siltstone interbeds. Planar laminations and crossbedding are present in channel bedforms. Chert-rimmed,

spar-filled voids, resembling dissolution gypsum rosettes, are

frequently present in the peloid wackestone bench. Calcitic

fenestrae, reminiscent of "bird's eye" fabrics, were noted at

several locations.

Limy, sandy siltstones constitute the remainder of the unit

above the peloid wackestone bench. The siltstones are

noticeably coarser-grained in comparison with those in the

members below. Coarse siltstones contain a moderate amount

of fine to medium-sized quartz sand. Quartz grains are angular.

Calcareous and dolomitic cements are commonly present. Thin

sections of the peloid wackestones are textually and compositionally uniform. Wackestones possess minor amounts of

angular quartz silt and/or sand. Anhedral and subhedral microdolospar cements prevail over calcitic microspar cement.

Allochems consist of abundant micritized skeletal grains and

peloids. Lithoclasts are present in a few beds, but very few were

observed in thin section (Figure 11-16). Recrystallized (dolomitized?) skeletal grains are present in many thin sections. The

majority of the carbonates consist of very well-sorted, skeletal

(foraminiferal-algal), peloid wackestone. Peloid lime mudstones and packstones are present, but they occur less

commonly.

Skeletal elements appear to represent a restricted marine

environment. Few marine megafossils were observed in the

field. The brachiopod Hustedia and fusulinid molds were noted

in exposures near hill 6129 (Figure 11-4), and skeletal-bearing

intraclasts were noted southeast of section 5. Of the fossils

observed in thin section, all appeared to be juvenile forms.

Foraminifers and algal remains are common constituents in

many thin sections. Many foraminifers resemble poorly
NUMBER 32 307

FIGURE 11-16.—Photomicrographs of carbonates from the limy sandy siltstone

member of the Word Formation. A, sandy, silty lime mudstone (sample 5-299).

B, slightly silty, skeletal, lithoclastic wackestone (sample 3-6). Scale of the long

axis in the photomicrographs equals 2.9 cm.

oriented specimens of the fiisulinacean Rauserellcf!. Algal

remains consist of the partially recrystallized dasycladaceans,

MacroporellaP. and EpimastoporaP.. Other elements include

heavily recrystallized and/or micritized echinoderm plates,

ostracodes, fusulinids, and brachiopod spines.

Peloids constitute the dominant allochem in all of the

carbonates sampled. Peloids are composed of fine sand-sized

grains of structureless micrite. All are well sorted and most are

well rounded. Shapes vary from ovoid particles to elongate,

subangular grains. Ovoid particles possibly represent fecal

grains, whereas larger, elongate grains may represent organically decomposed skeletal fragments.

Siltstones and wackestones of the limy, sandy siltstone

member apparently conformably overlie the carbonates of the

Appel Ranch Member. Dolomitic peloid wackestones are more

common in the majority of the western exposures. Siltstone

distribution is erratic, apparently reflecting a response to the

paleotopography and to the overlying unconformity below the

Vidrio Formation, which commonly cuts out the member.

VIDRIO FORMATION

Carbonates of the Vidrio Formation typically form fairly

steep convex cliffs along the east-west trending canyons.

Generally, the Vidrio exhibits little topographic expression in

areas where slope gradients are low and/or uniform. The

majority of the Vidrio consists of massive recrystallized and

dolomitized carbonates, nearly devoid of bedding. Thin to

medium-thick beds may be locally present near the upper and

lower boundaries.

Unaltered and moderately recrystallized carbonates consist

of silty and nonsilty, lithoclastic, skeletal mudstones, wackestones, and packstones (Figure 11-17). Mudstones and wackestones are commonly peloid-rich. Peloid packstones are present

in section 3 and section 5. Sedimentary structures are rare.

Wispy, planar laminations resembling algal laminites are

present in two thin sections. Scattered grains of coarse quartz

silt and very fine sand are present in many thin sections. Quartz

grains are angular to subround. Authigenic quartz grains are

rare. Ferroan stains and opaque minerals sporadically occur

along fractures and in the groundmass. Silt-rich beds are

present at the base and the top of the formation. Siltstone

lithoclasts and void/cavern fillings are locally present in the

middle and upper portions of the formation. Siltstone fillings

are interpreted to represent vadose/karst silt infillings. Corroded, angular to subround pebbles and cobbles of carbonate

are commonly found in larger karstic zones, near the upper

boundary of the formation (Figure 11-18).

Thin section and cathodoluminescence studies document a

complex history of post-depositional diagenetic events that

include extensive recrystallization and dolomitization. Commonly, peloids have been completely replaced with ankerite or

dolomite. Microspar cements have been replaced with microJ;'

FIGURE 11-17.—View of corroded limestone pebbles and cobbles floating in a

silty lime mudstone matrix, which represent karst sink infill, in the Vidrio

Formation near section 6.
308 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 11-18.—Photomicrographs of the Vidrio and Altuda formations. A, recrystallized bryozoan in a peloid

wackestone (sample PLMDUGOUT, recrystallized Altuda for comparsion with Vidrio lithologies). B,

recrystallized fusulinid in a peloid packstone (sample 3-9). c, recrystallized and dolomitized skeletal, peloid

wackestone? (sample 5-405). D, recrystallized and dolomitized skeletal lime mudstone (sample 179). Scale of the

long axis in the photomicrographs equals 2.9 cm.

dolospar. Fractures and voids are common, and fractures are

commonly coated with dolomite linings. Skeletal grains are

recrystallized and show internal dolomite growth. Rarely,

depositional textures and skeletal grains are completely

obliterated. Calcite infilling of voids and fractures, which show

dozens of generations or zones, has been observed. Dolomite

and/or ankerite growth is rarely observed in the calcite void fill.

Dedolomitization is rare. Chalcedony replacement of calcite

void filling also has been observed. Micritic, nonskeletal, fine

sand-sized allochems are preferentially dolomitized over other

allochems. Thin sections reveal that peloids are commonly

replaced first, followed by micritic lithoclasts, lime mudstones,

calcitic cement, and skeletal components.

Local variations in lithology, permeability, and diagenetic

susceptibility appear to be primary constraints influencing the

degree of alteration. Shallow-burial meteoric diagenesis is

probably responsible for most of the recrystallization seen in

the Vidrio Formation, a large part of which may be attributable

to subaerial exposure.

Skeletal constituents varied in abundance from sample to

sample. Normal marine forms, such as crinoids, ostracodes,

dasycladacean algae, bryozoans, sponges and sponge spicules,

fusulinids, and brachiopods, are present. Bryozoans are present

in virtually every sample. Allochems are commonly micritized

or recrystallized.

Fossils in the Vidrio Formation are generally poorly

preserved. A small number of silicified brachiopods and fairly

well-preserved fusulinids are present in a fault block, 701 m

(2300 ft.) northeast of hill 4893 (Cooper and Grant, 1972:162,

1977:3270-3271, 3316), originally mapped by King (1931) as

the lower massive member of the Capitan (= Vidrio) and

identified as Capitan by Cooper and Grant. The fauna clearly

belongs to the Altuda, and it has been mapped as a dolomitized

fault sliver of the Altuda Formation.
NUMBER 32 309

The contact relationship of the Vidrio Formation with the

underlying and overlying units appears to vary over the extent

of its exposure. Basal conglomerates and lags are very rare. The

lower depositional surface is generally level; however, in the

north-facing slopes of Red Haw Spring Canyon, the Vidrio

appears to be deposited on a highly irregular surface. Estimates

indicate that in this area there is 18 m (60 ft.) of depositional

relief developed on the pre-Vidrio surface. The origin of this

relief cannot be completely ascertained due to poor exposures.

Outcrop symmetry is suggestive of a massive channel fill, but

channel features are not clearly developed. A similar type of

contact is present in the immediate vicinity of section 5, but the

relief involved appears to be less than 3 m (10 ft.). This relief

appears to be primary, suggesting that a channel surface may be

locally developed. No such relief was noted in the remaining

exposures. Field observations of the Vidrio along sections 3, 5,

and 6 note the presence of locally abundant siltstone-rich layers

and void fillings. These features are highly suggestive of

meteoric diagenetic processes. Karstic surfaces and void fills

are well developed in section 6. There, irregular voids and sinks

are filled with angular, corroded pebbles and boulders of

carbonate encased in a siltstone fill (Figure 11-18). The

presence of abundant karst features in the vicinity of section 6

suggests a period of subaerial exposure prior to deposition of

the Altuda Formation. The wide variation in preserved

thickness (0-41 m; 0-133 ft.) in the Del Norte Mountains is

believed to reflect extensive pre-Altuda erosion. In the vicinity

of section 6, pre-Altuda erosion has removed more than

one-half of the Vidrio, leaving a large erosional remnant of the

member nearly isolated by surrounding elastics of the Altuda.

An estimated erosional relief of 12 m (40 ft.) is developed in the

area on top of the Vidrio.

ALTUDA FORMATION

Clastics and carbonates of the Altuda Formation crop out in

limited exposures in northern and central portions of the study

area. The unit commonly forms uniform, intermediate slopes,

occasionally broken by small benches. Thin and medium beds

are common in all Altuda lithologies.

Altuda carbonates consist of moderately to extensively

recrystallized, peloid, skeletal, lithoclastic, dolomitic lime

mudstones and wackestones with beds of slightly recrystallized

peloid, skeletal, lithoclastic packstones. Carbonates are generally silty. Sedimentary structures include channel bedforms,

planar and wavy laminations, and slightly cross-stratified

laminations. Stromatolitic laminations were noted in several

thin sections of the lime mudstones.

The majority of the lime mudstones and wackestones have

undergone extensive dolomitization. Dolomitized carbonates

are characterized by a roughly uniform, subhedral to euhedral,

medium to coarse silt-sized ankerite and subordinate dolomite.

Ankerite rhombs frequently possess thin isopachous rims of

dolomite. Nonferroan calcitic cements commonly consist of

microspar and pseudospar with blocky cement limited to just

dissolution voids. Many voids have been replaced by secondary

chert cements. Skeletal content and diversity are markedly low

in the lime mudstone/wackestone lithologies and are represented by only minor occurrences of crinoids and trilobites.

Possible silicified fecal pellets are present in section 6.

Slightly recrystallized packstone occurs at irregular intervals

in the Altuda. Cement characteristics are similar to those of the

lime mudstones and wackestones with the exception of minor

micrite cement in one thin section. Dolomitized carbonates are

rare in thin section. Skeletal elements are very abundant,

consisting of bryozoans, brachiopods, crinoids, ostracodes,

foraminifers, dasycladacean algae, trilobites, fusulinids, and

sponge spicules (Figure 11-19).

The vast majority of the Altuda Formation consists of limy,

peloid siltstone and limy, sandy siltstone. Combined, these two

lithologies form beds that are visually similar to the peloid

wackestone bench-former of the Word limy, sandy siltstone

FIGURE 11-19.—Photomicrographs of skeletal carbonate in the Altuda

Formation. A, skeletal packstone (sample 3-261). B, fusulinid, skeletal

packstone (sample 3-261). Scale of the long axis in the photomicrographs

equals 2.9 cm.
310 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

unit. Sedimentary structures include planar and ripple laminations, low-angle cross-stratification, and horizontal burrows.

Peloid siltstone beds frequently contain small chert rosettes,

possibly after gypsum. Lithoclasts of siltstone and limestone

occur in sections 3 and 6, respectively.

The siltstones are composed of angular grains of medium- to

coarse-grained quartz silt that is cemented in a wispy

laminated, ferroan-stained calcitic microspar. Crosslaminations and minor medium silt-sized rhombs of dolomite

are present in thin section. Peloids are medium- to coarse-silt

size and consist of occluded, moderately sorted, ovoid- to

rod-shaped grains of micrite. No internal structures were visible

in thin section. Skeletal grains are represented by rare, poorly

preserved sponge spicules. Skeletal debris appears to be

relatively rare overall.

The Altuda Formation is unconformably overlain by

Cretaceous sandstones and limestones in the study area.

Pre-Cretaceous erosion has removed much of the Altuda. The

three informal units of the Altuda recognized by Wardlaw et al.

(1990) in the northern Del Norte Mountains can be generally

recognized in the northern part of the study area. In comparison

to the study area, it appears that all three units have thinned,

indicating that the Altuda thins to the south in addition to being

progressively more cut out to the south by the overlying

Cretaceous deposits.

Depositional Environments

A foreland basin developed along the southern "shelf of the

Delaware basin in front of and in response to the Marathon

orogen (Marathon Fold Belt, Rohr et al., this volume). Early

Permian (middle Wolfcampian) orogenic deformation and

uplift of the Dugout and Marathon allochthons resulted in the

widespread development of thick conglomerate deposits of the

Lenox Hills Formation in the Glass Mountains area (Ross,

1986). Coarse elastics of the Lenox Hills are overlain by

conglomeratic delta front, sandy fore-delta, marine carbonates,

and fine elastics of the Skinner Ranch and Cathedral Mountain

formations (Ross, 1986). Wolfcampian and lower Leonardian

lithologies in the Del Norte-Dugout Mountain-Lenox Hills

area are dominated by a transgressive fining upward sequence

of nonmarine, marginal marine, and marine deposits (Cooper

and Grant, 1972; Ross, 1986). Regional tectonic stability

following the mid-Wolfcampian orogeny is reflected by the

decreased abundance of coarse-grained elastics in middle and

late Leonardian time (King, 1937; Cooper and Grant, 1972;

Ross, 1986).

In the study area, the Cathedral Mountain Formation consists

of conglomerates, sandstones, sandy conglomerates, argillaceous skeletal limestones, and siltstones interpreted to be

deposited in lower delta plain, distributary channel, and

marginal delta plain/tidal flat settings (Rudine, 1988). Wardlaw

et al. (1990) interpreted the Cathedral Mountain Formation

north of the study area as deposited in a marine, distal fan delta

lobe plain, interlobe plain, and prodelta, implying more distal

deposition on the same delta system prograding out from the

Marathon fold belt into the foreland basin. Guadalupian

deposition begins over this setting in the Del Norte Mountains.

Sediments of the Road Canyon and lowest Word formations

are characterized by repetitious beds of thin, flaggy siltstones

separated by laterally discontinuous lenses and sheets of

limestone. The overall morphology, internal sedimentary

structure, and allochem character indicate deposition in a

channel complex in a shallow basinal setting. The siltstones

offer few clues as to their depositional origin due to the scarcity

of biogenic and primary sedimentary structures. Homogenized

siltstones are believed to represent intensive burrowing of

sediments by infaunal organisms, as burrow traces are locally

abundant in some of the siltstones.

Carbonates are separable into two depositional categories

based on thickness, sedimentary structures, grain size, sorting,

and composition. Medium- to thick-bedded, peloidal, lithoclastic, skeletal wackestones, packstones, and coarse grainstones

are interpreted to represent channel deposits, whereas thinbedded, well-sorted, peloidal packstones and grainstones

represent channel overbank deposits. Cross-bedding, lithoclast

lags, and current-oriented skeletal elements are common.

Fusulinids are the dominant skeletal channel constituent in the

sequence. Channels contain reworked shallow marine faunas

with common dasycladacean and solenoporacean algal remains. Stromatolitic lime mudstones and plant remains were

found capping some of the channel sequences. Thin channel

overbank deposits consist of well-sorted peloidal packstones

and grainstones and contain abundant fecal derived peloids,

dasycladacean algae, and algal-coated grains. Coarse-grained

skeletal and lithoclast allochems are rare constituents compared

to the channel deposits.

The Road Canyon deposits in the study area appear to be

distal to the rare massive conglomerates found in the Road

Canyon Formation of the Glass Mountains and the more

continuous limestones, both in the northern Del Norte

Mountains (north of the study area) and the Glass Mountains,

which implies an opposite direction of flow (south vs. north) to

that hypothesized by Harris et al. (this volume) and deposition

into the foreland basin.

The upper half of the basal siltstone member of the Word is

interpreted to represent a transitional environment from the

foreland basin deposits below, devoid of channel influence, and

the sandstones above. Concretions in the upper half of the unit

may represent early paleosol development (Miall, 1982).

The massive character, the presence of minor cross-bedding,

and abundant burrowing in the first sandstone member of the

Word Formation indicate a lower shoreface setting (McCubbin,

1982). Muscovite placers in the lowest portions of section 4 are

reminiscent of the beach shoreface placers described by

Galloway (1976). Siltstone interbeds in the first sandstone

member contain numerous penecontemporaneous concretions,

some of which are reworked with marine skeletal material in
NUMBER 32 311

planar laminated and poorly graded conglomeratic beds.

Conglomeratic beds are relatively rare, but when present they

contain reworked pebbles of siltstone, marine fossils, and

silicified wood. The highest bed in the first sandstone member

is uniquely identifiable in the study area due to the presence of

a 1.2 m (4 ft.) horizon of heavily burrowed (Skolithos-type)

sands.

The second siltstone member represents a transitional

depositional environment, juxtaposed between the strand line

and shallow basinal settings. Deposition is believed to be

similar to that of the upper part of the first siltstone member.

The carbonate masses of the Appel Ranch Member appear to

represent shallow-water mud mound deposition, formed by a

baffle of crinoids, bryozoans, and sponges. Repeated or

prolonged exposure is suggested by the recrystallization,

dolomitization, and cement history. Whether the masses were

deposited in situ is problematic. The lack of enveloping

breccia, the consistency of mass core and flank lithic

successions, bed loading, and drape beds implies that if these

masses did move, their movement was slight, and they all

appear to be right side up implying they slid into place if they

did not develop where they now reside.

The upper member of the Word Formation suggests

regression. The initial sediments consists of skeletal, peloidal

wackestones that are overlain by siltstones.

Skeletal, peloidal lime mudstones, wackestones, and packstones of the Vidrio Formation represent carbonate shelf

deposition. Marine fossils are scattered throughout the unit, but

extensive recrystallization and dolomitization obscure most of

the primary features. Subaerial exposure and karst formation

are abundantly evidenced.

Siltstones of the Altuda Formation possess ripple, planar,

and cross-laminations and are dolomitic in part. Peloidal

siltstones frequently contain small chert rosettes, possibly

representing replacement after gypsum. Altuda carbonates are

extensively recrystallized and dolomitized in the lower and

middle part of the Altuda. Sedimentary structures are identical

to those of the siltstones. Stromatolitic laminations were noted

in several carbonate thin sections. Skeletal content and

diversity are markedly low in mudstone/wackestone lithologies, suggesting a restricted and/or stressed environment. The

highest Altuda carbonates in the study area are slightly

recrystallized and contain a rich, normal marine fauna.

Abundant channel bedforms and thin, even beds suggest a

return of channel complexes in a shallow basinal setting.

Wardlaw et al. (1990) suggested a deepening upwards/

shallowing upwards sequence to explain the three general

members of the Altuda, with the mudstone representing the

deepest deposition; however, it appears that the carbonate and

clastic members (equivalent to their units 14 and 15 and 17 and

18) represent transgressive-regressive (T-R) packages unto

themselves, and the mudstone represents instead shallowest

deposition (see Wardlaw and Rudine, this volume). The

mudstone of the middle member laterally changes to siltstone

to the south.

Summary

The Guadalupian rocks of the northern Del Norte Mountains

confirm deposition within a foreland basin (Rohr et al., this

volume) between land of the Marathon orogen and a carbonate

shoal established on the geanticline fringing the Delaware

basin. Deposition was alternately influenced by coarse clastic

input from the south-southeast and carbonate input from the

north-northwest, which interrupted the shallow basinal siltstone deposition that pervades the section.

The Road Canyon Formation and the first siltstone member

of the Word Formation represent a shallow basinal setting of

bioturbated siltstones with scattered channel and channel

overbank carbonate deposits derived from the shallow carbonate shoal to the north and northwest.

The first sandstone member of the Word Formation indicates

lower shoreface deposition.

The second siltstone member of the Word Formation reflects

a change back to a shallow basinal setting.

The Appel Ranch Member represents a return to carbonate

channel deposition derived from the north-northwest and

contains carbonate masses, which represent shallow-water mud

mounds that were frequently exposed, and which probably slid

into the area from a very local source. The limy, sandy siltstone

member of the Word suggests regression and a return to a

shallow basinal setting. The Vidrio Formation represents

unconformably bounded carbonate shelf deposition that was

extensively recrystallized, dolomitized, and karstified by

frequent subaerial exposure. The Altuda Formation indicates

shallow deposition in its lower part and a return to carbonate

channels in a basinal siltstone setting in its upper part.

Relatively deep-water deposition appears to be characterized

by carbonate channels and masses and influence from the

carbonate shoal. Relatively shallow-water deposition appears

to be characterized by sandstone deposition or unconformities

and influence from the Marathon orogen.

Deposition was in five general transgressive-regressive

(T-R) packages that are eustatically driven. The first is

represented in the Road Canyon Formation and first siltstone

and first sandstone members of the Word Formation, with

maximum transgression at the top of the Road Canyon

Formation. The second general T-R package includes the

second siltstone member, the Appel Ranch Member, and the

limy, sandy siltstone member of the Word, with maximum

transgression in the Appel Ranch Member.

Work by Wardlaw et al. (this volume), Rathjen et al. (this

volume), and Rohr et al. (this volume) shows that these T-R

packages can be further divided for the Road Canyon and Word

formations. The finer differentiation of T-R packages, which is

easily discernable near the carbonate shoal, is masked by the

clastic input from the Marathon orogen, preserving only the

major eustatic signals.

The third general T-R package is wholly contained within

the unconformity bounded Vidrio Formation.

The fourth general T-R package includes the lower member
312 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

and part of the second member of the Altuda Formation, but it

is very small. Maximum transgression is represented in the

upper part of the lower member, whereas maximum regression

is represented in the middle of the second member.

The fifth general T-R package includes the upper part of the

second member and the third member of the Altuda. Maximum

transgression is evidenced in the lower part of the third

member.

Literature Cited

Cooper, G.A., and R.E. Grant

1972. Permian Brachiopods of West Texas, I. Smithsonian Contributions

to Paleobiology 14:1-231, plates 1-23.

1977. Permian Brachiopods of West Texas, VI. Smithsonian Contributions

to Paleobiology, 32:3161 -3370.

Dott, R.H.

1964. Wacke, Graywacke, and Matrix—What Approach to Immature

Sandstone Classification? Journal of Sedimentary Petrology,

34(3):625-632.

Galloway, W.E.

1976. Sediments and Stratigraphic Framework of the Copper River

Fan-Delta, Alaska. Journal of Sedimentary Petrology, 46(3):726-

737.

Haneef, Mohammad, S.F. Rudine, and B.R. Wardlaw

1990. Shelf to Basin Transition in the Capitanian (Permian) Deposition in

the Glass Mountains, West Texas. [Abstract.] Geological Society of

America, Abstracts with Programs, 22:A46.

Harris, M.T., D.J. Lehrmann, and L.L. Lambert

2000. Comparison of the Depositional Environments and Physical Stratigraphy of the Cutoff Formation (Guadalupe Mountains) and the

Road Canyon Formation (Glass Mountains): Lowermost Guadalupian (Permian) of West Texas. In B.R. Wardlaw, R.E. Grant, and

D.M. Rohr, editors, The Guadalupian Symposium. Smithsonian

Contributions to the Earth Sciences, 32:127-152, 25 figures.

King, P.B.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part I:

Descriptive Geology. University of Texas Bulletin, 3038: 167 pages,

15 plates. [Date on title page is 1930; actually published in 1931.]

1937. Geology of the Marathon Region, Texas. United States Geological

Survey Professional Paper, 187: 148 pages, 24 plates.

Loucks, R.G.

1977. Porosity Development and Distribution in Shoal-Water Carbonate

Complexes: Subsurface Pearsall Formation (Lower Cretaceous),

South Texas. University of Texas, Bureau of Economic Geology,

Report of Investigations, 89:97-126.

McCubbin, D.G.

1982. Barrier-Island and Strand-Plain Facies. In P.A. Scholle and D.

Spearing, editors, Sandstone Depositional Environments. American

Association of Petroleum Geologists, Memoir, 31:247-280.

Miall, A.D.

1982. Analysis of Fluvial Depositional Systems. American Association of

Petroleum Geologists, Education Course Notes Series, 20: 73 pages.

Rathjen, J.D., B.R. Wardlaw, D.M. Rohr, and R.E. Grant

2000. Carbonate Deposition of the Permian Word Formation, Glass

Mountains, West Texas. In B.R. Wardlaw, R.E. Grant, and D.M.

Rohr, editors, The Guadalupian Symposium. Smithsonian Contributions to the Earth Sciences, 32:261-289,22 figures.

Rohr, D.M., B.R. Wardlaw, S.F. Rudine, M. Haneef, A.J. Hall, and R.E. Grant

2000. Guidebook to the Guadalupian Symposium. In B.R. Wardlaw, R.E.

Grant, and D.M. Rohr, editors, The Guadalupian Symposium.

Smithsonian Contributions to the Earth Sciences, 32:5-36, 31

figures.

Ross, C.A.

1986. Paleozoic Evolution of Southern Margin of Permian Basin. Bulletin

of the Geological Society of America, 97(5):536-554.

Rudine, S.F.

1988. Geology and Depositional Environments of the Permian Rocks,

Northern Del Norte Mountains, Brewster County, Texas. 186 pages.

Unpublished master's thesis, Sul Ross State University, Alpine,

Texas.

Rudine, S.F., B.R. Wardlaw, D.M. Rohr, R.A. Davis, and R.E. Grant

1987. Depositional Setting of Late Leonardian-Wordian (Permian) Rocks,

Southern Margin, Permian Basin: Basin or Lagoon? [Abstract.]

Geological Society of America, Abstracts with Programs, 19(7):826.

Wardlaw, B.R., R.A. Davis, D.M. Rohr, and R.E. Grant

1990. Leonardian-Wordian (Permian) Deposition in the Northern Del

Norte Mountains, West Texas. United States Geological Survey

Bulletin, 1881-A:A1-A14.

Wardlaw, B.R., C.A. Ross, and R.E. Grant

2000. Cyclic Deposition of the Permian Road Canyon Formation, Glass

Mountains, West Texas. In B.R. Wardlaw, R.E. Grant, and D.M.

Rohr, editors, The Guadalupian Symposium. Smithsonian Contributions to the Earth Sciences, 32:121-126, 3 figures.

Wardlaw, B.R., and S.F. Rudine

2000. The Altuda Formation of the Glass and Del Norte Mountains. In

B.R. Wardlaw, R.E. Grant, and D.M. Rohr, editors, The Guadalupian Symposium. Smithsonian Contributions to the Earth Sciences,

32:313-318,4 figures.
12. The Altuda Formation of the

Glass and Del Norte Mountains

Bruce R. Wardlaw and

Shannon F. Rudine

ABSTRACT

The Altuda Formation was deposited in a variety of environments

from shelf to basin settings. The formation is divided into five

informal units, which are increasingly limited in their areal distribution. The first unit is widespread and deposited in shelf, slope, and

basin settings, whereas the last unit is only common to basinal settings.

Introduction

The Altuda Formation is a unit that is commonly misinterpreted to have been deposited in a single depositional setting;

however, evidence is presented herein to demonstrate that it

was deposited in several settings from shelf to basin. It contains

the youngest conodont and fusulinid faunas found in the Glass

and Del Norte mountains (see Wardlaw, this volume; Wilde

and Rudine, this volume).

The shelf-to-basin stratigraphy of the Altuda was examined

along two south-to-north transects; one in the Del Norte

Mountains (sections 1-6, Figure 12-1), and one through the

central Glass Mountains (along Old Blue Mountain) to a

control well in the plains to the north of the mountain range

(sections 7-12, Figure 12-1). Sections 1 and 2 were originally

described by Rudine (1988) and appear in Rudine et al. (this

volume). Sections 3 and 4 were originally described by Davis

(1984). Davis lost the description of the upper part of section 4

Bruce R. Wardlaw, U.S. Geological Survey, 926A National Center,

Reston, Virginia 20192. Shannon F. Rudine, Geology Department, Sul

Ross State University, Alpine, Texas 79832.

(the Altuda Formation!), and it was redescribed by Rudine and

is reported herein (Figure 12-2). The conodont data for both

sections 3 and 4 was preliminarily reported by Wardlaw et al.

(1990). The conodonts recovered from any of the sections used

for this study are reported in Wardlaw (this volume). Section 5

is reported herein (Figure 12-2). Section 6 is reported by Rohr

et al. (this volume). Sections 7-10 were originally reported by

Faliskie (1989). Those descriptions are not very detailed, and

section 7, originally measured by Wardlaw, is reported herein

(Figure 12-2). Section 11 is reported by Rohr et al. (this

volume). The control well to the north of the Glass Mountains

(section 12) was originally described by Bloom (1988) as

Kalinga Corporation's Margaret #1 and is reinterpreted herein

(Figure 12-2).

Stratigraphy

The clastic and carbonate sediments of the Altuda Formation

unconformably overlie the Vidrio Formation shoreward along

the first transect (Figure 12-3). They overlie sands of the Word

Formation (second sandstone member, Wardlaw et al., 1990)

further from shore. The Altuda is unconformably overlain by

Cretaceous limestone in the southern two sections and by the

Tessey Formation in the northern four sections. King (1931)

originally mapped the collapse breccias (Tessey Formation),

which overlie the Altuda, as the massive member of the Capitan

Limestone. In the second transect (Figure 12-4), the Altuda also

unconformably overlies the Vidrio Formation in the south and

the Word Formation in the north. Differentiating the siltstones

and sandstones of the Word Formation and the siltstones and

limestones of the Altuda Formation along the second transect

can be difficult. In the well (section 12, Figure 12-2), a silty

dolostone divides the two formations. This dolostone is thought

to be a weathering profile on top of the Word Formation

developed by the exposure surface, which represents the

313
314 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

30°30'

30°15'

103°30' 103°15'

3O°3O'

3O°15'

103°30' 103°15'

FIGURE 12-1.—Map of the Glass Mountains and Del Norte Mountains in West Texas showing the locations of

sections.

unconformity that separates it from the Altuda. The upper part

of the Altuda Formation clearly interfingers with the Capitan

Limestone along the second transect. The Capitan was missing

from the first transect and may not have been deposited in the

Del Norte Mountains.

The Altuda Formation can be divided into five informal units

based on the presence or absence of carbonates, which alternate

in the units in the sections. Generally, all units have a clastic

component.

UNIT 1.—The first limestone member. This unit in the Del

Norte Mountains is represented by interbedded carbonate,

mudstone, and siltstone that changes from mudstone to

siltstone upwards. This unit in the Glass Mountains is

represented by silty, sandy carbonates. Carbonates in both areas

are generally lime mudstones to skeletal wackestones.

UNIT 2.—The first clastic member. This unit in the Del Norte

Mountains is represented by mudstone. A few sparse carbonate

channels are present. In the Glass Mountains it is represented

by interbedded siltstone and carbonate.

UNIT 3.—The second limestone member. This unit in the Del

Norte Mountains is represented by interbedded carbonate,

mudstone, and siltstone. Mudstone is the common clastic

sediment in the north, and it is replaced by siltstone to the

south. The carbonate is generally lime mudstone. In the Glass

Mountains the unit is represented by sandy carbonates,

commonly wackestones.

UNIT 4.—The second clastic member. This unit in the Del

Norte Mountains is represented by siltstone. Carbonates are

very rare. In the Glass Mountains it is represented by siltstone

and sandstone. Here too, carbonates are rare.

UNIT 5.—The third limestone member. This unit is

represented by interbedded carbonate and siltstone in both

mountain ranges. The carbonates are lime mudstone to skeletal

wackestone, rarely packstone.
NUMBER 32 315

300

| | limestone

| // | dolostone

| | sandstone

|— | sandy siltstone

| — - | siltstone

I 1 mudstone

| — | shale or claystone

| —i— | limy or thin limestones

H

dolomitic or recrystallized

limestone

|A V | limestone breccia

| ^ | cherty

I X I crossbedded

250-

SECTION

4

200-

150-

100-

50

Tessey

Formation

Word Formation

Capitan

Limestone

Altuda

Formation

Word

Formation

SECTION

12

Tessey

Formation

Altuda

Formation

s

Leonard

Formation

•2400

•2500

•2600

•2800

2700

2900

3000

3100

3200

3300

FTBS

METERS

FIGURE 12-2.—Columnar sections showing stratigraphic units; locations of the sections are shown in Figure 12-1.
316 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

DOLOSTONEAND

RECRYSTAUZED LIMESTONE OF

THE VIDRIO FORMATION

FIGURE 12-3.—Fence diagram of the units comprising the Altuda Formation and the formations immediately

overlying and underlying the Permian units on transect 1 (sections 1-6) in the Del Norte Mountains. Sections

shown are in proportionally true distance from section 1. The base of the Cretaceous was used as an arbitrary

datum because it reflects the depositional nature of the transect in this diagram.

Interpretation

Haneef et al. (1990) first pointed out that the Altuda

Formation is not everywhere a seaward equivalent of the

Capitan Limestone. They noted that it also underlies the

Capitan, and this underlying part represents ramp deposition

that developed during a major regression, which destroyed the

carbonate platform of the Vidrio Formation. The ramp existed

before the development of the carbonate platform of the

Capitan Limestone.

The units of the Altuda Formation appear to represent

depositional response to general large scale sea-level fluctuations, with carbonate-rich units representing transgression

(sea-level rise) and clastic-rich units representing regression

(sea-level fall). Prior to Altuda deposition, a major regression

resulted in the exposure and destruction of the Vidrio carbonate

platform. This regression is also recorded in the unconformity

between the Cherry Canyon and Bell Canyon formations in the

Guadalupe Mountains.

The Capitan carbonate platform developed during deposition

of unit 2 of the Altuda Formation (during regression) in the

Glass Mountains and managed to maintain itself through

ensuant sea-level rises in the Guadalupian. In the Del Norte

Mountains, carbonate platform development may not have

occurred. The first three units of the Altuda Formation carry all

the way to the south, supposedly well up on the shelf. Erosion

prior to Tessey deposition and/or Cretaceous deposition has

removed any evidence of whether carbonate platform deposition existed during the deposition of units 4 and 5 of the Altuda

Formation in this area. The lack of widespread carbonate

platform development suggests that tectonic driven subsidence

may still have been an important factor in deposition in the

southern foreland basin in the late Guadalupian (see Rudine et

al., this volume, for a discussion of tectonic effects in the

Leonardian and early Guadalupian).
NUMBER 32 317

500-

400-

300-

200-

•&.%£/cjjO <£t=y. <>.'%£ '<^ &*=C- <

ALTUDA FORMATION

DOLOSTONE OR RECRYSTALIZED LIMESTONE

DOLOMITIC LIMESTONE

100-

100-

200-

METERS

FIGURE 12-4.—Fence diagram of the units comprising the Altuda Formation and the formations immediately

overlying and underlying the Permian units on transect 2 (sections 7-12) in the central Glass Mountains. Sections

shown are in proportionally true distance from section 7. The base of the Altuda Formation was used as an

arbitrary datum because it reflects the depositional nature of the transect in this diagram.

Literature Cited

Bloom, M.A.

1988. A Subsurface Geologic Study of Northern Brewster County, Texas.

157 pages. Unpublished master's thesis, Sul Ross State University,

Alpine, Texas.

Davis, R.A.

1984. Depositional Environments of the Western Cathedral Mountain,

Road Canyon, Word and Capitan Formations (Permian), Glass

Mountains Area, West Texas. 104 pages. Unpublished master's

thesis, Sul Ross State University, Alpine, Texas.

Faliskie, R.A.

1989. Depositional Environments of the Vidrio Member of the Word,

Altuda, and Capitan Formations (Upper Permian) in the Northwestern Glass Mountains, West Texas. 87 pages. Unpublished master's

thesis, Sul Ross State University, Alpine, Texas.

Haneef, Mohammad, S.F. Rudine, and B.R. Wardlaw

1990. Shelf to Basin Transition in the Capitanian (Permian) Deposition in

the Glass Mountains, West Texas. [Abstract.] Geological Society of

America, Abstracts with Programs, 22(7):A46.
318 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

King, P.B.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part I:

Descriptive Geology. University of Texas Bulletin, 3038: 167 pages,

15 plates. [Date on title page is 1930; actually published in 1931.]

Rohr, D.M., B.R. Wardlaw, S.F. Rudine, M. Haneef, J.A. Hall, and R.E. Grant

2000. Guidebook to the Guadalupian Symposium. In B.R. Wardlaw, R.E.

Grant, and D.M. Rohr, editors, The Guadalupian Symposium.

Smithsonian Contributions to the Earth Sciences, 32:5-36, 31

figures.

Rudine, S.F.

1988. Geology and Depositional Environments of the Permian Rocks,

Northern Del Norte Mountains, Brewster County, Texas. 186 pages.

Unpublished master's thesis, Sul Ross State University, Alpine,

Texas.

Rudine, S.F., B.R. Wardlaw, D.M. Rohr, and R.E. Grant

2000. Geology and Depositional Environments of the Guadalupian Rocks

of the Northern Del Norte Mountains, West Texas. In B.R. Wardlaw,

R.E. Grant, and D.M. Rohr, editors, The Guadalupian Symposium.

Smithsonian Contributions to the Earth Sciences, 32:291-312, 19

figures.

Wardlaw, B.R.

2000. Guadalupian Conodont Biostratigraphy of the Glass and Del Norte

Mountains. In B.R. Wardlaw, R.E. Grant, and D.M. Rohr, editors,

The Guadalupian Symposium. Smithsonian Contributions to the

Earth Sciences, 32:37-87, 3 figures, 12 plates 1 table.

Wardlaw, B.R., R.A. Davis, D.M. Rohr, and R.E. Grant

1990. Leonardian-Wordian (Permian) Deposition in the Northern Del

Norte Mountains, West Texas. United States Geological Survey

Bulletin, 1881-A:A1-A14.

Wilde, G.A., and S.F. Rudine

2000. Late Guadalupian Biostratigraphy and Fusulinid Faunas, Altuda

Formation, Brewster County, Texas. In B.R. Wardlaw, R.E. Grant,

and D.M. Rohr, editors, The Guadalupian Symposium. Smithsonian

Contributions to the Earth Sciences, 32:343-371,3 figures, 9 plates.
13. A Deep Water Turbidity Origin for the

Altuda Formation (Capitanian, Permian),

Northwestern Glass Mountains, Texas

Mohammad Haneef, David M. Rohr,

and Bruce R. Wardlaw

ABSTRACT

The Altuda Formation (Capitanian) in the northwestern Glass

Mountains is comprised of thin, evenly bedded limestones, dolostones,

mixed clastic-carbonates, and silt/sandstones interbedded with basinward dipping wedge-shaped clinoforms of the Capitan Limestone. The

formation is characterized by graded bedding, planar laminations,

flame structures, contorted/convolute bedding, horizontal branching

burrows, and shelf-derived normal marine fauna. A detailed study of

the Altuda Formation north of Old Blue Mountain, Glass Mountains,

reveals that the formation in this area was deposited by turbidity

currents in slope to basinal settings.

Introduction

The Altuda Formation is early to late Capitanian (late

Guadalupian) in age and is correlated with the Bell Canyon

Formation of the Delaware basin. Conodont biostratigraphic

studies of the Altuda Formation in the Del Norte Mountains

(Rudine et al., 1987; Wardlaw, 1987, this volume) report

Mesogondolella aserrata from the lower part, correlating it

with the Hegler Limestone Member of the Bell Canyon

Formation.

Wilde and Rudine (this volume) identified three fusulinid

subzones (herein regarded as zones) in the Altuda Formation in

Mohammad Haneef and David M. Rohr, Geology Department, Sul

Ross State University, Alpine, Texas 79832. Bruce R. Wardlaw, U.S.

Geological Survey, 926A National Center, Reston, Virginia 20192.

the Glass and Del Norte mountains. From top to bottom they

are the Paraboultonia-Lantscichites Zone, the Richelina

lamarensis Zone, and the Paradoxiella Zone. Rocks below

those containing Paradoxiella were not investigated by Wilde

and Rudine (this volume), but they are suspected to contain the

Yabiena texana Zone as this zone is found below the

investigated zones in the Guadalupe Mountains. They reported

a biostratigraphic correlation with the upper part of the Bell

Canyon Formation (Lamar Limestone Member and post-Lamar

siltstones) and the Tansill Formation (shelf) of the Guadalupe

Mountains.

The Altuda Formation exhibits lateral and vertical variations

in facies relationships over the entire extent of the outcrop

(King, 1931). The lateral variation in facies is marked by time

equivalent lithostratigraphic units represented by, from west to

east, the Altuda Formation, the Capitan Limestone, and the

Gilliam Limestone. At Old Blue Mountain, the Altuda

Formation laterally merges into the Capitan Limestone,

exhibiting interfingering of both facies.

The present study offers an environmental analysis of the

Altuda Formation north of Old Blue Mountain, Glass Mountains, Texas (Figure 13-1).

Stratigraphy

The Altuda Formation lies unconformably on the Vidrio

Formation. Rudine et al. (1988) reported a major unconformity

between the two units based on the erosional (karstic) upper

surface of the Vidrio and on the change in fusulinid fauna from

Parafusulina to Polydiexodina. Faliskie (1989) noted undulatory, erosional contacts marked by discordance in dip between

the two units. In the study area, the base of the Altuda

Formation is not exposed. All lithologies belong to the

Altuda's upper unit, the third limestone member (Unit 5 as

319
320 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

30'

MARATHON

FIGURE 13-1.—Map of the Glass Mountains region with the study area indicated.

identified by Wardlaw and Rudine (this volume)). The lateral

relationships with the foreset beds of the Capitan Limestone are

transitional and are marked by the interfingering of both

formations. The Altuda Formation has an unconformable upper

contact with the overlying upper part of the Capitan in sections

BR5, BR6, and BR 8. In sections BR 1, BR3, BR4, and

BR 7, the Altuda Formation shows an unconformable upper

contact with the Tessey Formation of Ochoan (postGuadalupian) age.

Exposures of the Altuda Formation in the western and

southwestern part of the Glass Mountains can be traced

continuously for about 7.2 km in a northwest-southeast

direction and for about 14.5 km in a northeast-southwest

direction from Old Blue Mountain. The thickness of the

formation varies from 15.2 m (King's (1931) section number 8,

6.6 km NNW of Altuda Mountain) to 254.2 m in the vicinity of

Sullivan Peak (King's (1931) section number 12). Rudine

(1988) reported the thickness of the Altuda Formation at Bird

Mountain to be 168 m, and Faliskie (1989) measured its

thickness as being 128.6 m at 4 km south of Gilliland Peak.

In the study area, the thickness of the Altuda Formation

varies from 35.7 m in section BR 7 to 90.1 m in section BR 6

(Figure 13-2).

Lithofacies

The Altuda Formation is composed of carbonates, elastics,

and mixed clastic-carbonate units interbedded with Capitan

Limestone foreset beds.

Sedimentary structures vary and include planar laminations,

cross-stratification, graded bedding, slump deformation, flame

structures, dish structures, vertical and horizontal burrows,

wavy to channelized bedforms, and spar- and chert-replaced

anhydrite rosettes. The rocks of the Altuda Formation are

broadly subdivided into three major lithofacies: sandstone/

siltstone lithofacies, silty, spiculitic dolomud-wackestone lithofacies, and mixed skeletal wackestone/packstone lithofacies.

SANDSTONE/SILTSTONE LITHOFACIES

Laminated to bioturbated, poorly sorted, fine sandstone and

siltstone occur in thin- to medium-sized (2-30 cm), planar,

wavy, and convolute beds in the Altuda Formation. Weathered

surfaces are colored light yellow, brownish yellow, and brown.

The sandstone is dominated by fine, angular to subangular,

monocrystalline quartz (> 80%) with subordinate amounts of

polycrystalline quartz, muscovite, and biotite, which is cemented by calcite or finely crystalline dolomite (Figure 13-3A).
NUMBER 32 321

matrix supported

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BR4

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BR8

BR6

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FIGURE 13-2.—Stratigraphic correlation of the lithofacies in Old Blue Mountain, Glass Mountains, Texas.

In the siltstone, the abundance of micaceous minerals varies

from 5 percent to 25 percent, whereas angular monocrystalline

quartz makes up 30 percent to 60 percent of the rock (Figure

13-3B). Anhedral pyrite is common in brownish sandstone and

siltstone. Sandstone is volumetrically minor compared to

siltstone, which constitutes approximately 75 percent of the

lithofacies. The sandstone/siltstone lithofacies represents approximately 10 percent of the total measured sections. The

lithofacies is repeated six times vertically and occurs laterally

in all sections except BR 2; however, this section represents

only the top 10 m of the Altuda Formation and lacks

siliciclastics. This lithofacies lacks lateral continuity in all the

stratigraphic sections. The thickness of the lithofacies varies

from 3-20 m.

The sandstone/siltstone lithofacies is characterized by planar

bedforms wherever it has lower and upper contacts with the

skeletal packstone lithofacies, and it shows wavy to undulatory

contacts with foreset beds of the Capitan Limestone. Most beds

display millimeter-scale planar lamination and are accentuated

by iron oxide and chert layers that parallel the bedding. The

laminations are caused by minor variations in grain size and/or

biotic content. Fossils are generally rare or absent. Skeletal

fragments are siliceous sponge spicules that comprise less than

5 percent of the rocks. Many small tube-shaped branching

burrows (Figure 13-3C), probably representing grazing traces,

and rare, small (1-3 cm long) vertical tube burrows (Figure

13-3D) are present on the bedding surfaces of some homogenous beds, indicating organic activity. The homgeneous beds
322 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 13-3.—A, photomicrograph of poorly sorted, fine-grained sandstone of the Altuda Formation. Note size

variations and angularity of the grains. Dark areas in the photo are lime-mud. Long axis of the photo equals 2 mm.

B, photomicrograph of Altuda Formation siltstone. Long axis of the photo equals 1 mm. C, bedding plane view

of small, tube-shaped branching burrows in sandstone beds of sandstone/siltstone lithofacies of the Altuda

Formation. D, vertical escape burrow in laminated, quartzose sandstone beds of the Altuda Formation. Camera

lens cap is 5.5 cm in diameter.

are probably caused by fairly uniform grain size as well as by

organic activity. The recessive nature of the sandstone/siltstone

outcrops and the differential weathering of these beds also

makes the recognition of burrows difficult.

This lithofacies contains small-scale graded bedding, dish

structures, ball and pillow structures, cross-laminations, and

convolute laminations (Figure 13-4A,B). Ball and pillow

structures or pull-apart structures are restricted to mediumbedded sandstone. Figure 13-4c shows these structures

associated with laminated siltstone interbedded with sandstone.

The pillows are parallel to the bedding and display uniform

thickness with rounded and tapering ends, and they are coated

with thin (1-2 cm), brownish chert layers. The length of the

pillows varies from 15-20 cm, whereas the width is uniformly

2-5 cm. Pillows assume spheroidal, nodular shapes downslope

within the same beds. Dish structures in some beds, which are

barely visible on the surface, are 1-3 cm long, arc-shaped, and

concave and have faint, dark lines that are irregularly stacked

on top of each other. Convolute or contorted bedding and

slump features (Bouma interval Tc) are typically associated

with this lithofacies and are common to both lithologies. The

axes of the slump folds are perpendicular to the dip directions

of the beds. Small-scale cross-laminations are present in some

beds.

SILTY, SPICULITIC DOLOMUD-WACKESTONE LITHOFACIES

This lithofacies constitutes about 35 percent of the Altuda

Formation. The thickness of the beds varies from 10-40 cm.

Vertical repetition of this lithofacies occurs in various
NUMBER 32 323

FIGURE 13-4.—A, sandstone/siltstone lithofacies of the Altuda Formation displaying planar laminations, wavy

ripple laminations, and cross-laminations marked by chert layers. B, laminated, internally graded, sandstone beds

of the Altuda Formation. Note chert accentuated penecontemporaneous slump deformation in the uppermost bed.

Bar scale is 28 cm. C, ball and pillow structures in the Altuda Formation. D, thin section reversal print showing

thin, alternating layers of bioclastic packstone and silty, spiculitic mud-wackestone. Note irregular chert stringers

marking the contacts of the layers. Bar scale is 1 mm.

noncorrelatable intervals in the majority of the sections. The

lithofacies shows planar contacts with the superjacent beds and

is characterized by millimeter-scale internal laminations.

The siliciclastic content of the lithofacies varies from 10

percent to 30 percent and is represented predominantly by

poorly sorted, angular to subrounded, monocrystalline and

polycrystalline quartz and by chert fragments. Feldspar and

mica constitute less than 5 percent of the siliciclastics in the

rocks. The most abundant skeletal elements are calcareous and

siliceous sponge spicules, generally monaxons. In 75 percent of

the thin sections studied from this lithofacies, sponge spicules

and quartz sand and silt, either laminated or unlaminated, mark

the top of the graded bed. Other skeletal debris include worn,

abraded, and partially to completely recrystallized or dolomitized grains of brachiopods, bryozoans, Tubiphytes, echinoderms, pelecypods, small foraminifers (uniserial and biserial),

and ostracodes in varying proportions. In laminated beds,

intrastratification of alternating thin (mm to few cm thick)

layers of skeletal wackestone, packstone, and silty dolomudstone is common (Figures 13-4D, 13-5). The irregular

scoured contact of these layers is evident in thin section. It

appears that each layer or set of layers was deposited from

successive turbidity currents. The sequence is marked by

numerous small scale (mm to cm) cyclic repetitions within a

single bed, and these reptitions consistently occur in a majority

of the beds. A complete Bouma sequence is not present in this

lithofacies; however, Bouma intervals Ta, Tab, and Te

commonly occur (Figure 13-6A).

Dolomitization varies from moderate to complete replacement and obliteration of depositional textures. The dolomite

occurs from fine anhedral to subhedral crystals to a xenotopic

mosaic including fabric selective to fabric destroying types of

dolomitization. Chert occurs as micro-quartz, polycrystalline

grains, nodules, thin wavy layers, and as partial to complete

skeletal replacement.
324 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Spiculitic mud-wackestone

Fusulinid bioclastic

packstone

Fining upward fusulinid

bioclastic packstone

Silty, spiculitic mudstone

FIGURE 13-5.—Thin section reversal print and line drawing of intrastratified, silty mudstone and bioclastic

packstone. Note the irregular, scoured contacts of the layers and the internal grading within each layer. The

Bouma intervals shown are (bottom to top) Te, Tac, and Tab. Bar scale is 1 mm.

FIGURE 13-6.—A, thin section reversal print of silty, spiculitic dolomudstone grading upwards into mixed

bioclastic, intraclastic packstone. The allochthonous nature of the allochems is evident from the worn and abraded

condition of the clasts of a diverse fauna. Bar scale is 1 cm. B, thin section reversal print of laminated, graded,

bioclastic packstone. Note silty spiculitic dolowackestone at the base (Te) grading upwards into cherry,

microstylolitic, mixed bioclastic, intraclastic packstone (Ta). The allochems include Tubiphytes, Archaeolithoporella, fusulinid, intraclast, and sponge. Note the irregular, wavy contact between Bouma intervals Te and

Ta and also the normal graded bedding. The bar scale is 0.8 cm.
NUMBER 32 325

The typical feature of these rocks is the presence of small

circular to semicircular spar calcite-filled cavities. These

cavities range from microscopic size to more than 4 cm in

diameter (Figure 13-7A,B). Most cavities are lined by an iron

oxide coating and are filled with uniform, large calcite crystals.

Length-slow chalcedony representing partial to complete

replacement is present in some cavities. These cavities are

frequently associated with a completely dolomitized fabric in

dolomudstone lithologies, but they are also present in rocks that

show dolo-wackestone textures. These features are interpreted

as relic evaporite fabrics that formed after the dissolution of

anhydrite rosettes. The presence of length-slow chalcedony, the

circular shape, and the lack of evidence suggesting the

replacement of allochems favor this interpretation. The timing

of the formation of these features is not known.

MIXED SKELETAL WACKESTONE/PACKSTONE LITHOFACIES

This lithofacies is characterized by thin to medium thick

(4-20 cm) planar beds (Figure 13-7C). The thickness of this

lithofacies ranges from 2-20 m. The lithofacies is present in all

sections, although there is a general increase in thickness

towards the basin in sections BR 3 and BR 4 (Figure 13-2). On

weathered surfaces the rocks are light gray to olive gray. The

skeletal elements are diverse and include brachiopods, bryozoans (fenestrate and ramose), foraminifers, Tubiphytes, Archaeolithoporella, echinoderms, pelecypods, ostracodes, ammonoids, trilobites, and calcareous and siliceous sponge

spicules (Figures 13-6B, 13-7D, 13-8). Small foraminifers and

fusulinids include Richelina, Codonofusiella, and Rauserella.

Other allochems are represented by partly to completely

FIGURE 13-7.—A, small, circular to semicircular coarse spar-filled cavities interpreted as replaced anhydrite

rosettes within the silty dolomud-wackestone lithofacies of the Altuda Formation. The rocks show vague

laminations and lack fossils. B, thin section reversal print of replaced anhydrite rosettes. The rosettes are replaced

by coarse sparry calcite with a thin coating of brownish chert. The width of the photo is 2.3 cm. C, laminated,

planar-bedded, mixed bioclastic packstone of the Altuda Formation. The thickness of the beds varies from 2-15

cm. Notebook is 28 cm in length. D, thin section reversal print of mixed bioclastic packstone-floatstone. Note the

large, worn and abraded skeletal grains of bryozoans, echinoderms, and brachiopods. Also visible is a fractured

echinoderm in the lower right corner of the photograph. Bar scale is 1 cm.
326 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 13-8.—Thin section reversal print of intraclastic, mixed bioclastic packstone-floatstone. The line

drawing shows the whole shell of a brachiopod (BR), echinoderm fragments (E), sponge (S), bryozoans (B),

Tubiphytes (T), Archaeolithoporella (A), and intraclast (I). Note micrite envelopes on the skeletal grains. Bar

scale is 0.5 cm.

micritized skeletal elements and pellets. Intraclasts vary from a

few millimeters to 3 cm and contain various combinations of

allochems. They are common and most occur in the basal part

of the graded beds. Skeletal elements typically show micrite

rinds and are worn and abraded. The matrix of these rocks is

predominantly lime-mud. Chert composed of microquartz,

megaquartz, and cryptocrystalline quartz occurs as nodules,

lenses, and layers. Silicification of skeletal elements is common

to this lithofacies. Sparry calcite replacement and dolomitization of the allochems and matrix is present throughout the

lithofacies.

The rocks are characterized by micrograding and intrastratification of alternating wackestone, packstone, and spiculitic

mudstone layers. The sequence may be repeated 3 to 4 times in

a single, thin bed (4 cm). The thickness of the intrastratified

layers vary from a few millimeters to a few centimeters. The

basal layer always shows a scoured, irregular contact. The

rocks show Tab, Tabc, and Tad Bouma sequences. No

complete Bouma sequence was observed.

Interpretations

The Altuda Formation has been studied in both the Del Norte

Mountains and the northwestern Glass Mountains. In the Del

Norte Mountains, it is interpreted as a marine tidal flat deposit

marked by shallow subtidal to supratidal facies (Rudine, 1988;

Wardlaw et al., 1990). In the northwestern Glass Mountains,

south of the study area, Faliskie (1989) recognized three

lithofacies and concluded that the Altuda Formation represents

deposition in a transitional setting from lagoon on the middle

shelf to foreslope of the platform.

In the Benge Ranch area (Old Blue Mountain) of the Glass

Mountains, the Altuda Formation exhibits transitional lateral

facies relationships with shelf-edge reef facies of the Capitan

Limestone. The Altuda is interpreted as successive turbidity

current deposits in slope to basinal settings basinward of the

Capitan shelf-edge because of its interfingering stratigraphic

relationship with the Capitan Limestone and its depositional

fabrics and sedimentary structures, which include planar
NUMBER 32 327

laminations, macro- and micro-grading, diverse allochthonous

fauna, synsedimentary deformation, and Bouma intervals.

Except for the planar laminations, these features are not

common where the Altuda has been interpreted to be a

shallow-water deposit (see Wardlaw et al., 1990).

PLANAR LAMINATIONS

The rocks typically display fine millimeter-scale, planar

laminations in all the lithofacies. Laminations occur in

fine-grained siltstones, sandstones, and skeletal wackestonepackstone lithologies (Figures 13-9A,B, 13-10A, 13-1 1A,B).

Laminae range from 1-4 cm in coarser rocks with abundant

allochems, but they are only in the millimeter range in siltstone

and dolomudstone. Fine-grained rocks contain size-graded

couplets of siliciclastic/carbonate layers (Figure 13-10B). Some

layers have a mixture of quartz silt and calcareous sponge

spicules or parallel-bedding alignment of spicules (Figure

13-12A). Burrows are common to sandstones. Where the

sandstone beds display surface tracks and trails, the underlying

units are generally bioturbated and homogenized. Commonly,

burrowing within the sandstone beds is not deep enough to

affect the underlying layers. These layers contain undisturbed

laminations that suggest partly stagnant, poorly oxygenated

bottom conditions that lacked indigenous benthic fauna on the

slope and basinal environments. Fluid escape structures (dish

structures) also destroyed the depositional fabric, but they are

rare. Laminated intervals in the Altuda Formation represent Td

and Te Bouma intervals and are interpreted as fall-out from

turbidity currents.

MACRO- AND MICRO-GRADING

Graded bedding is the most common sedimentary structure

in the Altuda Formation, amounting to about 70 percent of the

formation. Graded beds or layers vary in thickness from a few

millimeters to about 4 cm. The beds display normal grading,

with coarse skeletal, lithoclastic, and intraclastic grains at the

base of the bed, or layer, that grades upwards into finer grains.

In the uppermost interval of the graded bed, fine silt is

commonly mixed with calcareous and siliceous sponge

spicules. The basal contact of the graded bed with the

underlying layers is marked by a scoured, irregular, wavy

surface truncating the sedimentary structures. In macro-graded

beds the scoured contact is easily visible. In micro-graded

layers where contacts are sharp, small-scale scoured contacts

are present on a microscopic scale (Figure 13-13A,B). Most

units have thin chert layers, silicified skeletal fragments, or thin

dolomitized and silicified layers marking the boundary

between beds.

The ratios of skeletal elements, lithoclasts, and intraclasts

varies among lithofacies. Some dolomitic rocks have their

textural details completely obliterated, so graded intervals

cannot be ascertained. Where skeletal elements are selectively

Ta

FIGURE 13-9.—A, intrastratified bioclastic packstone-mudstone showing multiple

alternating chert-accentuated layering. Note several incomplete Bouma sequences marked

by wavy contacts. Camera lens cap is 5.5 cm in diameter. B, alternating layers of silty

spiculitic mudstone and mixed bioclastic packstone displaying several turbidity intervals

marked by Ta-Tc and Ta and Te. Note irregular, wavy, scoured base of cherty, bioclastic

packstone graded interval (Ta) overlying contorted silty spiculitic wackestone-mudstone.
328 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 13-10.—A, thin section reversal print of cherty, bioclastic packstone

grading upwards into silty, fine dolomudstone. Note the irregular, scoured

contact between Bouma Ta and Te. The long axis of the photograph is 3.5 cm.

B, thin section reversal print of spiculitic mudstone-wackestone (dark layers)

alternating with silty dolomudstone. The dominant allochems in wackestone

layers are siliceous sponge spicules (monaxons), calcispheres, and possibly

radiolarians. Note planar lamination caused by the alignment of the spicules.

silicified, grading is visible even in a dolomudstone matrix.

Coarse lags in the graded beds are represented by grains of

skeletal elements, intraclasts, and lithoclasts. Skeletal elements

include brachiopods, bryozoans, echinoderms, Tubiphytes,

Archaeolithoporella, fusulinids, ostracodes, pelecypods, and

sponges and sponge spicules. Intraclasts contain peloidal,

skeletal wackestone to packstone textures. Lithoclasts include

angular rip-up mudclasts, quartz sandstone and siltstone, and

chert fragments.

DIVERSE ALLOCHTHONOUS FAUNA

The Altuda Formation is characterized by a wide diversity of

imported biogenic components, which indicates the skeletal

elements were transported from various environments. The

mixed skeletal elements include fusulinids, Tubiphytes, Archaeolithoporella, echinoderms, brachiopods, bryozoans, trilobites, sponges and sponge spicules, ostracodes, pelecypods,

corals, and ammonoids (Figures 13-12B,C, 13-13B-D). A

shallow-water origin of the skeletal elements is indicated by the

fusulinids and alga mixed with peloidal grains, the micrite rinds

on most skeletal elements, and the boring of skeletal grains.

The allochthonous origin of the allochems is evident from the

worn, abraded, fractured, and disarticulated nature of the

skeletal grains.

Lime-mud formed the matrix of the carbonate dominated

lithofacies. This lime-mud is believed to have originated by the

disintegration of organisms and by biochemically induced

precipitation in shallow waters (<30 m deep). As pointed out

by Wilson (1969), mud can be washed down into deeper waters

just as easily as it is carried landwards into the tidal flats. The

lime-mud in the Altuda Formation likewise was transported

from the shallow-water shelf areas to slope and basinal

environments.

SYNSEDIMENTARY DEFORMATION

Synsedimentary depositional features of the Altuda Formation include slump structures, flame structures, and convolute

laminations or bedding. These features are typically associated

with slope and basinal environments. The slump and convolute

structures occur predominantly in the sandstone/siltstone

lithofacies, but they are also present in other facies (Figure

13-12D). Flame structures are associated with intrastratified

carbonate/clastic rocks, as they developed under fluidized flow

where stringers of water-saturated sediments were injected into

overlying layers under loading pressure.

BOUMA INTERVALS.—The Altuda Formation characteristically displays Bouma turbidity intervals in carbonates and

terrigenous clastic lithologies. As pointed out by Thomson and

Thomasson (1969:74), a complete Bouma sequence is rare in

carbonate rocks; rather, various types of partial or incomplete

sequences are the rule. The Bouma intervals recognized in the

Altuda lithofacies include, Tab, Tabc, and Tde. Among these

intervals, Tab and Tde are the most common type of turbidity

intervals, as they are present in 70 percent of the lithofacies.

The thickness of a single Bouma interval in the Altuda

Formation varies from 2-20 cm.

Acknowledgements

This study is based on one of the author's (Mohammad

Haneef) masters thesis research at Sul Ross State University.

Funding for this study was provided by an A APG Grant-in-Aid

to Mohammad Haneef and an American Chemical Society,

Petroleum Research Fund (Grant # 22216-ACS) to David Rohr.
NUMBER 32 329

FIGURE 13-11.—A, planar laminated, thin, evenly bedded, internally graded, intrastratified, bioclastic

packstone-mudstone turbidites of the Altuda Formation. Field notebook is 28 cm in length. B, close-up of the

uppermost bed in A. Note bed displays alternating multiple layers of bioclastic packstone and laminated

siliciclastic, spiculitic mudstone-wackestone. The bioclastic packstone layers have an irregular scoured contact

with the underlying layers and are composed of shelf and shelf-edge derived, allochthonous, diverse fauna. The

beds display multiple turbidity intervals labelled Tac, Td, and Tabc. The camera lens cap is 5.5 cm in diameter.
330 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 13-12.—A, photomicrograph of silty, spiculitic mudstone-wackestone. Note the calcareous sponge

spicules (monaxons and triaxons) and calcispheres in a silty dolomudstone matrix. Width of the photo equals 1

mm. B, photomicrograph of silty bioclastic packstone showing Tubiphytes, fusulinids, and peloids in a lime

mudstone matrix. Field of view is 2 mm. C, photomicrograph showing fusulinids {Richelina) in the bioclastic

packstone lithofacies. These fusulinids are common throughout the Altuda Formation. Field of view is 2 mm. D,

contorted bedding (Bouma Tc) in thinly bedded sandstone/siltstone lithofacies of the Altuda Formation. Note

truncation of the top of the contorted bed.
NUMBER 32

331

FIGURE 13-13.—A, thin section reversal print of cherry, intraclastic, bioclastic packstone. The dark allochem in

the center is a mollusk shell fragment. Bar scale is 1 cm. B, thin section reversal print of bioclastic

wackestone-packstone grading upwards into finely laminated spiculitic wackestone. Bouma intervals present are

a graded layer with a scoured base (Ta), Tc, and Te. Bar scale is 0.5 cm. C, thin section reversal print of a mixed

bioclastic packstone. Note the parallel alignment of brachiopods. Bar scale is 1 mm. D, thin section reversal print

of reworked allochthonous skeletal grains of calcareous sponges in the graded bed of mixed bioclastic packstone.

The rock is composed of the skeletal debris of brachiopods, bryozoans, echinoderms, small foraminifers, and

sponge spicules. The bed grades upwards into finely laminated, silty spiculitic mudstone. Field of view is 2.3 cm.
332 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Literature Cited

Faliskie, R.A.

1989. Depositional Environments of the Vidrio Member of the Word,

Altuda, and Capitan Formations (Upper Permian) in the Northwestern Glass Mountains, West Texas. 100 pages. Unpublished master's

thesis, Sul Ross State University, Alpine, Texas.

King, P.B.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part I:

Descriptive Geology. University of Texas Bulletin, 3038: 167

pages, 15 plates. [Date on title page is 1930; actually published in

1931.]

Rudine, S.F.

1988. Geology and Depositional Environments of the Permian Rocks,

Northern Del Norte Mountains, Brewster County, Texas. 186 pages.

Unpublished master's thesis, Sul Ross State University, Alpine,

Texas.

Rudine, S.F., B.R. Wardlaw, D.M. Rohr, R.A. Davis, and R.E. Grant

1987. Depositional Setting of the Late Leonardian-Wordian (Permian)

Rocks, Southern Margin, Permian Basin: Basin or Lagoon?

[Abstract.] Geological Society of America, Abstracts with Programs,

19(7):826.

Rudine, S.F., R.A. Faliskie, D.M. Rohr, and B.R. Wardlaw

1988. Major Unconformity Defines Wordian-Capitan Boundary (Upper

Permian) in Glass and Del Norte Mountains, Texas. [Abstract.]

Geological Society of America, Abstracts with Programs, 20:

A122-A123.

Thomson, A.F., and M.R. Thomasson

1969. Shallow to Deep Water Facies Development in the Dimple

Limestone (Lower Pennsylvanian), Marathon Region, Texas. In

G.M. Friedman, editor, Depositional Environments in Carbonate

Rocks. Society of Economic Paleontologists and Mineralogists,

Special Publication, 14:57-78.

Wardlaw, B.R.

1987. Leonardian-Wordian (Permian) Conodont Biostratigraphy of the

Del Norte and Glass Mountains, West Texas. [Abstract.] Geological

Society of America, South Central Section, Abstracts with Program,

19(7): 180.

2000. Guadalupian Conodont Biostratigraphy of the Glass and Del Norte

Mountains. In B.R. Wardlaw, R.E. Grant, and D.M. Rohr, editors,

The Guadalupian Symposium. Smithsonian Contributions to the

Earth Sciences, 32:37-87, 3 figures, 12 plates, 1 table.

Wardlaw, B.R., R.A. Davis, D.M. Rohr, and R.E. Grant

1990. Leonardian-Wordian (Permian) Deposition in the Northern Del

Norte Mountains, West Texas. United States Geological Survey

Bulletin, 1881-A:A1-A14.

Wardlaw, B.R., and S.F. Rudine

2000. The Altuda Formation of the Glass and Del Norte Mountains. In

B.R. Wardlaw, R.E. Grant, and D.M. Rohr, editors, The Guadalupian Symposium. Smithsonian Contributions to the Earth Sciences,

32:313-318, 4 figures.

Wilde, G.L., and S.F. Rudine

2000. Late Guadalupian Biostratigraphy and Fusulinid Faunas, Altuda

Formation, Brewster County, Texas. In B.R. Wardlaw, R.E. Grant,

and D.M. Rohr, editors, The Guadalupian Symposium. Smithsonian

Contributions to the Earth Sciences, 32:343-371, 3 figures, 9 plates.

Wilson, J.L.

1969. Microfacies and Sedimentary Structures in "Deeper Water" Lime

Mudstones. In G.M. Friedman, editor, Depositional Environments in

Carbonate Rocks: A Symposium. Society of Economic Paleontologists and Mineralogists, Special Publication, 14:4-19, plates 1, 2.
14. Anatomy and Origin of Capitan Limestone

Foreset Beds in the Glass Mountains, West Texas

Mohammad Haneef

ABSTRACT

Foreset beds found in the Capitan Limestone in the Glass

Mountains are clinoforms of basinward dipping, massive, partially to

completely dolomitized beds that interfinger with the slope and

basinal facies of the time-equivalent Altuda Formation. The foreset

beds represent deposition of reef and backreef derived, allochthonous

sediments shed off of the Capitan shelf-edge in shelf-to-basin slope

transition. On the basis of lithology, texture, and bedforms various

subaqeous gravity flow processes are recognized, including debris

flow, grain flow, and submarine slide and slump blocks. High energy

conditions along with sea-level fluctuations on the Capitan shelf-edge

produced carbonate debris that moved under the influence of gravity

and was deposited on the foreslope as multiple debris sheets.

Introduction

The Capitanian stratigraphic sequence in the Glass Mountains is represented by the Gilliam Limestone, the Capitan

Limestone, and the Altuda Formation in a shelf-to-basin

transition (Haneef et al., 1991). The Capitan Limestone crops

out in a narrow, laterally discontinous carbonate belt along the

rim of the Delaware basin (Pray, 1989). Along the entire extent

of exposure, only the Guadalupe Mountains, at the northwestern shelf of the Delaware basin, have been the focus of

extensive sedimentological studies in the past six decades. In

the Glass Mountains, the Capitan Limestone fringes the

southern shelf of the Delaware basin and has largely been

ignored. Most of the previous work in the Glass Mountains

dealt with stratigraphic and biostratigraphic relationships.

Mohammad Haneef, Geology Department, Sul Ross State University,

Alpine, Texas 79832.

Emerging from the Capitan Limestone (late Guadalupian)

are clinoforms of steeply dipping, massive beds that extend

downslope and interfinger with the gently inclined Altuda beds

(Figure 14-1). King (1931) noticed this peculiar feature along

the east face of Old Blue Mountain, which he refered to as

upper massive (Capitan) foreset beds. The purpose of the

present study is to document the nature and origin of these beds

on Old Blue Mountain in the Glass Mountains (Figure 14-2).

Field Relations

The Capitan foreset beds are light to dark gray to olive in

color on weathered surfaces and white to cream in color on

fresh surfaces. In outcrop, the majority of the beds are fractured

and jointed and are marked by honeycombed weathering and

wavy, nonsutured to sutured microstylolites with brownish iron

residue seams. Most of the fractures are irregular and are filled

with coarse spary calcite. The beds are hard, resistant, and

massive with obscure bedding. They contain irregular vuggy

porosity, coarse spar-filled cavities, brownish chert layers/

lenses or isolated pods, and partially to completely recrystallized internal fabric, and they are sparsely bioclastic. Lithoclasts and intraclasts of various shapes, sizes, and compositions

are present in the majority of the foresets but are difficult to

recognize on weathered surfaces because of the chaotic internal

structure and dolomitized fabric. The foresets typically weather

to large irregular to semicircular blocks that litter the lower

slopes around the mountain.

The foreset beds typically form resistant ledges and can be

differentiated from the recessive, slope-forming, bedded Altuda Formation in which they occur. The foreset beds display a

variety of bedforms, including irregular (hummocky), wavy,

channelized, and planar bedding surfaces (Figure 14-3A-C).

The thickness range of the foreset beds is from a few

centimeters to more than eight meters. The beds display pinch

and swell bedforms and generally exhibit a decrease in

333
334 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 14-1.—Panoramic view of the east face of Old Blue Mountain on the Parker Ranch. The Capitan

Limestone is represented by massive, resistant beds at the top. The recessive weathering profile is the Altuda

Formation. Note the eastward-dipping, thick, massive, wedge-shaped foreset beds interfingering with the Altuda

Formation.

30'

0 5 10 15

o

MARATHON

FIGURE 14-2.—Map of the Glass Mountains region with the study area indicated.
NUMBER 32 335

FIGURE 14-3.—A, view of a jointed and complexly fractured massive foreset bed with an undulatory base and top.

The massive bed is vuggy, lithoclastic, sparsely bioclastic, dolo-floatstone. It is characterized by large (centimeter

size), irregular coarse spar-filled cavities/fractures and brownish chert nodules. The planar beds beneath the

foreset are silty spiculitic dolomudstone of the Altuda Formation. Field notebook is 18 centimeters in length. B,

view of vuggy, recrystallized skeletal dolomudstone/wackestone beds of the Capitan foreset. The lower contact

of the foreset bed is wavy (hummocky) with the thin-bedded Altuda Formation. Note truncation of beds near the

hammer (length 28.5 cm). The foresets exhibit a downslope decrease in thickness and die out within a short

distance. C, view of the irregular base of a Capitan foreset beds. The foreset bed displays pinch and swell

bedforms. Note the abrupt truncation of the underlying thin, graded beds of the Altuda Formation. D, view of the

symmetrical folding in thin-bedded Altuda that is formed by the drag created by the overriding debris flow bed

of the Capitan foreset. Also visible are recumbent folds outlined by brownish cherry layers within the massive,

matrix-supported foreset bed.

thickness along dip and die out within a few kilometers down

dip. The massive beds also display variation in depositional dip

from a low angle (8°-10°)in the upper reaches of the outcrop

where they seem to emerge, to as steep as 25° in the lower

slopes of the outcrop at the termination of the beds. The beds

below the foreset beds are characterized by planar, abruptly

truncated, drag-folded contact relationships (Figure 14-3D). At

places, these beds are marked by the squeezing upwards

(injection) of Altuda beds into the massive foreset beds (Figure

14-4) and by ball and pillow structures (Figure 14-5A,B).

Lithological Characteristics

In the study area more than 10 foreset beds occur within the

Altuda Formation, although only five of these foresets are

mapable and can be traced laterally. Detailed field observations, petrographic examinations of polished slabs, and thin

sections of the foreset beds reveal a wide spectrum of

lithologies, textures, and fabric variations with genetic implications. The variation in sedimentary parameters has a bearing on

the mode and mechanism of transportation, paleotopography,

and source, which can be explained in terms of the sedimentary
336 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 14-4.—View of a sedimentary dike formed by the squeezing up

(injection) of thin-bedded Altuda sandstone beds into the Capitan debris

foreset. The foreset is interpreted as a grain flow deposit.

processes and then related to environments of deposition. The

following lithological and fabric types are recognized in the

foreset beds.

MATRIX SUPPORTED DOLO-BRECCIA.—The matrix as well

as the clast lithology of these beds is predominantly dolomudstone (Figure 14-5C). The clasts range in size from a few

millimeters to more than three centimeters. The shape of the

clasts varies from irregular sharp edged to subangular. The

FIGURE 14-5 (right).—A, view of ball and pillow structures within matrixsupported, sandy debris flow beds of the Capitan foreset. The parallel alignment

of the subrounded sandstone clasts indicates a pull-apart structure as the result

of the compaction of a modified gravity flow. B, view of the same foreset bed

about 100 meters down slope exhibiting nodular fabric. The clasts are

subrounded to rounded and include chert-coated sandstone clasts, large

silicified sponges, and chert nodules. The foreset bed does not show any

appreciable decrease in thickness. Apparently the gravity flow began as a

matrix-supported debris flow and changed into a grain flow down slope. C,

polished slab of a 1 m thick foreset bed. Note the monomict clast lithology

represented by the resedimented clasts of dolomudstone and dolowackestone.

Note the poorly sorted, subangular to subrounded clasts with rare echinoderm

fragments. The foreset displays grain flow to debris flow fabric, which indicates

multiple episodic deposition of material derived from the shelf and shelf-edge.

clasts are composed of fine dolomudstone with rare siltstone,

sandstone, chert, and micritized bioclasts. Angular, fine, quartz

silt occurs scattered in the dolomudstone matrix. In some cases,

localized disruption and brecciation of the original bedding can

be inferred on the basis of the similarity of clast lithology and

parallel orientation. The rocks display irregular fractures and

solution vugs filled with clear, coarse cavity-filling sparry

calcite. Microstylolitic seams mark the boundaries of the

grains. The clast to matrix ratio of these beds is generally 3:1 .
NUMBE

R 32 337

CLAST-SUPPORTED, LITHOCLASTIC, BIOCLASTIC FLOAT-

STONE.—This lithology is represented by angular to sub-

rounded clasts exhibiting a mixture of rectangular, tabular,

elongate, and irregular shapes. The clast lithologies include

dolomudstone, intraclasts and lithoclasts of siltstone, silty

spiculitic dolomudstone, and detrital chert fragments (Figure

14-6). The matrix of these beds is dolomudstone with quartz

silt, fine sand, and micritized skeletal debris. The bioclasts are

represented by brachiopods, bryozoans, echinoderms, Archaeolithoporella sp., Tubiphytes, dasycladacean algae, and sponge

spicules. The rocks display a variety of internal structures

varying from chaotic to faint normal to reverse grading. The

upper and lower contacts with the Altuda beds vary from

planar, irregular, wavy, and undulatory to channelized (Figures

14-7A,B, 14-8A). The truncation of, and the injection into, the

underlying Altuda sandstone and siltstone beds is visible in

some beds.

LITHOCLASTIC, INTRACLASTIC, BIOCLASTIC RUDSTONE.—

The foresets characterized by rudstone texture are dominantly

clast-supported with a clast to matrix ratio of 6 : 1. The matrix

is lime-mud with varying admixtures of quartz silt, fine sand,

skeletal debris, and chert fragments. Irregular microstylolite

swarms are abundant and exhibit compacted fabric (fitted lens

response of Wanless, 1979). The clasts are marked by irregular

interpenetrating stylolitic grain boundaries. Dolomite rhombs

and brownish iron oxide residue occur along the stylolitic

boundaries. The irregular, nonparallel orientation of the

stylolites indicate compacted grain fabric. These beds are

characterized by large clast sizes, generally in the centimeter

range. The lithology is dominated by broken and whole shells

of brachiopods and bivalves. Other bioclasts include sponges,

echinoderms, encrusting algae, Tubiphytes, Archaeolithoporella sp., sponge spicules, solitary corals, and foramanifers. Chert occurs as replaced bioclasts, cavity fill, and nodules.

The intraclasts are subround to round in shape and contain

bivalves and peloids in a lime mudstone-dolomudstone matrix.

The lithoclasts (rip-up, noncarbonate clasts) constitute 10

percent to 15 percent of the rudstone fabric and are represented

by laminated siltstone, spiculitic siltstone, and nonfossiliferous

sandstone clasts (Figure 14-8B,C). A prefered orientation of the

clasts is not evident. The beds are characterized by chaotic to

crude normal to reverse graded bedding.

RECRYSTALLIZED, DOLOMUDSTONE/WACKESTONE.—The

recrystallized dolomudstone/wackestone lithology represents

CM

FIGURE 14-6 (right).—A,B, polished slabs of the Capitan foreset displaying

clast-supported fabric interpreted as a grain flow deposit. The grain flow bed

has an irregular (scoured) contact with the laminated spiculitic mudstone-

wackestone beds of the Altuda slope facies. The clasts are represented by

intraclasts, lithoclasts of siltstone and sandstone, and bioclasts of echinoderms,

solitary corals, fenestrate bryozoans, dasycladacean algae, Tubiphytes,

Archaeolithoporella sp., and disarticulated bivalves. The foreset bed is poorly

sorted and exhibits clast-size variation from a few millimeters to more than four

centimeters. Note the reverse grading and slight alignment of the clasts.
338 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 14-7.—A, cross-sectional view of massive Capitan debris flow foreset.

The foreset bed is more than 2 m thick and has an irregular channelized base

truncating the Altuda beds below. The debris flow forms a channel 4 m wide

and 2 m deep. The beds below display truncation and compactional

deformation. The debris flow is characterized by jointed and brecciated

lithoclastic, vuggy, recrystallized, sparsely skeletal, cherty dolomitic floatstone

texture. The lithoclasts include vaguely skeletal, dolowackestone and laminated

to nonlaminated dolomudstone. The rock possesses irregular, coarse, calcitefilled cavities and fractures. The stadia rod scale is 1 m long. B, view of Capitan

debris flow bed displaying lithoclastic, bioclastic, dolomitic floatstonerudstone fabric. The lower contact of the foreset is channelized into thin-bedded

dolomudstone of the Altuda Formation. The debris flow bed shows a slight

alignment of clasts parallel to the flow direction. The upper contact of the debris

flow with Altuda silty, spiculitic, laminated dolomudstone beds is planar.

Hammer length is 28.5 centimeters.

the majority of the foreset beds. The thinner foreset beds are

composed exclusively of this lithology. These beds are 30 cm

to less than 1 m thick and display planar bedding surfaces.

Spar-filled vugs and fractures are the only similarity these beds

show with the other types of foresets. The rocks are extensively

dolomitized, and there is complete obliteration of the depositional fabric. Rarely, some silicified echinoderms, sponges,

solitary corals, brachiopods, and bryozoans are visible on the

outcrop surface. The beds are massive internally. The lower and

upper contacts of these foresets with the Altuda Formation are

planar. Some of the foresets have broad wavy (hummocky),

nonchannelized bedforms. The foresets of this lithology appear

to extend farther into the basin, and the decrease in thickness is

more gradual than those of the other lithologies. Chert

accentuated slump structures and recumbent folding are

commonly associated (although not restricted) with this

lithology. The trend of all the deformational features found in

the foreset beds indicate basinward movement. The beds

beneath the foresets mimic the bedforms of the foresets and

exhibit load and drag deformation without any evidence of

truncation.

CARBONATE SLIDE BLOCK.—Interbedded with the thinbedded sandstone and siltstone of the Altuda Formation on the

south side of Old Blue Mountain is a large carbonate block

composed of sponge, bioclastic wackestone/packstone. The

block is about 10 m long, 0.5-5 m thick, and has a lenticular

shape with an updip tapering end. On weathered surfaces the

block is olive gray in color, and on fresh surfaces it is pink. The

block is internally massive and lacks any discernable bedding.

Included bioclasts consist of calcareous sponges, fenestrate

bryozoans, brachiopods, dasycladacean algae, echinoderms,

and bivalves. The rock contains abundant spar-filled irregular

cavities. The basal part of the block is composed of a mixture

of clasts of sandstone, siltstone, and skeletal fragments. The

lower contact of the block with the underlying Altuda

Formation is undulatory, and the upper contact is covered with

alluvium. The geopetal fabric indicates that the block is

right-side up without any rotation.

DETACHED BRECCIA BLOCK.—An isolated large semicircular block of lithoclastic breccia overlies thin- to mediumbedded dolomudstone beds of the Altuda Formation (Figure

14-8D). The block contains boulder- to pebble-sized, angular to

subangular clasts of dolomudstone, silty dolomudstone, and

fine sandstone. The block displays a chaotic internal structure

with crudely inclined bedding and slump features in the center.

The top of the block is irregular with outward-projecting clasts.

The block contains coarse spar-filled irregular cavities and

fractures.

Interpretations

King (1931:79) described these foreset beds as reef-derived

material poured over the slope. He also observed similar

features on the slopes of the Guadalupe Mountains and

regarded them as part of the Capitan forereef facies. Newell

(1957) believed the foresets are composed of reef-derived

material but did not agree with the notion that they represent

part of the reef itself. The detailed study of these rocks reveal

that they are composed of shelf, backshelf, and shelf-edge

derived allochthonous material. Garber et al. (1989), in their

study of the Capitan foreslope facies in the Guadalupe
NUMBER 32 339

FIGURE 14-8.—A, view of channelized bedforms displayed by the Capitan foreset beds. The rocks are massive,

cherty, lithoclastic, recrystallized bioclastic floatstone. Note the multiple shifting shallow channels labelled 1 and

2 within the bed. The Altuda beds below the debris flow are truncated along the channel floor. B, debris flow bed

from the upper part of the Capitan foreset is 1.5 m thick at this locality. Pinch and swell bedforms are shown

throughout this foresets extent. The foreset is characterized by a basal zone of shearing followed upwards by

clast-supported, poorly sorted, randomly oriented, outward projecting, subangular to rounded clasts of fine

quartzose sandstone and laminated siltstone clasts. The clast size in this foreset is exceptionally large as compared

to other foresets in the study area. The similarity of the clasts to the Altuda sandstone beds of the slope facies

suggests that these clasts are probably rip-up clasts of the underlying bed being incorporated into the debris flow.

The lack of sandstone clasts within the basal part of the foreset indicates dispersive pressure and buoyancy effects

within the debris flow. Camera lens cap is 5.5 centimeters in diameter. C, close-up view of the same area. Hammer

is 28.5 centimeters in length. D, view of rotated slump block of Capitan foreset within thin- to medium-bedded

Altuda dolomudstone. The block displays slump deformation outlined by the inclined disrupted bedding in the

middle of the photograph. The basal part of the block contains boulder-sized angular clasts of dolomudstone and

silty dolomudstone. Note brecciated internal fabric and spar-filled fractures and cavities. Field notebook is 19 cm

in length.

Mountains, concluded that similar clinoforms are shelf-derived

allochthonous carbonate debris deposited on the Capitan

foreslope. Carbonate breccia deposited around the seaward

margin of carbonate shelves and buildups is known from many

places in the geologic record (Hopkins, 1977).

The Capitan foreset beds in the Glass Mountains display

features diagnostic of subaqueous gravity-flow deposits. The

presence of poor sorting, grading, variation in sizes and

compositions of clasts, lack of distinct internal structure, slump

folding, truncation of underlying beds, wavy, channelized and

planar bedforms, slide and slump blocks, and basinward

inclined, laterally thining wedges favor this interpretation. This

interpretation also best fits the overall shelf-to-basin transition

for the Guadalupian sequence in the Glass Mountains (Haneef

et al., 1991; Rohr et al., this volume). The variations in texture,

fabric, and bedforms within the Capitan foresets represent a

variety of transport and depositional mechanisms. The following gravity flow types are recognized in the study area.
340 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

DEBRIS FLOW DEPOSITS.—The foresetbeds characterized by

the matrix-supported dolobreccia and the recrystallized dolomudstone-wackestone lithology types are interpreted as debris

flow deposits. The matrix support, angular clasts, and

hummocky to planar bedforms indicate coherent, nonturbulent

movements of the mass on a gently sloping surface. Dott

(1963), Carter (1975), Middleton and Hampton (1976), Lowe

(1976, 1979), and Nardin et al. (1979) classified debris-flow

deposits according to rheological behavior, grain matrix ratio,

angle of slope, shear stress, viscosity, and yield strength, as

these are the main factors that influence the nature and lateral

extent of the gravity flow deposits. According to these workers,

the matrix in a debris flow serves several purposes, including

lubrication of clasts, buoyant support for denser clasts, and

elevated pore pressure to overcome frictional resistance to

flow. The presence of slump/recumbent folding, restricted only

to some foresets beds, indicates a lack of intragranular support,

steeper slopes, and a rapid rate of deposition of these foresets

(Figure 14-9A,B). The drag and distortion produced in the

underlying beds by overriding debris flow tongues illustrates

the cohesive nature of these flows.

GRAIN FLOW DEPOSITS.—Foreset beds dominated by clastsupported floatstone and rudstone fabrics are interpreted as

grain flow deposits. The clasts in these beds were derived from

the shelf and shelf-edge environments (Figures 14-9C, 14-10).

Some of the clasts are similar to the Altuda slope facies and

probably represent rip-up clasts incorporated during flow. The

high grain to matrix ratio and the reverse grading indicate that

grain interaction in these beds was the main transporting

mechanism, which resulted in an upward movement of the

larger clasts.

SUBMARINE SLIDE AND SLUMP BLOCKS.—The large carbonate block and detached brecciated block are believed to be

submarine slide and rockfall deposits derived from the

shelf-edge and slope environments. The carbonate slide block

exhibits lithological characteristics similar to the massive

facies of the Capitan reef. The block appears to have been

detached by waves and currents on the seaward side of the reef,

whereupon it slid downslope under the influence of gravity

without any significant rotation. The block displays lithology

similar to the Capitan foreset beds.

The isolated breccia block in Figure 14-8D exhibits

brecciated and deformed internal structure. The rotation of the

block is evident from the tilted geopetal fabric. It probably

represents a detached segment of a debris flow tongue during a

subsequent flow.

Conclusions

The Capitan foreset beds in the Glass Mountains were

formed by a subaqueous gravity flow processes. Figure 14-11

shows the proposed depositional setting of the Capitan foreset

FIGURE 14-9.—A, view of penecontemporaneous slump deformation and

contortion accentuated by dark brown cherry layers within Capitan foreset beds

formed as a consequence of downslope en masse movement of matrixsupported debris flow. B, view of penecontemporaneous slump deformation

and contortion in a predominantly sandy matrix. C, close up of weathered

surface of one of the Capitan foreset beds exhibiting clast-supported texture.

The stylolitic compacted fabric and predominantly sandy, cherty matrix clearly

displays the internal fabric not visible in most of the Capitan foreset beds. The

clasts are angular to subrounded and represent a mixture of lithologies, shapes,

and sizes. The foreset is interpreted as a grain flow deposit. The pen length is

10 centimeters.
NUMBER 32 341

FIGURE 14-10.—View of a clast-supported Capitan foreset grain flow deposit.

The foreset is 1.2 m thick and has a flat top and bottom with the superjacent

Alruda silty dolomudstone beds. The lower contact contains a brownish

iron-oxide coated thin chert layer. The foreset lacks any grading and is

composed of poorly sorted dolomudstone breccia.

beds. The high energy conditions on the seaward side of the

reef along with fluctuations in sea level produced carbonate

debris on the shelf-edge. The material thus formed moved

downslope under the influence of gravity and was deposited on

the foreslope. A lack of deep submarine channels and

associated features suggest that the sediment movement was

predominantly in the form of widespread debris sheets with

only a few shallow and rare deep channels.

Acknowledgements

This paper stems from the author's masters thesis research at

Sul Ross State University. The research for this study was

funded by an AAPG Grant-in-Aid and a teaching assistantship

by the Department of Geology to Mohammad Haneef, and an

American Chemical Society Research Grant # 1641-24595 to

David Rohr.

Literature Cited

Carter, R.M.

1975. A Discussion and Classification of Subaqueous Mass Transport with

Particular Application to Grain-flow, Slurry-flow and Fluxoturbidites. Earth Science Reviews, 11:145-177.

Dott, R.J., Jr.

1963. Dynamics of Subaqueous Gravity Depositional Processes. Bulletin

of the American Association of Petroleum Geologists, 47(1): 104-

128.

Garber, R.A., G.A. Grover, and P.M. Harris

1989. Geology of the Capitan Shelf Margin-Subsurface Data from the

Nothern Delaware Basin. In P.M. Harris, and G.A. Grover, editors,

Subsurface and Outcrop Examination of the Capitan Shelf Margin,

Nothern Delaware Basin. Society of Economic Paleontologists and

Mineralogists, Core Workshop. 13:3-269.

Haneef, Mohammad, S.F. Rudine, and B.R. Wardlaw

1991. Shelf to Basin Transition in the Capitanian (Permian) Deposition in

the Glass Mountains, West Texas. [Abstract.] Geological Society of

America, Abstracts with Programs, 22:A46.

Hopkins, J.C.

1977. Production of Foreslope Breccia by Differential Submarine Cementation and Downslope Displacement of Carbonate Sands, Miette and

Ancient Wall Buildups, Devonian, Canada. In H.E. Cook and P.

Enos, editors, Deep-Water Carbonate Environments. Society of

Economic Paleontologists and Mineralogists, Special Publication,

25:155-170.

King, P.B.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part I:

Descritive Geology. University of Texas Bulletin, 3038: 167 pages,

15 plates. [Date on title page is 1930; actually published in 1931.]

Lowe, D.R.

1976. Grain Flow and Grain Flow Deposits. Journal of Sedimentary

Petrology, 46(11): 188-199.

1979. Sediment Gravity Flows, Their Classification and Some Problems of

Application to Natural Flows and Deposits. In L.J. Doyle and O.H.

Pilkey, editors, Geology of Continental Slopes. Society of Economic

Paleontologists and Mineralogists, Special Publication, 27:75-82.

Middleton, G.V., and M.A. Hampton

1976. Subaqueous Sediment Transport and Deposition by Gravity Flows.

In D.J. Stanley and D.J.P. Swift, editors, Marine Sediment Transport

and Environmental Management, pages 197-218. New York: John

Wiley.

Nardin, T.R., F.J. Hein, D.S. Gorsline, and D. Edwards

1979. A Review of Mass Movement Processes, Sediment and Acoustic

Characteristics, and Contrasts in Slope and Base-of-Slope Systems

Versus Canyon-Fan-Basin Floor Systems. In L.J. Doyle and O.H.

Pilkey, editors, Geology of Continental Slopes. Society of Economic

Paleontologists and Mineralogists, Special Publication, 27:61-73.

Newell, N.D.

1957. Paleoecology of Permian Reefs in the Guadalupe Mountains Area. In

H.S. Ladd, editor, Treatise on Marine Ecology and Paleoecology,

Volume 2: Paleoecology. Geological Society of America, Memoir,

67:407-436.

Pray, L.C.

1989. Lateral Variability of the Capitan Reef Complex, West Texas and

New Mexico. In P.M. Harris and G.A. Grover, editors, Subsurface

and Outcrop Examination of the Capitan Shelf Margin, Northern

Delaware Basin. Society of Economic Paleontologists and Mineralogists, Core Workshop, 13:273-278.

Rohr, D.M., B.R. Wardlaw, S.F. Rudine, M. Haneef, J.A. Hall, and R.E. Grant

2000. Guidebook to the Guadalupian Symposium. In B.R. Wardlaw, R.E.
342 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 14-11.—Block diagram showing the proposed depositional setting of Capitan foreset beds in the Glass

Mountains.

Grant, and D.M. Rohr, editors, The Guadalupian Symposium. Wanless, H.R.

Smithsonian Contributions to the Earth Sciences, 32:5-36, 31 1979. Limestone Response to Stress: Pressure Solution and Dolomitizafigures. tion. Journal of Sedimentary Petrology, 49( 12):437-462.
15. Late Guadalupian Biostratigraphy and Fusulinid

Faunas, Altuda Formation, Brewster County, Texas

Garner L. Wilde and Shannon F. Rudine

ABSTRACT

Occurrences of late Guadalupian (Zone PG-6, Wilde, 1990)

fusulinid faunas in the Altuda Formation of the western Glass

Mountains, Texas, confirm a biostratigraphic correlation with the

upper Bell Canyon Formation (Lamar Limestone Member and

post-Lamar siltstones) and the Tansill Formation of the Guadalupe

Mountains.

Codonofusiella (Lantschichites) altudaensis, new species,

Paraboultonia splendens Skinner and Wilde, Reichelina lamarensis

Skinner and Wilde, and Rauserella bengeensis, new species, all occur

in the upper part of the Altuda Formation and above the zone of

Polydiexodina (Zone PG-5, Wilde, 1990). The Altuda beds are

overlain unconformably by strata referred to the Tessey Formation

(originally King's upper massive member, Capitan Limestone).

At least three important fusulinid subzones (in the sense of Wilde,

1990, but referred to herein as zones) have been identified in the

Altuda, and another is suspected. Paraboultonia and Lantschichites

mark a zone in the upper part of the Altuda covering a maximum

thickness of about 20 m (65 ft.); Reichelina lamarensis marks the next

older zone covering a maximum of approximately 12 m (40 feet);

Paradoxiella marks a zone below this of unknown thickness. Although

not identified as yet from collections, a lower zone of Yabeina texana

should be expected below Paradoxiella because of its presence in this

identical zonal configuration in the Guadalupe Mountains.

Paraboultonia and Lantschichites are both recognized on the basis

of their coiling habit, and Lantschichites is returned to Codonofusiella

as a subgenus.

Lateral thickness changes of strata in each of the fusulinid zones

and the nature of the sediments therein are suggestive of a

northeastward transgression accompanied by a gradual steepening of

the shelf margin and a southwestward deepening in the Del Norte

Mountains area.

Garner L. Wilde, GLWInternational, Midland, Texas 79705. Shannon

F. Rudine, Geology Department, Sul Ross State University, Alpine,

Texas 79832.

Introduction

During the course of detailed mapping and stratigraphic

studies in the western Glass and northern Del Norte mountains,

one of the authors (Rudine) discovered a tiny fusulinid fauna in

the Altuda Formation. A cursory examination suggested that

the fauna might be similar, if not identical, to that described by

Skinner and Wilde (1954, 1955) from the late Guadalupian

Lamar Limestone Member, upper Bell Canyon Formation,

southern Delaware and Guadalupe mountains. Rudine contacted the senior author for verification and possible collaboration. The present paper is the result of that collaboration.

Locality Data

Closely spaced samples were collected from four measured

sections (Figure 15-1), three of which are located in the Bird

(Altuda) Mountain area of the northern Del Norte Mountains,

and a fourth is at the northwest point of Old Blue Mountain in

the western Glass Mountains. Each section covers portions of

the Altuda and Tessey formations. The four measured sections

are identified as follows.

Section 1 was measured and collected by Rudine as MS77-2

(the second section on the 77 Ranch). The section begins at the

4880 foot contour, located 4000 feet (1219 m) N48E of the

summit of Bird Mountain, U.S.G.S. 7.5 minute Bird Mountain

Quadrangle. It begins at the top of the second unnamed

sandstone member of the Word Formation (Wardlaw et al.,

1990), proceeds in a westerly direction toward the northwestern

corner of Bird Mountain, and ends in the lower portion of the

Tessey Formation at the 5320 foot contour.

Section 2 was measured by Bruce Wardlaw and collected by

Rudine as MS-W90. The section is located approximately 1 km

west of Section 1, on the west side of a small spur. There is a

mine location on the opposite, or east, side of the spur. The

section begins at the 5080 foot contour, proceeds upwards (due

south) to the 5280 foot contour, U.S.G.S. 7.5 Bird Mountain

Quadrangle, and ends in the lower Tessey Formation.

343
344 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PECOS

COUNTY

BREWSTER

COUNTY

FIGURE 15-1.—Location of the four measured sections in the Glass and Del Norte mountains.
NUMBER 32 345

Section 3 was measured by Rudine as MS-BM5, about 0.5

km from Section 2, northwestward across a canyon. It is located

about 4600 feet (1402 m) NNW of the summit of Bird

Mountain, beginning at the 4920 foot contour line at the point

where the "8" in road elevation marker 4897 contacts the 4920

contour, and proceeds NW along the projecting spur where it

stops at the 5000 foot contour, U.S.G.S. 7.5 minute Bird

Mountain Quadrangle. The area in which the above three

sections were measured is referred to in this paper as the Bird

Mine area, named for mining activity associated with Tertiary

intrusives.

Section 4 was measured by Rudine as MS-B1, on the Benge

Ranch, beginning just below a stone quarry approximately

5700 feet (1737 m) NW of the 5186 foot elevation marker on

Old Blue Mountain, western Glass Mountains, U.S.G.S. 7.5

minute Quadrangle. It begins a short distance north of the stone

quarry road and below the 4200 foot contour, proceeds SE up

a prominent spur to the 4400 foot contour, and ends in the

lower portion of the Tessey Formation.

In the systematic paleontology portion, locations of collections within the individual measured sections can be identified

as feet above the base (ex. Coll. BM5-34, is 34 feet above the

base of Section 3).

Zonation and Stratigraphic Analysis

The correlation of fusulinid occurrences, shown in Figure

15-2, allows for the stratigraphic analysis of these rock

sequences with an eye to better understanding the sedimentology. This paper, however, is not intended to be definitive in that

regard. Our main concern is to demonstrate the presence and

sequential accuracy of a late Guadalupian fusulinid zonation

already recognized farther to the north in the southern Delaware

and Guadalupe mountains.

The stratigraphic relationships in the area of study are

already reasonably well known, thanks to the early excellent

work of P.B. King (1931), R.E. King (1931), and later workers

(Figure 15-3).

Rohr et al. (1991) and Rudine's continuing studies in the

area, show that the rocks, which overly the Altuda Formation

and were originally assigned to the upper massive member of

the Capitan Limestone by RB. King (1931), actually belong to

the Tessey Formation. The Tessey in this area is composed of

a complex sequence of laminated, stromatolitic, and evaporitic

limestones at the base, followed by a sequence of collapse

breccias that are dolomitic. These breccias resemble what have

been called "Castiles" within the Castile Formation. The two

formations are probably coeval, at least in part.

This paper, however, is concerned with only the upper

Altuda Formation. The middle and late Guadalupian boundary

is identifiable at the base of the lower Altuda in the Bird

Mountain area. This separation is based upon occurrences of

the fusulinid genera Parafusulina, of the middle Guadalupian

Word Formation, and Polydiexodina, of the late Guadalupian

Altuda Formation. The study, however, considers only those

rocks of the Altuda Formation that are younger than the highest

occurrence of Polydiexodina. This is illustrated at the base of

Figure 15-2 to show the stratigraphic relationships of the

younger faunas to the older.

These relationships are important to note because in the

Guadalupe Mountains, Polydiexodina occurs no higher than

the McCombs Limestone Member of the Bell Canyon

Formation (Newell et al., 1953). We believe that this same level

is identifiable in the northern Del Norte and western Glass

Mountains.

In the section on systematic paleontology the various levels

in the upper Altuda Formation have been determined from

which fusulinid faunas have been identified. Those occurrences

are the basis for the zonation summarized in Figure 15-2. At the

top of the Altuda is the zone of Paraboultonia-Lantschichites,

underlain by the zone of Reichelina lamarensis. Based upon a

single, but well-documented float collection, the zone of

Paradoxiella appears to underlie the Reichelina zone. A lower

zone of Yabeina texana might be expected, but specimens of

this species have not been found.

Skinner and Wilde (1954, 1955), Wilde (1955, 1990), and

Tyrrell (1964, 1969) have demonstrated the presence of just

such a zonation in the Guadalupe Mountains in the Lamar-post

Lamar beds of the Bell Canyon Formation and its shelf

equivalent, the Tansill Formation. Interestingly, a decade after

the first recognition of these faunal zones, Tyrrell (1964), who

made a detailed stratigraphic analysis of core drill material

taken from the Dark Canyon area, a number of miles north of

the type localities of the above noted species of Skinner and

Wilde, found an identical sequence of faunas. From time to

time these kinds of data have been attacked as being erroneous

by those whose agenda seem not to have been based upon an

understanding of lateral facies and faunal succession. Only

recently, for example, Achauer (1990), in reviewing an

important publication of the Society of Economic Paleontologists and Mineralogists, comments, "the efforts of the book's

authors should stimulate additional work on the Capitan ... this

reviewer is convinced that the widely accepted correlation of

the Lamar Limestone to the Tansill [sic] Formation across the

Capitan shelf is questionable" (Achauer, 1990:1665). Perhaps

the present data describing a similar sequence of fossils from

coeval rocks located at a greater distance will help to convince

skeptics of the reality of these correlations.

What are some of the sedimentological implications that can

be drawn from the fusulinid zonation shown in Figure 15-2?

First, one needs to understand that all of these sections are

located near the edge of the Hovey channel, which provided the

only known connection between the Delaware basin and the

open ocean during late Guadalupian time. The Benge Ranch

area (MS-4) probably laid farthest shelfward during late Altuda

deposition; however, even there, the facies probably represents

toe of slope deposition. In Section 4 the zone of Paraboul-
346 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PARABOULTONIA -

Paradoxiella

single occurence

NORMALIZED BASE OF MEASURED SECTIONS

130 FT.

HIGHEST OCCORENC E

FIGURE 15-2.—Correlation of the fusulinid zones in the Altuda Formation.

tonia-Lantschichites is thickest and contains a rich, silicified

megafauna, especially brachiopods and ammonoids.

At Section 3 the underlying zone of Reichelina lamarensis is

at its thickest development. There, too, an abundant, silicified

megafauna occurs. Not enough zonal definition is known from

Section 2, but it is suggested that the zone of Paradoxiella

should exhibit its thickest development there, based upon the

type of rocks and megafaunal content.

Comparison of the location map (Figure 15-1) with Figure

2-2 (Rohr et al., this volume) suggests the shelf edge was

prograding northward through the area during deposition of the

Altuda. There is a vague hint, however, that a gradual

steepening of slope was occurring through time, beginning in

the Bird Mine area and progressing northeastward toward the

Benge Ranch area. Further illumination of the depositional

history of this portion of the Altuda Formation can only be

obtained from a detailed study of the sequence stratigraphy of

this interesting unit.
NUMBER 32 347

DEL NORTE MTNS.

S N

Tessey Limestone

Second Limestone

and Clastic Member

Mudstone Member

First Limestone

and Clastic Member

Appel Ranch

Third Siltstone

Member

Member

Williis Ranch Member

—

Second

Siltstone Mbr.

First Sandstone Member

First

Siltstone Mbr.

Road Canyon Formation

Cathedral Mountain Formation

OLD BLUE MTN.-

GILLILAND CANYON

NW SE

Tessey Limestone

Undifferentiated

Appel Ranch Member

Siltstones

Williis Ranch Member

Undifferentiated

Siltstones

Road Canyon Formation

Cathedral Mountain Formation

GILLILAND

CANYON

W

HESS

CANYO N CONODONTS FUSULINIDS

Tessey Limestone

Gilliam Fm.

Appel Ranch Member " ^

Undifferentiated < T. L.

Siltstones ' ^ y £

Williis Ranch Member

Undifferentiated Siltstones

China Tank Mbr.

Road Canyon Formation

Cathedral Mountain Formation

-L

FlGURE 15-3.—Stratigraphic relationships in the northern Del Norte and Glass mountains. (Modified after Cooper

and Grant (1972), Davis (1984), Rudine (1988), Wardlaw et al. (1990), and Wilde (1990).)

Systematic Paleontology

Family OZAWAINELLIDAE Thompson and Foster, 1937

Reichelina Erk, 1942

Reichelina lamarensis Skinner and Wilde, 1955

PLATE 15-2: FIGURES 1-5, PLATE 15-3: FIGURES 1-11, PLATE 15-4:

FIGURES 1-9, PLATE 15-5: FIGURES 1-3

Reichelina lamarensis Skinner and Wilde, 1955:927-940, pi. 89: figs. 1-9.

Inner whorls with sharply rounded or bluntly angular

periphery; ultimate whorl periphery usually sharply angular in

adult specimens. Mature individuals with 4B-5B whorls; axial

length 0.36-0.52 mm, average 0.41 mm in nine specimens.

Specimen width 0.76-1.13 mm, average 0.43 mm. Final V3-V2

volution greatly expanded in height in fully mature specimens,

with corresponding increase in septa length. Rarely specimens

appear uncoiled, but condition of such specimens too poor for

accurate determination.

Spirotheca very thin, consisting of a tectum and diaphanotheca. Septa unfluted but strongly convex anteriorly. Some

specimens with tunnel rising from floor in last few septa

coincident with marked inflation of final volution. Septal pores

common, usually appearing as dark spots due to plugging by

secondary material. In 11 specimens: first whorl with 7-12

septa, average 9; second whorl with 11-16 septa, average 14;

third whorl with 12-18 septa, average 16; fourth whorl with

16-22 septa, average 19. In three specimens: fifth whorl with

22-25 septa, average 24.

Proloculus minute, spherical, with outside diameter varying

from 33-56 microns, average 45 microns for 15 specimens.

Tunnel low, narrow, averaging 18° in fourth whorl. Chomata

low, broad, extending laterally to poles and joining across

tunnel floor.

DISCUSSION.—The material described herein appears to fall

well within the limits of specific variation for the species. The

studied specimens are slightly larger in most whorls and have

a slightly smaller form ratio. Correspondingly, the specimens

have a slightly greater number of septa per whorl. Skinner and

Wilde's types are from the Lamar Limestone Member of the

Bell Canyon Formation, Guadalupe Mountains, which corresponds very well stratigraphically with the studied material.
348 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

OCCURRENCE.—Reichelina lamarensis Skinner and Wilde

occurs, often in profusion, in each of the four measured sections

discussed herein. In Section 1, however, the zone is poorly

represented by a single collection, Coll. 77-2-718. In Section 2,

the species is represented in two collections. In Coll. W90-48,

the species is not common; however, in Coll. W90-50+2, it is

abundant. In Section 3, it is seen in abundance in Colls.

BM5-34, 91, 95, 103, 109, and 114. It also occurs in Coll. 343

(float). At Section 4, it was found in Colls. Bl-48, 52, 59.5,

60.25, 76, 77.5, 77.6, and 83. Thus, there is a slight overlap of

the zone of Reichelina lamarensis with the higher zone of

Paraboultonia-Lantschichites in sections 2, 3, and 4.

Rauserella Dunbar, 1944

Rauserella bengeensis, new species

PLATE 15-1: FIGURES 1-9, PLATE 15-2: FIGURES 6-10

Shell extremely minute and highly irregular in shape. Mature

specimens with 4-5 volutions; first 2-3 volutions commonly

coiled askew or even at right angles to later axis of coiling.

Direction of axis of coiling commonly shifting, so appearance

varying greatly among mature specimens. Shell length 0.54-

0.81 mm, average 0.68 mm; shell width 0.34-0.43 mm,

average 0.37 mm. Form ratio for five specimens 1.42-2.4,

average 1.85. Spirotheca very thin, composed of a tectum and

diaphanotheca. Septa unfluted throughout, but commonly

convex anteriorly, particularly in later whorls. In five specimens: first whorl with 6 septa; second whorl with 10-13 septa,

average 11; third whorl with 11-13 septa, average 12. In one

specimen: fourth whorl with 8 septa; fifth whorl with 6 septa.

Septal pores relatively common throughout.

Proloculus very small, with outside diameter 22-56 microns, average 33 microns for five specimens. Tunnel narrow in

juvenarium, becoming wider in adult whorls, but practically

impossible to measure with accuracy because of changes in

coiling and absence of prominent chomata bordering tunnel in

outer whorls.

DISCUSSION.—Rauserella bengeensis, new species, is perhaps the smallest member of the genus yet known; thus, it bears

little resemblance to previously described forms of the genus.

Somewhat similar forms have been seen from rocks as old as

late Leonardian, but no significant size increase occurred

before the late Guadalupian. That such a tiny species as R.

bengeensis is seen in these late Guadalupian beds may indicate

the presence of two lineages of Rauserella, an early minute and

less differentiated group, and a later, small but fully differentiated group.

OCCURRENCE.—Rauserella bengeensis, new species, occurs

in all four of the measured sections of this paper. It occurs in a

single sample from Section 1, Coll. 77-2-718. In Section 2, it

occurs in Coll. W90-48, but like Reichelina, it is only poorly

represented in terms of numbers, although the preservation is

excellent. In Section 3, it occurs in Coll. 343 (float) and in

Colls. BM5-34, 95, and 114. In Section 4, it occurs in Colls.

Bl-40, 46, and 59.5. It thus occurs throughout the zone of

Reichelina lamarensis and the lower portion of the overlying

zone of Paraboultonia-Lantschichites, but never in great

numbers.

Subfamily BOULTONIINAE Skinner and Wilde, 1954

Paraboultonia Skinner and Wilde, 1954

Paraboultonia splendens Skinner and Wilde, 1954

PLATE 15-8: FIGURES 1-11, PLATE 15-9: FIGURES 1-16

Paraboultonia splendens Skinner and Wilde, 1954:441, pi. 44: figs. 1-7, pi.

45: figs. 1-4.

Shell minute, slender cylindrical, with bluntly rounded

poles, particularly in outer volution. Adult specimens with 4B

to 5B whorls; first whorl discoidal and coiled askew to

succeeding whorls. Shell length 2.14-3.86 mm, average 2.84

mm. Shell width 0.57-1.02 mm, average 0.75 mm. Form ratio

for 10 specimens 3.2-4.6, average 3.83. Last '/4 volution in

ultimate whorl rather abruptly expanded; expansion commonly

occurring at any point following beginning of fifth volution,

but can begin earlier in fourth.

Spirotheca and septa very thin, consisting of a tectum and

diaphanotheca. Septa intensely fluted from pole to pole; folds

high and regular throughout shell, except in expanded portion

of final volution. Cuniculi present, at least in outermost

volution; septal pores abundant and easily identified because of

plugging with dark, secondary material (a common characteristic of the Boultoniinae). In 10 specimens: juvenarium with 8 or

9 septa; second whorl with 9-15 septa, average 11; third whorl

with 13-20 septa, average 17; fourth whorl with 20-29 septa,

average 24. One specimen: fifth whorl with 32 septa.

Proloculus spherical, with outside diameters 35-86 microns,

average 55 microns in 10 specimens. Tunnel low, narrow, and

quite erratic throughout, but not commonly observed in outer

whorls.

DISCUSSION.—Paraboultonia splendens Skinner and Wilde

remains the only described species of this genus. The genus has

been confused with Codonofusiella (Lantschichites) Toumanskaya, 1953, and indeed, the two are difficult to separate in

some axial sections. In Paraboultonia, however, only the

ultimate whorl expands, and all septa continue to touch the

floor of the penultimate volution (Plate 15-9: Figures 1, 2,

10-12, 14, 15). In C. (Lantschichites), on the other hand, the

final whorl not only greatly expands, but it lifts off of the

penultimate volution, uncoiling, and the septa in the uncoiled

portion implant themselves against the previous septal face, as

in typical Codonofusiella (Plate 15-6: Figure 13; Plate 15-7:

Figures 1-4, 7, 9).

The studied specimens differ only slightly from Skinner and

Wilde's types from the southern Delaware Mountains. Indeed,
NUMBER 32 349

the form ratios differ by less than 0.20, and average proloculus

diameters differ by less than 10 microns. This is extremely

close for such an unusual species as they are separated by the

Hovey channel and a distance of about 90 miles (145 km).

OCCURRENCE.—Paraboultonia splendens Skinner and

Wilde occurs, commonly in abundance, in Sections 2, 3, and 4.

In Section 2, it occurs with Lantschichites altudaensis, new

species, and Reichelina lamarensis Skinner and Wilde in Coll.

W90-50+2. In Section 3, it occurs in Colls. BM-109 and 114.

In Section 4, it occurs in Colls. Bl-77.5, 77.6, 83, 83.1, 85.5,

87.5, 92.7, 96, 97, 97.5, 100, 108.5, 108.7, 110, 114, 115.1,

116.5, 121.5, 128, 135, 136, and 138.

Codonofusiella Dunbar and Skinner, 1937

Subgenus Lantschichites Toumanskaya, 1953

Codonofusiella {Lantschichites) altudaensis, new species

PLATE 15-5: FIGURES 4-7, PLATE 15-6: FIGURES 1-13,

PLATE 15-7: FIGURES 1-7,9

Shell minute, bluntly cylindrical, with bluntly rounded poles

except in penultimate whorl, which varies from bluntly

rounded to bluntly pointed. Mature specimens with 4-5

volutions; first volution commonly discoidal and coiled askew

to succeeding volutions, in such instances proloculus quite

small. Specimens with normally coiled initial whorl, proloculus

quite large. Adult specimen shell length 1.91-3.26 mm,

average 3.00 mm; shell width 0.56-0.94 mm, average 0.81

mm. Form ratio 2.6-4.9, average 3.2 in 7 specimens.

Final-whorl expansion similar to Paraboultonia, but expansion developing into uncoiling, commonly of great extent, with

concomitant axial extension, much as in Codonofusiella

extensa Skinner and Wilde, 1937. In some specimens, coiled

portion rectangular-shaped with extremely blunt polar areas,

followed by a greatly expanded, uncoiled portion, resulting in

strange appearance.

Spirotheca and septa very thin, consisting of a tectum and

diaphanotheca. Septa intensely fluted from pole to pole; folds

high and regular throughout coiled portion, becoming highly

irregular as expansion begins. High septal folds squared off at

top, as in Paraboultonia, but folds more extreme. In Paraboultonia splendens such folds with more secondary material

associated with them than in C. (L.) altudaensis. Cuniculi not

detected, but their presence still possible.

Septal count for juvenarium undeterminable. For five

specimens: second whorl with 9-16 septa, average 11; third

whorl with 14-21 septa, average 17; fourth whorl with 19 to

more than 26 septa, average 23. In two specimens: fifth whorl

with average of 34 septa.

Proloculus spherical, outside diameters 57-86 microns,

average 78 microns. Tunnel low, narrow, and more easily

discernible than in Paraboultonia splendens.

DISCUSSION.—Codonofusiella (Lantschichites) altudaensis,

new species, is closely similar to the type of the subgenus, L.

maslennikovi Toumanskaya (1953), particularly in the large

size of the proloculus compared to the shell size, and in the

cylindrically quadrate shape of the coiled test. The new species

is much larger than the type in both length and width. One of

Toumanskaya's specimens of nearly 5 whorls, measures only

0.05 mm in length and 0.45 mm in width (pi. X: fig. 2), yet the

proloculus is 50 microns in outside diameter. On the same plate

(fig. 3) she illustrates C. (L.) weberi (Schubert), which also has

5 complete whorls and measures only 1.18 mm in length and

0.50 mm in width, yet the proloculus is also 50 microns in

outside diameter, which is quite large for the overall size of the

specimen.

Sosnina (1968) described three new species of Lantschichites: L. exilis, L. elegans, and L. tenuitheca. Lantshichites

elegans is elongate cylindrically, as is Paraboultonia splendens

Skinner and Wilde; however, Sosnina illustrated a sagittal

section of the species that shows appreciable uncoiling, as do

the other two species, which are also more quadrate-shaped, as

in the types.

Sheng (1963) identified two species as Lantschichites from

the south China province of Kwangsi. One of the species,

Lantschichites minimus (Chen), was described originally as

Gallowaiinella minima; however, Sheng's specimens demonstrate extremes of uncoiling in a number of specimens, which

supports its placement in Lantschichites. In the same paper,

Sheng identified other specimens as Lantschichites splendens

(Skinner and Wilde). These forms do not uncoil, but they do

inflate in the final whorl. The specimens may or may not

belong to P. splendens, as they appear to be more slender than

the types. Regardless, there is a consistency with the types in

the absence of an uncoiled portion.

Wang, Sheng, and Zhang (1981) described some fusulinid

faunas collected on an expedition to the Qinghai-Xizang

Plateau Region in which they report Lantschichites kalamulunica, new species, L. xizangicus, new species, and L. minimus

(Chen). Based on their description and illustrations, L.

kalamulunica is obviously a Codonofusiella and is similar to C.

extensa Skinner and Wilde. Wang et al. (1981) did not illustrate

sagittal sections of L. xizangicus, but it could be a Paraboultonia. Sagittal illustrations were included for L. minimus, and

they show that the species is correctly placed in the genus.

To be fair, there is no sound basis for concluding that the

sagittal sections shown on Plate 15-7: Figures 5, 6 actually

belong to this new species. No flare is present, and the septal

counts and proloculus measurements are not different from

some of Paraboultonia splendens. Both species occur in the

collections from which these specimens came. It is suspected

that without the prominent uncoiled flare one might have some

difficulty in making a separation based on sagittal sections.

Finding well-oriented sagittal sections that show the flaring

portion is difficult at best.

The reasons for placing Lantschichites once again as a

subgenus of Codonofusiella are twofold. First, the only
350 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

difference between the two is the length of the coiled portion,

which is hardly a generic difference. Furthermore, by going

back to Toumanskaya's original designation, the differences

between Lantschichites and Paraboultonia can be amplified,

not merely to preserve the generic name of the latter, but to

demonstrate what so many workers seem to have overlooked,

namely the former uncoils, but the latter does not (Wilde,

1975:80). This characteristic is certainly generic, as is the

overall difference in shape.

OCCURRENCE.—Codonofusiella {Lantschichites) altudaensis, new species, is present in three of the measured sections of

this paper. It is found in great profusion in Coll. W90-50+2 of

Section 2, in Coll. BM5-109 of Secion 3, in Colls. Bl-83, 87.5,

and 136 in Section 4, and in Coll. BR4-113. In all but the last

cited collection, the new species occurs with Paraboultonia

splendens Skinner and Wilde and with Reichelina lamarensis

Skinner and Wilde.

Paradoxiella Skinner and Wilde, 1955

Paradoxiella pratti 1 Skinner and Wilde, 1955

PLATE 15-7: FIGURE 8

A single specimen of an undoubted Paradoxiella was

recovered, and it is suspected to belong to P. pratti; however,

it is only a parallel section, so it is difficult to unquestionably

assign it to P. pratti. By straightening the specimen for

maximum dimension of the annular flare, a size of 1.44 mm

was obtained; however, because the specimen is not sectioned

near the center of the shell, this would be a minimum width.

Maximum width of the entire flare in the types for P. pratti was

2.88 mm. The measured width of the coiled portion of the shell

is 0.46 mm, compared to 0.34 mm for the type specimens.

Again, comparisons are practically meaningless because of the

location of the cuts of the section.

Regardless of the difficulty of comparisons, the discovery of

Paradoxiella beneath the zone of Reichelina lamarensis is

important. Further search will almost certainly produce better

material.

OCCURRENCE.—The single specimen occurred in a float

sample picked up by Rudine in Section 3. The sample (Coll.

343) is shown on the cross section (Figure 15-2) by a symbol.

Rudine believes this to be very close to the in situ occurrence of

Paradoxiella.

Acknowledgments

The authors are grateful to a number of persons for their

generous hospitality and assistance in various aspects of this

study. Mr. and Mrs. Mac Benge, owners of the Benge Ranch,

Mr. and Mrs. Kyle Seales, owners of the 77 Ranch, and Mr.

Tommie Woodward, owner of the Bird Mine, generously

allowed access to properties for mapping, section-measuring,

and collecting. Bruce Wardlaw, U.S. Geological Survey,

measured Section 2 and shared generously considerable

stratigraphic data. Merlynd Nestell, University of Texas,

Arlington, translated important Russian papers. David Rohr

and the Geology Department of Sul Ross State University

kindly made facilities available for thin-section preparation.

Finally, the authors thank Bruce Wardlaw, David Rohr,

Richard Grant, and Merlynd Nestell for critically reading the

manuscript and making useful suggestions.

All of the illustrated specimens included in this study are

deposited in the Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington,

D.C.
NUMBER 32 351

Literature Cited

Achauer, C.W.

1990. Subsurface and Outcrop Examination of the Capitan Shelf Margin,

Northern Delaware Basin. Bulletin of the American Association of

Petroleum Geologists, 74(10): 1665.

Cooper, G.A., and R.E. Grant

1972. Permian Brachiopods of West Texas, I. Smithsonian Contributions

to Paleobiology, 14:1-231, plates 1 -23.

Davis, R.A.

1984. Depositional Environments of the Western Cathedral Mountain,

Road Canyon, Word and Capitan Formations (Permian), Glass

Mountain Area. 104 pages. Unpublished master's thesis, Sul Ross

State University, Alpine, Texas.

Dunbar, CO.

1944. Permian and Pennsylvanian (?) Fusulines. In R.E. King, CO.

Dunbar, RE. Cloud, Jr., and A.K. Miller, Geology and Paleontology

of the Permian Area Northwest of Las Delicias, Southwestern

Coahuila, Mexico. Geological Society of America, Special Paper,

52:35-45, plates 9-16.

Dunbar, CO., and J.W. Skinner

1937. Permian Fusulinidae of Texas: The Geology of Texas, Part 2.

University of Texas Bulletin, 3701:519-825, plates 42-81.

Erk, A.S.

1942 ("1941"). Sur la presence du genre Codonofusiella dans le Permien

de Bursa (Turquie). Eclogae Geologicae Helvetiae, 34:234-253,

plates 12-14. [Date on title page is 1941; actually published in

1942.]

King, P.B.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part I:

Descriptive Geology. University of Texas Bulletin, 3038: 167

pages, 15 plates. [Date on title page is 1930; actually published in

1931.]

King, R.E.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part II: Faunal

Summary and Correlation of the Permian Formations with Description of Brachiopoda. University of Texas Bulletin, 3042: 245

pages, 44 plates. [Date on title page is 1930; actually published in

1931.]

Newell, N.D., J.K. Rigby, A.G. Fischer, A.J. Whiteman, J.E. Hickox, and J.S.

Bradley

1953. The Permian Reef Complex of the Guadalupe Mountains Region,

Texas and New Mexico: A Study in Paleoecology. 236 pages. San

Francisco: W.H. Freeman and Company.

Rohr, D.M., B.R. Wardlaw, S.F. Rudine, A.J. Hall, R.E. Grant, and M. Haneef

1991. Guidebook to the Guadalupian Symposium. In B.R. Wardlaw, R.E.

Grant, and D.M Rohr, editors, Proceedings of the Guadalupian

Symposium, March 13-15, 1991, Sul Ross State University, Alpine,

Texas, pages 18-111.

Rudine, S.F.

1988. Geology and Depositional Environments of the Permian Rocks,

Northern Del Norte Mountains, Brewster County, Texas. 186 pages.

Unpublished master's thesis, Sul Ross State University, Alpine,

Texas.

Sheng, J.C

1963. Permian Fusulinids of Kwangsi, Kueichow, and Szechuan. Palaeontologia Sinica, 149, new series B(10): 247 pages, 35 plates. [In

Chinese and English.]

Skinner, J.W., and G.L. Wilde

1954. The Fusulinid Subfamily Boultoniinae. Journal of Paleontology,

28(4):434-444, plates 42-45.

1955. New Fusulinids from the Permian of West Texas. Journal of

Paleontology, 29(6):927-944, plates 89-95.

Sosnina, M.L.

1968. New Species of Fossil Plants and Invertebrates of the USSR.

Ministry of Geology of the USSR, Nedra Press, 2(1): 124-128, 31

plates. [In Russian.]

Toumanskaya, O.G.

1953. O verkhnepermskilch fuzulinidakh yuzhno-Ussuriyskogo Kraya.

[Concerning Upper Permian Fusulinids in the Southern Ussuri

Territory.] Pages 19-21, plates 10-12. Moscow: Trudy, Vsesoyuznogo Nauchno-Issledovatel'skogo Geologicheskogo Instituta

(VSEGEI). [In Russian.]

Tyrrell, W.W., Jr.

1964. Paleontology and Stratigraphy of Near-Reef Tansill-Lamar Strata,

Guadalupe Mountains, Texas and New Mexico. In Geology of the

Capitan Reef Complex of the Guadalupe Mountains, Culberson

County, New Mexico. Roswell Geological Society Guidebook, pages

66-82.

1969. Criteria Useful in Interpreting Environments of Unlike but TimeEquivalent Carbonate Units (Tansill-Capitan-Lamar), Capitan

Reef Complex, West Texas and New Mexico. In G.M. Friedman,

editor, Depositional Environments in Carbonate Rocks: A Symposium. Society of Economic Paleontologists and Mineralogists,

Special Publication, 14:80-97.

Wang, Y., J.C. Sheng, and L. Zhang

1981. Fusulinids from Xizang, China. In The Comprehensive Scientific

Expedition of the Qinghai-Xizang Plateau. 80 pages, 21 plates.

Palaeontology of Xizang, Science Press, Book III.

Wardlaw, B.R., R.A. Davis, D.M. Rohr, and R.E. Grant

1990. Leonardian-Wordian (Permian) Deposition in the Northern Del

Norte Mountains, West Texas. United States Geological Survey

Bulletin, 1881-A:A1-A14.

Wilde, G.L.

1955. Permian Fusulinids of the Guadalupe Mountains. In Permian Field

Conference, October 1955. Society of Economic Paleontologists and

Mineralogists, Permian Basin Section, Publication, 55-1:59-62.

1975. Fusulinid-Defined Permian Stages. In J.M. Cys and D.F. Toomey,

editors, Permian Exploration, Boundaries, and Stratigraphy. Society

of Economic Paleontologists and Mineralogists, West Texas

Geological Society and Permian Basin Section, Publication,

75-65:67-83.

1990. Practical Fusulinid Zonation: The Species Concept; with Permian

Basin Emphasis. West Texas Geological Society, Bulletin, 29(7):

5-34.
Plates 15-1-15-9
354 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 15-1

FIGURES 1-9.—Rauserella bengeensis, new species: 1, axial section, x90, paratype, USNM 462297, Coll.

W90-48, Section 2, Bird Mine area; 2, axial section, x90, paratype, USNM 462298, Coll. W90-48, Section 2,

Bird Mine area; 3, tangential section, x90, paratype, USNM 462299, Coll. W90-48, Section 2, Bird Mine area;

4, 5, axial sections, x90 and xl80, respectively, holotype, USNM 462300, Coll. Bl-59, Section 4, Benge

Ranch; 6, tangential section, xl80, paratype, USNM 462301, Coll. 343, Section 3, Bird Mine area; 7, axial

section, xl80, paratype, USNM 462302, Coll. 77-2-718, Section 1, Bird Mine area; 8, sagittal section, xl80,

paratype, USNM 462303, Coll. 77-2-718, Section-1, Bird Mine area; 9, sagittal section, x 180, paratype, USNM

462304, Coll. 77-2-718, Section 1, Bird Mine area. (Reduced to 94% of original for publication.)
NUMBE

R 32

355
356 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 15-2

FIGURES 1-5.—Reichelina lamarensis Skinner and Wilde: 1, two tangential sections with a nearby calcisphere

or radiolarian?, x35, USNM 462305, Coll. W90-50+2, Section 3, Bird Mine area; 2, sagittal section, x35,

USNM 462306, Coll. W90-50+2, Section 3, Bird Mine area; 3, sagittal section, x35, USNM 462307, Coll.

W90-50+2, Section 3, Bird Mine area; 4, sagittal section, x90, USNM 462308, Coll. W90-50+2, Section 3,

Bird Mine area; 5, sagittal section, x90, USNM 462309, Coll. BM5-114, Section 3, Bird Mine area. (Reduced

to 93% of original for publication.)

FIGURES 6-10.—Rauserella bengeensis, new species: 6, parallel section, x35, hypotype, USNM 462310, Coll.

BM5-34, Section 3, Bird Mine area; 7, tangential section, x35, hypotype, USNM 462311, Coll. BM5-95,

Section 3, Bird Mine area; 8, tangential section, x35, hypotype, USNM 462312, Coll. BM5-114, Section 3,

Bird Mine area; 9, tangential section, x90, hypotype, USNM 462313, Coll. BM5-114, Section 3, Bird Mine

area; 10, tangential section, x90, hypotype, USNM 462314, Coll. BM5-114, Section 3, Bird Mine area.

(Reduced to 93% of original for publication.)
NUMBER 32 357
358 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 15-3

FIGURES 1-11.—Reichelina lamarensis Skinner and Wilde: 1-5, axial and near-axial sections, x90, USNM

462315-462319, Coll. BM5-34, Section 3, Bird Mine area; 6-8, 10, axial and near-axial sections, x90, 8 is a

portion of same specimen as 7, xl80, USNM 462320, 462321, 462323, Coll. BM5-95, Section 3, Bird Mine

area; 9, near-axial section, USNM 462322, Coll. BM5-34, Section 3, Bird Mine area; 11, near-axial section,

USNM 462324, Coll. BM5-103, Section 3, Bird Mine area. (Reduced to 94% of original for publication.)
NUMBER 32 359

8

1 1
360 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 15-4

FIGURES 1-9.—Reichelina lamarensis Skinner and Wilde: 1-5, sagittal sections, x90, USNM 462325-462329,

Coll. BM5-109, Section 3, Bird Mine area; 6, sagittal section, x90, USNM 462330, Coll. BM5-114, Section

3, Bird Mine area; 7-9, sagittal sections, x90, USNM 462331-462333, Coll. BM5-109, Section 3, Bird Mine

area. (Reduced to 94% of original for publication.)
NUMBER 32 361
362 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 15-5

FIGURES 1-3.—Reichelina lamarensis Skinner and Wilde: 1, sagittal section, x90, USNM 462334, Coll.

BM5-95, Section 3, Bird Mine area; 2, 3, sagittal sections, x90, USNM 462335, 462336, Coll. BM5-109,

Section 3, Bird Mine area. (Reduced to 94% of original for publication.)

FIGURES 4-7.—Codonofusiella (Lantschichites) altudaensis, new species: 4, axial section, x35, holotype, USNM

462337, Coll. W90-50+2, Section 2, Bird Mine area; 5-7, axial sections, x35, paratypes, USNM

462338-462340, Coll. W90-50+2, Section 2, Bird Mine area. (Reduced to 94% of original for publication.)

FIGURES 8-10.—Codonofusiella {Lantschichites) altudaensis ?: 8, tangential section, x35, USNM 462341, Coll.

W90-50+2, Section 2, Bird Mine area; 9, tangential section, x35, USNM 462342, Coll. BM5-109, Section 3,

Bird Mine area; 10, tangential section, x35, USNM 462343, Coll. BR4-113, Section 4, Benge Ranch. (Reduced

to 94% of original for publication.)
NUMBER 32

363

10
364 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 15-6

FIGURES 1-13.—Codonofusiella (Lantschichites) altudaensis, new species: 1-5, axial and near-axial sections,

x35, paratypes, USNM 462344-462348, Coll. W90-50+2, section 2, Bird Mine area; 6-10, tangential and

oblique sections, x35, paratypes, USNM 462349-462353, Coll. W90-50+2, section 2, Bird Mine area; 11,12,

sagittal sections, x35 and x90, respectively, paratype, USNM 462354, oblique section of Reichelina lamarensis

Skinner and Wilde seen in matrix, Coll. W90-50+2, section 2, Bird Mine area; 13, near-sagittal section

showing flare, x35, paratype, USNM 462355, same specimen as Plate 15-7: Figure 9, Coll. W90-50+2, section

2, Bird Mine area. (Reduced to 94% of original for publication.)
NUMBER 32 365
366 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 15-7

FIGURES 1-7, 9.—Codonofusiella (Lantschichites) altudaensis, new species: 1, parallel section, x35, paratype,

USNM 462356, Coll. Bl-136, Section 4, Benge Ranch; 2, parallel section, x35,paratype, USNM 462357, Coll.

Bl-87.5, Section 4, Benge Ranch; 3, parallel section, x35, paratype, USNM 462358, Coll. Bl-83, Section 4,

Benge Ranch; 4, near-sagittal section, x35, paratype, USNM 462359, Coll. Bl-136, Section 4, Benge Ranch;

5, sagittal section without flare, x90,paratype, USNM 462360, Coll. Bl-83, Section 4, Benge Ranch; 6, sagittal

section without flare, x90, paratype, USNM 462361, Coll. Bl-87.5, Section 4, Benge Ranch; 7, parallel

section, x90, paratype, USNM 462362, Coll. W90-50+2, Section 2, Bird Mine area; 9, near-sagittal section

showing flare, x90, paratype, USNM 462364, same specimen as Plate 15-6: Figure 13, Coll. W90-50+2,

Section 2, Bird Mine area. (Reduced to 94% of original for publication.)

FIGURE 8.—Paradoxiellapratti ? Skinner and Wilde: parallel section, x90, USNM 462363, Coll. 343, Section 3,

Bird Mine area. This is the only specimen of Paradoxiella thus far recovered in any of the four sections, and

it was in a float sample. The characteristic "tail," however, makes the generic identification undeniable.

(Reduced to 94% of original for publication.)
NUMBER 32

367

9
368 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 15-8

FIGURES 1-11.—Paraboultonia splendens Skinner and Wilde: 1-11, axial sections, x35, USNM 462365-

462375, Coll. BR4-113, Section 4, Benge Ranch. Pseudomorphic gypsum blades obliterate portions of some

specimens. (Reduced to 94% of original for publication.)
NUMBER 32 369
370 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 15-9

FIGURES 1-16.—Paraboultonia splendens Skinner and Wilde: 1, sagittal section, x35, USNM 462376, Coll.

B 1-87.5, Section 4, Benge Ranch; 2, sagittal section, x35, USNM 462377, Coll. B 1-87.5, Section 4, Benge

Ranch; 3, sagittal section, x35, USNM 462378, Coll. Bl-87.5, Section 4, Benge Ranch; 4, sagittal section, x35,

USNM 462379, Coll. Bl-87.5, Section4, Benge Ranch; 5, sagittal section, x35,USNM 462380, Coll. Bl-87.5,

Section 4, Benge Ranch; 6, sagittal section, x35, USNM 462381, Coll. B 1-97.5, Section 4, Benge Ranch; 7,

sagittal section, x35, USNM 462382, Coll. Bl-87.5, Section 4, Benge Ranch; 8, sagittal section, x35, USNM

462383, Coll. Bl-87, Section 4, Benge Ranch; 9, sagittal section, x35, USNM 462384, Coll. Bl-97, Section

4, Benge Ranch; 10, sagittal section, x90, USNM 462385, Coll. Bl-87.5, Section 4, Benge Ranch; 11, sagittal

section, x90, USNM 462386, Coll. Bl-97, Section 4, Benge Ranch; 12, sagittal section, x90, USNM 462387,

Coll. Bl-97, Section 4, Benge Ranch; 13, sagittal section, x90, USNM 462388, Coll. Bl-83, Section 4, Benge

Ranch; 14, sagittal section, x90, USNM 462389, Coll. Bl-97, Section 4, Benge Ranch; 15, sagittal section,

x90, USNM 462390, Coll. Bl-97, Section 4, Benge Ranch; 16, sagittal section, x90, USNM 462391, Coll.

Bl-97, Section 4, Benge Ranch. (Reduced to 94% of original for publication.)
NUMBER 32 371

13

15
16. Lithofacies and Depositional History of the

Tessey Formation, Frenchman Hills, West Texas

Mohammad Haneefand Bruce R. Wardlaw

ABSTRACT

The Tessey Formation in the Frenchman Hills, northwestern Glass

Mountains, represents deposition in a basinal setting. The formation

consists of at least two shallowing-upward sequences of carbonate and

evaporite deposition marked by two episodes of subaerial exposure,

meteoric water dissolution, and collapse brecciation.

Introduction

The Tessey Formation is generally poorly understood.

Udden (1917) first proposed the name Tessey Formation for an

unstratified dolomitic rock located 3.2 km north of Gilliam

(Gilliand) Canyon. It appears, however, that Udden (1917)

included some fossiliferous Gilliam Limestone in the description of the unit because he refered to abundant fusulinids,

which are absent from the Tessey as currently defined. King

(1931) corrected most of the relationships of the Tessey as he

described the unit as a poorly bedded dolomite and dolomitic

limestone about 304.8 m (1000 ft.) thick that extends from

Gilliand Canyon in the Glass Mountains to the hills southwest

of Sierra Madera. About 6.4 km north of Sanderson Cabin,

King found Permophorous concentrated in one bed. An arroyo

12 km S 75° W of the summit of Sierra Madera contains a

coarsely brecciated mass of dolomite, sandstone, and gypsum

that passes laterally into undisturbed Tessey strata. The coarse

breccia represents a slump into a leached out, underground

gypsum bed (King, 1931). King (1931) mapped the massive

limestone breccia as the upper massive member of the Capitan

Mohammad Haneef, Geology Department, Sul Ross State University,

Alpine, Texas 79832. Bruce R. Wardlaw, U.S. Geological Survey,

926A National Center, Reston, Virginia 20192.

Limestone in the Frenchman Hills and Bird (Altuda) Mountain,

but they are better placed into the Tessey Formation. The

purpose of this paper is to describe the Tessey exposed in the

Frenchman Hills and to clarify its depositional history.

The Tessey Formation unconformably overlies the Gilliam

Limestone (upper Guadalupian) in the eastern part of the Glass

Mountains and the Altuda Formation in Old Blue Mountain

and the Frenchman Hills. The upper boundary of the formation

is an erosional unconformity with the Bisset Conglomerate

(Cretaceous; Wilcox, 1986). The Tessey Formation lacks any

recognizable fossils that can be used for assigning a relative

age. It is regarded as laterally correlatable with the Ochoan

Castile and Salado formations of the Delaware basin (Ross,

1986).

Subsurface well-log studies by Bloom (1988) show that the

Tessey Formation was penetrated by wells drilled in the Hovey

channel 8 km northwest of the Glass Mountains, near the

Frenchman Hills. The Tessey Formation there consists of

sparsely fossiliferous limestones, gray and brown in color, with

anhydrite nodules and inclusions interbedded with red to brown

calcareous, silty to sandy shales and dolomites of microcrystalline to finely crystalline texture. The limestone is reported to

contain charophytes, ostracodes, and rare bryozoans, echinoderms, sponge spicules, foraminifers, calcispheres, peloids,

intraclasts, and detrital quartz (Bloom, 1988). The anhydrite

inclusions are composed of bladed to fine-grained "chicken

wire" fabric. Locally brecciated peloidal wackestonepackstone was encountered for 4 m in the core from the

Gunnel's Kim #1 drillhole. The thickness in the subsurface is

reported as 700 m (Bloom, 1988).

Stratigraphy

The study area consists of three isolated erosional remnants

of the Tessey Formation in the Frenchman Hills, northwestern

Glass Mountains, approximately 1 km northwest of Old Blue

Mountain (Figures 16-1, 16-2). The stratigraphic thickness of

the Tessey Formation measured on the south side of hill 4544

373
374 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

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1 11- 'in f

^-——s^y

A> y

^r 9 5

r^ °

• MARATHON

103°00'

/

5

 I 0 MILES

1.0 1.5 KM

FIGURE 16-1.—Map of the Glass Mountains region with the study area indicated.

is 121.9 m (Figure 16-3). There the lower contact of the Tessey

Formation is covered but appears to be conformable or

paraconformable with basinal facies of the Altuda Formation.

Three lithically distinct units are recognized in this area (Figure

16-4A).

The basal unit defined informally as Tessey unit 1 (Tul) is

composed of fine (mm scale), evenly laminated lime mudstone

with thin alternating laminae of calcitized anhydrite/gypsum

with typical laminated to nodular to "chicken wire" fabric. The

unit is 0.5-1.5 m thick and is present in the Frenchman Hills

outcrop as well as in Old Blue Mountain. The unit is locally

folded and intensely fractured with coarse, clear-calcite fracture

infilling.

The middle unit (Tu2) is characterized by massive, slope

forming, clast supported, spar-cemented, limestone breccia

(Figure 16-4B). The unit is 45-83 m thick across the extent of

the outcrop. No intact bedding was found in the entire area of

the outcrop. The clasts are composed dominantly of light gray,

gray, yellowish brown, to brown lime mudstone, sandstone,

and siltstone and display a variety of shapes and sizes. The size

of the clasts varies from a few millimeters to more than

one-half meter. Clasts generally are angular with rare subrounded and rounded shapes. Clasts shapes are tabular,

rectangular, blocky, and irregular. At the base and in a few

restricted horizons up-section, papery laminated lime mudstone

in rectangular clast shapes predominate. Composition of the

clasts varies from lime mudstone/dolomudstone, light gray,

dark gray, and olive in color, to yellowish brown to brown,

laminated siltstone and fine sandstone. Chert and dolomite

clasts of various shapes and sizes are less abundant. The clasts

are predominantly cemented by clear coarse sparry calcite.

Matrix-supported breccias composed of dolomite clasts and

matrix occur locally within the section. This unit contains

conglomerate lenses or patches that are 1 -2 m in lateral extent

and about 0.5 m thick with round clasts of lime mudstone,

sandstone, siltstone, quartz, and chert. The matrix of the

conglomerates varies from lime-mud to fine silt and sand. The

conglomerates are rarely cemented by sparry calcite. Unlike the

Frenchman Hills outcrop, conglomerates are 4-7 m thick in

Old Blue Mountain. The olive color lime mudstone clasts

become the dominant lithology in the middle and upper part of

the unit. The rocks show no bedding and weather into large

circular blocks 4-5 m in diameter. Irregular, nonsutured

stylolites with brownish residue occur throughout the unit.

Clasts generally lack skeletal fragments.

The uppermost unit (Tu3) is characterized by matrixsupported carbonate breccia. The matrix and the clasts are

composed of dolomudstone. The clasts are angular, irregular to
NUMBER 32 375

103°20'W

30°27.5' N

Quaternary

Matrix supported breccia

Spar cemented breccia

Laminated lime mudstone

^/ Measured section

/ Contact

Contour Interval 200 FT

FIGURE 16-2.—Geologic map of the Frenchman Hills area of the Glass Mountains.

blocky in shape. Most clasts display lamination with fenestral

fabric. Planar to wavy algal lamination containing bird's eye

features, is typical. The unit is marked by hard, resistant,

cliff-forming, massive beds. The contact of this unit with the

lower spar-cemented breccia is irregular and mostly covered by

its own debris. Northern outcrops have a matrix of pinkish

siltstone.

Lithofacies

Based on lithic characteristics, two depositional facies

comprising three lithostratigraphic units are recognized in the

Frenchman Hills. These include the laminated lime mudstone/

calcitized anhydrite lithofacies and the matrix-supported

dolomudstone lithofacies.

LAMINATED LIME MUDSTONE/CALCITIZED ANHYDRITE

LITHOFACIES.—This lithofacies comprises the stratigraphic

units Tul and Tu2 of the Tessey Formation. The lithofacies is

characterized by the following features.

Papery Lamination: The basal beds of the Tessey Formation are composed of thin (mm scale), even, planar, non-algal

laminations, locally folded and brecciated (Figure 16-4c,D).

These basal beds are present throughout the study area. The

lithofacies grades upwards into brecciated and folded beds and

contains alternating clear calcite laminae. The calcite laminae

exhibit nodular mosaic, enterolithic folding, and chicken wire
376 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Matrix supported dolo-breccia

o

Spar cemented carbonate breccia

with conglomerate pods/lens

50 FT

Laminated lime mudstone

FIGURE 16-3.—Stratigraphic section in the Frenchman Hills. Location of the

section is shown in Figure 16-2.

fabric similar to modern anhydrite (Figure 16-5A,B). The beds

are devoid of any skeletal material.

Spar-Cemented Breccia: Stratigraphic unit 2 (Tu2) of the

Tessey Formation is characterized by carbonate breccia with

angular to subangular clasts with sharp edges. The breccia

composition is dominated by laminated lime mudstone clasts

with a subordinate amount of sandstone, laminated siltstone,

and rare chert fragments. The distinct feature of these breccias

is the presence of coarse calcite as both a cement and as fracture

fill (Figure 16-5c,D). The cements include equant and

circumgranular equant spar.

Polymictic Conglomerate: Interbedded with the breccias

are isolated pods and lenses of conglomerate. The conglomerate is composed of rounded clasts of laminated to nonlaminated

lime mudstone, fossiliferous mudstone, dolomudstone, silty

dolomudstone, siltstone, and chert (Figure 16-6A). The matrix

is composed of angular to subangular quartz silt and sand,

micritized grains, and varying amounts of lime-mud and

dolomite-mud. Coarse spar coating of the grains or cavity fill is

present.

Scalloped Surfaces: The contact of the spar-cemented

breccia with the underlying laminated lime mudstone and

overlying matrix-supported breccia is highly irregular, producing scalloped surfaces.

MATRIX-SUPPORTED DOLOMUDSTONE LITHOFACIES.—This

lithofacies comprises stratigraphic unit Tu3 and is distinguished by its clast lithology and dolomite fabric. Exposures

have irregular contacts and draping beds.

Clast Lithology: The lithofacies is dominated by rectangular to tabular dolomudstone clasts exhibiting planar to wavy,

algal lamination and fenestral fabric (Figures 16-6B, 16-7A,B).

Laminations are thin, planar to wavy and display alternating

layers of light dolomudstone and dark organic-rich algal layers.

Other clasts include nonlaminated dolomudstone, peloidal

dolowackestone, and silty dolomudstones. The matrix is

predominantly dolomudstone with minor quartz silt and sand.

Dolomite Fabric: The breccia is characterized by fine,

euhedral, equigranular dolomudstone, both as clasts and

matrix. The dolomite is interpreted to be penecontemporaneous

in origin. Algal laminated dolomudstone clasts and matrix

support this interpretation.

Interpretation

The laminated lime mudstone/calcitized anhydrite lithofacies is interpreted herein as a solution collapse breccia formed

as a result of karstification of a shallowing-upwards evaporitic

basinal facies (Figure 16-8). The presence of evaporite fabric,

pyrite, and an unfossiliferous lime mudstone lithology indicates that the lithofacies was deposited in hypersaline, reducing

(anaerobic?) environments. This interpretation is further supported by the presence of thick interbeds of anhydrite and

gypsum in the Tessey Formation of the subsurface (King, 1931;

Bloom, 1988) and the overall restricted hypersaline basinal

conditions in the Permian basin at the onset of Ochoan time

(King, 1931; Ross, 1986). The sediments were deposited in

deep water, not in a subaerial environment, as evidenced by the

absence of algal stromatolites and desiccation structures that

normally are associated with subaerial or peritidal conditions.

The deeper water origin is supported by the presence of parallel

laminations and by alternating lime mudstone/calcite (originally calcium sulphate) couplets. Studies in the Castile

Formation of Texas and New Mexico by Anderson and

Kirkland (1966) and Anderson et al. (1972), and studies of

similar couplets in western Canada by Davis and Ludlam

(1973) and Wardlaw and Reinson (1971) favor this interpretation. Kendall (1984) ascribed the presence of planar laminations to stagnant, permanently stratified bodies of water.

The third phase (Figure 16-8) of laminated lime mudstone/

calcitized anhydrite facies development is marked by subaerial

exposure, meteoric dissolution of evaporites, and the subse-
NUMBER 32

377

FIGURE 16-4.—A, outcrop of Tessey Formation at Frenchman Hills in the Benge Ranch area showing various

stratigraphic units. Tul, laminated lime mudstone; Tu2, spar-cemented breccia; and Tu3, matrix-supported

breccia. Note the irregular contact between the units. B, spar-cemented limestone breccia weathering in large

circular blocks at the base of the Frenchman Hills outcrop, c, view of locally folded laminated lime mudstone unit

(Tul). D, view of intensely brecciated spar-cemented breccia (Tu2). The size of the clasts varies from a few

millimeters to more than 20 centimeters. Note spar infilling of fractures. (Camera lens cap is 5.5 cm in diameter.)

quent collapse brecciation of the suprastructure. It is presumed

that extensive dissolution of evaporites and carbonates was

achieved by the development of a subterranean erosional

landscape associated with karst. The lack of intact bedding and

karst related geomorphic features, such as dolines, rundkarren,

and kamenitzas, which are regarded as paleokarst indicators, is

attributed to complete dissolution and subsequent brecciation.

The presence of extensive intraformational brecciation, nonferroan, nonluminescent, coarse blocky calcite, and speleothems

attest to this interpretation. The subaerial exposure might have

been achieved by the filling of the basin and/or a drop in sea

level. Scalloped surfaces at the top of the lithofacies represents

an erosional unconformity.

The matrix-supported dolomudstone lithofacies is interpreted as a collapse breccia of a shallowing-upwards sequence

of intertidal/supratidal (sabkha) dolostones. Initial deposition

of the matrix-supported dolomudstone lithofacies marks the

return (or near return) of marine waters following the exposure

that created the lower breccia. The common algal lamination

and the fenestral fabric of the clasts and matrix indicate

deposition on a frequently exposed tidal flat. The collapse

brecciation of the intertidal/supratidal sequence did not take

place at the same time as the brecciation of the lower

lithofacies. This is evident from the presence of two discrete

lithofacies. One collapse brecciation would have resulted in the

vertical mixing of lithologies. A second collapse brecciation of

the original intertidal/supratidal sequence probably resulted

from a further drop in sea level. The area was subaerially

exposed, resulting in fresh water dissolution and the formation

of collapse breccia (Figure 16-8).
378 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 16-5.—A, view of laminated to relic anhydrite nodular mosaic fabric in the laminated lime

mudstone/calcitized anhydrite lithofacies. (Camera lens cap is 5.5 cm in diameter.) B, photograph of polished slab

showing enterolithic folding in the laminated lime mudstone/calcitized anhydrite lithofacies. C, view of outcrop

surface of spar-cemented breccia of Tu2. D, close-up of area shown in c. (Camera lens cap is 5.5 cm in diameter.)

Literature Cited

Anderson, R.Y., and D.W. Kirkland

1966. Intrabasin Varve Correlation. Bulletin of the Geological Society of

America, 77(3):241-256, plates 1-5.

Anderson, R.Y., W.E. Dean, Jr., D.W. Kirkland, and H.I. Snider

1972. Permian Castile Varved Evaporite Sequence, West Texas and New

Mexico. Bulletin of the Geological Society of America, 83(1): 59-86.

Bloom, M.A.

1988. A Subsurface Geologic Study of Northern Brewster County, Texas.

150 pages. Unpublished master's thesis, Sul Ross State University,

Alpine, Texas.

Davis, G.R., and S.D. Ludlam

1973. Origin of Laminated and Graded Sediments, Middle Devonian of

Western Canada. Bulletin of the Geological Society of America,

84(ll):3527-3546.

Kendall, A.C.

1984. Evaporites. In R.G. Walker, editor, Fades Models. Geoscience

Canada Reprint Series # 1, 2nd edition, pages 259-296.

King, P.B.

1931 ("1930"). The Geology of the Glass Mountains, Texas, Part I:

Descriptive Geology. University of Texas Bulletin, 3038: 167 pages,

15 plates. [Date on title page is 1930; actually published in 1931.]

Ross, C.A.

1986. Paleozoic Evolution of Southern Margin of Permian Basin. Bulletin

of the Geological Society of America, 97(5):536-554.

Udden, J.A.

1917. Notes on the Geology of the Glass Mountains. University of Texas

Bulletin, 1753: 59 pages.

Wardlaw, N.C., and G.E. Reinson

1971. Carbonate and Evaporite Deposition and Diagenesis, Middle

Devonian Winnipegosis and Prairie Evaporite Formations of

South-Central Saskatchewan. Bulletin of the American Association

of Petroleum Geologists, 55(10): 1759-1786.

Wilcox, R.E.

1986. Evidence for an Early Cretaceous Age for the Bissett Formation,

Western Glass Mountains, Brewster and Pecos Counties, West

Texas: Implications for Regional Stratigraphy, Paleogeography, and

Tectonics. 250 pages. Unpublished master's thesis, Sul Ross State

University, Alpine, Texas.
NUMBER 32

379

CENTIMETERS

FIGURE 16-6.—A, view of polymictic conglomerate in Tu2. Note the size variation and roundness of the clasts.

Clast lithologies consist of lime mudstone, dolomudstone, silty dolomudstone, and siltstone. B, close-up of

matrix-supported dolomudstone breccia. Note the algal-laminated dolomudstone clasts. (Hammer is 28 cm in

length.)

FIGURE 16-7 (right).—A, view of weathering surface of matrix-supported

dolomudstone breccia (Tu3). B, polished slab of matrix-supported dolomudstone breccia showing brecciated fabric.
380

N

SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

HOVEY CHANNEL S

FIGURE 16-8.—Idealized development of the Tessey Formation. Phase 1,

deposition of basinal lithofacies (Tul). Phase 2, deposition of subtidal/intertidal

lithofacies (Tu2). Phase 3, subaerial exposure, development of karst, and

collapse brecciation. Phase 4, deposition of intertidal/supratidal sabkha

lithofacies (Tu3). Phase 5, fresh water dissolution and collapse brecciation of

Tu3.
17. Conodont Biostratigraphy of the Permian

Beds at Las Delicias, Coahuila, Mexico

Bruce R. Wardlaw, Shannon F. Rudine,

and Merlynd K. Nestell

ABSTRACT

Conodont faunas from the basinal deposits of the Permian near Las

Delicias, Mexico, are dominated by shallow-water species of

Hindeodus. Three long-ranging Hindeodus zones, similar to those

recognized in shallow-water deposits in much of the world, are H.

excavatus, H. wordensis, and H. julfensis. The conodonts indicate an

age range for the Permian deposits from Sakmarian to Dzhulfian. The

conodonts and brachiopods are closely related to those from the

Permian basin of West Texas.

Introduction

The Permian rocks near Las Delicias, Coahuila, Mexico, are

of great interest because they have yielded excellent ammonoid

collections of much of the Permian, including some of the

youngest Permian preserved in North America. However, the

geology of the area is far from clear, and the Permian rocks are

remote and difficult to access. The area has been visited by

many parties of geologists that included King et al. (1944),

Newell (1957), Spinosa et al. (1970), Wardlaw et al. (1979),

and McKeeetal. (1988).

General Geology

The Permian rocks of Las Delicias are exposed in an arcuate

pattern below the steep cliffs and high mountains of Cretaceous

Bruce R. Wardlaw, U.S. Geological Survey, 926A National Center,

Reston, Virginia 20192. Shannon F. Rudine, Geology Department, Sul

Ross State University, Alpine, Texas 79832. Merlynd K. Nestell,

Geology Department, University of Texas, Arlington, Texas 76019.

limestone to the west (Figure 17-1). One narrow pass through

the high mountains exposes lower beds of the Permian

sequence. The structure of the Permian rocks is dominated by

a major syncline (as mapped by King et al., 1944; and Wardlaw

et al., 1979). This syncline is disrupted by normal faults that

trend to the northeast and locally fold the beds (Figure 17-2).

McKee et al. (1988) interpreted the geology much differently,

as they reported a major syncline disrupted by northwesttrending faults and also confused the basal conglomerate as part

of their volcanic chaotic lithosome on the eastern flank of the

syncline (the southwestern tip of the outcrop, Figure 17-1).

This later interpretation is highly implausible because fossils

collected by King et al. (1944), Wardlaw et al. (1979), and even

McKee et al. (1988) clearly indicate Early Permian in the

southern portion of the outcrop belt. The beds in question

yielded the oldest fauna from the basal unit of the Permian

succession (Las Sardinas beds) (see Gordon and Wardlaw,

written comm., in McKee et al., 1988:39).

The sequence is very difficult to map as it is covered by a

thick pediment that supports a lush cover of Leehiguia plants.

Exposures are generally along the arroyos that cut through the

pediment and in resistant beds that stand as hills above the

pediment. The geology is such that there is tremendous lateral

variability. The several ammonoid shales of King et al. (1944)

and modified by Spinosa et al. (1970; i.e., Perrinites,

Waagenoceras, Timorites, Kingoceras, and Eoaraxoceras) can

be traced from arroyo to arroyo with reliability. Two major

resistant units that form a string of hills throughout the area are

critical to mapping the geology. The first unit is composed of

two prominent limestone block-bearing megabreccias in close

stratigraphic succession (referred to by Wardlaw et al., 1979, as

the La Difunta limestone beds). These beds can be traced

throughout the area (Figure 17-2) and can be easily followed. It

was the consistency of these beds that unraveled the geology

for Wardlaw et al. (1979), but it also led them astray in their

interpretation as they could not imagine a megabreccia that

381
382 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Arroyo Palo Quemado

Arroyo las Animas

Cerro San Pedro

A\ Arroyo la Difunta

Arroyo la Colorada

Cerro Pichagiiilla

5 KM

Las Sardinas

beds

Fault, dashed where infered.

Axis of syncline.

— — —.... . Contact, dashed where approximately

located, dotted where covered or

obscured by structure.

FIGURE 17-1.—Location and geologic map of the Permian beds at Las Delicias, Coahuila, Mexico.

cropped out the entire length of the mapped area (over 21 km).

The second unit is a volcanic megabreccia (volcanic chaotic

lithosome of McKee et al., 1988). This unit also can be traced

throughout most of the area in the upper part of the section. It

occurs just above the Timorites shale.

General Stratigraphy

The general informal units proposed by Wardlaw et al.

(1979) are still the most useful division of the sequence at Las

Delicias. The units are, in ascending order, as follows: (1) the

Las Sardinas beds, (2) the El Tordillo beds, (3) the Palo

Quemado beds, (4) the La Difunta beds, and (5) the La

Colorada beds. The Las Sardinas beds are composed of a basal

conglomerate and the overlying Perrinites shale. The El

Tordillo beds are a thick sequence dominated by graywackes

between the underlying Perrinites shale and the overlying

Waagenoceras shale. The Palo Quemado beds are composed of

the Waagenoceras shale and overlying graywackes, shales, and

tuffaceous sands. The La Difunta beds start with the marker

unit, the limestone megabreccia, which is largely overlain by

graywackes. In the upper part of the La Difunta beds is a

laterally inconsistent limestone megabreccia lying just beneath

the Timorites shale, which makes up the top of the unit. The La

Colorada beds are marked at their base by the volcanic

megabreccia and overlain by graywackes, conglomerates, and

the Kingoceras and Eoaraxoceras shales (Figure 17-3).

LAS SARDINAS BEDS.—The lower part of the Las Sardinas

beds are composed of conglomeratic shales and graywackes

(Figure 17-4A,B). Most clasts are cobble- to boulder-sized,

igneous rock, graywacke, and limestone. The matrix is sandy

shale to coarse graywacke; the shale has slatey cleavage. The
NUMBER 32 383

FIGURE 17-2.—Aerial photograph of the Permian beds at Las Delicias and surrounding Cretaceous highlands

clearly showing major structural faults and folds of the beds.

limestone clasts are mostly crinoidal packstone to grainstone

with scattered skeletal packstone and wackestone containing

bryozoans, fusulinids, and brachiopods in addition to crinoids.

The ammonoid Perrinites was found within the conglomeratic

beds in matrix. The remainder of the fauna recovered from

these beds was reported by Wardlaw et al. (1979) and indicates

a Permian, probably Artinskian to Leonardian age (conodont

stages of Wardlaw, 1994). The base of the conglomeratic beds

was not observed.

The upper part of the Las Sardinas beds is composed of the

Perrinites shale. This is a thick black shale with common lime

mudstone concretions in its upper and lower parts, which are

separated by a dark sandy shale. The limestone concretions

yield an abundant ammonoid fauna, but mollusks other than

ammonoids are rare. Plant leaves and brachiopods are also

common. One large petrified gymnosperm log also was found

in the shale. Conodonts are common to the concretions. The

base of the Perrinites shale is undulatory.

EL TORDILLO BEDS.—The El Tordillo beds consist of a thick

section of graywackes, thin impure shales and siltstones, and

thin dirty skeletal limestones (mudstones to wackestones) with

the skeletal elements barely recognizable. One S element to

Hindeodus sp. was recovered from one of the thin limestones.

Near the top of the El Tordillo beds are graywackes interbedded
384 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

O _

O

O

o ° 4' •

• ' P ." • "

~""/T*N. * *

o , ^~ o .

_!_?.

 -.-°' ' °

O. o. 0 • 0

0 .' 0

o- 0 •' 0

Eoaraxoceras shale

Kingoceras shale

Timorites shale

rt La Difunta Limestone

) Waagenoceras shale

Waagenoceras shale

Perrinites shale

1

La Colorada beds

La Difunta beds

Palo Quemado beds

El Tordillo beds

Las Sardinas beds

Graywacke

Shale

Igneous rocks Volcanic megabreccia

Limestone, Limestone megabreccia

channelform beds

o o

o ^s O

Conglomerate and conglomeratic

FIGURE 17-3.—Columnar section of the Permian rocks at Las Delicias.
NUMBER 32

385

FIGURE 17-4.—Photographs of Las Sardinas, El Tordillo, and Palo Quemado beds. A,B, Perrinites shale in Puerto

de las Sardinas. c, Waagenoceras shale along Arroyo las Animas. D, interbedded graywackes and radiolarian

cherts in the El Tordillo beds near El Tordillo.

with thin radiolarian-rich shales (Figure 17-4D). Rip-ups of the

shales are common in the graywackes. Some of the graywacke

beds show a cross-bedded conglomeratic top. The radiolarians

appear to be too badly preserved to be useful. The base of the

El Tordillo beds is undulatory.

PALO QUEMADO BEDS.—The Palo Quemado beds show the

greatest diversity of lithic units, which are dominated by

graywackes, but contain many varied channeliform and

turbiditic mixed units (Figures 17-4C, 17-5A,C,D, 17-6A-D,

17-8B, 17-10A). Channeliform beds include tuffaceous sandstone, sandy limestone, limey conglomeratic sandstone, and

limey and silty mudstone. The channeliform beds commonly

display cross-bedding and pinching and swelling of beds,

especially in the upper part of the unit. Many of the graywackes

are locally conglomeratic with mixed lithoclasts, including

sandstone, skeletal limestone, and chert. The skeletal limestone

lenses are generally sandy and commonly contain abundant

broken and abraded skeletal debris. One igneous sill was

identified in close proximity to a large tuffaceous sandstone

channel in the Arroyo las Animas. The tuffaceous sandstone

channel displays scour and load features and abundant soft

sediment deformation. Also close to the tuffaceous sandstone is

a megabreccia with vague boundaries laterally merging with a

conglomeratic graywacke. The megabreccia is composed of

tuffaceous conglomerate clasts in tuffaceous conglomerate,

graywacke clasts, sandy mudstone clasts, and conglomeratic

fusulinid limestone clasts with a graywacke matrix. An

ammonoid was floating in the matrix as a clast (Figure

17-9c,D). Two black shales, referred to as the Waagenoceras

shale (Spinosa et al., 1970), occur within the unit; one marks

the base of the unit, and the other marks the middle. The lower

Waagenoceras shale has a sharp contact with the underlying El

Tordillo beds. Limestone nodules within the lower Waagenoceras shale are scarce in the lower part and contain a sparse
386 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 17-5.—Photographs of ammonoid occurrences. A, large concretion in Waagenoceras shale in Arroyo las

Animas. B, concretion bed in Timorites shale between Arroyo la Difunta and Arroyo la Colorada. C,

Waagenoceras in skeletal conglomerate of Palo Quemado beds along Arroyo las Animas. D, Waagenoceras shale

in Arroyo las Animas.
NUMBER 32

FIGURE 17-6.—Photographs of Palo Quemado beds. A, cross-bedded sandstone channel. B, large irregular body

of tuffaceous sandstone. C, D, tuffaceous sandstone overlain by chaotic conglomerate, from a distance and

close-up (hammer as scale).

fauna of brachiopods, echinoids, ammonoids, clams, fish

debris, and conodonts. Nodules become more abundant, silty,

and larger in the upper part of the lower Waagenoceras shale

and contain poorly preserved bryozoans, ammonoids, and

conodonts. The upper Waagenoceras shale is a thinner bed than

the lower shale and becomes alternating graywacke and sandy

mudstone in its upper part. It contains nodules with conodonts

and ammonoids. The brachiopods, ammonoids, and fusulinids

recovered from this unit are listed in Wardlaw et al. (1979).

LA DIFUNTA BEDS.—The La Difunta beds are characterized

by two limestone megabreccias at its base, which crop out for

the entire length of the outcrop area, and are referred to as the

La Difunta limestone (Figures 17-5B, 17-7A, 17-8A,C,D,

17-IOB-D). These limestone megabreccias generally consist of

a skeletal limestone conglomerate composed of granule- to

cobble-sized clasts dominated by crinoidal packstone in a

graywacke matrix throughout its extent. Locally, large blocks

of the limestone megabreccia form resistant hills. The

limestone blocks vary from a few meters to nearly a kilometer

in width and a few to nearly 100 meters in height. The

composition of the limestone blocks is of three types: (1)

recrystallized limestone or dolostone with poorly preserved

primary features appearing very much like the Capitan

Limestone in West Texas; (2) sponge framestone, boundstone,

and floatstone; and (3) bryozoan-brachiopod (Sestropoma)

framestone, bafflestone, and packstone. The limestone blocks

are always associated with the skeletal limestone conglomerate.

The conglomerate is generally below and to the sides of the

blocks and rarely occurs above the blocks. To complicate the

issue, the area of Permian exposure is an exhumed pediment

with many large exotic limestone blocks across the surface.

Typically, these exotic blocks are recrystallized limestone from

the nearby Cretaceous cliffs, but rarely, Permian limestone

blocks are also encountered. These exotic blocks are always

floating in the alluvium and not in the skeletal limestone

conglomerate. The bases of the limestone megabreccias are

very undulatory.

The middle part of the La Difunta beds is similar to the Palo

Quemado beds, in that they are dominated by graywacke, but

they are less variable with fewer channels and more volcano-
388 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 17-7.—Photographs of ammonoid-bearing shales. A, Timorites shale between Arroyo la Difunta and

Arroyo la Colorada. B, Kingoceras shale along Arroyo la Colorada. C, Eoaraxoceras shale along Arroyo la

Colorada. D, Kingoceras shale along Arroyo la Colorada; note S-fold in beds showing soft-sediment deformation.

clastic clasts in the graywacke. The upper part of the La Difunta

beds consists of a local limestone megabreccia and the

Timorites shale. The limestone megabreccia is typified by the

limestone block at Cerro Pichaguilla, which is composed of a

bryozoan-brachiopod-crinoid packstone to framestone. The

Timorites shale is a thick black shale traceable throughout the

area. It has a sharp contact with the underlying limestone

megabreccia or graywacke. Limestone concretions are spread

throughout the unit but commonly occur in three zones,

namely, near the base, middle, and top. The lower concretion

zone is a narrow zone, only about 3 m thick, immediately below

a sandy skeletal limestone to limey skeletal graywacke that is

conglomeratic in places. The middle zone is also narrow. In one

section it is about 1 m thick and contains small, generally

cobble-sized concretions. The upper zone is about 8 m thick

and is located approximately 6 m below the top of the unit.

Ammonoids are very common to all three zones, and conodonts

are common to the lower and upper concretion zones. The

brachiopods, ammonoids, and fusulinids recovered from this

unit are listed in Wardlaw et al. (1979).

LA COLORADA BEDS.—The La Colorada beds consist of a

lower unit that contains a thick volcanic megabreccia at its base

and the Kingoceras shale at its top, and an upper unit of

graywacke with the Eoaraxoceras shale very near its top

(Figures 17-7B-D). The thick volcanoclastic megabreccia at the

base of the La Colorada beds (the chaotic volcanic lithsome of

McKee et al., 1988) contains many large volcanic blocks,

which are several meters to tens of meters in width and height,

that occur in a conglomeratic matrix of volcanoclastic

graywacke. Common within the volcanoclastic graywacke are

limestone cobbles to boulders that are fusulinid (Polydiexodina) packstones to grainstones. These are particularly common

on the north side of Cerro San Pedro. The large volcanic blocks

consist of andesite, dacite, welded tuff, and laharic breccia

(McKee et al., 1988). Like in the La Difunta limestone

megabreccia in the unit below, these large blocks, here of

igneous rock, form hills because they are more erosionally

resistant than the surrounding conglomeratic matrix. The basal

contact of the volcanic megabreccia with the Timorites shale is

very irregular. After a short intervening graywacke interval, the
NUMBER 32 389

FIGURE 17-8.—Photographs of Palo Quemado beds and La Difiinta megabreccias. A, large reefoid limestone

blocks floating in skeletal conglomerate-making limestone knobs and peaks. Cerro Prieto del Norte is in the

distance. B, interbedded graywacke and shale of Palo Quemado beds in Arroyo las Animas. C, large reefoid

limestone blocks in skeletal conglomerate. D, close-up of knob in left corner in C showing Sestropoma limestone.

Kingoceras shale occurs above the volcanoclasitc megabreccia.

The Kingoceras shale is a black shale with several thin to

medium beds of skeletal conglomeratic graywacke, which

pinch and swell and commonly show low angle cross-bedding.

Limestone nodules are common in the lower 12 m and are

mostly composed of lime mudstone with a sparse fauna of

ammonoids, brachiopods, and some radiolarians. The contact

with the underlying graywackes is fairly sharp.

The upper unit of the La Colorada beds begins with a

relatively thick graywacke, which is locally conglomeratic, and

contains abundant volcanic debris in places. The Eoaraxoceras

shale is a poorly developed dirty shale located very near the top

of the section and has an indistinct basal contact. Silty,

argillaceous graywacke in thin beds is common within the thin

shale unit. Limestone nodules and thin limestone lenses, which

are both generally silty, are not common and contain a sparse

fauna of ammonoids and brachiopods. A graywacke containing

sparse ammonoids immediately overlies the Eoaraxoceras

shale and is folded into a small anticline. This graywacke

represents the highest bed exposed in the sequence. The

brachiopods, ammonoids, and fusulinids recovered from this

unit are listed in Wardlaw et al. (1979).

Conodont Biostratigraphy

Conodonts, together with mollusks and leaves, are common

to the concretions in the black shales of the sequence, but they

are uncommon in the megabreccias, volcanoclastic graywackes, and limestone turbidites, all of which represent rapid

deposition.

Hindeodus excavatus (Behnken) is common in the Perrinites

and Waagenoceras shales. Hindeodus wordensis, new species,

(see Wardlaw, this volume) is common to the La Difunta

limestone and the Timorites shale. Hindeodusjulfensis Sweet is
390 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 17-9.—A, view of the upper part of the Permian sequence from the limestone knob east of Cerro Prieto

del Norte looking across the northern outcrop belt to the chaotic volcanic megabreccia that forms the hills in the

distance. B, view of the upper part of the sequence from top of the hill of chaotic volcanic megabreccia on the

south side of Arroyo la Colorada. C, view of the conglomeratic tuffaceous sandstone in channel. D, closeup of

ammonoid in the conglomeratic tuffaceous sandstone (Waagenoceras).

common to the volcanic megabreccia containing Polydiexodina

cobbles immediately above the Timorites shale. Other important conodonts include Mesogondolella nankingensis (Ching)

from the Waagenoceras shale, Mesogondolella aserrata (Clark

and Behnken) and Sweetina triticum Wardlaw and Collinson

from the La Difunta limestone, and Sweetognathus expansus

(Perlmutter) from the conglomerate beds at the base of the

section. Conodonts were not recovered from the Kingoceras

and Eoaraxoceras shales.

The rocks at Las Delicias can be divided into three conodont

zones based on the nearshore genus Hindeodus. In ascending

order they are Hindeodus excavatus, Hindeodus wordensis, and

Hindeodus julfensis. These zones are similar to those recognized by Wardlaw (1988) for the shallow-water Permian

sequence in the Salt Range, Pakistan. Although the conodonts

are dominantly washed in, there appears to be little stratigraphic reworking or mixing of faunas, suggesting that the

conodonts represent contemporaneous to penecontemporaneous deposition of forms transported in from nearby shelves and

slopes on or about volcanic edifices.

The Hindeodus zones are long-ranging. The base of the

Hindeodus excavatus Zone is not well constrained, but it is at

least as old as Sakmarian. It ranges through the Roadian. The

presence of Sweetognathus expansus in the basal conglomerate

of the Las Sardinas beds suggests a Sakmarian age for the base.

The Sakmarian is generally missing from the Permian rocks of

West Texas, indicating a local hiatus and a relative low stand of

sea level, which could possibly correlate to conglomerate

shedding into the basin at Las Delicias. The Hindeodus

wordensis zone is Wordian-Capitanian. The Hindeodus

julfensis zone is post-Guadalupian and Wuchiapingian (it

appears that a part of the upper Maokouan in China is
NUMBER 32 391

FIGURE 17-10.—A, close-up of the skeletal conglomerate at the top of the Palo Quemado beds. B, view of the

folded beds within the La Difunta limestone near spring in Arroyo la Difunta. C, view of interbedded shales and

graywackes and turbiditic limestone in the La Difunta beds along Arroyo la Difunta. D, coarse conglomeratic sand

below the Timorites shale in the La Difunta beds along Arroyo la Difunta.

post-Guadalupian and, of course, pre-Wuchiapingian). In the

lower Waagenoceras shale the ranges of Hindeodus excavatus

and Mesogondolella nankingensis overlap, which is also the

case in the Road Canyon Formation, and thus indicates that this

part of the Palo Quemado beds is Roadian. The upper

Waagenoceras shale is probably Wordian. The La Difunta

limestone megabreccia also appears to be Wordian and may be

equivalent to the Manzanita Limestone Member of the Cherry

Canyon Formation in the Delaware basin, as both were

deposited during a major low stand of the sea, hence the major

carbonate-block shedding in the Las Delicias area. The

remainder of the La Difunta beds, including the Timorites

shale, is Capitanian. The Timorites shale is roughly equivalent

to the Lamar Limestone Member of the Bell Canyon Formation

where Timorites also occurs. The volcanic megabreccia at the

base of the La Colorada beds is post-Guadalupian and contains

Hindeodus julfensis, just like the uppermost beds of the Altuda

Formation in the Del Norte Mountains, Texas (Kozur, 1992).

The breccia shedding, which caused the volcanic megabreccia,

probably is also related to a major low stand of sea level, and it

appears to be the same low stand that caused the end of

Guadalupian deposition in West Texas. The Kingoceras and

Eoaraxoceras shales are post-Guadalupian, possibly Wuchiapingian (Dzhulfian), but no conodonts were recovered to refine

the correlations.

Paleogeographic Affinities of the Faunas

The presence of shallow-water conodonts and common

leaves in the black shales indicates a very close source from

which these biotic elements were washed in. The conodonts

from the black shales and the brachiopods from the massive

limestones blocks within the megabreccias indicate very close

affinities to faunas of West Texas. The coralliform brachiopod
392 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Sestropoma is common to, and only known from, Guadalupian

faunas of West Texas and Las Delicias (Cooper and Grant,

1975). The overall brachiopod fauna as reported in King et al.

(1944) and Wardlaw et al. (1979) is very close to that found in

West Texas. Mesogondolella aserrata with common Sweetina

are restricted to the West Texas and China warm-water

endemic provinces (Wardlaw, 1994). The fauna indicates a

close proximity to West Texas, suggesting that the Las Delicias

basin developed along a volcanic arc in the sea or seaway that

led to the Permian basin of West Texas and New Mexico and

the Pedregosa basin of Arizona, New Mexico, and northern

Mexico. As noted by King et al. (1944) and Wardlaw et al.

(1979), the conglomerate at the base of the section (Las

Sardinas beds) thins from west to east, as do most of the units

in the sequence. The cobbles and boulders within the Las

Sardinas conglomerate appear to become smaller (more

cobbles than boulders) in the east. This all suggests a source to

the west, which would indicate the basin developed on the east

side of a volcanic arc. McKee et al. (1988) suggested that "the

arc lay to the south or southeast of the Las Delicias area,

judging from the facies relations and macroscopic structures

that form the principal basis for our interpretation of

paleoslope" (McKee et al., 1988:39).

Conclusions

The conodonts recovered from the Permian beds at Las

Delicias can be divided into three zones: Hindeodus excavatus,

H. wordensis, and H. julfensis. The conodonts, along with the

previously reported ammonoids and fusulinids, indicate that

deposition was Sakmarian through Wuchiapingian (basal

Dzhulfian).

The Las Delicas basin developed as a deep basin along the

east side of a volcanic arc of size significant enough to develop

occasionally widespread carbonate platforms. Black shale was

deposited in the basin during times of quiescence (high-water

stands?). Megabreccia and conglomerate were deposited during

low stands of sea level. Graywacke was deposited during most

other times. Faunas indicate that the volcanic arc was in close

proximity to and related to the Permian and Pedregrosa basins

to the north.

Literature Cited

Cooper, G.A., and R.E. Grant

1975. Permian Brachiopods of West Texas, III. Smithsonian Contributions

to Paleobiology, 19:795-1921, plates 192-502.

King, R.E., CO. Dunbar, P.E. Cloud, and A.K. Miller

1944. Geology and Paleontology of the Permian Area Northwest of Las

Delicias, Southwestern Coahuila, Mexico. Geological Society of

America, Special Paper, 52: 172 pages, 45 plates.

Kozur, Heinz

1992. Dzhulfian and Early Changxingian (Late Permian) Tethyan Conodonts from the Glass Mountains, West Texas. Neues Jahrbuch fur

Geologie und Paldontologie, Abhandlungen, 187(1):99-114, figures 1-21.

McKee, J.W., N.W. Jones, and T.H. Anderson

1988. Las Delicias Basin: A Record of Late Paleozoic Arc Volcanism in

Northeastern Mexico. Geology, 16:37-40.

Newell, N.D.

1957. Supposed Permian Tillites in Northern Mexico are Submarine Slide

Deposits. Bulletin of the Geological Society of America,

68(11): 1569-1576, plates 1,2.

Spinosa, C, W.M. Furnish, and B.F. Glenister

1970. Araxoceratidae, Upper Permian Ammonoids from the Western Hemisphere. Journal of Paleontology, 44(4):730-736, plate

109.

Wardlaw, B.R.

1988. Permian Conodonts from the Salt Range, Pakistan. [Abstract.]

Geological Society of America, Abstracts with Programs, 20:393-

394.

1995. Permian Conodonts. In P.A. Scholle, T.M. Peryt, and D.S.

Ulmer-Scholle, editors, The Permian of Northern Pangea, 1:

Paleogeography, Paleoclimates, Stratigraphy, pages 186-195.

Heidelberg: Springer-Verlag Publishers.

Wardlaw, B.R., W.M. Furnish, and M.K. Nestell

1979. Geology and Paleontology of the Permian Beds near Las Delicias,

Coahuila, Mexico. Bulletin of the Geological Society of America,

90(l):l 11-116.
Plate 17-1
394 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

PLATE 17-1

Conodonts from Las Delicias, Mexico.

FIGURES 1-6.—Hindeodusjulfensis Sweet: 1, lateral view, Pa element, x81.5, USNM 482792; 2, lateral view, Pa

element, x79.4, USNM 482793; 3, lateral view, Pa element, x79.4, USNM 482794; 4, lateral view, Pa element,

x79.4, USNM 482795; 5, lateral view, Pa element, x79.4, USNM 482796; 6, lateral view, Pa element, x79.4,

USNM 482797. All specimens from USGS 31655-PC (W88-16M), Polydiexodina cobbles in igneous

dominated megabreccia above the Timorites shale, lower La Colorada beds. (Reduced to 90% of original for

publication.)

FIGURE 7.—Hindeodus wordensis Wardlaw (new species, this volume): lateral view, Pa element, x79.1, USNM

482798. From USGS 31652-PC (W88-5M), from concretions near the base of the Timorites shale, upper La

Difunta beds. (Reduced to 90% of original for publication.)

FIGURES 8-16.—Hindeodus wordensis Wardlaw (new species, this volume): 8, posterior view, Sa element,

x79.5, USNM 482799; 9, posterior view, Sb element, x79.4, USNM 482800; 10, inner view, Pb element,

x80.8, USNM 482801; 11, posterior view, M element, x79.4, USNM 482802; 12, inner view, Sc element,

x79.4, USNM 482803; 13, lateral view, Pa element, x80.8, USNM 482804; 14, lateral view. Pa element, x80.8,

USNM 482805; 15, lateral view, Pa element, x80.8, USNM 482806; 16, inner view, Sc element, x79.4, USNM

482807. All specimens from USGS 31654-PC (W88-14M), from the mollusk limestone within the La Difunta

limestone, lower La Difunta beds. (Reduced to 90% of original for publication.)

FIGURES 17-19.—Mesogondolella aserrata (Clark and Behnken): 17, upper view, Pa element, x79.1, USNM

482808; 18, upper view, Pa element, x79.4, USNM 482809; 19, upper view, PA element, x79.4, USNM

482810. All specimens from USGS 31654-PC (W88-14M). (Reduced to 90% of original for publication.)

FIGURE 20.—Sweetina triticum Wardlaw and Collinson: lateral view, Pa element, x79.1, USNM 482811. From

USGS 31654-PC (W88-14M). (Reduced to 90% of original for publication.)

FIGURES 21, 22.—Mesogondolella nankingensis (Ching): 21, upper view, Pa element, x79.4, USNM 482812; 22,

upper view, Pa element, x79.4, USNM 482813. Both specimens from USGS 31649-PC (W88-2M), from large

limestone nodules near the top of the lower Waagenoceras shale, lower Palo Quemado beds. (Reduced to 90%

of original for publication.)

FIGURES 23-25.—Hindeodus excavatus (Behnken): 23, lateral view, Pa element, x79.1, USNM 482814; 24,

lateral view, Pa element, x79.4, USNM 482815; 25, lateral view, Pa element, x79.4, USNM 482816. All

specimens from USGS 31650-PC (W88-3M), from limestone nodules near the top of the lower Waagenoceras

shale, lower Palo Quemado beds. (Reduced to 90% of original for publication.)

FIGURES 26, 27.—Hindeodus excavatus (Behnken): 26, lateral view, Pa element, x79.4, USNM 482817; 27,

lateral view, Pa element, x80.8, USNM 482818. Both specimens from USGS 31651 -PC (W88-4M), from a bed

of marble-sized concretions near the bottom of the lower Waagenoceras shale, lower Palo Quemado beds.

(Reduced to 90% of original for publication.)

FIGURES 28-30.—Mesogondolella nankingensis (Ching): 28, upper view, Pa element, x79.4, USNM 482819; 29,

upper view, Pa element, x79.4, USNM 482920; 30, upper view, Pa element, x76.3, USNM 482821. All

specimens from USGS 31648-PC (W88-1M), from scattered limestone nodules at the base of the lower

Waagenoceras shale, lower Palo Quemado beds. (Reduced to 90% of original for publication.)

FIGURES 31, 32.—Sweetognathus expansus (Perlmutter): lateral view, x80.0, upper view, x79.4, Pa element,

USNM 482822. From USGS 31653-PC (W88-13M), from a large ammonoid-bearing cobble from the

conglomerate beds, lower Las Sardinas beds. (Reduced to 90% of original for publication.)
NUMBER 32 395
18. Ancestral Araxoceratinae

(Upper Permian Ammonoidea)

from Mexico and Iran

Claude Spinosa and Brian F. Glenister

ABSTRACT

Araxoceratinae are ceratitoid ammonoids that characterize the

restricted marine facies of the Upper Permian Dzhulfian Stage.

Representatives of the ancestral genera Kingoceras and Eoaraxoceras

are abundant in the post-Guadalupian upper La Colorada beds of

Coahuila, Mexico. Both genera from the Araxoceras beds of Abadeh,

central Iran, which can be correlated in turn with the type Dzhulfian of

the Araxes River valley, are described. Agreement on the precise

definition of the Dzhulfian is yet to be achieved, but it is concluded

that the Dzhulfian Stage can be defined to succeed the Guadalupian

without major overlap or omission. Eoaraxoceras robustum is

proposed as a new species from central Iran.

representative of the family (e.g., Tozer, 1988); however, both

the definition of the Erathem boundary and the correlation of

adjacent strata are still open to question (Sweet, 1992), casting

the strictly Triassic age in doubt.

Among the earliest araxoceratins are Eoaraxoceras Spinosa

et al. (1970) and, questionably, Kingoceras Miller (1944). Both

genera have been reported from the upper portion of the

stratigraphic section in Arroyo La Colorada (Coahuila, Mexico) and from Kuh-e-Hambast, Abadeh, central Iran (Spinosa et

al., 1975). Four Iranian specimens of Eoaraxoceras were

subsequently described (Bando, 1979) and were referred to the

Mexican species E. ruzhencevi Spinosa et al. (1970). The

purpose of the present study is to describe additional

collections of Abadeh Eoaraxoceras and Kingoceras and to

reevaluate the taxonomic assignments and biostratigraphic

implications of these ancestral otoceratids.

Introduction

Araxoceratinae are otoceratid ammonoids (Ceratitida) that

are a distinctive element of Upper Permian (Dzhulfian) faunas.

They originated from the ancestral ceratitids, the xenodiscid

subfamily Paraceltitinae, are found across the middle Permian

(Guadalupian)-Upper Permian (Dzhulfian) boundary, and

serve significantly in the correlation of that datum. The

phylogenetic relationships of these groups were outlined by

Spinosa et al. (1975) and are reproduced in a somewhat

modified form herein (Figure 18-1). The nominate genus of

Otoceratidae is generally considered to be Lower Triassic

(Griesbachian) and is believed to constitute the youngest

Claude Spinosa, Department of Geosciences, Boise State University,

Boise, Idaho 83725. Brian F. Glenister, Department of Geology, The

University of Iowa, Iowa City, Iowa 52242.

Correlation of the Guadalupian-Dzhulfian Boundary

in North America and Transcaucasia

The youngest Permian outcrops at Las Delicias (Coahuila,

Mexico) occur in Arroyo La Colorada, where the top 375 m of

the section have been designated the "upper La Colorada beds"

(Wardlaw et al., 1979). Neither fusulinaceans nor conodonts

are known from this interval, and only ammonoids have any

biostratigraphically useful representation. Ammonoids are

abundant (Spinosa et al., 1970; Wardlaw et al., 1979) and are

represented by at least eight species (Figure 18-2): Kingoceras

kingi Miller, Timorites sp., Stacheoceras toumanskyae Miller

and Furnish, Xenodiscus wanneri Spinosa, Furnish, and

Glenister, Neocrimites sp., Difuntites hidius (Ruzhencev),

Nodosageceras nodosum (Wanner), and Eoaraxoceras ruzhencevi Spinosa, Furnish, and Glenister. Eoaraxoceras is particularly noteworthy as the probable ancestor of the Araxoceratinae, the otoceratid subfamily that characterizes the restricted397
398 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

U

CL

01

U

Q_

QL

D

Z

<

D

I

N

Q

latlssimum

Eoaraxoceras ruzhencevi

U

a:

u

z

<

<

2

Q:

LJ

Q.

u

_J

Q

Q

O

z

<

<

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Prototoceras tropitum

Xenodiscus carbonarlus

Paraceltltes rectangularis

Paraceltltes etegans
NUMBER 32 399

FIGURE 18-1 (left).—The early evolution of the ceratitoid ammonoid families

Xenodiscidae and Otoceratidae. The otoceratid subfamily Araxoceratinae can

be interpreted to have been derived from a Guadalupian paraceltitin ancestor,

such as Cibolites; it underwent spectacular diversification at the base of the

Dzhulfian to characterize that stage.

circulation facies of the Dzhulfian (Zhou et al., 1989).

Associations of Eoaraxoceras, Kingoceras, Xenodiscus, and

Timorites also occur in the bottom one-half of the Araxoceras

beds (Taraz, 1971) at Abadeh in central Iran (Figure 18-3),

which in turn can be correlated bed-for-bed with the Guadalupian/type-Dzhulfan transition sequence of the Araxes River

valley of Transcaucasia.

Agreement on the precise definition of the base of the

Dzhulfian is yet to be achieved (e.g., Kotlyar et al., 1989);

however, pending such agreement, the common consensus of

recognizing the base of the Dzhulfian in the type section at

Dorasham 2, Nakhichevan, Azerbaijan (Ruzhencev and Sarycheva, 1965) is adopted as the base of the AraxocerasOldhamina beds, which is the equivalent of the Araxoceras

beds of Abadeh (Taraz, 1971). This base corresponds to the

initial diversification of the Araxoceratinae. The upper La

Colorada beds in Coahuila thus correlate with the basal type

Dzhulfian.

The upper La Colorada beds occur in objective stratigraphic

superposition with the lower La Colorada beds. The uppermost

15 m of the latter (Bed 57 of Newell, 1957; Figure 18-2) can be

demonstrated by reference to both fusulinaceans and ammonoids (Wilde, 1990; Wardlaw et al., 1979) as the approximate equivalent of the Bell Canyon Formation, which is the

uppermost type Guadalupian. It follows that the Dzhulfian can

be defined to succeed the Guadalupian without major overlap

or omission.

Systematic Paleontology

The origin and affinities of the Otocerataceae were reviewed

by Spinosa et al. (1975), Zhao et al. (1978), Shevyrev and

Yermakova (1979) amongst others, and most recently by

Zhakharov (1988). Despite fundamental disagreements in

interpretation, it seems clear that the Otocerataceae evolved

Q

< H

Sri

64

63

61

60

59

5B

57

56

o o °'o o °.°'oo.oc

o o

AMMONOID SUCCESSION

LA COLORADA BEDS

LAS DELICIAS, MEXICO

T—Eoaraxoceras ruzhencevi

TT

Nodosageceras nodosum

Difuntites hidius

— Neocrimites sp.

Xenodiscus wanneri

Stacheoceras toumanskyae

Timorites sp.

Kingoceras kingi

FIGURE 18-2.—The ammonoid succession in the uppermost part of the Permian section, Las Delicias area,

Coahuila, Mexico. Occurrences are related to sections published by King et al. (see Miller, 1944) and Newell

(1957).
400 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

AMMONOID SUCCESSION

OF THE ARAXOCERAS BEDS,

KUH-E-HAMBAST, ABADEH, IRAN

Araxoceras sp.

69T12B— Vesc °toceras sp.

Araxoceras sp.

69T127—Eoaraxoceras ruzhencevi

69T126—araxoceratids indet.

Timorites ruzhencevi

69T123—Eoaraxoceras ruzhencevi

Kingoceras cf. K. kingi

69T121 — ?Eoaraxoceras

69T120—?Kingoceras sp.

Eoaraxoceras robustum, n. sp.

FIGURE 18-3.—The ammonoid succession in the Araxoceras beds of Kuh-e-Hambast, Abadeh area, central Iran.

Stratigraphic control is courtesy of Hooshang Taraz; the section is modified after Taraz (1971).

from the Paraceltitinae. Two of the genera involved in this

transition are the subject of the present study. Eoaraxoceras is

an unquestionable otoceratid and is considered to belong in the

Araxoceratinae. The assignment of Kingoceras is less certain

(Spinosa et al., 1975), and it can be referred with almost equal

propriety to either the Paraceltitinae or the Otoceratidae. In the

present study it is continued to be regarded as having been

derived from the paraceltitin genus Cibolites Plummer and

Scott (1937), but it is best considered an araxoceratin.

Superfamily OTOCERATACEAE Hyatt, 1900

Family OTOCERATIDAE Hyatt, 1900

Subfamily ARAXOCERATINAE Ruzhencev, 1959

Eoaraxoceras Spinosa, Furnish, and Glenister, 1970

TYPE SPECIES.—Eoaraxoceras ruzhencevi Spinosa, Furnish,

and Glenister, 1970:732-734, pi. 109: figs. 1-9, text-figs. 1,

2A, 3; original designation.

DIAGNOSIS.—Ancestral araxoceratins with strongly evolute

conch (U/D ranges from 0.2 to 0.45 at D 25-35 mm), broadly

acuminate venter, and pronounced umbilical flange. Sutures of

mature and submature specimens comprise ten lobes; lobes

serrate, except dorsal and ventral elements bifid.

DISTRIBUTION.—The type species of Eoaraxoceras is

abundant in the lower Dzhulfian upper La Colorada beds of

Mexico (Spinosa et al., 1970). The genus also occurs in the

lower Dzhulfian Araxoceras beds of Abadeh, central Iran

(Spinosa et al., 1975; Bando, 1979; Taraz et al., 1981), from

whence it was identified and described. A new species (E.

robustum) also occurs in the Araxoceras beds of Abadeh,

where it is a rare element. These two species represent the

oldest araxoceratins in the succession. Closely related forms are

abundant in strata of comparable age in the Longtan Formation

(Wujiapingian = Dzhulfian) of South China (e.g., Zhao et al.,

1978), but a detailed assessment of these occurrences is beyond

the scope of the present study.

Eoaraxoceras ruzhencevi Spinosa, Furnish, and

Glenister, 1970

FIGURE 18-4A-M

Kingoceras kingi Miller in King et al., 1944:125-126, pi. 42: figs. 8, 9 [in part,

not pi. 42: figs. 6, 7, text-fig. 29E].
NUMBER 32 401

Eoaraxoceras ruzhencevi Spinosa, Furnish, and Glenister, 1970:732-735, pi.

109: figs. 1-9, text-figs 1, 2A, 3. [Not E. ruchencevi [sic], Bando, 1979:116,

pi. 2: fig. 6a,b, text-fig. 6c (= lAraxoceras sp.); pi. 2: fig. 3a,b (= E.

robustum, new species).]

DESCRIPTION.—Holotype: SUI 32895 (Figure 18-4A-C);

Paratypes: SUI 31948, 31949 (Figure 18-4G), 31951, 31952,

32890 (Figure 18-4D-F). Approximately 400 additional topotypes of Eoaraxoceras ruzhencevi from the lower Dzhulfian

La Colorada beds of Mexico are available for study. Most were

analyzed when the species was erected, and new collections

from Mexico add nothing significant to an understanding of the

taxon; however, additional material from the Araxoceras beds

of central Iran (Figure 18-3) can now be compared directly with

the topotypes. Included are one well-preserved hypotype (GSI

69 T 123, Figure 18-4H-J) and two unillustrated specimens

from the same horizon, as well as one hypotype (GSI 69 T 127,

Figure 18-4K-M) and two poorly preserved representatives

(GSI 69 T 121) provisionally referred to E. ruzhencevi. The

assignment of Iranian specimens (GSI Ab-72158, Bando, 1979,

pi. 2: fig. 6a,b; 72174, Bando, 1979, pi. 2: fig. 3a,b, text-fig. 6B;

72224; 72302, Bando, 1979, text-fig. 6c) previously referred to

E. ruzhencevi by Bando (1979) is rejected, based on published

information.

Known representatives of Eoaraxoceras ruzhencevi are

small, with the maximum observed conch diameter being

approximately 35 mm. The holotype demonstrates subparallel

but slightly concave flanks that converge from the prominent

ventrolateral shoulders to form a tectiform venter (Figure

18-4A,B). Flanged dorsolateral regions form a conspicuously

raised umbilical shoulder that possesses a series of faint nodes

extending a short distance across the dorsolateral flanks. Nodes

are more pronounced in conchs less than 20 mm in diameter

(e.g., Miller, 1944, pi. 42: figs. 8, 9).

Figure 18-4C-G portrays the sutural ontogeny of the primary

types. Larger representatives display a pair of roundsd

nonserrate ventral prongs and a narrowly bifid dorsal lobe; four

intervening lobes can be observed to be serrate in wellpreserved specimens. In addition to the 10 major lobes, as

many as six incipient elements are sporadically observable on

the umbilical and internal saddles (e.g., Figure 18-4G).

COMPARISONS.—The previous analysis of conch form and

sutures of the abundant Mexican representatives of Eoaraxoceras ruzhencevi suggests high intraspecific variation.

Relatively rare representatives now known from central Iran

seem to fall within this range; therefore, they do not warrant a

separate designation. The relationship to the new Iranian

species, E. robustum, is considered under the heading for that

species.

OCCURRENCE.—Detailed occurrence data for the Mexican

representatives were presented previously (Spinosa et al.,

1970). In summary, they are apparently confined to the

uppermost 60 m of the youngest Permian known from the site,

which is near the top of the upper La Colorada beds, Las

Delicias, Coahuila. Most were derived from the upper 2 m of

Bed 63 of Newell (1957), but the best preserved specimens

were from calcareous nodules in the uppermost unit, Bed 64 of

Newell. Iranian representatives were from Kuh-e-Hambast,

Abadeh area, central Iran, 2.8 m (69 T 123) and 5.3 m (69 T

127) above the base of the Araxoceras beds of Taraz (1971).

REPOSITORY.—Topotype YPM 16282 is reposited at the

Peabody Museum, Yale University. Holotype SUI 32895,

paratypes SUI 31948, 31949, 31951, 31952, and 32890 are in

the University of Iowa, and hypotypes GSI 69 T 123, 69 T 127,

and 69 T 121 are in the collections of the Geological Survey of

Iran, Tehran.

Eoaraxoceras robustum, new species

FIGURE 18-5A-D

Eoaraxoceras ruzhencevi Spinosa, Furnish, and Glenister, 1970.—Bando,

1979:116, pi. 2, fig. 3a,b, text-fig. 6B [in part, published as Eoaraxoceras

ruchencevi (sic)].

DIAGNOSIS.—A species of Eoaraxoceras characterized by a

relatively broad conch (W/D approaching 0.5 in larger

specimens) and narrow umbilicus (U/D near 0.25).

DESCRIPTION.—The species is based upon the holotype (GSI

69 T 120), from the base of the Araxoceras beds (Taraz, 1971)

at Abadeh, central Iran; however, an additional specimen (GSI

Ab-72174) from the same localilty is compared with question.

The holotype is a well-preserved specimen of 33 mm diameter

that retains one-half volution of body chamber but does not

display the contours of the aperture. The umbilical ratio U/D

ranges from 0.36 at 16 mm diameter to 0.22 at 33 mm, and the

width ratio W/D decreases from 0.66 to 0.47 over this same size

interval. Figure 18-5A,C reveals change in the ventral transverse profile in the ultimate one-half volution, from rounded at

20 mm to strongly tectiform at diameters greater than 30 mm.

In this same interval, the ventrolateral shoulders become better

defined, partially due to flattening and eventual slight

concavity of the dorsolateral flanks. Low nodes that are

discernible on the outer umbilical wall become faint as they

extend onto the umbilical shoulder.

The external suture (Figure 18-5D) exhibits rounded,

nonserrate ventral prongs separated by a median ventral saddle

slightly higher than one-third the depth of the entire lobe. The

first "lateral" lobe, located on the ventrolateral shoulder, is

symmetrical, narrow, and approximately one-third deeper than

the adjacent lobes. It is serrate and is constricted slightly

two-thirds the distance from the base. The second "lateral" is

asymmetrical, comparable in depth to the ventral lobe, and

displays a flat base with numerous small but conspicuous

crenlations. A small, narrow, simple lobe is positioned on the

umbilical shoulder, and two similar elements are located on the

umbilical wall. The internal suture is unknown.

COMPARISONS.—The conch of the type for Eoaraxoceras

robustum is much broader in all growth stages than that of E.
402

SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

G

E

D

M

FIGURE 18-4.—Eoaraxoceras ruzhencevi Spinosa, Furnish, and Glenister, 1970, from the upper La Colorada

beds, Las Delicias, Mexico (A-G), and the Araxoceras beds, Kuh-e-Hambast, Abadeh area, central Iran (H-M).

A-C, holotype, SUI 32895: A, B, x2.1; c, diagrammatic representation of the external suture, diameter 23 mm.

D-G, inferred sutural ontogeny: D-F, paratype, SUI 32890, diameters 4.6 mm, 7.1 mm, and 11.7 mm, respectively

(sutures D and E are complete, F is external only); G, paratype, SUI 31949, complete suture, diameter 20.8 mm.

H-J, hypotype, GSI 69 T 123: H, I, x3.5; J, external suture, diameter 14.4 mm. K-M, hypotype, GSI 69 T 127: K,

L, x2.8; M, external suture, diameter 15 mm. (Reduced to 64% of original for publication.)
NUMBER 32

403

D

FIGURE 18-5.—Eoaraxoceras robustum, new species, Araxoceras beds, Kuh-e-Hambast, Abadeh area, central

Iran. Holotype, GSI 69 T 120; A-C, X2.2; D, diagrammatic representation of the external suture, diameter is

approximately 17 mm. (Reduced to 73% of original for publication.)

ruzhencevi, and the umbilicus is significantly narrower. The

sutures of the two species are similar, with most elements of E.

robustum falling within the limits of variation documented for

E. ruzhencevi; however, the first "lateral" lobe of E. robustum

is proportionally narrower, with distinctive adoral constriction.

Specimen GSI Ab-72174, described by Bando (1979) as

Eoaraxoceras ruzhencevi (E. ruchencevi [sic]) and questionably referred herein to E. robustum, closely resembles the type

species in conch form. However, the illustrated suture (Bando,

1979, text-fig. 6B), if accurately portrayed, may permit

discrimination based primarily on the divergent form of the

first "lateral" lobe.

OCCURRENCE.—The holotype is from Kuh-e-Hambast,

Abadeh area, central Iran, within the basal 1 m of the

Araxoceras beds of Taraz (1971). It represents the lowest

araxoceratin occurrence recorded by Taraz (1971, fig. 3). The

questionable second specimen is from the "lower part of Unit

6..." at the same locality (Bando, 1979:116), presumably from

a level closely comparable to that of the holotype.

REPOSITORY.—Holotype GSI 69 T 120 and the questionably

referred specimen (GSI Ab-72174) are in the collections of the

Geological Survey of Iran, Tehran.

Kingoceras Miller, 1944

TYPE SPECIES.—Kingoceras kingi Miller, 1944:125-126,

pi. 42: figs. 6, 7, text fig. 29E [in part, not pi. 42: figs. 8, 9,

text-fig. 29E (= Eoaraxoceras ruzhencevi Spinosa, Furnish, and

Glenister, 1970)].

DIAGNOSIS.—Transitional between Paraceltitinae and

Araxoceratinae, and characterized by a thinly lenticular conch

form and sutures with only eight fully isolated lobes.

DISTRIBUTION.—The type species of Kingoceras is abundant

throughout the lower Dzhulfian upper La Colorada beds of

Mexico and the uppermost unit (Bed 57 of Newell, 1957) of the

subjacent lower La Colorada beds (Spinosa et al., 1975). This

lower occurrence is assigned to the upper Guadalupian

Capitanian Stage (Figures 18-1, 18-2). Congeneric occurrences
404 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

A

E

D

II

FIGURE 18-6.—Kingoceras kingi Miller, 1944, La Colorada beds, Las Delicias, Mexico (A-G), and Araxoceras

beds, Kuh-e-Hambast, Abadeh area, central Iran (H-K). A-C, holotype, YPM 16281, x2.0; D-G, diagrammatic

representation of the sutures; D,E, complete sutures, hypotype, SUI 12055, diameters 5 mm and 10 mm; F,

complete suture, hypotype, SUI 12056, diameter 20 mm; G, external suture, hypotype, SUI 12052, diameter 23

mm. H,l,K, hypotype, GSI 69 T 123: H,l, x3.6. K, diagrammatic representation of the external suture, diameter is

approximately 21 mm. J, hypotype, GSI 69 T 123, diagrammatic representation of the external suture, diameter

is approximately 10 mm. (Reduced to 67% of original for publication.)
NUMBER 32 405

have been reported as a rare element in the lower Dzhulfian

Araxoceras beds of Abadeh, central Iran (Spinosa et al., 1975)

and are described herein (Figures 18-3, 18-6H-K).

Kingoceras kingi Miller, 1944

FIGURE 18-6A-K

Cibolitesi sp. Miller and Furnish, 1940:73.

Kingoceras kingi Miller in King et al., 1944:125-126, pi. 42: figs. 6, 7, text-fig.

29E [in part, not pi. 42: figs. 8, 9 (= Eoaraxoceras ruzhencevi)].—Spinosa,

Furnish, and Glenister, 1975:280-281, pi. 5: figs. 4, 5, text-figs. 2, 15A, 16,

tables 2, 3.

Kingoceras n. sp., Spinosa, Furnish, and Glenister, 1975:281, table 3.

DESCRIPTION.—Holotype: YPM 16281 (Figure 18-6A-C);

Hypotypes: SUI 12052, 12055, 12056 (Figure 18-6D-G),

31946. Several hundred additional SUI topotypes, all from the

La Colorada beds of Mexico, are available for study. Most were

analyzed by Spinosa et al. (1975), and new collections from

Mexico add nothing to the understanding of this taxon.

Additional material from the Araxoceras beds (Taraz, 1971) of

central Iran (Figure 18-3), however, can now be compared

directly with the topotypes. Included are two hypotypes (GSI

69 T 123, Figure 18-6H-J) and two poorly preserved specimens

from the same horizon. An additional poorly preserved

specimen from a slightly lower horizon (GSI 69 T 120) is

tentatively assigned to K. kingi.

All known representatives of Kingoceras kingi are small,

with the largest achieving a diameter of 35 mm, including

one-half volution of the body chamber. The Mexican type

material displays a narrowly discoidal, moderately evolute

conch. The width ratio W/D decreases from 0.3 to 0.15, and the

umbilical ratio Umin/D increases from 0.2 to 0.35 as the

diameter increases from 10-35 mm. Coarse transverse ribs are

present up to the 10 mm conch diameter, but they are

progressively replaced in larger whorls by relatively inconspicuous plications. Growth striations form a low salient across

the midflanks and on the venter.

The sutural ontogeny of Mexican Kingoceras kingi is

represented by Figure 18-6D-G. The first "lateral" lobe is twice

as deep as any other external sutural element; serration of this

lobe appears in whorls as small as 12 mm diameter, and is

present almost invariably at diameters greater than 25 mm. The

primary internal element (I) is located externally, adjacent to

the lateral lobe; it is approximately one-half as deep as the

lateral and is commonly serrate at maturity. Characteristically,

a variable number of tertiary internal elements (72, 73...) is

present on either side of the umbilical seam. The number and

depth of these tertiary lobes increase with growth from a single

element at approximately 5 mm diameter to four or more at

maturity. There exists, however, no consistent correlation

between conch size and the number or depth of tertiary internal

elements, as some small conchs possess numerous tertiary

lobes whereas some larger forms have significantly fewer. The

secondary internal element 71 is located internally, adjacent to

the dorsal lobe; it is approximately one-half as deep as element

I, and it usually remains unserrated.

The occurrence of Kingoceras in the Dzhulfian of Iran is

significant in supporting the correlation with the Eoaraxoceras

beds of Mexico. Four of the Iranian specimens (GSI 69 T 123)

are moderately well preserved, and they exhibit sutures (Figure

18-6J,K) that fall within the range of K kingi (Figure 18-6D-G).

The Iranian conchs, however, appear to be broader (W/D 0.25

at 35 mm diameter) than Mexican specimens of similar size

(compare Figure 18-6H,I with 18-6A,C). The confirmation of

this relationship with better-preserved material would warrant

erection of a new species. One additional Iranian specimen

(GSI 69 T 120), from slightly below those figured herein, is

referable to Kingoceras with reservation, but it is too poorly

preserved for specific assignment.

OCCURRENCE.—Detailed occurrence data for the Mexican

representatives of Kingoceras kingi were presented previously

(Spinosa et al., 1975). In summary, they range (Figure 18-2)

from the top of the lower La Colorada beds (Bed 57 of Newell,

1957), Las Delicias, Coahuila, to association with Eoaraxoceras ruzhencevi in the uppermost unit of the superjacent upper

La Colorada beds (Bed 64 of Newell, 1957). This range is

interpreted as upper Guadalupian (Capitanian) to lower

Dzhulfian. The better-preserved Iranian representatives (GSI

69 T 123) are from Kuh-e-Hambast, Abadeh area, central Iran,

2.8 m above the base of the Araxoceras beds of Taraz (1971).

The questionably assigned specimen (GSI 69 T 120) is from the

same section but is within the basal 1 m of the Araxoceras beds.

REPOSITORIES.—The holotype, YPM 16281, is reposited at

the Peabody Museum, Yale University. Mexican hypotypes

(SUI 12051, 12052, 12055, 12056, 31946) and several hundred

topotypes are in the University of Iowa. Described Iranian

specimens (GSI 69 T 123, 69 T 120) are in the collections of the

Geological Survey of Iran, Tehran.

Acknowledgments

The authors thank their colleagues W.M. Furnish (University

of Iowa), Zhou Zuren (Nanjing Institute of Geology and

Palaeontolgy), and W.W. Nassichuk (Geological Survey of

Canada) for stimulating discussions. Hooshang Taraz (Nicholls

State University) and personnel of the Geological Survey of

Iran provided access to ammonoids from Iran, and Dora

Gallegos and Tamra A. Schiappa (both Boise State University)

contributed invaluable technical assistance. Financial support

came from the Idaho State Board of Education (S 92-127), the

National Science Foundation (INT-8822531 and EAR9004907), and the National Geographic Society (3948-88).
406 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

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Bando, Y.

1979. Upper Permian and Lower Triassic Ammonoids from Abadeh,

Central Iran. Memoires of the Faculty of Education, Kagawa

University, Part 2, 29:103-182, plates 1-11.

Hyatt, A.

1900. [Tetrabranchiate] Cephalopoda. In K.A. von Zittel, translated and

edited by C.R. Eastman, Text-Book of Palaeontology, volume 1, part

2:502-592. London.

Kotlyar, G.V., Y.D. Zakharov, G.S. Kropatcheva, G.P. Pronina, I.O. Chedijia,

and V.I. Burago

1989. Evolution of the Latest Permian Biota, Midian Regional Stage in the

USSR. Leningrad Nauka, 185 pages. [In Russian.]

Miller, A.K.

1944. Permian Cephalopods. In R.E. King, CO. Dunbar, P.E. Cloud, Jr.,

and A.K. Miller, Geology and Paleontology of the Permian Area

Northwest of Las Delicias, Southwestern Coahuila, Mexico. Geological Society of America, Special Paper, 52:71-127, plates 20-45.

Miller, A.K., and W.M. Furnish

1940. Permian Ammonoids of the Guadalupe Mountain Region and

Adjacent Areas. Geological Society of America, Special Paper, 26:

242 pages, 44 plates.

Newell, N.D.

1957. Supposed Permian Tillites in Northern Mexico are Submarine Slide

Deposits. Bulletin of the Geological Society of America,

68(11): 1569-1576, plates 1,2.

Plummer, F.B., and G. Scott

1937. Upper Paleozoic Ammonites in Texas. In The Geology of Texas,

Volume III, Part 1. University of Texas Bulletin, 3701:1-516, 41

plates.

Ruzhencev, V.E.

1959. Classification of the Superfamily Otocerataceae. Paleontologicheskii Zhurnal, 1959(2): 56-67. [In Russian.]

Ruzhencev, V.E., and T.G. Sarycheva, editors

1965. Evolution and Change of Marine Organisms at the Boundary

between the Paleozoic and Mesozoic. Trudy, Paleontologicheskogo

Instituta, Akademiya Nauk SSSR, 108: 431 pages, 58 plates. [In

Russian.]

Shevyrev, A.A., and S.P. Yermakova

1979. On the Systematics of Ceratitoids. Paleontologicheskii Zhurnal,

1979(l):52-58. [In Russian.]

Spinosa, C, W.M. Furnish, and B.F. Glenister

1970. Araxoceratidae, Upper Permian Ammonoids, from the Western

Hemisphere. Journal of Paleontology, 44(4):730-736, plate 109.

1975. The Xenodiscidae, Permian Ceratitoid Ammonoids. Journal of

Paleontology, 49(2):239-283, plates 1-8.

Sweet, W.C.

1992. A Conodont-Based High-Resolution Biostratigraphy for the

Permo-Triassic Boundary Interval. In W.C. Sweet, Yang Zunyi,

J.M. Dickins, and Yin Hongfu, editors, Permo-Triassic Events in

the Eastern Tethys, pages 120-133. Cambridge: Cambridge University Press.

Taraz, H.

1971. Uppermost Permian and Permo-Triassic Transition Beds in Central

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Taraz, H., F. Golshani, K. Nakazawa, D. Shimizo, Y. Bando, K. Ishii, M.

Murata, Y. Okimura, S. Sakagami, K. Nakamura, and T. Tokuoka

1981. The Permian and the Lower Triassic Systems in Abadeh Region,

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Series of Geology & Mineralogy, 47(2):61-133, plates 1-6.

Tozer, E.T.

1988. Towards a Definition of the Permian-Triassic Boundary. Episodes,

11:251-155.

Wardlaw, B.R., W.M. Furnish, and M.K. Nestell

1979. Geology and Paleontology of the Permian Beds near Las Delicias,

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Wilde, G.L.

1990. Practical Fusulinid Zonation: The Species Concept; with Permian

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Zakharov, Y.D.

1988. Parallelism and Ontogenetic Acceleration in Ammonoid Evolution.

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Cephalopod Symposium: Cephalopods Past and Present: O.H.

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Schweizerbart'sche Verlagsbuchhandlung.

Zhao, J., X. Liang, and Z. Zheng

1978. Late Permian Cephalopods of South China. Palaeontologia Sinica,

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Zhou, Z., B.F. Glenister, and W.M. Furnish

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19. Depositional Controls on Selective Silicification

of Permian Fossils, Southwestern United States

Douglas H. Erwin and David L. Kidder

ABSTRACT

Differential silicification imposes an important taphonomic control

on fossil biotas that must be considered before paleoecologic analysis,

but the nature of that control has received little attention. Permian

rocks in the southwestern United States contain a diversity of biogenic

and abiogenic silica from a variety of sources, and many different

types of replacement appear to be involved. Analysis of the

taphonomic effects of silicification requires understanding the sources

of silica, the timing and differential patterns of replacement, the

mechanisms, and the controls at single localities.

The controls on silicification include differences between open and

less open marine settings; more complete silicification and greater

fidelity of preservation occur in more open marine environments,

probably because of greater silica availability. A second factor

involves a taxonomic bias with better preservation in echinoids,

articulate brachiopods, and scaphopods than in various gastropods,

with bivalves, bryozoans, and corals most poorly preserved. A third

factor is imposed by a silicification bias against large-sized fossils;

echinoid spines and some infaunal or semi-infaunal organisms are the

exception, and their silicification may have been enhanced by

immediate postmortem isolation. The patterns are expected to differ

between localities, and different elements at a single locality may have

been subject to different episodes of silicification. Considerable work

remains to determine the relative significance of these and other

potential controls on silicification.

Introduction

Silicified faunas are ubiquitous throughout the fossil record.

Their fidelity of preservation and the relative ease of laboratory

Douglas H. Erwin, Department of Paleobiology, National Museum of

Natural History, Smithsonian Institution, Washington, D.C. 20560-

0121. David L. Kidder, Department of Geological Sciences, Ohio

University, Athens, Ohio 45701.

preparation via acid dissolution makes them important for

many paleontologic studies. The bulk of the recovered Permian

fossil record in the southwestern United States is silicified, yet

despite the importance of these deposits for systematic,

paleoecological, and evolutionary studies their taphonomic

history has been poorly studied (see Carson, 1991, for a recent

review). This is particularly striking since Newell et al. (1953;

see also Cooper and Grant, 1972) first noted the existence of

taxonomic selectivity, or differential silicification, within the

Guadalupe Mountains.

Differential silicification may have several taphonomic

consequences that influence the amount of information

paleontologists can recover from the sedimentary record.

Taxonomic selectivity may destroy particular components of

the fauna. For example, acid residues dominated by articulate

brachiopods and echinoids may reflect the original composition

of the durably skeltonized biota, or they may reflect incomplete

or nonreplacement of a more diverse biota resulting in the loss

of certain faunal elements (e.g., molluscs) during reworking or

laboratory processing. Without taphonomic analysis, it is

impossible to distinguish between these two alternatives. Other

potential taphonomic biases include differences in the extent of

replacement in different depositional environments and sizeselectivity. Each of these biases limits the amount of

information that can be retrieved from different settings, and

they limit our ability to compare faunas from different

localities. Although the diagenetic history of silicified material

is of interest in its own right, the taphonomic aspects of

silicified deposits become particularly important when different components of an assemblage respond to the same event in

different ways, biasing our record of the original fauna.

Differentially replaced faunas have played an important role

in reconstructing the paleoecology and paleoenvironments of

the Permian basin, and they are important for detailing the

extinction history of the marine biota during the end-Permian

mass extinction. For example, much of the Changxingian fauna

(latest Permian) in South China is silicified (R.L. Batten, pers.

comm., 1986). The last record of many genera of gastropods,

407
408 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

brachiopods, and other marine invertebrates occurs in the

Guadalupian of the southwestern United States. In both cases,

evaluating the extinction record depends upon an understanding of the silicification process.

This is the first detailed taphonomic and diagenetic analysis

of differential silicification, and it emphasizes the Wolfcampian-Leonardian Colina Limestone in southeastern Arizona

and the equivalent Hueco Formation in New Mexico (Figures

19-1, 19-2). We chose these units in part because there appears

to have been less silica in the system than in units in the

Permian basin of West Texas and greater overall taxonomic

diversity, although the absolute number of specimens is far

lower. The reduced amount of silica makes it easier to

determine the relative significance of different controls on

silicification. Our results shed light on paleoecological studies

of Guadalupian deposits in the Glass Mountains and elsewhere.

Previous studies of silicification in fossils include Carson

(1991), Hatfield (1975), Holdaway and Clayton (1982), Jacka

(1974), Leljdahl (1986), Maliva and Siever (1988b), Meyers

(1977), Schmitt and Boyd (1981), and Wilson (1966). Only

Boyd and Newell (1972) and Newton et al. (1987) considered

the taphonomic effects of silicification. In this preliminary

report the possible controls on differential silicification of fossil

material and their taphonomic implications are discussed.

Future work will consider in more detail the diagenetic patterns

of silicification and taphonomic history.

L

\ \

V

\

\

/

V ARIZON A

-&* •

150 miles

200 km

FIGURE 19-1.—Regional map showing the relationships among Permian basins and uplifts in the southwestern

United States (from various sources).
NUMBER 32 409

Central Arizona SE Arizona SC New Mexico Sierra Diablo Guadalupe Mountains Glass Mountains

FIGURE 19-2.—Generalized Permian stratigraphy of the southwestern United States. Correlations between the

Hueco, Colina, and Earp are controversial. Most sections are cut by numerous unconformities (e.g., Blakey

(1990)), which are not shown here.

The Process of Silicification

Important aspects of the replacement of original skeletal

material by silica include the sources of silica, the timing of the

replacement process(es), the mechanism of replacement, and

the controls that produce taphonomic variability. Silica in

replaced fossils may involve Beekite disks, siliceous coatings

or rinds on the surface, complete replacement with cryptocrystalline quartz, and void-filling silica (Cooper and Grant, 1972;

Schmitt and Boyd, 1981). The Colina Limestone is characterized by a wide variety of silica types (Lyons, 1987, 1989;

Kidder and Erwin, unpublished data) in addition to its

well-silicified faunas. The varieties of silica include replaced

vertical and horizontal burrows, dispersed siliceous blebs and

nodules, a very fine-grained, box-work silica structure, and

crack-filling silicification. The diversity of silica phases raises

the possibility that several episodes of silica genesis may have

occured, although further field, petrographic, and isotopic work

is needed to resolve the relative timing of these events.

Potential biogenic and abiogenic silica sources include the

siliceous tests or skeletons of sponges and radiolarians,

together with abundant Tertiary volcanics and clay diagenesis.

Data

The faunas of the Colina Limestone and Hueco Formation

(Figure 19-3) are dominated by gastropods and echinoid

fragments with lesser amounts of brachiopods, bivalves,

scaphopods, and corals (Table 19-1). Gastropod diversity is far

higher than in the Permian basin, but the diversity of

brachiopods is an order of magnitude less (Erwin, 1989). Field

data, slab and thin-section analysis, and the study of acidTABLE 19-1.—Faunal list for the upper portion of the section at Warren,

Arizona.

various corals, mostly tabulates

echinoid spines

fenestellid bryozoans

Composita

occasional large productid brahiopods

small nuculid bivalves

cephalopod fragments

scaphopods (p.Plagioglypta)

gastropods:

bellerophonts

Omphalotrochus

various pleurotomarids, including Apachella

Naticopsis

Glyptospira

Anomphalus

Stegocoelia

ISoleniscus

various caenogastropods
410 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Section A

(lower)

Wl S

Section B

(upper)

70

60

4 0 -

40

30

20

10

T

S Mostly

g Packstone

extensive

S silicification

METERS

METERS

p ^ i Carbonate mudstone (except where noted as packstone)

t = l Laminated carbonate mudstone

|»~ft| Bioturbated carbonate mudstone

I W. I Oolitic packstone/grainstone

~^r Shell fragments

| | Bivalves

G Omphalotrochus

S Silicified zones

FIGURE 19-3.—Measured sections of upper Colina Limestone at Warren, Arizona. Sections A and B are separated

by a fault of unknown displacement.

digested bulk samples have revealed considerable information

relating environmental factors to the degree of silicification.

We have noted correlations between silicification and taxonomic affinity, size of organism, depositional environment, and

fossil mode of life.

The taxonomic bias in silicification is presented as a series of

hierarchies for localities in the Hueco Formation (Florida

Mountains, New Mexico; Wolfcampian), and the Colina

Limestone (Tombstone Hills and Warren, Arizona; Wolfcampian-?Leonardian) (Tables 19-2, 19-3). Considerable variation

is obvious, but a general pattern emerges: echinoid spines,

brachiopods, and scaphopods are generally the best preserved

fossils, followed by bellerophontid and trochid gastropods,

then caenogastropods, and finally Omphalotrochus, Straparollus (sensu lato), and pleurotomarid gastropods. The best

preserved specimens are the most completely silicified; the

silica is finely crystalline quartz.

Fossil fragments are the bulk of the silicified material

recovered from most localities in the Colina Limestone and the

Hueco Formation. This fragmentation has a variety of causes,

including predepositional mechanical destruction and weathering, bioerosion, and chemical dissolution. Postdepositional

alteration may stem from destruction by bioturbation, incomplete silicification, fracturing during structural deformation of

the units, and breakage during the etching process as specimens

collapse.
NUMBER 32 411

TABLE 19-2.—Silicification hierarchies for selected localities (from best (most

complete, finest-scale silicification) to worst).

Warren, Arizona

approx. 70 m in section A

Composita, echinoid spines

caenogastropods

other gastropods, unidentified large brachiopod

bellerophontid gastropods, nuculid bivalves

fenestellid bryozoa

approx. 30 m in section B

Composita,, echinoid spines

Glyptospira, bellerophontids, Anomphalous

caenogastropods, unidentified large brachiopod

bivalves

[no bryozoans observed]

approx. 42-45 m in section B

all gastropods, scaphopods

bivalves

brachiopods, corals

Gym Limestone [= Hueco], Florida Mountains, New Mexico

brachiopods (several), echinoid spines, scaphopods

caenogastropods, Glyptospira, bellerophontids

Omphalotrochus, pleurotomarids

bivalves, corals

Estimates of the relative significance of each of these factors

for one sample collected from the 45 m level at the Warren,

Arizona locality (Figure 19-3) revealed that approximately

one-third of the insoluble residue is identifiable. Some 90

percent of identifiable specimens are gastropods, with only

minor contributions from (in descending order) echinoid

spines, brachiopods, scaphopods, and bivalves. Within the

silicified gastropod fraction, about 10 percent to 15 percent of

the specimens show considerable evidence of pre-depositional

weathering or breakage; however, the bulk of the specimens

show no signs of any mechanical degradation. This suggests

that the assemblage consists of a mixture of shells, most of

which were either alive or fairly recently dead when buried, and

a minor component of material that had either been lying on the

seafloor or was transported in from a higher energy setting prior

to burial. There is no apparent difference in the quality of

silicification between the two components.

Not surprisingly, the importance of predepositional weathering and transport varies widely between localities. A bed 2 m

TABLE 19-3.—A generalized hierarchy of silicification.

Best

brachiopods echinoid spines scaphopods

various gastropods

Glyptospira bellerophonts

Omphalotrochus straparolids pleurotomarids

Worst

below that described above (Figure 19-3) has a much higher

percentage of abraded specimens, indicating a higher energy

environment. An even more highly abraded sample collected

from near the top of Colina Ridge in the Tombstone Hills

consists solely of well-worn silicified fragments of large (6+

cm original shell length) bellerophontids.

Virtually all specimens with a maximum dimension greater

than 3-4 cm show signs of postdepositional fracturing.

Inspection of the residue suggests that such fracturing probably

accounts for a far higher percentage of the fragmentary remains

than does weathering. Evidently smaller specimens are less

subject to fracturing. Estimating the relative significance of the

remaining factors was not possible.

The incomplete replacement also imparts a clear size bias to

the silicified material recovered: smaller fossils are more

completely preserved than are larger fossils. Exceptions to this

generalization include echinoid spines, the brachiopod Composita, and the large gastropod Omphalotrochus. At the sample

from the 45 m level at Warren, discussed above, the only

identifiable fossils with a maximum dimension greater than 3

cm are high-spired gastropods, bellerophontids, echinoid

spines, Omphalotrochus, Straparollus, and some fragmentary

brachiopods. More than 80 percent of the specimens recovered

are less than 2 cm maximum dimension. This locality is

somewhat surprising in that brachiopods appear to have been

incompletely silicified and, thus, are more poorly represented

in the residues than they are in the initial deposit. Although

bivalves are relatively few, the small nuculid bivalves are much

better preserved than some larger, non-nuculid taxa; however,

smaller organisms always outnumber larger organisms and,

thus, should comprise a larger portion of the fossilized remains.

The degree of silicification varies systematically within the

Pedragosa region (Figure 19-4). When combined with stratigraphic and sedimentologic data, this suggests that the depositional environment influences the degree of silicification. The

coarseness of silicification among specimens of Glyptospira, a

widespread trochid gastropod (Erwin, 1988), varies within the

basin. The best preservation occurs at the top of the section at

Warren, Arizona (Figure 19-3; Table 19-4); fidelity decreases

toward the Tombstone Hills and Scherrer Ridge. A similar

pattern occurs in bellerophontid and pleurotomarid gastropods.

Lyons (1989) interpreted the Colina Limestone as a lagoonal

deposit that was restricted by ooid shoals in southeasternmost

Arizona. The Warren locality is within the lagoonal boundaries,

and Colina localities to the west and north, such as the

Tombstone Hills, Scherrer Ridge, and the Whetstone Mountains, were shoreward of Warren (Figure 19-4). Faunal

diversity in the Colina (Table 19-1) indicates that there must

have been significant interchange between lagoonal water and

marine water. If ooid shoals inhibited circulation, their main

function was to shelter the lagoon from high energy conditions,

and they did not completely cut off marine water. Samples

collected at the Warren section suggest that more open marine

conditions correlate with improved fidelity of silicification.
412 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

SOUTHERN

ARIZONA

Whetstone Mountains}

(Tombstone Hills)

Pedregosa Basin

"Level11 of Silicification

Most complete and finest-scale silicification

Intermediate

Least complete and coarsest-scale silicification

FIGURE 19-4.—Map of southeastern Arizona showing the general position of the Pedregosa basin and localities

of Colina Limestone investigated in this study. The basin has been contoured to show the rough variation in

completeness and general nature of silicification. Shells with the most complete and finest-scale silica

replacement are the best preserved.

The lower 33.5 m of section B at Warren are barren (Figure

19-3). Silicified infaunal bivalves appear at the 33.5 m level of

the Warren section; the lower part of the section lacks

macrofossils, but considerable bioturbation is apparent. Faunal

diversity and preservational fidelity increases up section, with

abundant echinoid spines and the brachiopod Composita,

well-preserved caenogastropods and nuculid bivalves, occasional remains of pleurotomarids and bellerophontids, and

fragments of fenestellid bryozoans and cephalopods. Scaphopods and corals appear near the top of the section. Although our

evidence is fragmentary, it suggests a similar pattern occurs in

the sections at Tombstone Hills. In general, both regional and

single-section comparisons suggest that the fidelity of preservation increases as one approaches more open marine

conditions.

TABLE 19-4.—The silicification hierarchy for Glyptospira.

Best

Upper part of section at Warren locality

Gym Limestone (Florida Mountains, New Mexico)

Middle part of section at Warren locality

Tombstone Hills sections

Worst

The only well-silicified bivalves at this locality were

infaunal, and they are always found in life position. Other

larger bivalves fragment during etching and are generally not

identifiable. Commonly the other silicified gastropods, echinoid spines, and bryozoans occur in beds that are interpreted as

storm beds (although some may be highly bioturbated).

Furthermore, many beds appear to be shell lags with silicified

fossils surrounded by unsilicified shell debris. This bias toward

replacement of buried taxa may partially explain the exceptions

to the bias against large-sized fossils. For example, the upper

silicified beds in Figure 19-3 are assemblages of mixed

silicified fossils and unsilicified shell hash. It is unclear why the

shell hash is generally resistant to silicification. Omphalotrochus is a large, suspension-feeding gastropod, which lived with

its apex buried in the sediment (Erwin and Kidder, unpublished

data), and is generally well-silicified. Similarly, when scaphopods are present they are well preserved.

Discussion

The factors that control fossil silicification fall into two

different classes: (1) environmental controls, including the

depositional environment, extent of transport and reworking of
NUMBER 32 413

fossils, rapidity of burial, and chemistry of depositional and

diagenetic pore waters; and (2) biologic controls, including

original shell mineralogy, skeletal microstructure, and the

organic content of shells. Newell et al. (1953) and Dapples

(1967) identified and summarized patterns of taxonomic

influence on silicification (presumably controlled by some of

the factors discussed above), in which fidelity of preservation

varied with taxonomic affinity. The hierarchical pattern varied

with locality, but little consideration has been given to what

produced these patterns.

General progress in isolating the effects of these controls has

been limited, but some advances have been made. Fluctuating

pH gradients can enhance precipitation of silica in certain

settings (e.g., alkaline lakes (Eugster, 1967)). The influence of

pH on silicification has led to the belief that pH fluctuations are

important in silicification of fossils in normal marine settings;

however, the dramatic fluctuations on a microscopic scale

needed for fine silicification may be possible, but are difficult

to test. More recent work (e.g., Holdaway and Clayton, 1982)

suggests that organic matter can be effective in lowering the

kinetic threshold that would otherwise prevent silicification.

Maliva and Siever (1988a,b) recently revived the concept of

force of crystallization as an important factor in silicification

and presented several specific textural criteria for recognizing

that mechanism. A combination of organics complexing with

silica and calcite dissolution driven by the force of crystallization might silicify fossils more easily than would drastic

fluctuations in pH.

More specific advances related to the influence of original

shell mineralogy on silicification come from Permian fossil

assemblages in the Park City Formation of Wyoming (Boyd

and Newell, 1972; Schmitt and Boyd, 1981) and from the

author's current studies in the southwestern United States.

Original mineralogy strongly influenced the patterns of

silicification in the bivalves of the Park City Formation. Much

of the silicification occurred preferentially in originally

aragonitic fossils; the aragonite dissolved, and the resulting

voids were filled with quartz (Schmitt and Boyd, 1981).

Conversely, our Permian localities reveal silicification patterns

that seem to have little to do with original mineralogy.

Petrographic and microprobe analysis indicates that silicification occurred by simultaneous dissolution and replacement by

cryptocrystalline quartz. The spongy texture of some fossils

and the fine-scale alternation between calcite and silica indicate

that dissolution and replacement is frequently incomplete or on

a very small scale. There is little indication of the void-filling

quartz described by Schmitt and Boyd (1981).

Evaluation of the relative significance of the environmental

and biologic controls in different settings is extremely

complex. It must be emphasized that these factors are not

mutually exclusive but often may act in concert. The evidence

presented below is limited to only Wolfcampian-Guadalupian

localities from the southwestern United States; other factors

may be of greater importance in other regions. The process of

silicification can be divided into the following phases.

ENVIRONMENTAL CONTROLS.—The depositional environment imposes general controls through sediment composition

and the quantity of sediment and through the nature and type of

silica, detritus, and/or organic material originally present (for

example, substantial organic material that was originally

present as algae). Individual deposits are affected by the

rapidity of burial and transport and/or by the extent of

mechanical, chemical, and biologic reworking of sediments

and fossils.

Davies et al. (1989) pointed out that the preservation of shell

material requires rapid burial to a point below the layer in

which taphonomic processes are common, in part because rates

of shell loss by dissolution greatly exceed those from biological

or mechanical degradation both at the sea floor and within the

upper layer of sediment. Many of the assemblages in the

limestones of the Hueco Formation and Colina Limestone

appear to be event beds of probable storm origin, and in some

cases the concentrated deposits seem to be more readily, and

perhaps more completely, replaced than dispersed fossils. The

apparent increased silicification in these concentrations might

also be due to rapid burial, rather than simply concentration of

the fossils, or to greater original porosity in the event bed. If

storms quickly killed and buried organisms, a greater amount

of organic matter in the shells may have been preserved and

facilitated later silicification. It seems unlikely that the

concentrations of shell beds in the Colina Limestone and Hueco

Formation could have arisen other than by rapid burial

associated with storm deposits. The preferential silicification of

the basinal facies of the Capitan Reef complex (e.g., Newell et

al., 1953) suggests that rapid burial of those fossils may have

enhanced their silicification (although radiolarians, the abundant silica source, also must have been a major factor in those

beds). The observation by Read (1985) that lagoonal deposits

and turbidites in carbonate settings are commonly silicified

suggests that rapid burial may be a significant factor in those

settings. Rapid burial, however, appears not to have been

involved in preservation of a silicified gastropod assemblage

from the Plympton Formation (Permian, Nevada) (Yochelson,

1973). In this case the bellerophontid and neritid gastropods

and the scaphopod Plagioglypta are highly worn, and the

deposit was apparently formed as a high energy beach deposit.

Environmental controls on later diagenesis include destruction of replaced fossils by leaching either the carbonate or the

siliceous phases (via the introduction of new pore waters, for

example) and the introduction of later silica phases. Many of

the localities in Cochise County, Arizona, with a rich silicified

fauna, are within one mile of volcanic necks; the Warren

locality is immediately adjacent to one of the largest copper ore

bodies in the country. These Tertiary events generated

substantial changes in pore waters, but there has been virtually

no attention given to what effect these events might have had

on silicified fossils.

The final phase in the history of silicified fossil deposits

involves weathering on the outcrop and laboratory etching

during preparation. Newton et al. (1987) noted that silicified
414 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Triassic faunas from Oregon generally contain many incompletely preserved fossils, which fall apart during the etching

process. Although the effects of incomplete replacement can be

partially ameliorated by coating such fossils with an insoluble

compound during etching, some degradation still occurs. The

controls on silicification that operate only during this phase

have not yet been identified.

BIOLOGIC CONTROLS.—The careful analysis of shell microstructure, the amount of organic material in the shell matrix, and

the size of the organisms are essential for understanding

patterns of silicification. These elements each influence the

amount of surface area available for the replacement reaction

and the mobility of silica. It would be expected that the rate of

silicification and the fidelity of preservation should increase

with surface area; however, brachiopods and bryozoans have

very similar mineralogies (Williams, 1990), but brachiopods

are far more readily preserved. In addition, bivalves have

broadly similar mineralogy, but the small, infaunal nuculid

bivalves are among the best preserved elements in the fauna

whereas other bivalves are generally only weakly silicified.

These examples indicate that in the Permian of the southwestern United States original mineralogy does not seem to have

been an important factor.

The striking size bias in etched residues in New Mexico and

Arizona may be due to differential silicification, which

suggests that silica was limiting. There is less evidence of size

bias in samples from the Glass Mountains, perhaps because

more silica was available in the Permian basin than on adjacent

carbonate shelf regions.

HIERARCHY OF HYPOTHESES.—Clearly there are multiple

controls on silica replacement of fossils within Permian rocks

in the southwestern United States. Present evidence suggests

the controls over silicification may be arranged hierarchically.

The primary control may have been between open and

restricted marine settings with increased silicification in more

open marine situations. This is supported by the lack of size

bias in the Permian basin and by stratigraphic and geographic

silicification gradients from southeastern Arizona to West

Texas. These gradients require further testing, as they span

several basins. A secondary level of control was provided by

taxonomic selectivity. The factors behind the taxonomic

selectivity have not yet been identified, but it is suggested that

differing degrees of organic material in the shells and/or shell

microstructure may be involved. A tertiary level of control was

provided by bias in favor of smaller shells. In part, this bias

may reflect the limiting nature of silica in some of these

systems, which also may be reflected by the difference between

open and restricted marine settings. Rapid burial of certain taxa

in storm deposits seems to have enhanced their degree of

silicification, but it is not certain where to place this potential

control within this possible hierarchy.

The pattern of differential silica replacement is an important

taphonomic control on paleoecological studies, although its

significance has not been generally appreciated. Differential

silicification can bias samples in several ways. First, the pattern

of taxonomic selectivity means that comparisons of entire

assemblages between localities may be biased by the completeness of silicification. A fauna of apparently high diversity may

simply represent more complete silicification. Second, particular depositional environments and settings (e.g., rapid burial

along slopes) appears to enhance silicification, so fossils found

in, or transported to, these areas will be well represented in

collections. Third, the preferential silicification of infaunal and

semi-infaunal elements may increase their representation in

collections relative to the epifauna. Fourth, there is at least

circumstantial evidence that in areas where silica is limiting,

larger specimens may be incompletely silicified, thus imposing

a size-bias on the assemblage. Because of the exquisite

preservation of silicified faunas, these difficulties hardly

suggest that paleontologists should ignore the paleoecologic

and paleoenvironmental potential of these assemblages, but

they do indicate that, as with all fossil assemblages, careful

taphonomic analysis is an essential prerequisite to paleoecologic studies.

Conclusions

1. Original shell mineralogy is not an important control on

silicification in the Permian of southeastern Arizona, although

there may be some exceptions to this generalization.

2. Specific environmental and biologic influences control

most of the silicification in the Permian of southeastern

Arizona. Environmental controls include open versus less open

marine settings, which could reflect the amount of locally

available silica. Rapid burial is also a significant control.

Biologic controls include taxonomic affinity and size.

3. The specific environmental and biologic influences

outlined above may be arranged into one or more hierarchies

that control silicification. If further work validates these

hierarchies of control in the Permian of the southwestern

United States, the approach may apply to many other settings.

Future Directions

This preliminary research has identified a number of

questions for future work in the complex problem of fossil

silicification. Although it was not possible to rule out original

shell mineralogy as influencing silicification in these deposits,

many other avenues of research remain, including the relationship between organic material and silicification; characterization of which depositional environments are more likely to

have silicified deposits; petrographic relations between microstructure and silicification patterns; and application of stable

isotopes to chart pore water history and to identify the origin of

different silica phases. Clearly, integrated paleontologic,

sedimentologic, and diagenetic studies may be able to further

isolate controls on silicification to the point of providing some

predictive value.
NUMBER 32 415

Acknowledgements

Douglas H. Erwin acknowledges support from the National

Museum of Natural History and prior support of this work from

the Petroleum Research Fund administered by the American

Chemical Society and National Science Foundation Grant BSR

87-22510. David L. Kidder acknowledges support from the

Ohio University Research Council. We appreciate reviews of

the manuscript from Richard Grant, Donald Boyd, David Rohr,

Bruce Wardlaw, and Ellis Yochelson.

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