AN ABSTRACT OF THE THESIS OF
James 0. Brown for the degree of Master of Science in Geology presented on February 2, 1982
Title: SEARCH FOR A WESTERN NORTH AMERICAN STRATOTYPE FOR THE
LOWER-MIDDLE COUNTY, NEVADA
Abstract approved: Redacted for privacy
Conodont samples were collected from sections at Sadler
Ranch, Modoc Peak, and in the northern Antelope Range in Eureka
County, Nevada in the hope of establishing a regional stratotype for the Lower-Middle Devonian boundary. Ideally, a regional stratotype contains the best fossils to correlate local and re- gional sections with the definitive boundary stratotype. Of the sampled sections, those in the northern Antelope Range appear to have the most potential for use as a regional stratotype because of the preservation, diversity, and the total number of repre- sentatives of species critical for zonal identification. The best section in the northern Antelope Range appears to be VB
(lower part of Section V of Johnson et al., 1980) when compared to the other sections collected there. Complete sections, criti- cal for identification of the Lower-Middle Devonian boundary, seem also to be present at Sadler Ranch and Modoc Peak. However, the serotinus, patulus, and costatus costatus Zones at these localities are not consistently recognized on a sample-by-sample basis and do not have readily identifiable boundaries. New information concerning conodonts in Nevada includes the ranges of Polygnathus cooperi cooperi, Icriodus lateri- crescens robustus, and Pandorjnelljna steinhornensis being ex- tended; the first representatives of Polygnathus costatus partitus and Eognathodus bipennatus being found; and three new morphotypes of Polygnathus, referred to as P. sp. 1, P. sp. 2,
and P. sp. 3, being illustrated. The lowest part of the Denay
Limestone of Trojan (1978) and Johnson et al. (1980) in the
northern Antelope Range has beds with a lithology similar to
the upper part of the underlying Coils Creek Member of the
McColley Canyon Formation indicating a transitional boundary
between the two formations and a need for redefinition. SEARCH FOR A WESTERN NORTH AMERICAN
STRATOTYPE FOR THE LOWER-MIDDLE DEVONIAN BOUNDARY
IN EUREKA COUNTY, NEVADA
by
James Oliver Brown
A THESIS
submitted to
Oregon State University
in partial fulfillment of the requirements for the degree of
Master of Science
Commencement June 1982 APPROVED:
Redacted for privacy
Prof esso of Geology in of major
Redacted for privacy
Chairman of the D Geo
Redacted for privacy Redacted for privacy Dean of Graduatp(caool
Date thesis is presented February 2, 1982
Typed by Priscilla Haselton for Jmss Oliver Brown DEDICATION
I would like to dedicate this thesis to my parents, William
0. and Ermalinda M. Brown. Without their love, support, and understanding I would probably not have been able to have gone this far or accomplish this thesis. ACKNOWLEDGMENTS
Many people have aided me in the logistics of completing this project. Foremost is my thesis advisor, J. G. Johnson.
His vast store of information, his suggestions and insights, and his availability to share these things with me all greatly helped. There were days when we were both learning what the conodonts and rocks had to tell, and at such times his enthu- siasm concerning the new and unknown was greatly appreciated.
I am especially indebted to G. Klapper of the University of
Iowa for coming to Corvallis for a week to help me with the trials and tribulations of conodont identification. Conversa- tions with him during that time helped in my better understand- ing the intent versus the reality of biostratigraphy and its potential into which Johnson had originally given me insight.
I am also grateful to Klapper for taking time out of his busy schedule to review the section of this thesis concerning system- atic paleontology and the accompanying SEN photographs.
K. F. Oles and W. H. Taubeneck helped review this manu- script and served on the thesis committee.
Claudia DuBois Regier showed me lab techniques crucial for doing thorough and proper sample preparation. She also helped pick two of the larger samples which otherwisewould not have been ready in time for Klapper's visit. Tim Heironimus and
Anne Pendergast also helped show me some of the procedures in- volving sample preparation. Both of them accompanied me on a field check in July of 1981.
A. Niem gave valuable insight concerning some of the petro- graphic slides used in this study. Ellen Mullen, Rich (Rick)
Conrey, and Rob Thomason showed me the techniques of petro- graphic slide preparation. Thomason also helped me with pho tomic rography.
Tom Sheft of R.I.T in Rochester, N.Y. gave some valuable insight on photography. Al Soeldner ran the SEM at O.S.U. that helped to achieve the conodont photographs shown in Plates 1-5.
Ed Howes did the final drafts of many of the tables and plates presented here.
Insights on getting and using a motor vehicle and returning from Nevada alive were given by Tryg Loken and Ed Deputy.
Fellow O.S.U. students who have helped along the way in- dude Max Rosenberg, Neil Bingert, John Graham, Paul McCarter, and the morning, afternoon, and evening gang at the Beanery.
(This last group includes anybody who I miht have missed).
I also thank my parents (to whom I have dedicated this), family, and friends for their long support and encouragement throughout the duration of this project.
Lastly, part of the financial burden of this thesis, in- cluding the cost of Klappers trip, acid used in sample prepa- ration, an PA stipend, a field trip subsidy, and the SEM photographs were covered by NSF Grant EAR-7926094 to
3. G. Johnson. TABLE OF CONTENTS
INTRODUCTION 1
STRATIGRAPRY
Introduction Sadler Ranch Section Modoc Peak Section Northern Antelope Range Sections
BIOSTRATIGRAPHY 18
Introduction 18 serotinus Zone 18 serotinus or patulus Zone 20 patulus Zone 20 costatus costatus Zone 21
CONCLUSIONS 24
SYSTEMATIC PALEONTOLOGY 25
REFERENCES CITED 52
APPENDICES 55
APPENDIX I 55 APPENDIX II 57 APPENDIX III 63 LIST OF TABLES
Table Page
1. SRB COLLECTIONS 13
2. MPB COLLECTIONS 14
3. NAB COLLECTIONS 15
4. NAB COLLECTIONS 16
5. VB COLLECTIONS 17 LIST OF FIGURES
Figure Page
1. Index map of Eureka County, Nevada 2
2. Photomicrograph ofMPB-1 showing mudstone 5 texture of Coils Creek Member
3. Photomicrograph ofMPB-O showing fossiliferous 5 wackestone textureof Coils Creek Member
4. Photomicrograph ofMPB-8 showing crionoidal 6 wackestone to packstone texture of the Sadler Ranch Formation
5. Photomicrograph ofNAB-2 showing wackestone 6 texture
6. Photomicrograph ofVB-O showing crinoidal 8 packstone texture
7. Photomicrograph ofNAB-S showing crinoidal 8 packstone texture
8. Photomicrograph ofNAB-7 showing crinoidal 9 packstone texture
9. Section VB 10
10. Sections NAB 12
11. Section NAB in vicinity of NAB-0 12 LIST OF PLATES
Plate Page
1. Eognathodus,Pandorinellina, and 66 Pe lekysgnathus
2. I crjodus 68
3. Polygnathus 70
4. Polygnathus 72
5. Polygnathus 74
6. Explanation of Sections Symbols in pocket
7. Sadler Ranch Section in pocket
8. Modoc Peak Section in pocket
9. Northern Antelope Range Sections in pocket PRELUDE
"All in all, it's just another brick in the wall."Pink Floyd SEARCH FOR A WESTERN NORTH ANERICAN STRATOTYPE FOR THE LOWER-MIDDLE DEVONIAN BOUNDARY tN EUREKA COUNTY, NEVADA
INTRODUCTION
The primary purpose of this study is to indicate a poten- tial site for a regional stratotype for the Lower-Middle.Devonian boundary in western North America. With this purpose in mind, samples were taken from previously studied (Kendall, 1975; Trojan,
1978) sites in Eureka County, Nevada at Modoc Peak, Sadler Ranch, and in the northern Antelope Range (Fig. 1), in the hope of find- ing relatively uninterrupted fossiliferous sections.
The samples were processed for conodonts and have provided new biostratigraphic information concerning the serotinus, patulus, and costatus costatus Zones in Nevada. Additions to the previous stratigraphic work of Kendall (1975) and Trojan (1978) are mentioned and illustrated (Plates 7-9). The systematic paleontology of important as well as new conodonts collected in this study is given.
Location and characteristics of a stratotype for the Lower-
Middle Devonian boundary are still pending (Klapper etal., 1978;
Kiapper and Ziegler, 1979). Once established, informal and pos- sibly formal stratotypes will be desired for local and regional correlations. The term 9regiorial stratotype" is used in this paper to refer to such a section. Information presented here indicates that the northern Antelope Range may be a good site
for such a section. -1----
\\\,
2O0
4 K,,Omelers
'11
1' .1 I V 'I I. / ISadler gnc
\ Modoc,
'Northern Antelope Range I
,, 1,' ) 4t1
'p.
I .5"
I
I
Figure 1. Index map of Eureka County, Nevada, showing the loca- tions of sections studied. Devonjan outcrops in black. 3
STRATIGRAPHY
Introduction
A brief discussion of the rocks in measured sections is presented below. The bases of the sections in this study were chosen according to the previous work of Kendall (1975) nd
Trojan (1978), and therefore do not all begin at a key marker bed as is common practice.
Sadler Ranch Section
All samples collected at the Sadler Ranch Section (Plate 7) were from the Sadler Ranch Formation, an informal unit (Johnson and Sandberg, 1977) proposed by Kendall (1975). The first hun- dred feet of section consists of brownish gray, dolomitic mud- stone to wackestone, having a fetid odor, and local beds of brownish gray, dolomitic quartzite. Some beds of dolomite con- tain abundant silt-to-sand-size quartz. Megafossils are rare, with the exception of sparse brachiopods and common to locally abundant crinoid ossicles. Some of the crinoid ossicles are of the two-hole variety (see Fig. 4, 8) discussed in Johnson and
Lane (1969). Bioturbation of the dolomite is indicated in some beds by the presence of burrows. This part of the section ap- pears to belong to Kendall's (1975) Lower Dolomite Unit of the
Sadler Ranch Formation. The remaining part of the section be- longs to Kendall's (1975) Middle Crinoidal Dolomite and con-
sists of brownish gray, crinoidal wackestorie to packstone with 4. local beds of brownish gray, slightly dolomitic quartzite.
Modoc Peak Section
The lowest three samples collected at Modoc Peak are from the Coils Creek Member of the McColley Canyon Formation (Plate
8). The Coils Creek is a brownish to dark gray mudstone. (Fig. 2) to fossiliferous lime wackestone (Fig. 3). It contains some chert nodules, sparse megafossils that locally are silicified, local burrows, and has a bed with abundant quartz at its contact with the overlying Sadler Ranch Formation (Plate 8).
The lower seventy feet of the Sadler Ranch Formaticn at
Modoc Peak consists of brownish to dark gray, poorly fossili- ferous, dolomitjc. mudstcrie with less common crinoidal wacke- stone (Plate 8). The remainder of the section consists of brownish to dark gray, dolomitic, crinoidal wackestone to pack- stone (Fig. 4). The measured section of Sadler Ranch Formation at Modoc Peak appears to belong to the Lower Dolomite and Middle
Crinoidal Units of Kendall (1975). Dolomitic quartzite beds are lacking, but the rocks otherwise are similar to those found at
Sadler Ranch.
Northern Antelope Range Sections
In this study, the strata in measured sections in the north- em Antelope Range are not being assigned to either the Coils
Creek Member of the McColley Canyon Formation or to the Denay
Limestone. The interbedded rock types present in the sampled 5
Figure 2. Photomicrograph with transmitted light of MPB-1 show- ing mudstone texture of the Coils Creek Member. Width of field of view is approximately 0.40 mm.
Figure 3. Photomicrograph with cross-polarized light ofMPB-0 showing fossiliferous wackestone textureof the Coils Creek Member. Note trilobite in the upper left cor- ner and partly silicifiedbrachiopod on right side. Width of field of view is approximately 0.40 mm. 6
Figure 4. Photomicrograph with transmitted light of MPB-8 show- ing crinoidal wackestone to packstone texture of the Sadler Ranch Formation. Note two-hole crinoid osicle on right and recrystallization of edges of fossils. Width of field of view is approximately 0.40 mm.
Figure 5. Photomicrograph with transmitted light of NAB-2 show- ing wackestone texture. Width of field of view is approximately 0.40 mm. 7
beds appear to be a part ofa transitional boundary sequence
between these two formations. One rock type is a light brownish
gray, silty-sandy limestone with a faint to distinct fetid odor,
typically distinct laminations, andsparse fossils. It typically
has a wackestone texture (Fig. 5), but at places grades into
either a muds-tone or packstone. The other rock type is light
to dark brownish gray, crinoidal packstone to grainstone (Fig.
6-8) with a strong fetid odor. Macrofossils vary in abundance
within the crinoidal packstone to grainstone rocks, and include
brachiopods, colonial and solitary corals, bryozoans, ostracodes,
vertebrate remains, tentaculites, and trilobites.
Trojan (1978, Plates 5, 10) and Johnson etal. (1980, Fig. 3)
show the Coils Creek- Denay boundary at the base of beds of
crinoidal packstone. However, the crinoidal packstone is not as
Continuous as depicted by them; instead, it alternates with beds
of silty-sandy wackestone similar to the underlying Coils Creek
Member from approximately the 25 to 50 feet interval of SectionV
(Fig. 9). Crinoidal packstone and grainstone are more common up
Section. The silty-sandy wackestone intercalated with the crinoidal packstone may resemble therare interbeds of mudtone
Trojan (1978, P1. 10) noted at Section Va for his description of
the section between 71 and 100 feet. Potter (1975, p.57) noted how some of the rocks of the Coils Creek Member appear without the aid of magnification to be uniform-textured lime mudstone.
The beds of Potter's (1975, P1. 3) section (from approximately
Lt 8782 appear to be lithologically 8
44 - V
4 %
a Figure 6. Photomicrograph with transmitted light of VB-0showiric crinoidal packstone texture. Note conodont, possibly of a Polygnathus. Width of field of view is approxi- mately 0.1 mm..
I..
(!.
r JL Figure 7. Photomicrograph with transmitted light of NAB-5 show- ing crinoidal packstone texture. Note conodont ele- ment. Width of field of view is approximately 0.16 mm. 9
PP -as-.--
L ____
Figure 8. Photomicrograph with transmitted light of NAB-7 show- ing crinoidal packstone texture. Note two-hole crinoid ossicle. Width of field of view is approxi- mately 0.40 mm. 10
-:--,-
- * ,
b
Figure 9. Section VB (V of Trojan, 1978). Note the interbeds of crinoidal packstone (light gray) with the silty- sandy wackestone (light brown). 11 similar to rocks collected in the northern Antelope Range in this study and approximately of the same age (Potter, 1975;
Kiapper, 1977; Trojan, 1978; Pers. Commun. of Klapper to
Johnson; Johnson etal., 1980; this study). The strata at sec- tions Va (71 to approximately 100 feet) and V (approximately
35 to 70 feet) are not as well exposed as depicted by the strati- graphic sections shown in Trojan (1978) and Johnson et al.
(1980), possibly explaining the discrepancy of formation assign- ment noted here (Fig. 10).
In the northern Antelope Range three sections were measured
(Plate 9). Two of these were measured in the vicinity of Tro- jan's (1978) section Va. The same labelling symbol, NAB, is used for both sections because of their originally being consi- dered a part of the same uninterrupted sequence of an offset sec- tion. However, further study of the area suggests the presence of a fault. An exposed indication of the fault is the bed repre- senting NAB-0, approximately at Trojan's (1978) 20 feet mark, being offset (Fig. 11) about two feet. The presence of the fault was not recognized prior to sampling. This has led to some dif-
ficulties in correlation which hopefully have been resolved.
Plate 9 shows the lower part of Trojan's (1978) section Va and
its stratigraphic position relative to the two NAB sections and
to the lower part of Trojan's (1978) sectiOn V (V of::thi$
study). 12
Figure 10. Section NAB (Va of Trojan, 1978). Note the expo- sure. Circled area is site collected in this study.
4 ..
Figure 11. Section NAB in vicinity of NAB-U (to left of Jacob staff). Possible fault is in center of picture where bed on left abruptly ends and begins again approxi- rnately two feet lower. '3
Table I
0 - CO N t- fl ) 0 , , , i SRB COLLECTIONS U) U) U) Cl) (1) Cl) Cl) Cl) U) U) U) U) U)
FEET IN SECTION 0N Ps
P Serot/nUS x x x x x x x x
Ponderodus sp. X X X X X X X X X X X X X X
P sp indet X X X X X X X X X X X X X
PkendoI// x ? x 7 x x x
Belode//osp. X X X X X X X X X X X
Pond.expanso X X X X X X X X X X e/mguirc#mis bu/tyncAi x ?
Pn. sp. B of Kiapper X 7
x x
I.sp.indet. X X X X X lirojani X
Pcooper/ cooperi x ? x x
P COStO/US par/mis ? 0 C 0 No N CON000NT ZONE 0 N ' N 0-.
Tables 1-5. Distributionofconodonts. The following abbreviations for conodont genera are used consistently throughoutthe tables: = Icriodus, Pond.: Pondorineiina; and : Po/ygnaThus. Referto Appendices I and II for number of specimens per sample. 14
Table 2
o- C4 K) jg (0 r (00)0= I I I I I I I MPR COLLECTIONS I I I
%() It) .- FEET IN SECTION 0 .-. o g
ttrojcn/ X X X X
1. sp.indet. X X X X
B./oa'eia sp. X X X X X X X X X X
Ponde,-odus sp. X X X X X X X X X X X
Isp x x
I. /o/er/crescans ,obusus X X X
P serot/nus X X X X X X X X Psp.indet. XXXXX X XXXX P kendall X
P n. sp. B of Klopper X X
Pspp X X X X X
P /rnqu,form,s bu/tyncki X X X
Pond.expcnsa X X X X X X X X X X
P cooperi cooperi X X p costemis potu/us x x PspI X X
P c costotus ? X
cs-. C a N4
CON000NT ZONE 15
Table 3
0 - ci r() a a a NAB COLLECTIONS z z z z z
O U) U) FEET IN SECTION 0 o CJ N)
Pond. steinhornensis subsp.indet. X
P cf.C. cooperi X
P kendo/li X X
I. latericrescens robus/us X X
I.sp. indet. x x x x x
P serot in us X X X X
Be/ode//c sp X X X X
I. trojoni x x x x
Ponderodus sp. X X X X X
P. sp. indet. X X X X X
P I/n gu/formis bu/Iyncki X X X X
P n sp B of K lapper X Pond expanse X X
Pcooperi coo pen X X
P costa/us cf. pc/u/us X
Psp. X
C'-. 0 0 C C - N0 N0 CONODONT ZONE
. 16
Table 4
NAB COLLECTIONS zzzzzzzzz
FEET IN SECTION 0
P cooper/ cooperi X
P sero//nus X X
P costa/us p0/u/us X X X X
Pcno' expense X X X X X X
Ponderodussp. X X X X X X X X
/spindet X X X X X X
Be/ode//c sp x x x x x x x x
Pspp X X X X X X
P linguiformis b/tj'ncki X X X X X X X
Psp.indet. X X X X X X X X X
PCOSICtUSport//US X X
P /otaricrescens robustus X X X
P c. costa/us X X X X X X X
I. ,wrford/ X X X X
/n sp A of Chatterton X X X X Eognc/hodusb,pennctus X
Pllnguiform/ssubsp. indet. X X
P//inguiformis theta morphotype X Psp3 X X Pe/ekygno thus sp X
N0 CONODONT ZONE '- .
0 N 17
Table 5
(%J 0 - t VB COLLECTIONS > > > > >
FEET IN SECTION 0 !
P kendall! X P n sp B of Kiapper X / trOjQii P spp P Cf C cooperi X X P serot/nus X X Pond spindet X P c. cooper! J_ P linguiformis bu/tyncki X X X X Pond expansa X X X X X Be/odella sp X X X X X Ponderodussp ..L__ / sp.indet. X X X X X Psp.indet. X X X X X Psp2 X P n sp f trigonicus X P cost a/us par titus X X P cost a/us p0/u/us X X / lot ericrescens robus/us -_L....JL P c costa/us X X X I nor fordi X / n sp A of Chotterton X P P. 3 - C 0
CONODONT ZONE
t..J 18
BIOSTRPTIGRAPI-JY
Introduction
Conodorits were found in the serotinus, patulus, and costatus costatus Zones, formally recognized in Nevada by Kiapper (1977) and Kiapper and Ziegler (1979). Other works useful for biostra- tigraphic zonation, used in this study, are Kiapper and Johnson
(1980), Johnson etal. (1980), and Johnson and Klapper (1981).
Information was also derived from conodont samples reported by
Kiapper in Kendall (1975). Kiapper (1977) discusses the advan- tages of using specific rather than generic names to identify conodont zones.
SEROTINUS Zone
The lowest occurrence of Polygnathus serotinus marks the lower boundary of the serotinus Zone (Klapper, 1977). MPB-0 is the only sample in this study which might be from a lower zone
(Table 2). It contains Icriodus trojani, which is also known from the underlying inversus Zone and therefore is not useful in zonal determination at this stratigraphic level. All other sam- ples represent the serotinus or higher zones.
To date (Kiapper and Johnson, 1980; Johnson etal., 1980;
Johnson and Kiapper, 1981), Polygnathus n. sp. B of Kiapper, P. kendalli, and Icriodus trojani. have not been found higher than the serotinus Zone. Therefore, samples in this study with any of these three species, with or without P. serotinus, but above 19 its first occurrence, and without P. costatus patulus, but below its first occurrence, have been assigned to the serotinus Zone.
NAB-3 contains a specimen identified as P. costatus cf. patulus, but the sample above, NAB-4, contains specimens of Icriodus trojani. For this reason these two samples have been question- ably assigned to the serotinus Zone.
Kiapper (in Klapper and Johnson, 1980, p. 413, explanation of P1. 4) suggests that Polygnathus n. sp. B of Klapper is a phyletic intermediate between P. laticostatus and P. cOstatus patulus. If so, one would expect the co-occurrence of P. n. sp.
B of Kiapper and P. costatus patulus at some level, but such an occurrence is as yet unknown. P. cooperi cooperi closely resem- bles both P. n. sp. B of Kiapper and P. costatus patulus and has been found associated with both morphotypes. It also may repre- sent a phyletic intermediate. The range of P. cooperi cooperi in Nevada (Kiapper and Johnson, 1980, Tables 6,7) has been cx- tended downward into the serotinus Zone. It may, with further study, be useful in determining the upper part of the serotinus
Zone at places such as Sadler Ranch and Mocloc Peak where ques- tionable zonal assignments exist (Tables 1, 2).
The occurrence of Icriodus latericrescens robustus at Modoc
Peak and in the northern Antelope Range helps to confirm previous observations of Kiapper (1977), Klapper and Johnson (1980), and
Johnson etal. (1980) concerning its range in Nevada. 20
SEROTINUS or PATULUS zone
Several samples at Sadler RanOh and Modoc Peak have ques- tionable zonal affinities as they do not containPolygnathus costatus patulus or P. costatus pa,rtitus ofthe patulus Zone or any of the species (P. kendalli, P. n. sp.B of Kiapper, or
Icriodus trojani) currently believed to characterizethe serotjnus Zone. As noted above, some of thesesamples contain specimens of P. coaperi cooperi (Tables 1, 2). It is therefore possible that most of these samples represent the upperportion of the serotinus Zone.
PATULUS Zone
The lowest occurrence of Polygnathus costatuspatulus mdi-
cates the lower boundary of the patulus Zone(Klapper, 1977).
This study found the patulus Zone at all threestudied areas.
77-9 of Kendall and Johnson (in press, Fig. 7)is probably in the
patulus Zone as SRB-12 (Plate 7) was collectedbelow it. Pre-
vious works noting the recognition of this zonein Nevada are
Kiapper and Ziegler (1979, P. 206), 1 Table 7), and Johnson eta].. (1980). The latter paper States that the absence of the patulus Zone at somenorthern localities in central Nevada is probably due to a localphysical uncon- formity. However, sections sampled in this study werechosen because they appeared to be continuous, asupposition verified here. 21 A problem with patulus Zone rocks at northern localities in central Nevada is that they contain undiagnostic faunas. This is also true for the patulus Zone at both Modoc Peak and Sadler Ranch because of small numbers of specimens and lack of diagnos- tic species (Tables 1, 2). The problem of adequate faunas for zonal identification is also evident in the samples at Modoc Peak (Table 2) where MPB-8 is assigned to the patulus Zone by strati- graphic position; MPB-8 lacks diagnostic species (Table 2). At all three areas in this study, species and total number of specimens of Icriodus are uncommon from the upper part of the serotinus Zone through the lower part of the costatus costatus Zone. When the ranges of Polygnathus sp. 1 and P. sp. 2 arebetter understood they may be useful in identifying the patulus Zonein Nevada. Both P. costatus patulus and P. costatus partitushave ranges extending into the costatus costatus Zone(Table 4, 5). Their usefulness in determining the patulus Zone is therefore limited. Other known species and subspecies of cOnodonts in Nevada (Tables 1-5); Klapper and Johnson, 1980, Tables 6,7; Johnson et al., 1980, Table 23) in the patulus Zone are long ranging species. COSTATUS COSTATtJS Zone The lowest occurrence of Polygnathus C. costatus marks the lower boundary of the costatus costatus Zone (Kiapper, 1977). Only in the northern Antelope Range was this zone definitelyideri- 22 tified in this study. At Sadler Ranch an undiagnostic fauna is present above a sample identified as part of the patulus Zone. At Modoc Peak a sample with a questionable specimen of P. costa- tus costatus was identified. Previous collections (Kendall and Johnson, in press) at both of these areas have yielded a costatus costatus Zone fauna in samples above or near the top of $ections studied here. Samples from the northern Antelope Range studied here (Ta- bles 4,5) judging from data in Johnson et al. (1980, Tables 15, 16) appear to represent only the lower part of the zone. This part of the costatus costatus Zone is characterized by the presence of long ranging species found in the lower zones such as Icriodus latericrescens robustus, Polygnathus linguiformis bultyncki, P. cooperi coopri, and Pandorinellina expansa. A difference be- tween the lower and higher beds collected in this study (which are from the lower part of the zone) is the relatively rare presence of Icriodus in the former and an abundance of I. norfordi in the latter. The hiqhest sampled bed, NAB-il, is also characterized by the presence of p. i linquiforrnis theta morphotype (Table 5). The upper ranges of Polygnathus cooperi cooperi and P. costatus partitus in Nevada are extended in the the costatus co- status Zone (see Kiapper and Johnson, 1980, Table 7) by samples collected in this study. This is the first report of specimens of Icriodus norfordi and I. latericresecens robustus in this zone northern Antelope Range (Johnson etal., L9Q, TXi 23). ogeographic range of the cosmopolitan Eognathodus 23 bipennatus (see Kiapper and Johnson, 1980, p. 423) is extended to Nevada by rare specimens found in NAB-9. Discussion Once a stratotype is established on an internationallevel it will be desirable to establish sections here called regional stratotypes, to be used for correlations on a morelocal and regional scale. Kiapper et al.(19:78) discussed the potential biostrati- graphic levels where the Lower-Middle Devonian boundary strato- type might be established. Of the levels based on coflodonts, one of the problems concerning Nevada at thetime was the lack of any known beds representing the patulus Zone. Since then (Klapper and Ziegler, 1979); Kiapper and Johnson, 1980; Johnson etal., 1980; this study) conodont-bearing bedsrepresenting the ilus Zone have been found. It is also feasible that the patu- lus Zone in Nevada may, with future work, be dividedinto lower and upper parts based on the first occurrence of P. costatus partitus. In this study, however, no single section hadsamples clearly indicating the division of the patulus Zone. All patulus Zone samples at each section were either lower or upperpat'41uS Zone. Location of the upper patulus Zone is particularlyiflipor- tant because current thought suggests this will beused as the Lower-Middle Devonian boundary marker by the Subcoitunission on Devoniart Stratigraphy (Pers. Coinmuri., Johnson, 1980; Pers. Commun., Klapper, 1981). 24 CONCLUS IONS Of the three areas reviewed in this study as possible re- gional stratotypes for Nevada, and possibly western North Amer- ica, the best location appears to be in the northern Antelope Range. Both Sadler Ranch and Modoc Peak have beds with consis- tently low numbers of conodont elements (see Appendices I, II) and with small faunas for zonal diagnosis. In contrast, the beds in the northern Antelope Range have well preserved specimens and fairly large faunas to determine the zones. Another advantage to the northern Antelope Range over the other sites is its higher diversity (compare Tables 1-5; Appendix II) including Eognathodus bipennatus, Icriodus norfordi, I. n. sp. A of Chatterton, Poly- gnathus 1. linguiformis theta morphotype, i'. sp. 2, P. sp. 3, and P. n sp. aff. P. trigonicus. It is therefore proposed that the sections in the northern Antelope Range be considered as poten- tial regional stratotype sites. The only area in Nevada outside of this study that may rival the northern Antelope Range is Summit 8782 in the Hot Creek Range (Kiapper and Ziegler, 1979; Johnson etal., 1980, Table 23; Johnson, person. cominun., 1981). The potential Lower-Middle Devonian boundary positions based on conodonts are the bases of the patulus, the upper patulus, and and the costatus costatus Zones (Klapper etal., 1978). From the preliminary work of this study, Trojan (1978), andJohnson et al. (1980), it is feasible that future bed by bedcollecting in the northern Antelope Range will Lie1d all three of these zonal boundaries. 25 SYSTEMATIC PALEONTOLOGY 26 Eognathodus bipennatus (BISCHOFF & ZIEGLER), 1957 P1. 1, Fig. 4, 5. 9, 10 1972 Spathognathodus cf. S. bipennatus BISCROFF & ZIEGLER sensu BULTYNCK (1970). - MCGREGOR & UYENO, P1. 5, Fig. 24-27. 1974 Eognathodus bipennatus (BISCHOFF & ZIEGLER). - PERRY, KLAPPER, & LENZ, p. 1084, 1086, P1. 6, Fig. 14, 15. 1977 Eognathodus bipennatus (BISCHOFF & ZIEGLER). - ZIEGLER, ed., p. 113-115, Eognathodus - P1. 1, Fig. 3. 1979 Eoqnathodus aff. E. bipennatus (BISCHOFF & ZIEGLER). - CHATTERTON, P. 187-188, P1. 5, Fig. 4, 5. 1980 Eoqnathodus bipennatus (BISCHOFF & ZIEGLER). - KLAPPER & JOHNSON, p. 447, Tables 7-9. D e s c r i p t i o n: Representatives of Eognathodus bipennatus are small, possibly being juveniles.The lip to the basal cavity is asymmetrical, the inner margin havinq a straighter edge out- line than the curved outer marqin. The platform lacks denticles along two-thirds of its upper side.A very faint median groove is present along this portion of the platform. The blade has distinct serrations. R e m a r k 5: The median groove is very poorly developed, possibly due to the small size of the specimens. R a n q e: Eognathodus bipennatus occurs in the costatus costatus Zone in the northern Antelope Rance.These are the first recorded specimens of E. bipennatus from Nevada. Material: 3speciniens. 27 Iriodus latericrescens robustus ORR, 1971 P1. 2, Fig. 7-10 1971 Icriodus latericrescens robustus n. subsp. - ORR, p. 37-38, P1. 2, Fig. 14-17. 1975 Icriodus latericresceris robustus ORR. - ZIEGLER, ed., p. 133-134, Icriodus - P1. 2, Fig. 2, Fig. 3, 4. 1980 Icriodus latericrescens robustus ORR. - KLAPPER & JOHNSON, Table 7, p. 448. 1980 Icriodus latericrescens robustus ORR. * JOHNSON, KLAPPER, & TROJAN, Table 23. D i a g n o $ i s: For diagnosis, seeZieg1er, ed. (1975, p. 133). R e m a r k s: None of the other icriodontan elements in this study have a lateral process and thus cannot be confused with Icriodus 1atericrescers robustus. R a n g e: The first specimens of Icriodus latericrescens robustus confirmed on the basis of diagnostic coexisting cono- donts from the serotinus Zone in Nevada were found at Modoc Peak and in the northern Antelope Range.The northern Antelope Range also has specimens in the costatus costatus Zone. No specimen of I. latericrescens robustus from the patulus Zone were found in this study and none are known in Nevada (Kiapper and Johnson, 1980. Table 7). Material: 23specimens. 28 Icriodus riorfordiCHATTERTON, 1979 P1. 2, Fig. 11, 13-20 1979Icriodus riorfordi, n. sp. -CHATTERTON,p. 202-203.P1. VI, Fig. 6-12. 1980 Icriodus norfordjCHATTERTON. - KLAPPER & JOHNSON, p. 448, Table7. 1980Icriodus norfordiCHATTETON. - JOHNSON, KLAPPER, & TROJAN, Table 23. D i a g n a s i s:For diagnosis, see Chatterton(1979, P. 202). R e m a r k s:The subtransverse ridges and platform outline of Icriodus norfordi vary greatly.Juvenile and smaller specimens are typically narrower in outline and have rows of nodes forming fused subttansverse ridges. The transversely expanding nodes, especially those fused to the middle row, help to distinguish Icriodus norfordi from the other icriodoritan elements in this study. R a n g e:Specimens of Icriodus norfordi were found in the northern Antelope Range in the costatus costatus Zone. M a t e r i a 1:435 specimens. 29 Icriodus trojani JOHNSON & KLAPPER, 1981 P1. 2, Fig. 1-6 1966 Icriodus curvatus BRANSON & MEHL. - CLARK & ETHINGTON, p. 680, P1. 83, Fig. 8. 1978 Icriodus n. sp. D. - JOHNSON, p. 177-178, P1. 3, Fig. 6-11, 14-16. 1980 Icriodus n. sp. 0 of D. B. JOHNSON. - KLAPPER & JOHNSON, p. 449, P1. 3, Fig. 1, 2, 7, 8. 1980 Icriodus n. sp. 0 of 0. B. JOHNSON. - JOHNSON, KLAPPER, & TROJAN, Table 15. 1981 Icriodus trojani n. sp. - JOHNSON & KLAPPER, p. 1242-1243, P1. 2, Fig. 8, 9, 15, 16, 19-20. D i a g n o s i s: See Johnson and Kiapper (1981). R e m a r k S: Icriodus trojani differs front I. norfordi in having less stongly defined ridges and a much higher cusp(s). R a n g e: Specimens of Icriodus trojani were found in the serotinus Zone at Sadler Ranch, Modoc Peak, and in the northern Antelope Range. The range of I. trojani may extend into the patulus Zone in the northern Antelope Range (Table 3) as indi- cated by specimens collected from NAB-4 where a specimen of Polygrtathus costatus cf. patulus was collected in the strati- graphically lower NAB-3. However, none of the samples in this study prove I. trojani to be in the patulus Zoned Material: 38specimens. 30 Icriodus n. sp. A ofCHATTERTON, 1979 P1. 2, Fig. 12 1979 Icriodus n. sp. A. -CHATTERTON, p.203, P1. 6, Fig. 19-25. 1980 Icrjodus n. sp. A of CHATTERTON. - KLAPPER & JOHNSON, p. 449, Table 8. R e m a r k s: Icriodus n. sp. A of Chatterton (1979, P1. 6, Fig. 19-25) has the middle row distinctively curved laterally near the posterior end. R a n g e: Specimens of Icriodus n. sp. A have been found in the costatus costatus Zone in the northern Antelope Range. This is the first recorded occurrence of I. n. sp. A in Nevada and within the costatus costatus Zone (Kiapper and Johnson, 1980, Tables 7, 8) N a t e r i a 1: 77 specimens. 31 Pandorinellina expansa UYEO & MASON, 1975 P1. 1, Fig. 11, 13, 15, 16, 21 1975Pandorinellina expansan. sp. - UYENO & MASON, p. 718-720, P1. 1, Fig. 6, 9, 11-19. 1975Spathognathodus n. sp. A. - TELFORD, p. 61, P1. 12, Fig. 9-17. 1977Pandoririellina expansaUYENO & MASON. - ZIEGLER,ed., p. 435-436, P1. 1, Fig. 9-17. 1980Pandorinellina expansaUYENO & MASON. - KLAPPER & JOHNSON, p. 450, Tables 6, 7. D I a g n0s IS: For diagnosis,see Uyerio and MaSon (1975, p. 718). R e m a r k s:Eognathodus bipennatus and Pandorinellina steinhornensis susp. indet. are the only other spathognatho- dontan elements observed in this study and can easily bedis- tinguished from Pandorinellina expansa on the basis of a number of characteristics. Representatives of the Oj element of Pandorinellina expansa were found in some collections. R a n g5: Pandorinellina expansa is a long ranging species found in the serotirius, patulus, and costatus costatus Zones. All of these zones, where identified in this study, atSadler Ranch, Modoc Peak, and in the northern Antelope Rangehad speci- mens present. Ma t e r i a 1:763 specimens. 32 Pandorinellina steinhornensis subsp. indet. P1. 1, Fig. 1-3, 6-8 1973 Pandorinellina steinhornensis (ZIELGER). - ZIEGLER, ed., p. 325-326, P1. 2, Fig. 13. R e in a r k 5: Representatives of an indeterminate subspecies of Pandorinellina steinhornensis are present in sample NAB-O Identification is difficult due to the fact that the anterior end of the better preserved specimens is broken. R a n g e: Specimens of Pandorinellina steinhornensis subsp. indet. were collected in the serotirius Zone in the northern Antelope Range. Material: 6 specimens. 33 Pelekysgnathus sp. P1. 1, Fig. 12, 14, 17-20 R e m a r k s: Specimens of the I element of an unidentified species of Pelekysgnathus are present in NAB-li. They are characterized by one or two cusps higher than the denticles, but fused to and in unison with them. The platforui outline of P. sp. resembles both of the new species described by Chatterton (1979, p. 205, P1. VII, Figs. 24, 25, 28). R a n g e: Representatives of Peiekysgnathus sp. were found in the northern Antelope Range in the costatus costatus Zone. Material: 6 specimens. 34 Polygnathus cooperi cooperi K-LAPPER, 1971 P1. 3, Fig. 4-6 1971 Polygnathus lingui.formis coqperi subsp. nov. - K-LAPPER, p. 64, P1. 1, Fig. 17-22, P1. 2,Fig. 21. 1971 Polygnathus costatus patulus P. linguiformis cooperi. - KLAPPER, p. 65, P1. 1, Fig. 10-16, P1. 2, Fig. 16, 17. 1977 Polygnathus linguiformis cooperiKLAPPER.- ZLEGLER, ed. P. 471-472, Polygnathus - P1. 9,Fig. 2, 3. 1978Polygnathus cooperi KLAPPER. - KLAPPER, ZIEGLER, & MASITKOVA, p. 108, P1. 2, Fig. 21, 22, 29, 30. 1980 Polygnathus cooperi cooperiKLkPPER. - KLAPPER & JOHNSON, P. 452, Tables 6, 7. 1980 Polygnathus co cooperi KLAPPER. - JOHNSON,KLAPPER, & TROJAN, Table 23, P1. 4, Fig 12. Di a g a o s I s: Representatives of Polygnathus cogperi cooperi have a platform outline Like that of P. costatus patulus. The pit is small and located in the anteriorthird of the platform. One or more transverse ridges are present,which may be interrupted and which extend laterally acrossthe pos- terior part of the platform.The carina generally terminates anterior of the transverse ridges. 35 R e m a r k s: The critical criterion differentiating P. cooperi cooperi from P. costatus patulus is the presence of one or more transverse ridges:ertending laterally across the platform orin contact with the ca.rina. On this basis, all transitional forms between P. cooperi cooperi and P. costatus patulus are here classified as P. cooperi cooperi.The posterior end ofhe plat- form of representatives of P. cooperi cooperi is not arched as far downwards as are those of P. linguiforntis bultyncki. P. cooperi cooperi is also differentiated from P. linguiformis bultyncki by its lesser number of posterior transverseridges and its platform outline. The pit of P. cooperi cooperi is farther anterior than the pit of P. n. sp. B of Kiapper (1977). R a n g e: The first specimens of Polygnathus coopericooperi from the serotinus and costatus costatus Zones in Nevada(Kiapper and Johnson, 1980, Tables 6,7) were collected from samples VB-0, VB-3, and VB-4 (Table 5) in thenortheri AntelopeRange. P. cooperi cooperi was also found in samples of questionablezonal affinities between the serotinus and patulus Zones atSadler Ranch, Modoc Peak, and from samples NAB-3 and NAB-4 in the northern Antelope Range. Specimens of P. cooperi cooperi were found in the patulus at all three localities. Material: l3lspecimens. I 36 Polygnathus costatus KLAPPER, 1971 1971 Polygnathus costatus sp. nov. - KLAPPER, p. 62-63. 1973 Polygnathus costatus KLAPPER. - ZIEGLER, ed., p. 343, 347-350. 1978 Polygnathus costatus KLAPPER. - KLAPPER, ZIEGLER, & MASHXOVA, p. 108. D i a g n a s i s: For diagnosis, see Klapper (1971, p. 62). 37 Polygnathus costatus.costatus KLAPPER, 197]. P1. 3, Fig. 13-15 1971 Polygnathus costatus costatus. subsp. nov. * KLAPPER, p. 63, P1. 1, Fig. 30-36, P1. 2, Fig. 1-7. 1973 Polygnathus costatus costatusKLAPPER. - ZIEGLER, ed., P. 347-348, Polygnathus - P1. 1, Fig. 3. 1978 Polygnathus costatus costatus KLAPPER. - I & MASHKOVA, p. 109, P1. 2, Fig. 10-12. 1980 Polygnathus costatus costatus KLAPPER. - KLA?PER & JOHNSON, p. 452, Tables 7, 8. 1980 Polygnathus costatus costatus KLAPPER. - JOHNSON, KLAPPER, & TROJAN, Table 23, P1. 4, Fig. 14, 15, 17. i a g n a s i s: For diagnosis, see Kiapper (1971, p. 63). R e m a r k s: Polygnathus costatus costatus is distinguished from P. costatus patulus by its narrower platform, deeper ad- carinal grooves, and constricted anterior part of the platform. The round outline of the posterior platform differentiates P. costatus costatus from the sagittate outline of P. costatus partitus. P. sp. 3 has a wider platform posteriorly and shal- lower adcarinal grooves than in P. c. costatus. R a n g e: Specimens of Polygnathus costatus costa.tus were col- lected from the costatus costatus Zone in the northern Antelope Range. A questionable specimen of P. C. costatus was collected at Sadler Ranch (Table 1). M a t e r i a 1: 107 specimens. 38 Polygnathus costatus partitus KLAPPER,ZIEGLER, & MASHKOSIA, 1978 P1. 3, Fig. 10-12 KLAPPER, 1978 Polygnathus costatus partitus subsp. nov. - ZIEGLER, & MASHKOVA, p. 109, P1. 2,Fig. 1-5, 13. ZIEGLER, & MASHKOVA. - 1979Polygnathus costatus partitus IZLAPPER, LANE & ORMISTON, p. 61, P1. 7, Fig.7, 33. ZIEGLER, & MASHKOVA. - 1980 Polygnathus costatus partitus KLAPPER, KLPPEP. & JOHNSON, p. 452, Table 7. D i a g n 0 S i 5: For diagnosis, see Klapper,Ziegler, and Mashkova (1978, p. 109). R a n g e: The first specimens of Polygnathuscostatus partitus from Nevada were collected in this study.A single specimen, used to define the patulus Zone atSadler Ranch, was collected. the All other specimens of P. costatuspartitus were collected in northern Antelope Range in the patulusand costatuS costatus Zones. M a t e r i a 1: 12 specimens. 39 Polygnathus costatus patulus KLAPPER, 1971 P1. 3, Fig. 7-9 1971 Polygnathus costatus patulus subsp. nov. - KLAPPER, p. 62-63, P1. 1, Fig. 1-9, 29; P1. 3,Fig. 16-18. 1973 Polygnathus costatus patulus KLAPPER. - ZIEGLER, ed., p. 349-359, Polygnathus - P1.1, Fig. 6. 1978 Polygnathus costatus KLAPPER. - KLAPPER, ZIEGLER, & MASHKOVA, P. 109, P1. 2, Fig. 6-9, 14-17. 1980Polygnathus costatus patulus KLAPPER. - KLAPPER & JOHNSON, p. 452, Table 7. 1980 Polygnathus costatus patulus KLAPPER. - JOHNSON, KLAPPER, & TROJAN, Table 23, P1. 4, Fig. 13. D i a g n o s i s: Representative specimens of Polygnathus costatus patulus are distinguished by the wider platform,curved margins of the platform posteriorly, and characteristically by having shallower adcarinal grooves as compared with other P. costatus subspecies. There are no transverse ridges in contact with the carina or extending across the entire width of theplat- form. R e m a r k s: As compared with the present subspecies, Poly- gnathus costatus partitus has a posterior platform withstraight rather than curved margins. P. n. sp. B of Kiapper may or may not have transverse ridges that cross theplatform, and is differentiated from P. costatus patulus by the more posterior 40 position of the pit. R a n g e: Specimens of Polygnathus costatus patulus were found in the patulus Zone at Modoc Peak and in the patulus and costatus costatus Zones in the northern Antelope Range. Material: 17 specimens 41 Polygnathus kendaili JOHNSON & KLAPPER, 1981 P1. 4, Fig. 10, 11 1975 Polygnathus sp. A. KLAPPER & JOHNSON, p. 75, P1. 3, Fig. 3-7, 11-14. 1980 Polygnathus sp. A of KLAPPER & JOHNSON. - KLAPPER & JOHNSON, p. 454, Table 6. 1980 Polygnathus sp. A of KLAPPER & JOHNSON. - JOHNSON, KLAPPER, & TROJAN, Table 23, P1. 4, Fig. 1-3. 1981 Polygnathus kendalli ri. sp. - JOHNSON & KLAPPER, p. 1243, 1245, P1. 2, Fig. 5-7. D i a g n o S i s: For diagnosis, see Johnson and Kiapper (1981) R e in a r k 5: Polygnathus kendalli is closely related to P. serotinus, but differs "in that the pit of the former is larger and is located farther anteriorly" (Johnson and l(lapper, 1981, p. 1245). The higher outer margin and asymmetrical shelf on the outer, posterior side of the pit distinguish P. kendalli from P. linguiforinis bultyncki. R a n g e: Specimens of Polygnathus kendalli were found in the serotinus Zone at Sadler Ranch, Modoc Peak, and in the northern Antelope Range. Material: 60 specimens. 42 Polygnathus linguiformis HINDE, 1879 1879 Polygnathus linguiformis n. sp. - HINDE, p. 367, P1. 17, Fig. 15. 1977 Polygnathus linguiformis linguiformis HINDE. - ZIEGLER, ed., p. 461-470, Polygnathus - P1. 9, Fig. 6-8, Poly- gnathus - P1. 10, Fig. 1-10, Polygnathus- P1. 11, Fig. 1-7. R e m a r k s: Some representatives of Polygnathus lingui- formis, particularly smaller specimens, closely resemble P. cooperi. However, P. cooperi is distinguished by typically having fewer transverse ridges that cross the posterior part of the platform and a platform outline resembling that of P. costatus. Specimens of P. serotinus have a distinct tongue, but can be differentiated from P. linguiformis by the shelf- like protuberance on the outer side of the pit. 43 Polygnathus linguiformis bultynckiWEDDIGE, 1977 P1. 4, Fig. 6-9 1977 Polygnathus linguiformis bultyncki n. sSp.- WEDDIGE, p. 213-214, P1. 5, Fig. 90-92. 1980 Polygnathus linguiformis bultynckiWEDDIGE. - KLAPPER & JOHNSON, p. 453, Tables 6,7 (see synonymy). Di a g n0s i s: See Diagnosis inZiegler, ed. (1977, p. 462). R e m a r k s: Polygnathus linguiformis bultyncki can be dis- tinguished from P. linguiformis linguiformis theta morphotype by its narrower platform and relatively straight anterior mar- gins. R a a g e: Specimens of Polygnathus linguiformis bultyncki were found in the serotinus Zone at Sadler Ranch andModoc Peak. P. linguiformis buityncki was found in the serotiflus, patulus, and costatus costatus Zones in the northern Antelope Range. M a t e r i a 1: 193 specimens. 44 Polygnathus linguiformis linguiformis HINDE theta morphotype KLAPPER, 1980 P1. 5, Fig. 10, 11 1980 Polygnathus linguiformis linguiformis HINDE theta morpho- type. - JOHNSON, KLAPPER, & TROJAN, p. 102, P1. 4,.Fig. 35,36. D i a g n 0 s i S: Polygnathus linguiformis linguiformis theta morphotype is characterized by having a broad, flat platform with a curved arc-like outer margin. Its narrow adcarinal grooves deepen toward the anterior. The tongue is round and has trans- verse ridges, not all of which are continuous. Some transverse ridges may intersect the carina. The pit is small. R eina r k $ Polygnathus linguiformis linguiformis theta mor- photype is easily distinguished from P. linguiformis bulyncki by its wide platform outline, round tongue and curved, arc-like outer margin. Kiapper (in Johnson etal., 19801 noted Polygnathus linguiforznis linguiformis theta morphotype to be rare in the costatus costatus Zone in the available northernAntelopeRange collections; however, specimens are fairly common in sample NAB-li. R a n g e: Specimens of Polygnathus linguiformislinguiformis theta morphotype were collected in the costatus costatus Zone in the northern Antelope Range. Material: 17 specimens. 45 Polygnathus sérotinus TELFORD, 1975 P1. 4, Fig. 1-5 1975 Polygnathus foveolatus serotinus subsp.nov. - TELFORD, p. 43-44, P1. 7,Fig.5-8. 1975 Polygnathus sp. nov. D.- KLAPPER & JOHNSON, p. 7475, P1. 3, Fig. 1, 2, 8-10. 1977Polygnathus serotinus TELFORD.- ZIEGLER, ed., p. 495-496, Polygnathus - P1. 9,Fig.4,5. 1978 Polygnathus serotinusTELFORD. -KLAPPER, ZIEGLER, & MASHKOVA, P1. 1, Fig.9, 10, 30, 31. 1979Polygnathus serotinus TLFOBD.- CHATTERTON, p. 198, P1. 1, Fig. 23-25. 1979Polygnathus serotjnus TELFORD.- LANE & ORMISTON, p. 63, P1. 7,Fig.13, 37; P1. 8,Fig. 2,6, 8-10, 13-16, 19-22, 32-35. 1980Polygnathus serotinus TELFORD.- KLAPPER & JOHNSON, p. 454, Tables 6,7. 1980 Polygnathus serotinus TELFORD. - JOHNSON, (LAPPER, & TROJAN, Table 23. D i a g n o si S: For diagnosis, see Ziegler, ed. (1977, P. 495). R e mar k 5: Polygnathus serotinus is easily distinguished from any other coexisting Polygnathus speciesby the nature of the shelf-like protuberanceon the outer side of the pit. P. 46 kendalli is a closely related species which alsohas a protuber- ance, but it "is less well developed andmore asymmetrical in outline, and the keel is not so sharplydeflected posterior of the pit" in P. kendalli (Johnson andKlapper, 1981, p. 1245). Upper sides of P. linguiforinis bultyncid. and P.serotinus closely resemble each other in some specimens, butcan easily be. distin- guished by features of the lower side. P a n g e: Specimens of Polygnathus serotinus were colleäted in the serotinus and patulus Zonesat Sadler Ranch, Modoc Peak, and in the northern Antelope Range. P. serotinus was also found in the costatus costatus Zone? at Modoc Peak (Table2). Although P serotinus is known from other areas in Nevada from thecosta- tus costatus Zone (Kiapper and Johnson, 1980; Johnsonet al., 1980, Table 23; Klapper in Johnson etal., 1981,p. 823), no specimens were collected in this study from thiszone in the northern Antelope Range. M a t e r i a 1: 2823 specimens. 47 Polygnathus n. sp. B of KLAPPER, 1977 P1. 3, Fig. 1-3 1977 Polygnathus n., sp. B. - KLAPPER, p. 52 1980 Polygnathus n. sp. B of KLAPPER. - KLAPPER & JOHNSON, p. 454, P1. 4, Fig. 13, 14, 17, 18. 1980 Polygnathus n. sp. B of KLAPPER. - JOHNSON, KLAPPER, & TROJAN, Table 23. D i a g n 0 S i 5: Representatives of Polygnathus n. sp. B have a flat broad platform resembling that of P. laticostatus in upper view. Most specimens have a posterior end which is blunt rather than pointed. A small pit is located slightly anterior of platform midlength. Transverse ridges may cross the posterior part of the platform. R e in a r k- s: No specimens of Polygnathus laticostatus were found in this study to compare with P. n. sp. B. However, Kiapper and Johnson (1980, p. 413) note that the pit of P. n. sp. B is much smaller, although it is in the same position as in P. laticostatus. Polygnathus n,sp. B resembles P. cooperi cooperi and P. costatus patulus. The main criterion for differentiating P. n. sp. B from these species is the location of the pit nearer to platform midlength. R a n g e: Specimens of Polygnathus n. sp. B were found in the serotinus Zone at Sadler Ranch, Modoc Peak, and in the northern 48 Antelope Rnage. Material: 24specimens. Polygnathus sp. 1 P1. 5, Fig. 2-4 o e s c r i p t i 0 n: Representatives of Polygnathus sp. 1 have a relatively straight platformoutline with a sagittate posterior end. The marginal transverse ridgesare extremely strong and give the platform marginsa serrated outline. A prominent carina with distinctdenticles as high or higher than the lateral margins of the platformis present. The adcarinal grooves are narrow and relatively deep towards theanterior. A distinct keel extends the entirelength of the platform. The pit is of moderate size, locatedat about platform uiidlength. R eina r k s: Polygnathus robusticostatus hasa larger and higher blade with stronger denticlesand a wider platform than that of P. sp. 1. Material: 6 specimens. 50 Polygnathus sp. 2 P1. 5, Fig. 1,5 O e $ c r i p t i 0 n: Polygnathus sp. 2 has a flat platform with poorly developed adcarinalgrooves. The carina is high and extends about two-thirds of theway across the platform sur- face. The anterior third of the platform isarched. Blade size relative to the rest of theplatform cannot be determined with the present fragmentaryspecimens. Transverse ridges are faint. The keel traverses the platform, except whereinter- rupted by the pit, and is grooved anteriorly. The pit is large with symmetrical, lips and isnear the anterior end of the platform. R e in a r k s: No other identified specimens in this study closely resemble the leaf-like platforzw' elementof Polygnathus sp. 2. A third, smaller specimen from thesame sample may also be a representative of P. sp. 2, because it hasa similar pit and relatively flat platform. However, this specimen has a carina that appears to extend all theway across the platform (the extreme posterior is broken) andmore sharply defined trans- verse ridges. R a ii g e: Rare specimens of Polygnathus sp. 2 have been found in the northern Antelope Range in the patulusZone. A fragmen- tary specimen in NAB-7 resembles P.sp. 2 and would extend its range into the costatus costatus Zone. M a t e r i a 1: 3 specimens. 51 Polygnathus sp. 3 P1. 5, Fig. 6-8 R e m a r k s: Polygnathus sp. 3 closely resembles P. pseudo- foliatus in platform outline. However, specimens that have the blade preserved show a ratio of blade to total length of plat- form element of slightly less than a third. Unfortunately, no specimens of P. pseudofoliatus were collected in this study to compare with P. sp. 3. R a n g e: Specimens of Polygnathus sp. 3 were collected in the costatus costatus Zone in the northern Antelope Range. The range of P. pseudofoliatus would be lowered to include the costa- tus costatus Zone if these specimens represent this species (see Kiapper and Johnson, 1980, Tables 7-10). Material: lspecimens. 52 REFERENCES CITED Chatterton, B. D. E., 1979, Aspects of late Early and Middle Devoniari conodont biostratigraphy of western and north- western Canada: Geol. Assoc. Can. Spec. Pap., v. 18, p. 161-231 (imprint 1978). Clark, D. L. and R. L. Ethington, 1966, Conodonts andbiostra- tigraphy of the Lower and Middle Devonian of Nevada and Utah: 3. Paleontol., v. 40, p. 659-689. Hinde, G. J., 1879, On conodonts from the Chazy and Cincinnati Group of the Caxnbro-Silurian, and from the Hamiltonand Genesee-Shale divisions of the Devoriian, in Canada and the United States: Q. 3. Geol. Soc. London, V.35, p. 351-369. Johnson, D.. 3., 1978, Analysis of Lower Devonian conodontecol- ogy, Eureka County, Nevada: Unpubi. Ph.D. Diss. Univ. Iowa, Iowa City, 186 p. and G. Klapper,1981, New early Devonian conodont species of central Nevada: 3. Paleontol., v. 55, p. 1237-2350. Johnson, 3. G., G. D. Hildreth, G. W. Kendall, and W.R. Trojan, Biostratigraphy and biotopes of the lower Middle Devonian Leptathyris circula Zone, central Nevada: 3. Paleontol., v. 55, p. 814-825. G. Kiapper, and W. R. Trojan, 1980,Brachiopod and conodont successions in the Devonian of the northernAnte- lope Range, central Nevada: Geol. et Palaeontol., v. 14, p. 77-116. and N. G. Lane, 1969, Two new Devoniancrinoids from central Nevada: 3. Paleontol., v. 43, p. 69-73. and C. A. Sandberg, 1977, Lower and MiddleDevonian continental-shelf rocks of the western United States: Univ. Calif. Riverside, Campus Mus. Contribs., v. 4, p.121-143. Kendall, G. W., 1975, Some aspects of Lower andMiddle Devonian stratigraphy in Eureka County, Nevada:Unpubl. MS. Thesis, Oregon State Univ., Corvallis, 199 p. and J. G. Johnson, in press, Sadler RanchFormation at the carbonate shelf edge, Lower andMiddle Devonian of Nevada. 53 Kiapper, G., 1971, Sequence within the conodont genusPolygnathus in the New York lower Middle Devonian: Geol. et Palaeontol., v. 5, p. 59-79. ______,1977, Lower and Middle Devonian conodont sequencein central Nevada; with contributions by D. B.Johnson: Univ. Calif. Riverside, Campus Mus. Contribs., v.4, p. 35-54. and D. B. Johnson, 1975, Sequence inconodont genus Polygnathus in Lower Devonjan at Lone Mountain,Nevada: Geol. et Palaeontol., v. 9, p. 65-83. and J. G. Johnson, 1980, Endemism anddispersal of Devonian conodonts: 3. Paleontol., V. 54, p. 400455. and W. Ziegler, 1979, Devonian conodontbiostrati- graphy: Spec. Pap. Palaeontol. v. 23, p.199-224. -, and T. V.Mashkova, 1978, Conodonts and correlation of Lower-Middle Devonian boundarybeds in the Barrandian area of Czechoslovakia:Geol. et Palaeontol. V. 12, p. 103-115. Lane, H. R., and A. R. Ormiston, 1979,Siluro-Devonian biostra- tigraphy of the Salmontrout River area,east-central Alaska: Gaol. et Palaeontol., v. 13, p. 321-361. McGregor, D. C., and T. T. Uyeno, 1972, Devonianspores and cono- donts of Melville and Bathurst Islands,District of Frank- lin: Can. Geol. Surv. Pap. 71-13, 37 p. Orr, R. W., 1971, Conodonts from MiddleDevonian strata of the Michigan Basin. Indiana Gaol. Surv. Bull. 45, 110 p. Perry, D. G., G. Klapper, and A. C. Lenz,1974, Age of the Ogilvie Formation (Devonian), northernYukon; based pri- marily on the occurrence of brachiopodsand coriodonts: Can. 3. Earth Sci., v. 11, p. 1055-1097. Potter, E. C. 1975, Paleozoic stratigraphyof the northern Hot Creek Range, Nye County, Nevada: Unpubi. M.S. Thesis, Oregon State Univ., Corvallis, 129 p. Telford, P. G., 1975, Lower and MiddleDevonian conodonts from the Broken River Embayment, northQueensland, Australia: Spec. Pap. Palaeontol. 15, 96 p. 54 Trojan, W. R., 1978, Devonianstratigraphy and depositional environments of the northern AntelopeRange, Eureka County, Nevada: Unpubi. M.S. Thesis, Oregon State Univ.,Corvallis, 134 p. TLJyeno, T. T., arid D. Mason, 1975,New Lower and Middle Devonian conodonts from northern Canada: J. Paleontol., V. 49, p. 710-723. Weddige, K., 1977, Die Conodontender Eifel-Stufe im Typusgebiet und in benachbarten Faziesgebieten: Senckenbergiafla lethaea, v. 58,P. 271-419. Ziegler, W.(ed,), 1973, Catalogue of conodonts: E. Schweizer- bart'sche Verlagsbuchhandlung,Stuttgart, I, 504 p. ______(ed.), 1975, Catalogue ofconodonts: E. Schweizer- bart'sche Verlagsbuchhandlung,Stuttgart, II, 404 P. ______(ed.), 1977, Catalogue of conodorits: E. Schweizer- bart'sche Verlagsbuchhandlung,Stuttgart, III, 574 p. APPENDICES 55 Appendix I Number of Conodonts per Weighed Sample The number of conodont elements from each sample is given regardless of the specimen's state of preservation or taxonomic affinities. Sample Number Weight of Number of Number of (in sectional acidjzed rock conodonts conodonts sequence) (in grams) per kg VB-4 5431 456 84.0 VB-3 9524 872 91.6 VB-2 5603 507 90.5 V-1 6314 909 144.0 VB-0 8160 1314 161.0 Subtotal 35032 4058 115.8 NAB-il 8465 772 91.2 NAB-b 10963 259 23.6 NAB-9 9585 270 28.2 NAB-8 7736 500 64.6 NAB-13 5050 66 13.1 MAB-7 4686 112 23.9 NAB-12 8103 365 45.0 NAB-5 3265 69 21.1 NAB-6 6361 487 76.6 Subtotal 64214 2900 45.2 NAB-4 4583 578 126.1 NAB-3 5381 1513* 281.1 NAB-2 3991 832 208.5 NAB-i 9171 336 36.6 NAB-0 4307 340 78.9 Subtotal 27433 3599 131.2 Subtotal for the northern Antelope Range 126679 10557 83.3 * Due to sample size, not entirely collected. 56 SainplNuither Weight of Number of Number of (in sectional acidized rock conodonts condonts sequence) (ingrains) per kg MPB-'-ll 6137 253 41.2 MPB-10 12000 210 17.5 MPB-9 12000 20 1.7 MPB-8 10247 211 20.6 MPB-7 9378 146 15.6 MPB-6 6056 20 3.3 MPB-5 6593 54 8.2 MPB-4 7354 682 92.7 MPB-3 6420 350 54.5 MPB-2 8289 848 102.3 MPB-1 16500 72 4.4 MPB-0 4453 13 2.9 Subtotal 105427 2879 27.3 SRB-13 5127 143 23.1 SRB-12 8574 380 44.3 SRB-11 6102 227 37.2 SRB-10 4747 180 37.9 SRB-9 7176 703 98.0 SRB-8 5932 200 33.7 SRB-3 5892 116 19.7 SRB-7 3576 85 23.8 SRB-2 3355 30 8.9 SRB-6 5211 24 SRB-1 4666 225 48.2 SRB-5 3182 22 I6.9 SRB-4 8825 568 64.4 S1B-0 5212 22 4.2 Subtotal 77577 2925 37.7 Total 309683 16361 52.8 57 Appendix II Number of Specimens per Sample The following gives thenumber of specimens per sample of a particular type of conodont. Abbreviations include: I. - Icriodus, P. - Polygnathus,Pand. - Pandorinellina, B.- Eogna- thodus. "P. sp." and "I. sp." includeall Polygnathus and Icriodus platform elementsrespectively, new or unidentified species, indeterminate speciesdue topreservation, or juvenile specimens. Refer to Tables 1-5 concerningwhether a sample contains unidentified versus indeterminate species. "Other1' in- cludes all conodont elementsexcept platform elements and frag- ments where preservation hindersgeneric assignment. Only plat- form elements are countedhere in generic and specific assignments. SRB COLLECTION SRB-O SRB-4 SRB-5 SRB-1 P. serotinus 1 146 5 1 Panderodus sp. 14 166 10 143 P. kendalli - 2 1? 4 Belodella sp. - 57 2 8 Pand. exparisa - 3 - - P. linguiformis bultyncki - - - 1 P. n. sp. B of Kiapper - - - 3 "P. sp." 2 41 2 12 "i sp." - - - 1 "Other" 5 153 2 50 Total 22 568 22 225 58 SRB COLLECTION sRB-6 SRB-2 SRB-7 SRB-3 Panderodus sp. 6 7 35 42 P. kendalli 1? 3 4 3 Belodella sp. 1 - 4 3 Pand. expansa 1 - 2 5 P. linguiforinis bultyncki 1? - - - P. n. sp. B - - 1? I. trojani - - 5 - "P. sp." 2 4 7 5 ".L Sp." - - 3 8 "Other" 12 16 25 49 Total 24 30 85 116 SRB COLLECTION SRB-8 SRB-9 SRB-10 SRB-11 SRB-12 P. serotinus 4 201 5 - 4 Panderodus sp. 53 89 74 74 74 Belodella sp. 7 2 - 3 5 Pand. expansa 33 35 9 16 74 P. c. cooperi - - 2 1? 3 P. costatus partitus - - - - 1? "P. sp." - 173 8 2 33 "L sP." 19 1 - - - "Other" 84 202 82 131 186 Total 200 703 180 227 380 SRB COLLECTION SRB-l3 Panderodus sp. 12 Belodella sp.. 7 Pand. expansa 12 P. c. cooperi 2 "P.sp." 3 "Other" 107 Total 143 59 MPB COLLECTION MPB-O MPB-1 MPB-2 MPB-3 I. trojani 2 6 14 2 Belodella sp. 1 2 6 9 Panderodus sp. 5 29 39 81 I. latericrescens robustus - 4 1 1 serotinus - 1 242 57 P. Ienda11i - - 3 - P. n. sp. B of Kiapper - - 1 1 P. linguiformis bultyncki - - 1 - Pand. expansa - - 19 10 "P. sp." - 1 209 70 "I. Sp." 2 18 122 28 "Other" 3- 10 191 91 Total 13 72 848 350 MPB COLLECTION MPB-4 MPB-5 MPB-6 MPB-7 Belodella sp. 18 4 3 5 Panderodus sp. 97 9 - 6 P. serotinuS 15 -. - 2 P. linguiformis bultyneki 9 1 - - Pand. expansa 60 11 4 36 P. c. cooperi 49 - - - P. costatus patulus - - P.sp.1 - 1 - 2 " Sr." 202 1 - 4 "Other" 232 28 13 90 Total 682 54 20 146 MPB COLLECTION MPB-8 MPB-9 MPB-10 MPB-ll Belodella sp. 6 - 1 - Panderodus sp. 14 1 66 28 P. serotinus - 1 4 24 Pand. expansa 33 5 14 3 P. c. cooperi 2 - - - P. cOstatuS patulus - 2 - - P.sp.1 4 - - - P. c. costatus - - - 1? "P. sp." 23 4 7 88 "Other" 129 7 118 109 Total 211 20 210 253 NAB COLLECTION NAB-O NAB-i NAB-2 Pand. steinhornensjs subsp. indet. 6 - - P. cf. c. cooperi 1 - - P. kendalli 1 55 - I. latericrescens robustus 2 - 1 P. serotinus 1 - 459 Belodeila sp. 140 13 3 I. trojani 1 2 2 Panderodus sp. 112 68 15 P. linguiformis buityncki - 5 1 P.n.sp.B - - 17 Pand. expansa - - "P. Sr." 3 48 174 "1. S." 6 2 22 "Other" 67 143 129 Total 340 336 832 NAB COLLECTION NAB-3 NAB-4 P. serotinus 1174 110 Belodella sp. - 132 I. trojani - 3 Panderodus sp. 9 109 P. linguiformis bultyncki 10 1 Pand. expansa - P. c. cooperi 13 5 P. costatus cf. patulus 1 - "P. sp." 257 75 "j- SP." 2 2 "Other" 47 136 Total 1513 578 61 NAB COLLECTION NAB-6 NAB-S NAB-12 NAB-7 P. C. cooperi 15 - - - P. serotinus 100 5 - - P. costatus patulus 1 2 - 1 Pand. expansa 3 2 49 23 Panderodus sp. 89 5 31 3 Belodella sp. 62 - 19 15 P. linguiformis bultyncki 5 8 34 4 P. costatus partitus - - 4 - I. latericrescens robustus - - 1 - p. costatus costatus - - 8 3 "P. sp." 126 25 76 31 "I. sp." 4 - 7 - "Other" 82 22 136 32 Total 487 69 365 112 NAB COLLECTION NAB-13 NAB-B NAB-9 NAB-b P. costatus patulus - 2 - - Pand. expansa 5 6 - Panderodus sp. 3 15 16 15 Belodella sp. 6 11 20 36 P. linguiformis bultyncki 3 5 - - P. costatus partitus - 1 - - I. latericrescens robustus - 5 - - P. costatus costatus 2 13 3 3 I. norfordi - 131 69 45 I. n. sp. A of Chatterton - 20 9 4 B. bipennatus - - 3 - P. Liaguifortnis subsp. indet. - - 1 2 P. sp.3 - - - 1 ,,.. SP." 18 55 17 32 "I. sp." 1 151 99 94 "Other" 28 85 33 27 Total 66 500 270 259 62 NAB COLLECTION NAB-ll Belodella sp. 7 P. linguiformis bultyncki 3 I. latericrescens robustus 1 P. costatus costatus 60 I. norfordi 94 I. n. sp. A of Chatterton 33 P. 1. linguiformis theta morphotype 17 P. sp. 3 5 Pelekygnathus sp. 6 "!. SP." flJ 190 pU 71 "Other" 285 Total 772 VB COLLECTION VB-O VB-J. VB-2 VB-3 VB-4 P. keadalli 3 - - - P. n. sp. B of Klapper 1 - - - I. trojani 1 - - - - P. cf. c. cooperi 1 1 - - P. erotinus 209 52 - - - Pand. sp. indet. 1 - - - - P. c. cooperi 21 16 - 1? 1 P. linguiformis bultyncki 14 28 18 41 - Pand. expansa 24 51 38 161 2 Belodella sp. 101 44 43 226 9 Panderodus sp. 130 14j 63 60 8 P.sp.2 - 2 - - - P. a. sp. f. trigonicus - 1 - - - P. costatus partitus 3 - 3 - P. costatus patulus - 7 - 1 I. latericrescens robustus - - 1? 1 5 P. costatus costatus - - 5 4 3 I. norfordi - - - - 96 I. n. sp. A of Chatterton - - - - 11 P.sp.3 - - - - 1 "P. Sp." 512 251 142 112 57 "I. sp." 11 1 2 2 201 "Other" 285 304 195 260 62 Total 1314 909 507 872 456 63 Appendix III The following is a. list ofmarked section and sample nurn- bers observed and made in thefield. Many are from sections or parts of sections not of significanceto this study, but are recorded here for reference. The symbols "r" for red,"y" for yellow, and "w" for white referto the painted color of the sec- tion or sample number. Parentheses indicate that this particu- lar part of a sectionor sample number is not painted in the field, but is referred to in Trojan (1978), Johnson eta]..(1980), Kendall and Johnson (in press),this study, and work in progress (Johnson, person. commun.). Sadler Ranch (highest) (77-) "w" : + 8 "y" 5R2-l0 "y" J26-74 "y" 6 y1t (SRB-9) 2 "y" KDL-22 "'w" KDL27$ "W"; 5 "7" SR-8 "y"; SPI "y" J25-741 "7" -4 flyfi SRB-3 fly" (DL-2l "w" 10 "W" SRB-7 "y" J24-74 "y" J68-74 "7" SR-2 "y" 3 Iyfl (SRB-6) J67-74 "y" START "w" SRB-l3 flyft SRB-1 "y" (lowest) (77-) 9 uw" SRB-5 "7" SRB-12 "y" (SRS-4) J28-74 "y" (SRB_ll)DL261w!I SRB-0 "y"; KDL-25 "w" 64 ModocPeak Northem Antelope Range MPB-l1"y" (I 60 "y" Cv)930"y" MPB-l0"7" (I) "y" (11) 905"r" MPB-9"7" (V)810"y" MPB-8"y" (II)1472 "y" (V) 712"r" J14-73"y" (II)1185 "y" (V)645"y" MPB-7"y" (II)1070 "y" (V)430"y" MPB-6"y" (II)960 "y" (V) 300"y" MPB-5NY" (II)860 "y" (V) 220"r" MPB-4"y" (II)740 "y" (V)175"y" MPB-3"y" (II)685 "y" (11) 153"r" MPB-2"y" (II)427 "y" (11) 139"y" MP8-1"y" (II)290 "y" (V) 95 "y" MPB-0"y"; MP-1 "y" (II)255 "y" V84"y";(V) 60 "y" 113-73"y" (II)210 "y" 118-3"y" J19-79"y" (II)180 "y" VB-2"y" (II)x "y" yB-i"y" NorthernAntelope Range 118-0 "y" (I)715"y" (V)1360 "r" (V)x (I)680"y" (V) 1240 "y" (I)642"y" (V)1195 "y" (I) 400"y" (V)1150 "y" (I)230"y" (11) 1020 "i" (I)130"y" (V)960 "y" 65 Northern Antelope Range (Va) 150 "r" (VII) 185 "rfl (Va) 120 t1r" (Va) 71 "y" (X) 115 "r" (Va) 45 "y (X) 27 "r" (Va) 30 "r" (X) 17 "r" (Va) 16 "r" (X) 14 "r" (Va) 0 "r" (X) 13"r0 (X)0 "r" NAB-il "y" NAB-la "y" NAB-9IyU NAB-8!lyJf NAB-13 "y" NAB-7 11y1' NAB-12UyU NAB-5UyI NAB-6 "y" NAB-4UyU NAB-3 "y" NAB-2 "y" NAB-iUyU NAB-0 "y" Plate 1 SEM (Axnray, 1000A model, using tungsten filament) photographs. Magnifications are approximately xSO unless noted otherwise. All specimens from the northern Antelope Range, Nevada. Pandorinellina steinhornensis subsp. indet. Fig. 1, 2: Upper and lateral views, NAB-U, Table 3, serotinus Zone, Ca. xlOO. Fig. 3: Lower view, same sample as Fig. l,,ca. xlOO. Fig. 6, 7: Same specimens as Fig. 1, 2. Fig. 8: Same specimen as Fig. 3. Eognathodus bipennatus (BISCHOFF & ZIEGLER). Fig. 4, 5: Lateral and upper views, NAB-9, Table 4, costatus costatus Zone, ca. xlOO. Fig. 9, 10: Same specimens as Fig. 4, 5. Pandorinelj.jna expansa UYENO & MASON. Fig. 11, 15: Lower and lateral views, VB-3, Table 5, costatus costatus Zone. Fig. 13: Lateral view of 01 element, NAB-4, Table 3, serotinus Zone?. Fig. 16, 21: Upper and lateral view's, NAB-12, Table 4, costatus costatus Zone. Pelekysgnathus sp. Fig. 12: Upper view, NAB-9, Table 4, costatus costatus Zone, ca. xlOO. Fig. 14: Same specimen. as Fig. 12. Fig. 17, 19: Lateral and lower views, same sample as Fig. 12, ca. xlOO. Fig. 18, 20: Same specimens as Fig. 17, 19. 4' 13 5 I 8 9 U '5 .4J '9a 12' 0 .4- '(- 14 .\ p.. it - 1 I .-; ..; i \ '4' / c..P'4LH7''18 V. 68 Plate 2 SEM photographs. Magnifications areapproximately x50 unless noted otherwise. All specimens fromthe northern Antelope Range, Nevada except Fig. 1-6, 9. Icriodus trojani JOHNSON & KLAPPER. Fig. 1: Upper view, MPB-2, Table 2, serotinus Zone at Modoc Peak, ca. xlOO. Fig. 2: Same specimen as Fig. 1. Fig. 3,4: Lower and lateral views, same sample as Fig. 1. Fig. 5,6: Lateral views at different angles, same sample as Fig. 1. Icriodus latericrescenspbustus ORR. Fig. 7: Lower view, NAB-O, able 3, serotinus Zone. Fig. 8: Upper view, NAB-B, Table 4, costatus costatuS Zone. Fig. 9: Upper view, MPB-1, Table 2, serotinus Zone at Modoc Peak. Fig. 10: Lower view, same sample as Fig. 8. Icriodus norfordi CHATTERTON. Fig. 11, 17: Lateral and upper views, NAB-il, Table 4, costatuS costatus Zone. Fig.13: Upperview,samesampleasFig.11,17. Fig.14: Upperview,samesampleasFig.11,17. Fig.15: Upperview,samesampleasFig.11,17. Fig.16: Upperview,samesampleasFig.11,17. Fig.18: Lowerview,samesampleasFig.11,17. Fig.19: Lowerview,samesampleasFig.11,17. Fig.20: Lowerview,samesampleasFig.11,17. Icriodus n. sp. A of CHATTERTON. Fig. 12: Upper view, NAB-li, Table 4, costatus costatus Zone. 69 70 Plate 3 SEM photographs. Magnifications are approximately xSO. All specimens from the northern Antelope Range, Nevada. Polygnathus n. sp. B of KLAPPER. Fig. 1: Upper view, VB-0, Table 5, serotinus Zone. Fig. 2: Lower view, NAB-2, Table 3, serotinus Zone. Fig. 3: Lower view, same sample as Fig. 2. Polygnathus cooperi cooperi KLAPPER. Fig. 4: Lower view, VB-0, Table 5, serotinus Zone. Fig. 5: Upper view, same sample as Fig. 4. Fig. 6: Upper view, same sample as Fig. 4. Polygnathus costatus patulus KLAPPER. Fig. 7: Upper view, NAB.-6, Table 4, patulus Zone. Fig. 8: Upper view, NAB-8, Table 4, costatus costatus Zone. Fig. 9: Lower view, yB-i, Table 5, patulus Zone. Polygnathus costatus partitus KLAPPER, ZIEGLER, & MASHKOVA. Fig 10 Upper view, NAB-12, Table 4, costatus costatus Zone Fig. 11: Lower view, same sample as Fig. 10. Fig. 12: Upper view, VB-3, Table 5, costatus costatus Zone. Polygnathus costatus costatus KLAPPER. Fig. 13: Upper view, NAB-il, Table 4, costatus costatus Zone. Fig. 14: Upper view, same sample as F ig. 13. Fig. 15: Lower view, same sample as Fig. 13. 71 72 Plate 4 SEM photographs. Magnifications are approximately x50 unless noted otherwise. All specimens from the northern Antelope Range except Fig. 10. Polygnathus serotinus TELFORD Fig 1: Lower view, VB-0, Table 5, serotinus Zone, ca. xlOO. Fig. 2: Same specimen, as Fig. 1. Fig. 3: Upper view, same sample as Fig. 1, Ca. xlOO. Fig. 4: Same specimen as Fig. 3. Fig. 5: Upper view, VB-1, Table 5, patulus Zone. Polygnathus linguiformis bultyncki WEDDIGE. Fig. 6: Lower view, note P. serotinus-like pit, NAB-12, Table4, costatus costatus Zone. Fig 7: Lower view, NAB-6, Table 4, patulus Zone. Fig. 8: Upper view, VB-0, Table 5, serotinus Zone. Fig. 9: Upper view, same sample as Fig. 6. Polygnathus kendalli, JOHNSON & KLAPPER. Fig. 10: Upper view, SRB-4, Table 1, serotthus Zone at Sadler Ranch. Fig. 11: Lower view, VB-0, Table 5, serotinus Zone. Polygnathus sp. Fig. 12: Upper view, VB-0, Table 5, serotinus Zone. 73 74 Plate 5 SEM photographs. Magnifications are approximately x50. All specimens from the northern Antelope Range except Fig. 2-4. Polygnathus sp. 2 Fig. 1: Upper view, VB-1, Table 5, patulus Zone. Fig. 5: Lower view, same sample as Fig. 1. Polygnathus sp. 1 Fig. 2: Lower view, MPB-8, Table 2, patulus Zone at Modoc Peak. Fig. 3: Upper view, MPB-7, Table 2, patulus Zone at Modoc Peak. Fig. 4: Lower view, same sample as Fig. 2. Polygnathus sp. 3 Fig. 6: Upper view, NAB-ll, Table 4, costatus costatus Zone. Fig. 7: Upper view, same sample as Fig. 6. Fig. 8: Lower view, same sample as Fig. 6. Polygnathus sp. Fig. 9: Upper view, NAB-4, Table 3, serotinus Zone?. Polygnathus linguiformis linguiformis HINDE theta morphotype Fig 10 Upper view, NAB-il, Table 4, costatuS costatus Zone Fig. 11: Lower view, same sample as Fig. 10. 75 LT43O UU$ $TATEtflVERSTY. CVM.0 EXPLANATION,PLATE6 / DOLOMITE BRACHIOPODS CRINOIDS DOLOMITE I.. ! CORALS 1/ / SILTY-SANDY BRECCIATED :j: DOLOMITIC CHERT / QUARTZITE NODULES I UMESTONE f FAULT LIMESTONE 10 I 1 SILTY-SANDY SCALE IN FEET VB 2 SAMPLE NUMBER SAMPLE Drafted Dy EdwinB. Mowes (SRB-1I) NUMBER UNMARKED L43 30 UiIthUN $ThTE UMVER$ITY. CURVALU SADLER RANCH SECTION, PLATE 7 4' ? Zone 160 SRB-12 pa/If/us Zone 50 40: (SR8-II) KDL-26 130- 77-8 SRB-I0 I- 110 ? Zone z 2 (SRB-9) 2 I- 100 0 I 90 z0 80 I.LI -J0 (I) 70 SRB-8sr f- 50 SR8-3 SRB-7 40 sero//nus Zone 30 20 SRB-2 (SRB-6) J67-74 I0 SRB-1 SRB-5 (SRB-4)J28-74 0 SRB-0 KDL-25 Drafted by Edwin R. Ilowes Y. CRVALiJ 133o MODOC PEAK SECTION, PLATES 190 %/0/0 csf c/us costa/us Zone? 00/00 ooko/cD 180 MPB-l0 ''o/Go/00/0 e/oO ' one 170 0o/0/Eb o0/c,O ieo 0/0/0Q M °c/o ° /EkiVo 6 0/Q/oc, 150 o'o/ 0/0 ' pc/u/us Zone 140cI4'o%cf 0o/c/0 MPB-8 9,//. J14-73 o9'oE'oMPB-7 130 Ock -- o oo/°o/o1o%/ 120 p'o1o® 00/0/0 Efc,0/E/ o MPB-6 = G9/0R'o/o /° o 110 d0'Q0. Z o,00/ MPB-5 0/0/0 /0/0 ? Zon /01 (1) /1// 90 // // 80 S/ / // /./ MPB-4 MPB-3 serot/nusZone 30 MPG 2 MPG-I 20 W LtJ C-) C') 10 0 ? Zone 0 MPB-0 MPI Drofted by Edwin R. Howes LD33O OUESDN STATh Lfl4IVE1SITYI CWIVALUa NORTHERN ANTELOPE RANGE, PLATE 9 -'1 70 I0oI %1Qj__NABIISI.. 60 (TROJAN, 1978) o P NAB- 50 costa/us EIIE©Ilo)-71 costa/us Io# ( 40 >-w I Zone I°NAB-8 I oIG 40 wo0 30 VB-4 60 30 cr LU \ ° II-45 20( E!°::: pa/u/us 20 0 NAB 4 ( 3O H! I Zone ( LU :.. serot/nus ?\\ pa/u/us 0 NAB-3 :!.:.1:i.\ Zone e (I) Zon H)-30 -J 2oH I0oJ_NAB6 0 0 \. 0 _\_ NAB-2 \ VB-0 io serof/nus \ NAB-i Zone \ sero//nus Zone 0 LNAB-0 < 16\ Drafted by Edwin R. Howes