Pennsylvanian and Permian Stratigraphy of the Northern Argus Range and Darwin Canyon Area, California
U.S. GEOLOGICAL SURVEY BULLETIN 1691
Pennsylvanian and Permian Stratigraphy of the Northern Argus Range and Darwin Canyon Area, California
By PAUL STONE, CALVIN H. STEVENS, and ROBERT T. MAGGINETTI
U.S. GEOLOGICAL SURVEY BULLETIN 1691 DEPARTMENT OF THE INTERIOR DONALD PAUL HODEL, Secretary
U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director
UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1987
For sale by the Books and Open-File Reports Section U.S. Geological Survey Federal Center, Box 25425 Denver, CO 80225
Library of Congress Cataloging-in-Publication Data
Stone, Paul. Pennsylvanian and Permian stratigraphy of the northern Argus Range, Darwin Canyon area, California.
(U.S. Geological Survey Bulletin 1691) Bibliography Supt. of Docs. No.: 119.3:1691 1. Geology, stratigraphic-Pennsylvanian. 2. Geology, stratigraphic-Permian. 3. Geology-California-Argus Range region. I. Stevens, Calvin H. II. Magginetti, Robert T. Ill. Title. IV. Series: U.S. Geological Survey Bulletin 1691. QE75.B9 No. 1691 557.3 s 86-600364 [QE673] [551.7'52'0979487] CONTENTS
Abstract 1 Introduction 1 Overview of the stratigraphy and stratigraphic nomenclature 1 Underlying rocks 1 Pennsylvanian rocks 1 Permian rocks 3 Overlying rocks 4 Tihvipah Limestone 4 Osborne Canyon Formation 5 Darwin Canyon Formation 7 Millers Spring Member 10 Panamint Springs Member 11 Regional extent of the Tihvipah Limestone, Osborne Canyon Formation, and Darwin Canyon Formation 12 Depositional history 12 References cited 13 Measured sections 14
FIGURES
1. Location map of region between Owens and Death Valleys, California 2 2. Chart showing comparison of stratigraphic nomenclature in northern Argus Range and Darwin Canyon area and southern lnyo Mountains, California 3 3. Geologic map of northern Argus Range and Darwin Canyon area, California, showing locations of measured sections 6 4. Measured stratigraphic sections 1-5 9
ID
Pennsylvanian and Permian Stratigraphy of the Northern Argus Range and Darwin Canyon Area, California
By Paul Stone, Calvin H. Stevens, and Robert T. Magginetti
Abstract formational rank instead of two-a basal unit of Pennsylvanian age and two units of Permian age--and The 2-km-thick Pennsylvanian and Permian that the Pennsylvanian and Permian rocks are stratal sequence in the northern Argus Range and separated by a major disconformity not previously adjacent Darwin Canyon area is herein divided into documented. We here describe these three units and three formations: the Lower and Middle Pennsylvanian introduce new formational names for two of them. We Tihvipah Limestone, originally described in the also present a geologic map of the northern Argus Cottonwood Mountains (northern Panamint Range) 50 Range and Darwin Canyon area, showing the locations km to the northeast, and the herein-named Lower of measured sections discussed in the text, and graphic Permian Osborne Canyon and Darwin Canyon columns of the measured sections. Written Formations, both of which are herein included in the descriptions of the sections follow the main text. newly revised Owens Valley Group. The Darwin Canyon Formation is divided into the herein-named Millers Spring and Panamint Springs Members. The OVERVIEW OF THE STRATIGRAPHY AND Tihvipah Limestone, which disconformably overlies the STRATIGRAPHIC NOMENCLATURE Upper Mississippian Santa Rosa Hills Limestone, is composed of cherty micritic limestone that was Underlying Rocks deposited on a deep carbonate ramp. The disconformably overlying Osborne Canyon Formation is Pennsylvanian rocks in the northern Argus Range composed of calcareous mudstone, bioclastic and Darwin Canyon area disconformably overlie about limestone, limestone conglomerate, and minor 200 m of massive light-gray limestone that Hall and calcareous siltstone that were deposited in slope and MacKevett (1962) and Hall (1971) mapped as the Lee basinal environments. The conformably overlying Flat Limestone, which they considered to be Darwin Canyon Formation is composed of very fine Mississippian and Pennsylvanian(?) in age. We here grained sandstone, bioclastic limestone, limestone reassign these rocks to the Upper Mississippian Santa conglomerate, and mudstone that were deposited in a Rosa Hills Limestone as defined by Dunne and others basinal environment. Unnamed marine strata of Early (1981), with which they are both lithologically and Triassic age overlie the Darwin Canyon Formation stratigraphically equivalent, and geographically along an angular unconformity that represents an restrict the Lee Flat Limestone from the area of this episode of uplift and tilting during which at least 1,000 report (fig. 2). This restriction follows the usage of m of strata was removed in places by subaerial Dunne and others (1981), who considered the Lee Flat erosion. to be a valid unit only at its type locality (fig. 1), where they demonstrated it to be a local member of the Perdido Formation (which underlies the Santa Rosa Hills Limestone) and thus not equivalent to the unit INTRODUCTION that previous workers have called the Lee Flat Limestone in the northern Argus Range and Darwin Sedimentary rocks of Pennsylvanian and Permian Canyon area. age are widely exposed in the northern Argus Range and the adjacent Darwin Canyon area in east-central California (fig. 1). In mapping these areas, Hall and PeiUlSylvanian Rocks MacKevett (1962) and Hall (1971) assigned these rocks to the Pennsylvanian and Permian Keeler Canyon Lying disconformably above the Santa Rosa Hills Formation and the Permian Owens Valley Formation, Limestone in the northern Argus Range and Darwin which Merriam and Hall (195 7) had defined in the Canyon area is a 100- to 125-m-thick sequence of nearby southern Inyo Mountains. As part of a regional dark-gray cherty limestone of Pennsylvanian age. This stratigraphic study, we recently examined the limestone is characterized by the abundance of small Pennsylvanian and Permian sequence in the northern spherical chert nodules that previous workers have Argus Range and Darwin Canyon area in greater detail called golfball chert. Pennsylvanian cherty limestone than had been done in the past. Our work has shown sequences of similar lithology and thickness are that this sequence consists of three units of present throughout much of the region between Owens
Overview of tbe Stratigraphy and Stratigraphic Nomenclature 1 ',,\
\ \ \ I \ '
\ '\ \ J..... \ \ I () I I I /0 Type locality -; \~(,y / .A \<< 1. ~ \~~ \)\ ~---:_
~ ~ L_ () '1 a EXPLANATION () 0 a ~ Paved rood '1 -:n ---- Unpaved road G) ~ v't- c (j) -z_ () -\ Warm Spring ~ 0 Canyon ( v .( A ~ ~~ \ \ AREA OF MAP v't \"f\ () ~ ~ 0 10 20 KILOMETERS
Figure 1. Region between Owens and Death Valleys, California, showing area discussed in report (see figure 3) and other localities mentioned in text. and Death Valleys (McAllister, 1952, 1956; Merriam Valley region was the Tihvipah Limestone, which was and Hall, 1957; Hall and MacKevett, 1962; Ross, 1965; used by McAllister (1952) for a sequence exposed near Hall, 1971; Moore, 1976; Stone, 1984; Stone and Quartz Spring in the Cottonwood Mountains (fig. 1). Stevens, 1984). Later, Merriam and Hall (1957) considered a The first formal name applied to a Pennsylvanian correlative cherty limestone sequence exposed in the cherty limestone sequence in the Owens Valley-Death southern Inyo Mountains as the informal lower member
2 Pennsylvanian and Permian Stratigraphy, Northern Argus Range and Darwin Canyon Area, California SOUTHERN INYO NORTHERN ARGUS RANGE-DARWIN CANYON AREA MOUNTAINS AGE MERRIAM AND HALL (1957l; ROSS HALL AND MACK EVETT THIS REPORT (1965); STONE AND STEVENS (1987) (1962); HALL(I971) ~ ~~· ....,.... t.l? .l~l l .I lJ J ~ -rl..,- ...... t.l? ~ ~1-llJJ < -;:: Unnamed marine strata c::::- 0 Unnamed marine strata ~ w ...... _., _.,_., ...... , ~ ~ Q) 0. Conglomerate Mesa ::::J Owens -0 0 Formation ...J ~ 1--- (!) Valley ~ ~~ ~ ~.....r- !"'~~ ,...,.,_ _,... z >. PUft rr-""-~ Q) Formation' >. Pan am in t <{ Q) Darwin - - - Springs Mbr. ~ 0 - Canyon >. 0 0. Millers a:: - > Lone Pine > ::::J w ~ 0 Formation Spring Mbr. 0 (/) (/) ~ a.. w c Formation Q) ~(!) 3: 3: Osborne Canyon Formation 0 0 ,...._ ~ ..._, ~ ...... ~r-- ~
z ...... Q) <{ 0 Keeler - ...J Keeler z 1--- Canyon Q) <{ - Canyon Formation 2 > "0 ...J "0 Formation .....__. ~ ...... ,...... ~~~ ~ ...... ~ >- ~ (/) 1--- z >. Tihvipah Limestone z ~ 0 w ...... a.. w .._,...,__ ...... ?.....r- ...... ~ ...... r~
.,.... ~ u) ~ ...... L ~ (/) ~ Rest Spring Shale Lee FIat Limestone 3 - 0 Santa Rosa Hi II s Limestone ~ ...J I Age given as Permian in reports cited. 2 Age given as Middle Pennsylvanian to Lower Permian in reports cited. 3Age given as Mississippian and Pennsylvanian(?) in reports cited. Figure 2. Comparison of stratigraphic nomenclature used in this report with that used by previous workers in the northern Argus Range and Darwin Canyon area and southern Inyo Mountains, California.
of the Pennsylvanian and Lower Permian Keeler considered the cherty limestone sequence in the Canyon Formation, rather than assigning this sequence northern Argus Range and Darwin Canyon area to be to the previously defined Tihvipah Limestone. part of the Pennsylvanian and Lower Permian Bird Following Merriam and Hall (195 7), Hall and Spring Formation, the type locality of which is in MacKevett (196 2) and Hall (1971) mapped the southern Nevada (Hewett, 1931). That assignment was Pennsylvanian cherty limestone sequence exposed in based on correlation with cherty limestone of similar the northern Argus Range and Darwin Canyon area as lithology and age ascribed by Stone (1984) and Stone the lower part of the Keeler Canyon Formation. Our and Stevens (1984) to the lower part of the Bird Spring work, however, has shown that the rocks mapped by Formation at Panamint Butte in the southern Hall and MacKevett (1962) and Hall (1971) as the upper Cottonwood Mountains and at Warm Spring Canyon in part of the Keeler Canyon Formation in the northern the southern Panamint Range (fig. 1). Argus Range and Darwin Canyon area are not similar in either lithology or age to the upper part of the type section of that formation, and that the name Keeler Permian Rocks Canyon is not applicable in this area. We therefore geographically restrict the Keeler Canyon Formation The Tihvipah Limestone in the northern Argus from the area of this report and reassign its strata in Range and Darwin Canyon area is disconformably this area to the Tihvipah Limestone (thus encompassing overlain by rocks of Early Permian age that have a the Pennsylvanian cherty limestone sequence exposed maxim urn thickness of about 1,900 m and comprise two here within the Tihvipah) (fig. 2). This usage of the units of formational rank. The lower unit, about 350m Tihvipah supersedes the nomenclature proposed by thick, is composed of mudstone, bioclastic limestone, Stone (1984) and Stone and Stevens (1984), who and limestone conglomerate; it encompasses most of
Overview of the Stratigraphy and Stratigraphic Nomenclature 3 the rocks previously mapped as the upper part of the as a means of establishing a formal tie between these Keeler Canyon Formation by Hall and MacKevett formations and the age-equivalent Lone Pine (1962) and Hall (1971). The upper unit consists of two Formation. In addition, the name Owens Valley has parts: (1) a lower part about 475 to 600 m thick and been established in the northern Argus Range and composed mainly of thick-bedded, very fine grained Darwin Canyon area for more than 20 years, and sandstone, bioclastic limestone, and limestone retaining the name at the group level provides conglomerate and (2) an upper part about 1,000 m in continuity in stratigraphic nomenclature. maximum thickness and composed mainly of thin bedded, very fine grained sandstone. This unit encompasses most of the rocks previously mapped as Over lying Rocks the Owens Valley Formation by Hall and MacKevett (1962) and Hall (1971). The Darwin Canyon Formation is overlain with Our work has shown that all of the Permian rocks angular unconformity by more than 800 m of marine in the northern Argus Range and Darwin Canyon area strata from which Lewis and others (1983) reported are age correlative with parts of the Owens Valley Early Triassic fossils. These unnamed marine strata Formation as originally defined in the southern lnyo originally were mapped as part of the Owens Valley Mountains. In contrast to previous interpretations, we Formation by Hall and MacKevett (1962). The angular believe that there are no rocks in this area that unconformity separating the Darwin Canyon Formation correlate in either lithology or age with the upper part and the Triassic marine strata spans the geologic time of the Keeler Canyon Formation, a sequence of interval represented by the Conglomerate Mesa bioclastic limestone more than 800 m thick. It is now Formation, which consists of coarse-grained clastic clear that the geologic time interval represented by rocks, in the southern Inyo rv-Iountains (fig. 2). the upper part of the Keeler Canyon Formation at its type locality (late Middle Pennsylvanian to earliest Permian) is spanned by the disconformity between the Tihvipah Limestone and the overlying Permian rocks in TIHVIP AH LIMESTONE the northern Argus Range and Darwin Canyon area. The rocks mapped as the upper part of the Keeler The Tihvipah Limestone, which is here Canyon Formation by Hall and MacKevett (1962) and geographically extended into the northern Argus Range Hall (1971) are not only distinctly younger than that and Darwin Canyon area (and additional areas noted unit, but contain proportionately more mudstone and later), is a cliff-forming unit ranging in thickness from less limestone and have more diverse and variable approximately 100 to 125 m. It is 121 m thick in lithology than that unit. measured section 1 in upper Osborne Canyon on the In a companion study to this one, Stone and east side of the northern Argus Range (figs. 3, 4). The Stevens (1987) have raised the Owens Valley Formation sharp, disconformable contact between the dark to group rank in the southern Inyo Mountains where it colored well-bedded Tihvipah Limestone and the consists of two newly named formations--the Lower underlying light-gray massive Santa Rosa Hills Permian Lone Pine Formation and the Upper Permian Limestone is one of the most conspicuous formational Conglomerate Mesa Formation--separated by an boundaries in Paleozoic rocks exposed between Owens angular unconformity (fig. 2). Our work has shown and Death Valleys. that the Permian rocks exposed in the northern Argus The Tihvipah Limestone consists primarily of Range and Darwin Canyon area are approximately the medium- to dark-gray micritic limestone that contains same age as the Lone Pine Formation, but differ abundant nodular, lenticular, and thinly bedded dark markedly in lithology from that formation. The Lone gray chert. Spherical chert nodules (golfball chert) are Pine Formation, which has a maximum thickness of especially diagnostic of the unit. Garlow (1984) about 1,000 m, consists mainly of dark-colored, thin showed that much of the chert in the formation bedded calcareous mudstone, lacks sandstone like that contains poorly preserved radiolarians. Tremolite present in the northern Argus Range and Darwin produced by widespread low-grade metamorphism is Canyon area, and contains only a minor amount of common in the limestone. The cherty limestone is bioclastic limestone. This difference in lithology interbedded with light-gray to light-brown silty or precludes the use of the name Lone Pine Formation in argillaceous limestone commonly metamorphosed to the northern Argus Range and Darwin Canyon area and fine-grained calc-hornfels. Typically, cherty necessitates the introduction of new formational limestone ledges 1 to 5 m thick alternate with names. We herein introduce the new name Osborne relatively thin recessive intervals of silty or Canyon Formation for the lower of the two Pa-mian argillaceous limestone. Bedding within the cherty units present in this area, and the new name Darwin limestone itself is defined mainly by beds, lenses, and Canyon Formation for the upper unit (fig. 2). We also aligned nodules of chert that divide otherwise uniform introduce the new name Millers Spring Member for the limestone intervals into even layers 10 to 50 em lower part of the Darwin Canyon Formation and the thick. A well-bedded appearance results. Also present new name Panamint Springs Member for the upper in the Tihvipah Limestone are rare beds 40 em to 1.5 part. Previously, Stone and Stevens (1984) used the m thick of bioclastic limestone and limestone informal names Formation B and Formation C for the conglomerate composed of poorly sorted echinoderm al units herein named the Osborne Canyon and Darwin debris, coral and bryozoan fragments, and limestone Canyon Formations, respectively. clasts suspended in a micrite matrix. We include both the Osborne Canyon and Darwin The Tihvipah Limestone locally shows evidence Canyon Formations in the Owens Valley Group mainly of large-scale soft-sediment deformation. Slump
4 Pennsylvanian and Permian Stratigraphy, Northern Argus Range and Darwin Canyon Area, California features that evidently formed during or shortly after distance from the underlying cliff-f cr ming Tihvipah deposition are particularly well developed in upper Limestone. Osborne Canyon a short distance north of measured The type section of the Osborne Canyon section 1 (fig. 3). Formation has a measured thickness of 346 m and Pennsylvanian cherty limestone sequences in the consists of three locally mappable, informally Owens Valley-Death Valley region, including the designated members (in ascending order, members A, sequence here assigned to the Tihvipah Limestone in B, and C). Member A, 52 m thick, is composed the northern Argus Range and Darwin Canyon area, primarily of light-gray to light-brown, plane-laminated have long been regarded to be of Atokan (early Middle calcareous siltstone; member B, 137 m thick, is Pennsylvanian) age based on the widespread composed mainly of light-gray to light-brown, massive occurrence of the fusulinid Fusulinella in their upper to vaguely bedded calcareous mudstone; member C, parts (McAllister, 1952; Merriam and Hall, 1957 Hall 157 m thick, is composed mainly of light-gray to light and MacKevett, 1962; Hall, 1971; Moore, 1976; Stone, brown, evenly bedded and laminated calcareous 1984). However, Morrowan (Early Pennsylvanian) mudstone. In addition to these slope-forming fine conodonts are now known to be present a few meters grained rocks, all three members contain randomly above the base of one such sequence exposed in the spaced resistant beds of medium- to dark-gray southern Darwin Hills (H.R. Lane and R.H. Miller, coarsely bioclastic limestone and limestone written commun., 1976), and also in the lower part of conglomerate. The base of the formation is placed at another such sequence exposed at Marble Canyon in the base of a limestone conglomerate bed that sharply the Cottonwood Mountains (J.E. Repetski, written overlies the highest cherty limestone bed in the commun. in Stone, 1984). On the basis of lithologic Tihvipah Limestone. The low-angle trW1cation of beds correlation with these sequences, we consider the at the top of the Tihvipah Limestone reflects erosion ·Tihvipah Limestone in the northern Argus Range and along this contact. The top of the formation, which Darwin Canyon area to range in age from Early into also is sharp, is placed at the base of the lowest thick Middle Pennsylvanian. In addition, correlative cherty sequence of brown-weathering, very fine grained limestone sequences that are regarded as the lower sandstone in the overlying Darwin Canyon Formation. part of the Keeler Canyon Formation in the southern The predominantly clast-supported bioclastic Inyo MoW1tains (Merriam and Hall, 1957; Ross, 1965) limestone and limestone conglomerate beds in the are here considered to range into the Early Osborne Canyon Formation have sharp bases and tops Pennsylvanian, rather than being restricted to the and range in thickness from 10 em to 7.5 m. Many Middle Pennsylvanian as has been previously thought graded beds show the Ta and Tb divisions of the Bouma (fig. 2). sequence. Clasts as large as 10 em in diameter consist We interpret the Tihvipah Limestone as having of echinodermal debris, fusulinids, other bioclasts, and accumulated in moderately deep water on a gently micritic limestone fragments. Coral fragments are sloping carbonate ramp. This interpretation is based present in a few beds near the top of the formation. on the fine grain size and dark color of the limestone, Limestone beds in members A and B of the type the abundance of chert containing radiolarians, the section are highly lenticular, commonly have erosive apparent absence of in-place benthic fossils, and the bases, and appear to be confined to channels. In presence of slump features. The rare matrix contrast, limestone beds in member C are planar, supported limestone conglomerates in the formation laterally extensive sheets. probably were deposited as debris flows. Most of the calcareous mudstone in member B of the type section is massive and contains inclusions of micritic limestone that have irregular, gradational contacts with the enclosing matrix. These inclusions appear to have been incorporated into the matrix before lithification. Some of the inclusions are OSBORNE CANYON FORMATION randomly distributed and appear to be redeposited clasts; others are aligned in wavy or convolute The Osborne Canyon Formation is here named patterns that probably developed by soft-sediment after Osborne Canyon, the northernmost major canyon deformation of bedding. In contrast, most of the on the east side of the Argus Range (fig. 1). This calcareous mudstone in member C is thinly and evenly formation disconformably overlies the Tihvipah bedded. Some of the mudstone in member C contains Limestone and is conformably overlain by the Darwin abundant dark-gray spherical to subspherical limestone Canyon Formation. The type section of the formation nodules or concretions that are aligned parallel to is located in measured section 1 (figs. 3, 4), high on the bedding. east side of the Argus Range above Osborne Canyon (in Less than 1 km south of the type section, a SW 1/4 sec. 13, T. 19 S., R. 41 E., Panamint Butte 15- lenticular body of massive limestone conglomerate minute quadrangle) about 7 km south of Panamint about 75 m thick occurs at the base of the Osborne Springs. Canyon Formation. This conglomerate appears to The Osborne Canyon Formation is composed of replace member A of the type section along strike and calcareous mudstone, bioclastic limestone, limestone evidently occupies a channel bounded laterally by beds conglomerate, and minor calcareous siltstone. The of member A. Southward along strike, the most characteristic features of the formation are the conglomerate rapidly decreases in thickness to only a abundance of mudstone and the presence of coarse few meters. grained limestone. The generally slope-forming The Osborne Canyon Formation is characterized Osborne Canyon Formation is easily distinguished at a by pronounced lateral variations in thickness and
Osborne Canyon Formation 5 lithology. For example, a section of the formation Leptotri tici tes? sp. near the eastern base of the Argus Range just outside Schwagerina aff. §_. wellsensis Thompson the area of figure 3 is only about 120 m thick; it and Hansen comprises about 60 m of pink to maroon calcareous Schwagerina spp. mudstone overlain by about 60 m of thick-bedded Pseudofusulina? aff. limestone conglomerate. Despite such variations, the P. loringi Thompson formation is easily recognized throughout and beyond Pseudoschwagerina uddeni Beede and Kniker the report area on the basis of its general lithology and Stewartina? sp. consistent stratigraphic relations. Eoparafusulina cf • .§_. linearis (Dunbar We have identified the following fusulinids from and Skinner) limestone beds at several horizons in the type section Eoparafusulina sp. of the Osborne Canyon Formation: Cuniculinella sp.
36° 17' 30" ~ ~~~v .. ~~~~~~~~~~ · ?~+~-~~t ~~~H~~+H•~-~~~~~
2 KILOMETERS
Figure 3. Geologic map of northern Argus Range and Darwin Canyon area, California, showing locations of measured sections discussed in text. See figure 1 for location of map. Base from U.S. Geological Survey, 1:62,500, Darwin, 1950; Panamint Butte, 1951 (contour interval 40 feet). Geology mapped in 1980-1981. Dikes mapped by G.C. Dunne.
6 Pennsylvanian and Permian Stratigraphy, Nortbern Argus Range and Darwin Canyon Area, California This fusulinid assemblage indicates a middle a change from a channeled slope environment to an Wolf cam pian age (Maggin etti, 19 83; Stone, 19 84). The unchanneled basin-floor environment. presence of Pseudoschwagerina and Eoparafusulina in In light of the relatively deep-water marine collection RTM-2 about 9.5 m above the base of the origin of both the Osborne Canyon Formation and the formation (fig. 4) 'indicates that no part of the underlying Tihvipah Limestone, we interpret the formation in the type section is older than middle disconformity between them to have resulted from Wolfcampian in age. Therefore, the disconformity submarine erosion or nondeposition on the slope rather between the Osborne Canyon Formation and the than from subaerial erosion. This interpretation is underlying Tihvipah Limestone represents most or all st.pported by the lack of pronounced angular of Late Pennsylvanian and earliest Permian time. discordance between the two formations and by the We interpret the Osborne Canyon Formation to nearly constant thickness of the Tihvipah Limestone have accumulated in deep-water marine slope and throughout the study area. basinal environments. We consider the limestone beds in the formation to be sediment-gravity-flow deposits derived from carbonate shelves or banks upslope from the site of deposition. The abundance of soft-sediment deformation features in mudstones of the lower part of DARWIN CANYON FORMATION the formation (member B) strongly suggests a slope environment. The lenticular limestone beds in The Darwin Canyon Formation is here named members A and B, including the massive lens of after Darwin Canyon, the major canyon between the limestone conglomerate at the base of the formation northern Argus Range and the Darwin Hills (fig. 1). just south of the type section, probably are slope This formation conformably overlies the Osborne channel deposits. The lateral continuity of limestone Canyon Formation and is unconformably overlain by beds in the upper part of the formation (member C) unnamed marine strata of Early Triassic age. and the general lack of soft-sediment deformation We here divide the Darwin Canyon Formation features in the associated mudstones probably reflect into two formally named members, the Millers Spring
EXPLANATION IPt Tihvipah Limestone (Middle and Lower Pennsylvanian)--Medium- to dark-gray, thin- to thick-bedded micritic limestone Qa Alluvium and talus (Quaternary) with abundant nodular, lenticular, and bedded chert; subordinate light-gray to Tv Volcanic rocks (Tertiary) light-brown silty or argillaceous limestone KJg Leucocratic granitoid rocks (Cretaceous? and Jurassic)--Quartz monzonite and granite Ms Santa Rosa Hills Limestone (Upper Mississippian)--Light-gray massive Jd-/ Mafic to intermediate dikes (Jurassic)- limestone Correlated with Independence dike swarm Mp Perdido Formation (Mississippian)--Dark-gray Jgb Gabbro, granodiorite, and minor quartz limestone and thin-bedded chert monzonite (Jurassic?) MOm Marble (Mississippian and (or) Devonian)- RS Marine sedimentary rocks (Lower Triassic)- Presumably correlative with the Devonian Light-brown calc-hornfels and gray Lost Burro Formation and (or) the marble; minor siltstone and shale; sandy Mississippian Tin Mountain Limestone, limestone and calcareous sandstone in Perdido Formation, and Santa Rosa Hills lowermost part Limestone Owens Valley Group (Lower Permian)--In this area, consists of: Contact Darwin Canyon Formation--Divided into: Fault--Dashed where approximately located, Pdp Panamint Springs Member--Brown, thin-bedded dotted where concealed. Arrows show siltstone and very fine grained relative movement direction sandstone; medium- to dark-gray limestone in lowermost part -t- Anticline Pdm Millers Spring Member--Brown, thick-bedded, very fine grained sandstone and medium Syncline--dashed where approximately located to dark-gray, thin- to thick-bedded -t- bioclastic to conglomeratic limestone Strike and dip of beds Po Osborne Canyon Formation--Light-gray to 60 light-brown, thin-bedded to massive _j_ Inclined calcareous mudstone and medium- to dark gray, thin- to thick-bedded bioclastic to Horizontal conglomeratic limestone; minor calcareous siltstone Line of measured section Figure 3. Continued. Darwin Canyon Formation 7 UJU.IOJ!f83 'ua.JV UOAU1l3 U!M.IUfi puu alJullll sn.S.Jv U.I3Qt-JON '{qdu.IliJl&llS UU!W.Jad pUB UU!UUA{ASUUacJ 8
PERMIAN ~TRIAS. Early ~Early = OWENS VALLEY GROUP c.n= ------~~= DARWIN CANYON FORMATION :~~ 1 MILLERS SPRING MEMBER PANAMINT SPRINGS MEMBER ~ ~~~~Unit! ~~~~~ Unit6 ~IIUnit,Basallime-J.::j ~1 ~~---: ~~~ ~;;:; 5 A] B ~~ D ] E 7 stone unit
HH c c ,..,., u-1
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:11:_:::_:_.:b (r\3\ ... :-:~:-. 0 b \Q)) ~-.~ >:: I
.:~/.~.{~tittf:~::::~~ J.:.td :.. ·: ·: H11+t8 ::-:..J~~ ~® ... :_·._:: .. :·'. :'_;.. z ·;::a..r.> ·:::~>·:,\·.. ·}::;.'· :·:-.~· 0 0::~ ~ - I- II) ...... 0 ~ ;tl ·- ...... <( WI~ I ~ ••:: :{:1'11850 ~ 0:: ~ ~ ~ 0 r<") /:~:::~).:}: LL :.. ·.:.:·: DCB z ~ ~ .:::::·.:_:·~-: 0:: C'J ·: ': :: :': 0 EXPLANATION >- a...... a.. z (f) ·;; II I 7 5 rl\ ::J <( (f) = II155 ~ DC3 Limestone 0 u 0:: 0::: ·.: .. ·.·:·· ~ m 0 z w ~ - _j . ::; _j Cherty limestone ~I >- 0::: ""' >. w <( ~I~ m - _j 0 2 lo... _j Silty and sandy w0 <( z ~ limestone rr > 0 u ~OCI6 I- Bioclastic limestone and w (f) <( ~ lo J..O J o_ z Q) limestone conglomerate w ~ ..0 l:i £-;-.0: 0:: E ~- OCI5 ::; 0 Limestone conglomerate Q) ~==-- 0 LL ~ ~~T<5To Mud supported z 0 t:ioTolOI-OCI4 >- rn So nd s to ne - Th i c k be dd ed , z II) ~~~; very fine grained <( I:D:ID LG u Q) fi7~~ Sandstone- Thin bedded, w ..0 -:::: :::-:::: F3 E F.:.---~ ~ very fine grained z Q) ~ 0::: 0 ~ II) ~ Siltstone (f) ~ 0 Member A
Q) ~ Mudstone- Plane bedded '0 I w ~ z i z:l>.~ w ~ z: -;::~ > ~ 0 Mudstone- Massive to L..LJ 0 - 1- ~ -..... •;· o..... W-u I _j ..- irregularly bedded c: - (f) ·'r.I~J-: ~ n 0 I- I» ;1~-' ~~~ = I"-"""' <( <( (f) I 1-- Correlation line ~ uj (]) I- (f) _j w 0::: ~ = (/) -o 2 o_j~ 10 Pennsylvanian and Permian Stratigraphy, Northern Argus Range and Darwin Canyon Area, California following taxa: submarine debris-flow deposits that resulted from collapse of large segments of the shelf and slope Schwagerina aculeata Thompson and adjacent to the basin. The lateral continuity of the Hazzard limestone units, and of many individual beds, strongly Schwagerina elkoensis? Thompson suggests that deposition took place on a generally and Hansen featureless basin floor. Schwagerina aff. §_.~lata Thompson Sandstone beds in the Millers Spring Member Schw~~rina aff. §_. thomp~~ll!. Needham probably are sediment-gravity-flow deposits akin to Schwag~~~na spp. turbidites, as indicated by their lateral continuity and Pseudofusulina? aff. their association with limestone turbidites and debris ~? lori.!!fj_ Thompson flow deposits. However, these beds differ from typical Chusenella compacta (White) turbidites in at least three important respects: they Paraschyv-agerina sp. lack a muddy matrix and Bouma sequences, they Pseu_2osch~agerina sp. generally lack flute and groove casts, and they are Stewartina. moranensis (Thompson) much more strongly and pervasively crosslaminated Stewa.rtiriasp:---- than typical turbidites of comparable thickness. Their Stewartina? spp. exact mechanism of deposition is unclear. Eoparafusl!lina cf • .§_. linearis (Dunbar and Skinner) Panamint Springs Member Cuniculinella spp. The Panamint Springs Member of the Darwin Canyon Formation is a lithologically homogeneous unit Collections from units 5 and 6 yielded the following composed mainly of light-brown, thin-bedded, very taxa: fine grained sandstone and siltstone. It is distinguished from the unaerlying Millers Spring Member by its Schwagerina ~uleata Thompson and consistently thin bedding and by its general lack of Hazzard coarse-grained limestone. ~chwa~ina cf. §_. crebrisepta Ross The Panamint Springs Member, where not ~hwagerina diversifor!fiiS Dunbar and covered at the top by alluvium or Tertiary volcanic Skinner rocks, is overlain with angular unconformity by Schwagerina elkoensis Thompson and Hansen unnamed Triassic marine strata (fig. 3). The best Schwag_erina cf. §_.~!~Thompson exposure of this unconformity is on a cliff face in Schwagerina aff. §_. thompsoni Needham Darwin Canyon immediately south of the Darwin fault, Schwagerina cf. §_. weJ:.!~~nsi~ Thompson and where thick-bedded sandy limestone and calcareous Hansen sandstone of Early Triassic age overlie the Panamint ~hwagerina spp. Springs Member with an angular discordance of about Chusenella sp. 15°. Owing to this angular relationship with the Pseudoschwagerina uddeni (Beede and overlying rocks, the Panamint Springs Member ranges Kniker) in thickness from zero in the western part of the Pseudoschwagerina ~~Thompson report area to about 1,000 m a short distance east of Pseudoschw!!_gerina sp. the area. The type section of the member in Darwin Stewartina sp. Canyon (measured section 2D) is 372 m thick. Chalarosc1iwagerina sp. Although the stratigraphic relations of the Parafusulina sp. Panamint Springs Member are clearly revealed in the type section, the lithologic features of the member are These fusulinid assemblages indicate a middle to somewhat obscure there as a result of late Wolfcampian age. Fusulinid assemblages from metamorphism. The original lithology of the member units 2 and 4 lack typical late Wolfcampian taxa and is better displayed in the vicinity of measured section are considered middle Wolfcampian in age. The 3 south of the Darwin fault (fig. 3). There, the assemblages from units 5 and 6 contain the typical late member is composed mainly of very fine grained Wolfcampian fusulinids Schwagerina cf. §_. crebriseeta, sandstone and siltstone in laterally extensive, graded, Schwa erina diversiformis, and C~aroschwagerina sp. laminated and crosslaminated beds 2 to 15 em thick. Magginetti, 1983; Stone, 1984}. We interpret the Many of these beds show the Ta, Tb, and Tc divisions presence of Parafusulina, a typical Leonardian genus, of the Bouma sequence. Beds are either amalgamated in one collection (1410, unit 5, measured section 4) as or are separated by mudstone partings that are an unusually early occurrence of this genus; the generally less than 1 em thick. Bedding is very even fusulinids in this collection, although redeposited, do and planar, although the basal surfaces of some beds not appear to have been significantly reworked. show evidence of scour. Most beds are composed of We interpret the Millers Spring Member to about 50 percent detrital quartz and feldspar and represent deposition in a deep-water marine basinal about 50 percent detrital and recrystallized calcite. environment, primarily because of the presence of Locally interbedded with the thin-bedded sandstone Bouma sequences in the clast-supported limestone and siltstone are relatively thick (20 em to 1 m) beds beds. These beds evidently are turbidites that were of coarse-grained sandstone containing chert pebbles derived from carbonate banks or shelves upslope from and silicified reworked fusulinids. Such beds, most of the site of deposition. We interpret the thick, matrix which are graded, are particularly common in the supported beds such as those in units 2 and 6E as lower part of the member. Darwin Canyon Formation 11 The lowermost part of the Panamint Springs Sections that we here regard as belonging to the Member is a distinctive unit of medium- to dark-gray, Tihvipah and which are nearly identical in lithology generally fine-grained calcarenitic limestone and and thickness to that occurring in the area of this light-gray, brown, and pink mudstone. This unit, which report are present at Knight and Bendire Canyons in has a measured thickness of 65 m in the type section the central Argus Range, the southern Darwin Hills, of the Panamint Springs Member, sharply overlies the and the Santa Rosa Hills (fig. 1). Hall and MacKevett highest thick-bedded sandstone unit in the Millers (1962) and Moore (1976) assigned these sections to the Spring Member. Locally, as in Darwin Canyon south of Keeler Canyon Formation, while Stone and Stevens the Darwin fault, the basal limestone unit is deformed (1984) alternatively assigned them to the Bird Spring by conspicuous folds that do not extend into the Formation. At Knight and Bendire Canyons, as in the enclosing sandstone beds. Although the lithology of report area, the Tihvipah Limestone rests directly on this limestone unit is atypical of the Panamint Springs the Santa Rosa Hills Limestone; in the southern Member, its base is the most objective horizon on Darwin Hills and the Santa Rosa Hills, a thin sequence which to define the base of the member. The basal of Upper Mississippian sandstone and shale lies limestone unit grades upsection into the thin-bedded between the Tihvipah and Santa Rosa Hills siltstone and sandstone that composes the rest of the Limestones. At Marble Canyon in the southern member. Cottonwood Mountains, cherty limestone similar in Within the immediate report area (fig. 3), the lithology to that of the Tihvipah Limestone forms the only fossils we have obtained from the Panamint major part of a Pennsylvanian section more than 600 m Springs Member are reworked fusulinids from a pebbly thick. This section, which Stone and Stevens (1984) sandstone bed 336 m above the base of the member in assigned to the Bird Spring Formation, overlies a thin measured section 3 (collection 11300). This collection sequence of Upper Mississippian sandstone and shale contains a typical late Wolfcampian fusulinid like that in the Santa Rosa Hills and southern Darwin assemblage that includes Schwa.g_~ri~ diversiformis Hills. As previously noted, cherty limestone Dunbar and Skinner, Sch~agerina cf. §_. crebrise~ lithologically similar to the Tihvipah Limestone forms Ross, ~~oschwageri~~ sp., and Ps~udoschwager!!!!!. the lower part of the Bird Spring Formation in the convexa Thompson. A short distance west of the southern Cottonwood Mountains and the southern report area, in the northern Darwin Hills, a similar Panamint Range, and the lower part of the Keeler pebbly sandstone bed somewhat lower in the member Canyon Formation in the southern Inyo Mountains. contains Para~~lina in addition to late Wolfcampian The Osborne Canyon and Darwin Canyon species of Schwagerina and Pseudoschwagerina. This Formations can be recognized at Knight and Bendire bed evidently is late Wolfcampian in age with an Canyons in the central Argus Range, in the Darwin unusually early occurrence of Parafusulina. At least Hills, and at Marble Canyon in the central Cottonwood part of the thick sequence of unfosshiferous siltstone Mountains (fig. 1), where they encompass some of the and sandstone in the Panamint Springs Member above rocks heretofore mapped as the Keeler Canyon and our fusulinid collections probably is Leonardian in age. Owens Valley Formations by Hall and IVIacKevett The Panamint Springs Member represents (1962), Stadler (1968), Johnson (1971), and Moore deposition in a deep-water marine basinal (1976). Rocks similar in general lithology and age to environment, as indicated by the dominance of thin the Osborne Canyon and Darwin Canyon Formations graded sandstone and siltstone beds of apparent are present in the northern Santa Rosa Hills and the turbidite origin. The absence of coarse-grained Conglomerate Mesa area in the southeastern Inyo limestone like that in the Millers Spring Member Mountains (Stone and Stevens, 1984). However, the indicates that the basin was no longer flanked by stratigraphy of the rocks in the northern Santa Rosa carbonate shelves and banks. This change in the shelf Hills and Conglomerate Mesa area differs sufficiently margin probably also resulted in the pronounced from that of the Permian section in the northern Argus decrease in average sandstone-bed thickness in the Range and Darwin Canyon area that, in our opinion, Panamint Springs Member relative to that in the the names Osborne Canyon and Darwin Canyon should Millers Spring Member. During deposition of the not be extended there. Rocks similar in lithology and Millers Spring Member, basin-rimming carbonate age to the Osborne Canyon Formation overlie the Bird buildups may have ponded sand prior to its discharge Spring Formation at Panamint Butte in the southern into the basin, resulting in high-volume sand flows and Cottonwood Mountains, and rocks that may correlate thick beds. The lack of such buildups during deposition with the Osborne Canyon Formation overlie the Bird of the Panamint Springs Member would have prevented Spring Formation at Warm Spring Canyon in the the ponding of sand, resulting in smaller sand flows and southern Panamint Range (Stone and Stevens, 1984). thinner beds. DEPOSfi'IONAL HISTORY REGIONAL EXTENT OF THE TIHVIP AH LIMESTONE, During the Late Mississippian, the report area OSBORNE CANYON FORMATION, AND DARWIN was part of a broad, shallow carbonate shelf upon CANYON FORMATION which the Santa Rosa Hills Limestone accumulated (Dunne and others, 1981). In Early and Middle The Tihvipah Limestone and numerous Pennsylvanian time, a substantial rise in relative sea correlative cherty limestone sequences can be level resulted in the deposition of the Tihvipah recognized throughout the region between Owens and Limestone in moderately deep, quiet water. This sea Death Valleys (Stone, 1984; Stone and Stevens, 1984). level rise probably was caused, at least in part, by 12 Pennsylvanian and Permian Stratigraphy, Northern Argus Range and Darwin Canyon Area, California tectonic subsidence of the shelf. Increased subsidence Lewis, Michael, Wittman, Charles, and Stevens, C.H., in Late Pennsylvanian and earliest Permian time led to 1983, Lower Triassic marine sedimentary rocks in the development of an unstable slope upon which no east-central California, in Marzolf, J.E., and Dunne, net sedimentation took place. Sediment accumulation G.C., eds., Evolutio~ of early Mesozoic resumed in middle Wolfcampian time with deposition tectonostratigraphic environments--southwestern of the Osborne Canyon Formation disconformably on Colorado Plateau to southern Inyo Mountains: Utah the Tihvipah Limestone and continued through late Geological and Mineral Survey Special Studies 60, p. Wolfcampian and probably into Leonardian time with 50-54. deposition of the Darwin Canyon Formation. Lico, M.S., 1983, Lower Permian submarine sediment Channeled slope environments prevalent in the report gravity flows in the Owens Valley Formation, area during the early phases of Permian sedimentation southeastern California: San Jose, Calif., San Jose were replaced by unchanneled basin-floor State University, M.S. thesis, 80 p. environments as the depositional system matured. The McAllister, J .F., 1952, Rocks and structure of the area subsequently was uplifted, tilted, and subjected to Quartz Spring area, northern Panamint Range, an episode of subaerial erosion during which at least California: California Division of Mines Special 1,000 m of strata (the maximum thickness of the Report 25, 38 p. Panamint Springs Member) was strippea away in 1956, Geology of the Ubehebe Peak quadrangle, places. Regional studies (Stone, 1984; Stone and -ciiifornia: U.S. Geological Survey Geological Stevens, 1984) sugg-est that uplift occurred primarily in Quadrangle Map GQ-95, scale 1:62,500. late Early or early Late Permian time, prior to the Magginetti, R. T., 1983, Fusulinid biostratigraphy of deposition of the Upper Permian Conglomerate Mesa the Darwin Canyon and Conglomerate Mesa areas, Formation outside the boundaries of the report area. Inyo County, California: San Jose, Calif., San Jose In response to renewed subsidence beginning in the State University, M.S. thesis, 417 p. Early Triassic, marine sediments were deposited Merriam, C.W., and Hall, W.E., 1957, Pennsylvanian unconformably on the tilted and erosionally truncated and Permian rocks of the southern Inyo Mountains, Lower Permian rocks. California: U.S. Geological Survey Bulletin 1061-A, 13 p. Moore, S.C., 1976, Geology and thrust fault tectonics of parts of the Argus and Slate Ranges, Inyo County, REFERENCES CITED California: Seattle, Wash., University of Washington, Ph.D. dissertation, 128 p. Dunne, G.C., Gulliver, R.M., and Stevens, C.H., 1981, Ross, D.C., 1965, Geology of the Independence Correlation of Mississippian shelf-to-basin strata, quadrangle, Inyo County, California: U.S. eastern California: Geological Society of America Geological Survey Bulletin 1181-0, 64 p. Bulletin, Part II, v. 92, p. 1-38. Stadler, C.A., 1968, The geology of the Goldbelt Spring Garlow, R.A., 1984, Stratigraphy, petrology, and area, northern Panamint Range, Inyo County, paleogeographic setting of the Middle Pennsylvanian California: Eugene, Ore., University of Oregon, Tihvipah Limestone of southeastern California: San M.S. thesis, 7 8 p. Jose, Calif., San Jose State University, M.S. thesis, Stone, Paul, 1984, Stratigraphy, depositional history, 134 p. and paleogeographic significance of Pennsylvanian Hall, W.E., 1971, Geology of the Panamint Butte and Permian rocks in the Owens Valley-Death Valley quadrangle, Inyo County, California: U.S. region, California: Stanford, Calif., Stanford Geological Survey Bulletin 1299, 67 p. University, Ph.D. thesis, 399 p. Hall, W.E., and MacKevett, E.M., Jr., 1962, Geology Stone, Paul, and Stevens, C.H., 1984, Stratigraphy and and ore deposits of the Darwin quadrangle, Inyo depositional history of Pennsylvanian and Permian County, California: U.S. Geological Survey rocks in the Owens Valley-Death Valley region, Professional Paper 368, 87 p. eastern California, in Lintz, Joseph, Jr., ed., Hewett, D.F., 1931, Geology and ore deposits of the Western geological e"ieursions, v. 4: Geological Goodsprings quadrangle, Nevada: U.S. Geological Society of America, Field Trip Guidebook, 1984 Survey Professional Paper 162, 172 p. annual meeting, p. 94-119. Johnson, E. A., 1971, Geology of a part of the Stone, Paul, and Stevens, C.H., 1987, Stratigraphy southeastern side of the Cottonwood Mountains, of the Owens Valley Group (Permian), southern Inyo Death Valley, California: Houston, Tex., Rice Mountains, California: U.S. Geological Survey University, Ph.D. dissertation, 81 p. Bulletin 1692. References Cited 13 MEASURED SECTIONS {LOCATIONS SHOWN ON FIG. 3) Section 1. Tihvipah Limestone; type sections of the Osborne Section 1: Lower Permian--Continued Canyon Formation and unit 1 of the Millers Spring Member of Darwin Canyon Formation--Continued the Darwin Canyon Formation. Measured on the east side of the Argus Range above Osborne Canyon in July 1981. Thickness meters Incomplete thickness Darwin Canyon Thickness Formation •••••••••••••••••••••••••••••••• 121.9 meters Darwin Canyon Formation (Lower Permian) Conformable contact. (incomplete): Osborne Canyon Formation (Lower Permian): Millers Spring Member (incomplete): Member C: Unit 2 (basal bed; not measured): 62. Mudstone, calcareous, light gray; Limestone conglomerate, poorly exposed ••••••••••••••••••••••• 5.0 bioclastic, medium gray ••••••••••••• 61. Limestone, dark gray; one bed Unit 1: (Bouma Ta); grades from bioclastic 9. Sandstone (25 percent) and cover limestone conglomerate at base to (75 percent). Sandstone, light-gray calcisiltite at top; quartzose, variably calcareous contains limestone clasts to 3 em and calcarenitic, gray to brown in diameter, broken fasciculate on weathered surface, very fine rugose corals to 5 em in diameter, grained; in beds 15 to 80 em thick; and fusulinids ••••••••••••••••••••••• 4.2 commonly plane laminated, less 60. Mudstone, calcareous, light gray; commonly crosslaminated and limestone beds (fine-grained convolute laminated. Covered calcarenite; Bouma Tb) 14 and intervals 60 em to 1.8 m thick ••••• 5.6 40 em thick present 4.0 and 5.4 m 8. Limestone; one bed (Bouma Tab); above base of interval ••••••••••••••• 6.6 grades from coarse-grained echino 59. Limestone; one bed (Bouma Ta); dermal calcarenite at base to silty grades from dark-gray bioclastic calcisiltite at top •••••••••••••••••• 1.8 limestone conglomerate at base to 7. Sandstone (50 percent) and cover light-gray calcareous mudstone at (50 percent), as in 9. Sandstone, top; contains limestone clasts to in beds 30 em to 1.7m thick; mean 4 em in diameter, coarse echino bed thickness about 1.0 m. Covered dermal debris, and fusulinids; upper intervals 10 em to 2.0 m thick •••••• 20.2 part of bed contains micritic lime stone clasts. Fusulinid collection 6. Interval occupied by cross-cutting 0Cl6: Stewart ina? sp., dike ••••••••••••••••••••••••••••••••• 3.5 Cuniculinella sp ••••••••••••••••••••• 1.7 5. Sandstone (45 percent) and cover (55 percent), as in 9. Sandstone, 58. Covered interval; light-gray calcareous mudstone scree •••••••••••• generally highly calcareous and 2.5 calcarenitic; in beds 10 em to 57. Limestone; one bed (Bouma Tab); 1.0 m thick; mean bed thickness grades from coarse-grained bio about 50 em. Covered intervals clastic calcarenite at base to 20 em to 1m thick ••••••••••••••••••• 14.3 laminated fine-grained calcar- enite at top; contains fusulinids •••• 0.6 4. Interval occupied by cross-cutting dike ••••••••••••••••••••••••••••••••• 3.0 56. Covered interval ••••••••••••••••••••• 3.5 3. Sandstone (60 percent), mudstone 55. Hudstone, calcareous, light gray, (5 percent), and cover (35 percent), massive; small dark-gray limestone as in 9 except for mudstone. Sand clasts present in basal 80 em •••••••• 4.5 stone in beds 15 em to 1.5 m thick; 54. Limestone, dark gray; one bed mean bed thickness about 60 em. Mud (Bouma Tab); grades from coarse stone, gray, pink, and brown; in beds grained bioclastic calcarenite at 1 to 70 em thick between sandstone base to fine-grained calcarenite beds. Covered intervals 20 em to at top; contains fusulinids •••••••••• 0.3 1.0 m thick•••••••••••••••••••••••••• 60.9 53. Mudstone, calcareous, light gray; 2. Interval occupied by cross-cutting poorly exposed ••••••••••••••••••••••• 3.0 dike ••••••••••••••••••••••••••••••••• 3.5 52. Limestone (calcarenite), dark gray, 1. Sandstone (65 percent), mudstone (20 percent), and cover (15 percent), as fine grained; one bed (Bouma Tbc) •••• 0.6 in 3. Sandstone in beds 20 to 70 em 51. Covered interval ••••••••••••••••••••• 0.2 thick; mean bed thickness about 50. Limestone (calcarenite), dark gray, 40 em. Mudstone in beds 5 to fine grained; one bed (Bouma Tb) ••••• (J.l 50 em thick. Covered intervals 10 to 40 em thick ••••••••••••••••••••••• 9.1 49. Mudstone, calcareous ••••••••••••••••• 0.1 Total thickness unit 1...... 121.9 48. Limestone (calcarenite), dark gray; one bed (Bouma Tab); grades from Incomplete thickness Millers Spring medium grained at base to fine Member ••••••••••••••••••••••••••••••••••• 121.9 grained at top ••••••••••••••••••••••• 0.1 14 Pennsylvanian and Permian Stratigraphy, Northern Argus Range and Darwin Canyon Area, California Section 1: Lower Permian--Continued Section 1: Lower Permian--Continued Osborne Canyon Formation--Continued Osborne Canyon Formation--Continued Member C--Continued Member C--Continued Thickness Thickness meters meters 47. Covered interval ••••••••••••••••••••• 1.7 contains limestone clasts to 5 em 46. Limestone, dark gray; one bed in diameter, coarse echinodermal (Bouma Ta); grades from coarse debris, and fusulinids ••••••••••••••• 2.4 grained bioclastic (largely 34. Mudstone, calcareous, light gray; echinodermal) calcarenite at base poorly exposed ••••••••••••••••••••••• 2.3 to medium-grained calcarenite at top; contains broken fasciculate 33. Limestone, dark gray; one bed rugose corals •••••••••••••••••••••••• 2.0 (Bouma Tabc); grades from coarse grained echinodermal calcarenite 45. Mudstone, calcareous, light gray to at base to fine-grained calcarenite light brown; poorly exposed •••••••••• 3.0 at top; upper part of bed convolute 44. Limestone, dark gray; one bed laminated ••••••••••••••••••••••• • • • • • 0.9 (Bouma Tab); grades from bioclastic 32. Mudstone, calcareous, light gray; limestone conglomerate at base to poorly exposed ••••••••••••••••••••••• 2.0 laminated fine-grained calcarenite at top; contains limestone clasts 31. Limestone, dark gray; one bed to 12 em in diameter, coarse echino (Bouma Tb); grades from fine-grained dermal debris, and broken fasciculate calcarenite at base to calcisiltite rugose corals; spherical limestone at top ••••••••••••••••••••••••••••••• 0.2 cobbles in lower part of bed may be 30. Mudstone, calcareous, light gray; reworked concretions ••••••••••••••••• 2.0 poorly exposed ••••••••••••••••••••••• 2.5 43. Mudstone, calcareous, light brown; 29. Limestone (calcisiltite), contains limestone concretions; light gray; one bed •••••••••••••••••• 0.6 poorly exposed; one bed of lam inated calcisiltite 8 em thick 28. Mudstone, calcareous, light gray; present 11.5 m above base of interbedded with brown siliceous interval ••••••••••••••••••••••••••••• 23.6 mudstone; poorly exposed ••••••••••••• 1.4 42. Limestone; one bed (Bouma Tab); 27. Limestone, dark gray; one bed grades from coarse-grained bio (Bouma Tab); grades from coarse clastic (largely echinodermal) grained bioclastic (largely calcarenite at base to laminated echinodermal) calcarenite at base calcisiltite at top; contains to calcisiltite at top; contains broken fasciculate rugose corals fusulinids ••••••••••••••••••••••••••• 0.9 2.5 and fusulinids••••••••••••••••••••••• 26. Limestone (calcarenite), bioclastic 41. Mudstone, siliceous, brown; (largely echinodermal), coarse contains gray limestone concretions; grained; one ungraded bed (Bouma subordinate light-gray calcareous Ta); contains fusulinids; capped muds tone • •••••••••••••••••••••••••••• 1.2 by 2 em of mudstone •••••••••••••••••• 0.8 40. Mudstone, calcareous, light gray; 25. Covered interval ••••••••••••••••••••• 3.0 contains rare limestone concretions 24. Limestone; one bed (Bouma Tab); in lower 6.5 m; poorly exposed; grades from dark-gray, coarse one bed of laminated calcisiltite grained echinodermal calcarenite 40 em thick 6.5 m above base of at base to light-gray calcisil- inte~al ••••••.•••••••••••••••••••••• 10.2 tite at toP•••••••••••••••••••••••••• 0.8 39. Limestone, dark gray; one bed 23. Covered interval ••••••••••••••••••••• 1.3 (Bouma Tab); grades from bioclastic limestone conglomerate at base to 22. Limestone; one bed (Bouma Tab); laminated calcisiltite at top; grades from dark-gray coarse contains limestone clasts to 2 em grained bioclastic calcarenite in diameter and fusulinids. at base to light-gray laminated Fusulinid collection OC15: calcisiltite at top; capped by Schwagerina spp., Stewartina? sp., 5 em of siliceous mudstone ••••••••••• 0.6 Leptotriticites? sp., Eoparafusulina 21. Mudstone ••••••••••••••••••••••••• •. • • 0.1 cf. E. linearis •••••••••••••••••••••• 3.5 20. Limestone, dark gray; one bed 38. Mudstone, calcareous; poorly (Bouma Tab); grades from coarse exposed •••••••••••••••••••••••••••••• 2.0 grained bioclastic calcarenite 37. Limestone (calcarenite), medium at base to laminated medium gray, medium grained; one bed •••••••• 0.4 grained calcarenite at top; contains fusulinids •••••••••••••••••• 0.4 36. Mudstone, calcareous, light gray ••••• 0.8 19. Covered interval ••••••••••••••••••••• 1.0 35. Limestone, dark gray; one bed (Bouma Tab); grades from bioclastic 18. Mudstone, calcareous, plane laminated; limestone conglomerate at base to contains dark-gray limestone laminated calcisiltite at top; concretions •••••••••••••••••••••••••• 0.6 Measured Sections 15 Section 1: Lower Permian--Continued Section 1: Lower Permian--Continued Osborne Canyon Formation--Continued Osborne Canyon Formation--Continued Member C--Continued Member C--Continued Thickness Thickness meters meters 17. Mudstone, siliceous, brown, thin at base to laminated fine-grained bedded; contains dark-gray limestone calcarenite at top; contains concretions to 5 em in diameter; fusulinids. Fusulinid collection poorly exposed ••••••••••••••••••••••• 1.7 OC14: Schwagerina aff. S. wellsensis, Schwagerina sp...... 2.0 16. Limestone, medium gray; one bed (Bouma Tab); grades from coarse Total thickness member C ••••••••••••••••••• 156.9 grained bioclastic (largely echinodermal) calcarenite at base to laminated calcisiltite at top; Member B: contains fusulinids •••••••••••••••••• 0.2 33. Covered interval; light-gray 15. Mudstone, siliceous, as in 17; calcareous mudstone scree •••••••••••••• 7.5 poorly exposed ••••••••••••••••••••••• 2.3 32. Mudstone, calcareous, light gray 14. Limestone (calcarenite), dark gray, to light brown; faintly laminated fine grained; one bed •••••••••••••••• 0.1 in irregular, convolute patterns; laminations defined by aligned 13. Covered interval; loose limestone small clasts of medium- to dark concretions in scree ••••••••••••••••• 2.5 gray micritic limestone; lentic 12. Mudstone, calcareous, light gray, ular beds of dark-gray massive; may grade up from limestone (fine-grained calcar underlying limestone ••••••••••••••••• 3.0 enite; Bouma Tb) 15 to 35 em thick present at base of interval 11. Limestone, dark gray; one bed (Bouma and 3.2, 8.8, 10.9, 16.3, 30.9, Tab); grades from coarse-grained 32.9, 33.3, and 39.7 m above bioclastic calcarenite at base to base of interval. A 1.5-m-thick light-gray, laminated calcisiltite dike present 1.3 m below top of at top; contains fusulinids •••••••••• 2.1 interval. Upper 20 m of 10. Mudstone, calcareous, light brown; interval poorly exposed...... 43.6 poorly exposed ••••••••••••••••••••••• 2.3 31. Covered interval...... 2.0 9. Limestone, medium gray; one bed 30. Mudstone, calcareous, light gray to (Bouma Tab); grades from coarse light brown, massive; contains grained bioclastic calcarenite at scattered large irregularly shaped base to fine-grained calcarenite clasts of medium- to dark-gray at top; contains fusulinids •••••••••• 0.4 micritic limestone; in part covered; 8. Interval largely covered; few one lenticular bed of dark-gray, outcrops of dark-gray micritic fusulinid-bearing bioclastic limestone in beds 10 to 25 em thick limestone 15 em thick present and light-gray calcareous mudstone; 2.4 m above base of interval...... 9.1 one bed of coarse-grained bioclastic 29. Limestone, dark gray; one bed limestone 13 em thick present 1.0 m Bouma Tab); grades from lime above base of interval ••••••••••••••• 10.6 stone-pebble conglomerate at 7. Mudstone, calcareous, light gray, base to laminated calcisiltite massive; may grade up from at top...... 0.5 underlying limestone ••••••••••••••••• 1.5 28. Mudstone, calcareous, as in 30; 6. Limestone, medium gray; one bed upper part poorly exposed...... 8.3 (Bouma Tab); grades from medium 27. Limestone, dark gray; one bed (Bouma grained echinodermal calcarenite Tab); grades from limestone at base to laminated calcisiltite conglomerate at base to fine at top ••••••••••••••••••••••••••••••• 1.0 grained calcarenite at top; 5. Mudstone, calcareous, light brown, contains limestone clasts to 2 em massive; about 50 percent covered •••• 7.2 in diameter...... 0.5 4. Limestone, medium gray; one bed 26. Covered interval...... 0.9 (Bouma Tab); grades from coarse 25. Limestone, dark gray; one bed (Bouma grained echinodermal calcarenite Tab); grades from coarse-grained at base to laminated calcisiltite bioclastic calcarenite at base to at top ••••••••••••••••••••••••••••••• 1.8 laminated calcisiltite at top...... 0.5 3. Covered interval ••••••••••••••••••••• 8.5 24. Mudstone, calcareous, as in 30; thin 2. Mudstone, calcareous, light brown; lenticular beds of bioclastic poorly exposed ••••••••••••••••••••••• 2.0 limestone conglomerate present 0.8 and 2.5 m above base of interval..... 4.8 1. Limestone, medium gray; one bed (Bouma Tab); grades from coarse 23. Siltstone, calcareous, light gray grained bioclastic calcarenite to light brown, laminated...... 0.6 16 Pennsylvanian and Permian Stmtigraphy, Northern Argus Range and Darwin Canyon Area, California Section 1: Lower Permian--Continued Section 1: Lower Permian--Continued Osborne Canyon Formation--Continued Osborne Canyon Formation--Continued Member B--Continued Member B--Continued Thickness Thickness meters meters 22. Limestone, (calcarenite), bioclastic, contains limestone clasts to dark gray, coarse grained; one 10 em in diameter and abundant ungraded bed (Ta) •••••••••••••••••••• 0.3 coarse echinodermal debris; clasts tightly packed; upper 21. Mudstone, calcareous, as in 30; 20 em is laminated poorly exposed ••••••••••••••••••••••• 2.0 calcisiltite...... 7.5 20. Limestone, dark gray; one bed 3. Covered interval; calcareous (Bouma Tab); grades from lime mudstone scree...... 4.0 stone conglomerate at base to laminated calcisiltite at top; 2. Mudstone, calcareous, light gray, contains limestone clasts to massive •••••••••••••••••••••••••••••• 6.0 6 em in diameter ••••••••••••••••••••• 1.0 1. Limestone, medium gray; one bed 19. Covered interval ••••••••••••••••••••• 0.8 (Bouma Tab); grades from bioclastic limestone conglomerate at base to 18. Limestone, dark gray; one bed laminated, fine-grained calcarenite (Bouma Tab); grades from lime at top; contains limestone clasts stone conglomerate at base to to 2 em in diameter and fusulinids. laminated calcisiltite at top; Fusulinid collection OC11: contains limestone clasts to Leptotriticites? sp., 3 em in diameter ••••••••••••••••••••• 0.5 Schwagerina sp. ••••••••••••••••••••• 7.0 17. Covered interval ••••••••••••••••••••• 0.7 Total thickness member B••••••••••••••••••• 136.9 16. Limestone, dark gray; one bed (Bouma Tab); grades from limestone conglomerate at base to laminated calcisiltite at top; contains lime Hember A: stone clasts to 15 em in diameter; 30. Covered interval ••••••••••••••••••••••• 1.0 clasts tightly packed •••••••••••••••• 1.0 29. Limestone, dark gray; one bed 15. Mudstone, calcareous, as in 30, (Bouma Tab); grades from very poorly exposed; one lenticular coarse grained bioclastic bed of bioclastic limestone 15 em (largely echinodermal) calc thick 3.5 m above base of arenite at base to laminated interval ••••••••••••••••••••••••••••• 4.5 calcisiltite at top; contains fusulinids. Fusulinid 14. Limestone, dark gray; one bed (Bouma collection OC10: Tab); grades from bioclastic lime stone conglomerate at base to lam Schwagerina SP••••••••••••••••••••••• 0.3 inated calcisiltite in upper 5 em; 28. Covered interval...... 2.0 contains limestone clasts to 5 em 27. Siltstone, calcareous, light gray in diameter •••••••••••••••••••••••••• 1.5 to light brown, laminated; a 13. Siltstone, calcareous, as in 23 •••••• 1.3 2-m-thick dike cuts interval 4.0 m above base...... 8.0 12. Limestone, dark gray; one bed (Bouma Tab); grades from bio 26. Limestone conglomerate, bio clastic limestone conglomerate clastic, dark gray; one at base to fine-grained calc ungraded bed (Bouma Ta); poorly arenite at top; poorly sorted; sorted; contains limestone contains limestone clasts to clasts, echinodermal debris, 30 em in diameter; clasts and fragmented bryozoa to 5 em tightly packed ••••••••••••••••••••••• 1.8 in diameter; clasts tightly packed.. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 1. 0 11. Siltstone, calcareous, as in 23 •••••• 2.0 25. Covered interval; calcareous 10. Covered interval ••••••••••••••••••••• 2.0 siltstone and mudstone scree...... 12.0 9. Mudstone, calcareous, as in 30 ••••••• 5.0 24. Limestone (calcarenite), bio 8. Covered interval ••••••••••••••••••••• 5.0 clastic (largely echinodermal), dark gray, coarse grained; one 7. Mudstone, calcareous, light ungraded bed (Bouma Ta); gray, laminated; interbedded contains fusulinids. Fusulinid with black-weathering calcareous collection OC9: Schwagerina sp., chert •••••••••••••••••••••••••••••••• 3.0 Pseudofusulina? aff. P.? 6. Limestone-pebble conglomerate; loringi •••••••••••••••••••••••••••••• 0.5 lenticular ••••••••••••••••••••••••••• 0.2 23. Covered interval; calcareous 5. Mudstone, calcareous, as in 30 ••••••• 1.5 siltstone scree •••••••••••••••••••••• 3.5 4. Limestone conglomerate, bio 22. Limestone conglomerate, dark clastic, dark gray, poorly gray; one ungraded bed (Bouma sorted; one bed (Bouma Tab); Ta); contains limestone clasts Measured Sections 17 Section 1: Lower Permian--Continued Section 1: Lower Permian--Continued Osborne Canyon Formation--Continued Osborne Canyon Formation--Continued Member A--Continued Member A--Continued Thickness Thickness meters meters to 2 em in diameter; clasts 1. Limestone (calcarenite), echinodermal, tightly packed ••••••••••••••••••••••• 0.3 medium gray; one bed (Bouma Ta); grades from coarse grained at base to 21. Limestone (calcarenite), bioclastic; fine grained at top...... 0.9 thinly interbedded with calcareous siltstone; poorly exposed •••••••••••• 1.0 Total thickness member A...... 52.1 20. Limestone (calcarenite), bioclastic, Total thickness Osborne Canyon Formation ••• 345.9 medium gray; in lenticular beds 5 to 10 em thick; contains fusulinids; interbedded with calcar eous siltstone. Fusulinid collection OC8: Pseudofusulina? a££. Disconformable contact. ..!:.·? loringi ••••••••••••••••••••••••••• 0.3 Tihvipah Limestone (Lower and Middle Pennsylvanian): 19. Siltstone, calcareous, as in 27; 23. Limestone (micrite), medium gray; poorly exposed ••••••••••••••••••••••• 3.0 contains abundant nodular, 18. Limestone conglomerate, medium gray; lenticular, and bedded chert; one ungraded bed (Bouma Ta); contains tremolite abundant...... 20.0 limestone clasts to 4 em in diameter; 22. Covered interval...... 1.0 clasts tightly packed •••••••••••••••• 0.5 21. Limestone (micrite), medium gray; 17. Siltstone, calcareous, as in 27; contains abundant nodular chert in poorly exposed ••••••••••••••••••••••• 3.0 basal 4 m and mostly lenticular 16. Limestone (calcarenite), echinodermal, and bedded chert above that; chert medium gray, coarse grained; layers in upper part of interval one bed •••••••••••••••••••••••••••••• 0.1 are 1 to 5 em thick and spaced 5 to to 20 em apart; bedding well 15. Covered interval ••••••••••••••••••••• 0.2 defined •••••••••••••••••••••••••••••• 19.5 14. Limestone (calcarenite), medium gray, 20. Limestone (micrite), cherty, as in fine grained; one bed (Bouma Tb) ••••• 0.3 23; forms ledges ••••••••••••••••••••• ll.O 13. Covered interval ••••••••••••••••••••• 0.4 19. Limestone, bioclastic and 12. Siltstone, calcareous, as in 27 •••••• 1.0 conglomeratic, light gray; contains echinodermal debris, fragmented 11. Covered interval ••••••••••••••••••••• 4.0 bryozoans, and limestone clasts 10. Limestone conglomerate, bioclastic, suspended in a micrite matrix •••••••• 0.4 medium gray; one ungraded bed (Bouma 18. Limestone (micrite), cherty, as Ta); contains limestone clasts and in 23; forms ledges •••••••••••••••••• 15.5 echinodermal debris to 3 em in diameter and fusulinids. Fusulinid 17. Limestone (micrite), variably collection RTM2: Schwagerina sp., silty or argillaceous, light to Pseudofusulina? a££ •.!:_. loringi, medium gray; contains abundant Pseudoschwagerina uddeni, nodular, lenticular, and bedded Eoparafusulina sp •••••••••••• 0.4 chert; beds 10 to 20 em thick defined by variations in silt or 9. Covered interval ••••••••••••••••••••• 0.2 clay content and by chert 8. Siltstone, calcareous, as in 27 •••••• 2.2 layering ••••••••••••••••••••••••••••• 8.7 7. Limestone (calcarenite), echinodermal, 16. Covered interval ••••••••••••••••••••• 1.0 medium gray, coarse grained; in two 15. Limestone (micrite), medium to lenticular graded beds (Bouma Ta) 25 dark gray, massive; contains sparse and 30 em thick; both beds wedge out nodular chert; forms ledges •••••••••• 7.5 within 10m along strike ••••••••••••• 0.5 14. Limestone (micrite), medium gray; 6. Siltstone, calcareous, as in 27; contains abundant nodular, lentic poorly exposed ••••••••••••••••••••••• 3.3 ular, and bedded chert; spherical 5. Limestone (calcarenite), echinodermal, chert nodules common; bedding medium gray; one bed (Bouma Ta); defined by chert layers spaced grades from coarse grained at base 20 to 50 em apart; tremolite to fine grained at top ••••••••••••••• 0.3 abundant ••••••••••••••••••••••••••••• 7.5 4. Siltstone, calcareous, as in 27 •••••• 1.1 13. Limestone (micrite), variably silty or argillaceous, as in 17; beds 10 3. Limestone (calcarenite), echinodermal, to 30 em thick ••••••••••••••••••••••• 1.8 medium gray; one bed containing internal size-sorted layers 2 to 12. Limestone (micrite), dark gray, with 10 em thick •••••••••••••••••••••••••• 0.6 rare chert; tremolite abundant ••••••• 2.0 2. Covered interval ••••••••••••••••••••• 0.2 11. Covered interval ••••••••••••••••••••• 3.0 18 Pennsylvanian and Permian Stratigraphy, Northern Argus Range and Darwin Canyon Area, California Section 1: Lower and Middle Pennsylvanian--Continued Section 2--Continued Tihvipah Limestone--Continued Thickness Thickness meters meters 10. Limestone (micrite), variably silty or argillaceous, as in 17...... 3.5 Unconformable contact (poorly exposed). 9. Covered interval...... 2.0 Darwin Canyon Formation (Lower Permian) (incomplete): 8. Limestone (micrite), silty or Panamint Springs Member: argillaceous, light gray; tremolite 75. Covered interval; scree of siltstone abundant••••••••••••••••••••••••••••• 1.0 and very fine grained sandstone •••••• 4.0 7. Limestone, bioclastic and 74. Limestone (calcisiltite), silty, conglomeratic; contains coarse light gray, laminated •••••••••••••••• 2.0 grained echinodermal debris, rare rugose coral fragments, and 73. Siltstone and very fine grained limestone clasts to 6 em in diameter sandstone, quartzose, calcareous, suspended in a micrite matrix; brown to reddish brown on weathered tremolite abundant...... 1.5 surface; in planar beds 2 to 10 em thick; most beds plane laminated to 6. Covered interval...... 1.0 gently crosslaminated •••••••••••••••• 70.0 5. Limestone (micrite), medium gray; 72. Limestone, silty, as in 74 ••••••••••• 2.0 nodular chert uncommon; minor light-gray silty or argillaceous 71. Siltstone and very fine grained limestone; coarse echinodermal sandstone, as in 73 •••••••••••••••••• 10.5 debris present locally...... 5.0 70. Limestone, silty, as in 74 ••••••••••• 1.0 4. Covered interval...... 1.5 69. Siltstone and very fine grained 3. Limestone (micrite), silty or sandstone, as in 73 •••••••••••••••••• 4.5 argillaceous, light gray; contains 68. Limestone, silty, as in 74 ••••••••••• 0.5 rare spherical chert nodules...... 2.0 67. Siltstone and very fine grained 2. Covered interval...... 1.5 sandstone, as in 73 •••••••••••••••••• 22.5 1. Limestone (micrite), medium gray; 66. Limestone (calcisiltite), silty, contains nodular, lenticular, and light gray; contains irregular brown bedded chert; small spherical chert silty layers 5 to 10 em thick •••••••• 3.0 nodules common; tremolite abundant... 2.8 65. Siltstone and very fine grained Total thickness Tihvipah Limestone...... 120.7 sandstone, as in 73 •••••••••••••••••• 2.0 Disconformable contact. 64. Limestone (calcarenite), medium gray, Santa Rosa Hills Limestone (Mississippian) fine grained; one graded bed ••••••••• 0.5 (not measured): 63. Siltstone and very fine grained Marble, white to light gray, massive, sandstone, as in 73 •••••••••••••••••• 2.0 coarse grained; forms cliffs ••••••••• 62. Limestone, silty, as in 74...... 1.5 61. Siltstone and very fine grained sandstone, as in 73 •••••••••••••••••• 1.5 Section 2. Type sections of the Millers Spring Member (units 2 through 7) and of the Panamint Springs Member of the Darwin 60. Limestone (calcisiltite), medium Canyon Formation. Measured in four segments (2A, 2B, 2C, gray; one bed •••••••••••••••••••••••• 0.5 2D,) in Darwin Canyon north of the Darwin fault in July 1981 59. Siltstone and very fine grained and September 1985. Section 2A includes units 2, 3, and 4 of sandstone, as in 73 •••••••••••••••••• 22.5 the Millers Spring Member; section 2B includes units 5, 6A, and 6B of the Millers Spring Member; section 2C includes units 6C, 58. Limestone (calcarenite), pebbly; 6D, and 6E of the Millers Spring Member and the Panamint contains fusulinids; poorly exposed. 0.2 Springs Member; section 2D includes unit 7 of the Millers 57. Limestone (calcisiltite), Spring Member and the Panamint Spring Member. medium gray; poorly exposed •••••••••• 3.0 56. Siltstone and very fine grained Section 2D. Type sections of the Panamint Springs Member and sandstone, as in 73 •••••••••••••••••• 12.0 unit 7 of the Millers Spring Member. 55. Sandstone, calcareous, coarse Thickness grained, plane laminated; one meters graded bed; contains bioclastic debris ••••••••••••••••••••••••••••••• 0.3 Unnamed marine strata (Lower Triassic) (not measured): 54. Limestone, as in 57 •••••••••••••••••• 1.0 Limestone and marble, sandy, 53. Siltstone and very fine grained light gray to brown; contains sandstone, as in 73; some beds planar to gently undulating, have spherical medium-gray limestone silty and sandy laminations; concretions 2 to 4 em in diameter •••• 72.0 forms resistant ledges averaging about 1m thick •••••••••••• 52. Limestone, as in 57 •••••••••••••••••• 0.5 Measured Sections 19 Section 2: Lower Permian--Continued Section 2: Lower Permian--Continued Darwin Canyon Formation--Continued Darwin Canyon Formation--Continued Panamint Springs Member--Continued Panamint Springs Member--Continued Thickness Thickness meters meters 51. Siltstone and very fine grained alternating beds. Sandstone, sandstone, as in 73 •••••••••••••••••• 4.5 quartzose, variably calcareous 50. Limestone (calcisiltite), silty, and calcarenitic, gray to brown on weathered surface, light gray; one bed •••••••••••••••••• 0.3 very fine grained; in beds 49. Siltstone and very fine grained 20 em to 2.8 m thick; mean sandstone, as in 73 •••••••••••••••••• 9.0 bed thickness about 80 em; 48. Limestone (calcisiltite), silty, generally plane laminated; commonly gently cross light brown; one bed; laminated •••••• 1.5 laminated and convolute 47. Covered interval; silty limestone laminated; bedding surfaces scree •• ...... •• 2.5 sharp. Mudstone, siliceous 46. Limestone (calcisiltite), silty, to calcareous, light brown to medium gray; one bed; plane light gray; in beds 2 em to 1.1 m thick; mean bed thickness laminated •••••••••••••••••••••••••••• 0.8 about 40 em...... 10.2 45. Siltstone or very fine grained 23. Limestone (calcarenite), silty, sandstone, brown ••••••••••••••••••••• 0.2 light gray, fine grained; one bed.... 0.4 44. Limestone, silty, as in 46; one 22. Sandstone (75 percent) and mudstone bed ••••••••••••••••• •. •. • • • • • • • • • • • • • 0.7 (25 percent), as in 24. Sandstone 43. Siltstone or very fine grained in beds 15 em to 2.3 m thick; mean sandstone, as in 45 •••••••••••••••••• 0.3 bed thickness about 75 em. Mudstone 42. Limestone, silty, as in 46; one bed •• in beds 10 to 75 em thick; mean bed o.s thickness about 25 em; locally 41. Siltstone or very fine grained contains dark-gray limestone sandstone, as in 45 •••••••••••••••••• 0.3 concretions...... 11.2 40. Limestone, silty, as in 46; one bed •• 0.6 Total thickness Panamint Springs Member 39. Limestone (calcisiltite), silty, not including basal limestone unit...... 307.0 light gray, laminated; poorly exposed •••••••••••••••••••••••••••••• 5.5 Basal limestone unit: 21. Limestone (calcisiltite) and 38. Limestone (calcisiltite), silty, siltstone; in irregular beds 5 medium gray, laminated; contains to 20 em thick. Limestone, irregular brown-weathering layers 5 variably silty, light to to 10 em thick; small limestone concretions at top of interval; medium gray; siltstone, light brown, calcareous...... 7.0 forms a massive ledge •••••••••••••••• 6.5 20. Covered interval...... 2.0 37. Covered interval ••••••••••••••••••••• 1.2 19. Limestone (fine-grained calcarenite 36. Sandstone, as in 24; one bed ••••••••• 0.3 and calcisiltite), silty, light to 35. Limestone (calcisiltite), light medium gray; one graded bed...... 2.0 gray; one bed; dark-gray lime 18. Mudstone (60 percent) and limestone stone concretions on upper {fine-grained calcarenite and bedding surface •••••••••••••••••••••• 0.1 calcisiltite) (40 percent); in 34. Sandstone, as in 24; one bed ••••••••• 3.5 alternating beds. Mudstone, siliceous to calcareous, light brown 33. Mudstone, as in 24 ••••••••••••••••••• 0.1 to light gray; in beds 10 to 80 em 32. Sandstone, as in 24; one bed ••••••••• 0.4 thick; mean bed thickness about 55 em. Limestone, silty and sandy, 31. Mudstone, as in 24 ••••••••••••••••••• 0.2 light to medium gray; in beds 15 30. Covered interval ••••••••••••••••••••• 3.5 to 80 em thick; mean bed thickness about 40 em; unlaminated to plane 29. Sandstone, as in 24; one bed ••••••••• 0.5 laminated, crosslaminated, and 28. Mudstone, as in 24 ••••••••••••••••••• 0.2 convolute laminated; bedding surfaces sharp...... 7.3 27. Sandstone, as in 24; one bed ••••••••• 0.4 17. Limestone {fine-grained 26. Mudstone, as in 24 ••••••••••••••••••• 0.1 calcarenite or calcisiltite), 25. Limestone (calcisiltite), medium gray, indistinctly bedded; light gray, laminated; locally forms flaggy outcrops •••••••••••••••• 3.5 contains dark-gray limestone 16. Mudstone (80 percent) and concretions; silty layers 2 to 5 sandstone (20 percent); in em thick in upper part ••••••••••••••• 2.0 alternating beds. Mudstone, 24. Sandstone (65 percent) and siliceous, gray, brown, and mudstone (35 -percent); in reddish gray, generally in beds 20 Pennsylvanian and Permian Stratigraphy, Northern Argus Range and Darwin Canyon Area, California Section 2: Lower Permian--Continued Section 2: Lower Permian--Continued Darwin Canyon Formation--Continued Darwin Canyon Formation--Continued Panamint Springs Member--Continued Panamint Springs Member--Continued Basal limestone unit--Continued Thickness Basal limestone unit--Continued Thickness meters meters 1 to 2 m thick. Sandstone, 1. Covered interval...... 0.8 quartzose, strongly calcarenitic, Total thickness basal limestone unit...... 65.2 gray to brown on weathered surface, very fine grained; in beds 15 to 80 em thick; Total thickness Panamint Springs Member.... 372.2 mean bed thickness about 35 em; commonly plane laminated, less commonly ripple cross- laminated and convolute laminated; bedding surfaces sharp ••••••••••••••• 15.5 Millers Spring Member (incomplete): 15. Covered interval ••••••••••••••••••••• 0.9 Unit 7: 7. Sandstone (80 percent) and 14. Sandstone (80 percent) and mudstone (20 percent); in mudstone (20 percent), as in alternating beds. Sandstone, 16. Sandstone in beds 20 em quartzose, variably calcareous to 1.0 m thick, mudstone in and calcarenitic, gray to beds 2 to 50 em thick •••••••••••••••• 3.6 brown on weathered surface; in 13. Covered interval ••••••••••••••••••••• 1.0 beds 40 em to 1.9 m thick; generally plane laminated, less 12. Limestone (calcarenite), silty, commonly crosslaminated and light gray to light brown, fine convolute laminated; bedding grained; in irregular beds 5 to surfaces sharp. Mudstone, 10 em thick defined by variations light gray, light brown, and in silt content; plane laminated ••••• 4.5 purplish gray; in beds 10 to 11. Covered interval ••••••••••••••••••••• 1.0 40 em thick •••••••••••••••••••••••••• 5.5 10. Sandstone, as in 16; two beds 33 6. Interval occupied by crosscutting and 55 em thick separated by dike ••••••••••••••••••••••••••••••••• 4.0 20 em of mudstone •••••••••••••••••••• 1.1 5. Sandstone (70 percent) and 9. Mudstone, as in 16 ••••••••••••••••••• 0.5 mudstone (30 percent), as in 7. Sandstone in beds 20 to 50 em 8. Limestone (calcarenite), thick. Mudstone in beds 10 to medium gray, fine grained; 40 em thick •••••••••••••••••••••••••• 2.9 plane laminated but indistinctly bedded; contains thin lenticular 4. Interval occupied by crosscutting partings of brown siliceous dike ••••••••••••••••••••••••••••••••• 1.0 muds tone ••••••••••••••••••••••••••••• 3.0 3. Sandstone, as in 7; two amalgamated 7. Mudstone, siliceous, brown; beds 26 and 30 em thick •••••••••••••• 0.6 contains a 7-cm-thick bed of 2. Limestone (calcarenite), medium-gray, fine-grained limestone echinodermal, medium gray, 1.0 m above base ••••••••••••••••••••• 1.4 coarse grained; one graded 6. Sandstone, as in 16; two beds 45 bed (Bouma Ta); base erosional ••••••• 0.5 and 33 em thick separated by 10 em 1. Sandstone (55 percent) and of light-gray calcareous mudstone •••• 0.9 mudstone (45 percent), as in 5. Covered interval ••••••••••••••••••••• 0.8 7. Sandstone in beds 5 em to 2.7 m thick; mean bed thickness 4. Sandstone, as in 16; one bed; about 60 em. Mudstone in beds lamina ted •••••••••••••••••••••••••••• 0.6 2 em to 2.3 m thick; mean bed 3. Mudstone, siliceous, brown; thickness about 50 em •••••••••••••••• 24.9 weathers to small chips •••••••••••••• 2.0 Total thickness unit 7 ••••••••••••••••••••• 39.4 2. Limestone (calcarenite and calcisiltite) (35 percent) and mudstone (65 percent); in alternating beds. Limestone, variably silty, light to medium gray; generally fine Unit 6E (uppermost bed, not measured): grained but rarely medium to Mudstone, calcareous, conglomeratic, coarse grained at bases of beds; pink, massive; contains scattered in graded and ungraded beds 10 to fusulinids, echinodermal debris, 40 em thick; mean bed thickness and limestone clasts ••••••••••••••••• about 20 em; faintly laminated; Incomplete thickness Millers Spring has a strong tectonic cleavage. Member.. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 39.4 Mudstone, siliceous, brown; in beds 10 em to 1.1 m thick; mean bed Incomplete thickness Darwin Canyon thickness about 50 em •••••••••••••••• 5.8 Formation •••••••••••••••••••••••••••••••••• 411.6 Measured Sections 21 Section 2: Lower Permian--Continued Section 2: Lower Permian--Continued Darwin Canyon Formation--Continued Hillers Spring Member--Continued Section 2C. Units 6A, 6B (incomplete due to faulting); type Unit 6C--Continued Thickness section of units 6C-6E, Millers Spring Member. meters at top; upper 20 em is ripple Thickness laminated...... 2.3 meters 5. Mudstone.. • • • • • • • • • • • • • • • • • • • • • • • • • • • 0. 3 Darwin Canyon Formation (Lower Permian) (incomplete): 4. Limestone-cobble conglomerate; Millers Spring Member (incomplete): one ungraded bed (Bouma Ta); Unit 7 (not measured): contains tectonically stretched Sandstone, quartzose, gray to clasts...... 1.5 brown, very fine grained, 3. Covered interval...... 0.5 thick bedded; interbedded with light-gray to light-brown 2. Limestone (calcarenite), silty, calcareous mudstone •••••••••••••••••• fine grained; one bed...... 0.1 Unit 6E: 1. Limestone, medium gray; one bed 4. Mudstone, calcareous, conglomeratic, (Bouma Tabc); grades from pink, massive; contains limestone limestone conglomerate at base to laminated calcisiltite at top; clasts and bioclasts averaging 1 em contains tectonically stretched in diameter; echinodermal debris limestone clasts to 15 em long; and fusulinids abundant; crude clasts tightly packed; upper normal grading defined by upward 15 em of bed is ripple laminated; decrease in abundance of clasts capped by 2 em of mudstone ••••••••••• 1.6 (clasts rare in upper 5 m of bed) •••• 10.0 Total thickness unit 6C •••••••••••••••••••• 6.3 3. Limestone, medium gray; one bed (Bouma Tab); grades from lime Unit 6B: stone conglomerate at base to 2. Mudstone; thin sandstone bed laminated calcisiltite at top; present 0,8 m above base ••••••••••••• 1.3 contains limestone clasts to 5 em in diameter...... 3.6 Fault; small but indeterminate amount of section missing. 2. Covered interval; pink mudstone 1. Sandstone (75 percent) and scree...... 2.0 mudstone (25 percent), as in 1. Limestone, medium gray; one bed unit 6D. Sandstone in beds (Bouma Ta); grades from lime 10 em to 1.1 m thick; mean bed stone conglomerate at base to thickness about 50 em. Mudstone medium-grained echinodermal in beds 1 to 75 em thick; mean calcarenite at top except for bed thickness about 20 em •••••••••••• 16 0 7 uppermost 25 em which is Total thickness unit 6B (incomplete inversely graded to coarse due to faulting) ••••••••••••••••••••••••• 18.0 grained calcarenite; contains limestone clasts to 10 em in Unit 6A: diameter; dark-gray spherical 4. Mudstone, calcareous, massive; limestone clasts 2 to 5 em in may grade up from underlying diameter abundant at base of 3.5 bed. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 3. 7 limestone•••••••••••••••••••••••••••• 3. Limestone, medium gray; one bed Total thickness unit 6E...... 19.3 (Bouma Tab), grades from limestone conglomerate at base (mean clast Unit 6D: size 1 em) to laminated calcisiltite Sandstone (35 percent) and mud at top; contains fusulinids •••••••••• 3.7 stone (65 percent); in alter nating beds. Sandstone, quartzose, 2. Covered interval ••••••••••••••••••••• 1.5 variably calcareous and calc 1. Limestone conglomerate; one arenitic, very fine grained; in bed (Bouma Ta); contains planar beds 10 em to 1.0 m thick; dark-gray micritic limestone mean bed thickness about 40 em; clasts averaging 1 em in generally plane laminated, less diameter; matrix is light gray to commonly crosslaminated and pinkish gray; clasts loosely packed •• 1.5 convolute laminated. Mudstone, light gray to pinkish gray; in Total thickness unit 6A •••••••••••••••••••• 10.2 beds 5 em to 2.5 m thick (mean bed thickness about 70 em)...... 25.5 Unit 5 (not measured): Sandstone and mudstone, as in Total thickness unit 6D •••••••••••••••••••• 25.5 unit 6D •••••••••••••••••••••••••••••• Unit 6C: Incomplete thickness Millers Spring 6. Limestone, medium gray; one bed Member ••••••••••••••••••••••••••••••••••• 79.3 (Bouma Tabc); grades from limestone-pebble conglomerate Incomplete thickness Darwin Canyon at base to laminated calcisiltite Formation •••••••••••••••••••••••••••••••• 79.3 22 Pennsylvanian and Permian Stratigraphy, Nortbern Argus Range and Darwin Canyon Area, California Section 2: Lower Permian--Continued Section 2: Lower Permian--Continued Darwin Canyon Formation--Continued Millers Spring Member--Continued Unit 6A--Continued Thickness Section 2B. Unit 4 (incomplete), type section of units 5, 6A meters and 6B; unit 6C (incomplete), Millers Spring Member. 4. Limestone conglomerate; one Thickness ungraded bed (Bouma Ta); composed meters of micritic limestone clasts and Top of section faulted. bioclasts (maximum diameter 2 em) Darwin Canyon Formation (Lower Permian) in a light-gray to pinkish-gray (incomplete): micritic matrix •••••••••••••••••••••• 2.0 Millers Spring Member (incomplete): 3. Limestone, medium gray; one bed Unit 6C (incomplete): (Bouma Ta); grades from coarse 8. Limestone conglomerate, grained bioclastic calcarenite at medium gray; one graded bed; base to medium-grained calcarenite median clast size 2 em at at top ••••••••••••••••••••••••••••••• 0.8 base and 5 mm at top; top of bed faulted...... 1.0 2. Sandstone, quartzose, brown, very fine grained ••••••••••••••••••••••••• 1.5 7. Covered interval...... 1.0 1. Limestone conglomerate, bioclastic; 6. Limestone (calcarenite), silty, one ungraded bed (Bouma Ta); medium gray, fine grained; one composed of medium-gray micritic bed; laminated...... 0.5 limestone clasts (maximum diameter 5. Limestone (calcarenite), 2 em, median diameter 1 em) and echinodermal, medium gray, subordinate bioclasts, including medium to fine grained; one fusulinids and broken fasciculate graded bed (Bouma Tab)...... 0.5 rugose corals, in a light-gray micritic matrix; clasts 4. Covered interval...... 3.0 loosely packed ••••••••••••••••••••••• 3.5 3. Limestone conglomerate, Total thickness unit 6A •••••••••••••••••••• 15.3 bioclastic, medium gray; one graded bed (Bouma Ta); contains Unit 5: limestone clasts to 10 em in 16. Covered interval ••••••••••••••••••••• 0.2 diameter and broken fasciculate rugose corals; median clast 15. Sandstone, quartzose, strongly diameter at top of bed 1 em; calcarenitic, brown, very fine clasts tightly packed •••••••••••••••• 2.0 grained; one bed ••••••••••••••••••••• 1.2 2. Covered interval ••••••••••••••••••••• 0.8 14. Covered interval ••••••••••••••••••••• 2.0 1. Limestone, medium gray; one bed 13. Sandstone, as in 15; one bed ••••••••• 1.7 (Bouma Ta); grades from limestone 12. Mudstone ••••••••••••••••••••••••••••• 0.1 conglomerate at base to fine-grained calcarenite at top; 11. Limestone, medium gray; one contains limestone clasts to 5 em bed (Bouma Tab); grades from in diameter; clasts strongly coarse-grained bioclastic imbricated (possibly a tectonic calcarenite at base to laminated fabric) •••••••••••••••••••••••••••••• 2.0 calcisiltite at top; contains fusulinids ••••••••••••••••••••••••••• 1.2 Incomplete thickness unit 6C ••••••••••••••• 10.8 10. Sandstone (50 percent) and Unit 6B: mudstone (50 percent); in Sandstone, quartzose; gray to alternating beds. Sandstone, brown on weathered surface; quartzose, strongly calcarenitic, very fine grained; in beds 10 em light gray; in beds 10 em to 1.5 m to 1.5 m thick; poorly exposed ••••••• 32.7 thick, generally plane laminated and crosslaminated, commonly Total thickness unit 6B •••••••••••••••••••• 32.7 convolute laminated; bedding Unit 6A: surfaces sharp. Mudstone, 7. Mudstone, calcareous, purplish calcareous, purplish gray; in beds 5 em to 1.0 m thick; mean bed gray, massive; may grade up from thickness about 50 em •••••••••••••••• 7.4 underlying limestone ••••••••••••••••• 3.0 9. Mudstone, purplish gray, massive; 6. Limestone, medium gray; one bed contains spherical to subspherical (Bouma Tab); grades from dark-gray limestone concretions 2 coarse-grained bioclastic to 5 em in diameter •••••••••••••••••• 0.7 calcarenite at base to laminated calcisiltite at top; contains 8. Limestone, medium gray; one bed fusulinids. Fusulinid collection (Bouma Tabc); grades from DC'S: Schwagerina aff. ~· medium-grained echinodermal thompsoni, Pseudoschwagerina calcarenite at base to laminated convexa •• ••••••••.••••••••••••••••••• 3.7 calcisiltite at top •••••••••••••••••• 0.7 5. Covered interval ••••••••••••••••••••• 0.8 7. Mudstone, purplish gray •••••••••••••• 0.3 Measured Sections 23 Section 2: Lower Permian--Continued Section 2: Lower Permian--Continued Darwin Canyon Formation--Continued Darwin Canyon Formation--Continued Millers Spring Member--Continued Millers Spring Member--Continued Unit 5--Continued Thickness Unit 4--Continued Thickness meters meters 6. Sandstone, quartzose, in part weakly calcareous and calcarenitic; and commonly convolute laminated; generally brown on weathered some beds may contain more than surface; very fine grained; thick 50 percent quartz silt and very bedded; poorly exposed ••••••••••••••• 13.7 fine sand. Mudstone, calcareous, gray to purplish gray; in beds 5 5. Sandstone (45 percent) and to 60 em thick; mean bed thickness mudstone (55 percent), as in 10. about 25 em •••••••••••••••••••••••••• 6.3 Sandstone, strongly calcarenitic; in beds 25 em to 1.5 m thick; 16. Mudstone, calcareous, purplish gray, mean bed thickness about SO em. massive; contains scattered diffuse Mudstone, in beds 5 em to 1.0 m clasts of medium-gray limestone •••••• 3.0 thick; mean bed thickness about 15. Limestone (fine-grained calcarenite 60 em •••••••••••••••••••••••••••••••• 10.9 or calcisiltite); one bed •••••••••••• 0.9 4. Covered interval ••••••••••••••••••••• 3.0 14. Mudstone ••••••••••••••••••••••••••••• 0.1 3. Interval occupied by crosscutting 13. Limestone, medium gray; one bed dike ••••••••••••••••••••••••••••••••• 2.0 (Bouma Tab); grades from limestone 2. Limestone, medium gray; one bed conglomerate at base to silty (Bouma Tab); grades from fine fine-grained calcarenite at top; grained calcarenite at base to contains limestone clasts to 5 em calcisiltite at top •••••••••••••••••• 2.0 in diameter •••••••••••••••••••••••••• 1.0 1. Sandstone (45 percent) and 12. Limestone and calcareous mudstone; mudstone (55 percent), as in 10. one massive bed, graded from Sandstone, strongly calcarenitic; well-sorted echinodermal calc in beds 10 em to 1.0 m thick; mean arenite in lower 3 m to pinkish bed thickness about 40 em. Mud gray calcareous mudstone in upper stone, in beds 10 em to 1.0 m 11 m; mudstone contains large thick; mean bed thickness about rounded limestone clasts with 50 em ••••••••••••••••••••••••••••••• 11.9 diffuse borders •••••••••••••••••••••• 14.0 Total thickness unit 5 •••••••••••••••••••• 59.0 11. Mudstone••••••••••••••••••••••••••••• 0.1 10. Limestone-pebble conglomerate, Unit 4 (incomplete): bioclastic; one ungraded bed 25. Limestone, dark gray; one bed (Bouma Ta); clasts loosely packed; (Bouma Tab); grades from fusulinids present at base ••••••••••• o.s coarse-grained bioclastic calcarenite at base to laminated 9. Muds tone ••••••••••••••••••••••••••••• 0.1 fine-grained calcarenite at top; contains fusulinids •••••••••••••••••• 1.2 8. Limestone-pebble conglomerate, bioclastic; one crudely graded bed 24. Mudstone, calcareous ••••••••••••••••• 0.8 (Bouma Ta); fusulinids abundant •••••• 4.0 23. Limestone (fine-grained 7. Mudstone, calcareous, purplish gray •• 0.4 calcarenite or calcisiltite), 6. Limestone (fine-grained calcarenite silty; one bed ••••••••••••••••••••••• 0.2 or calcisiltite); one bed •••••••••••• 0.1 22. Hudstone, calcareous; thin 5. Mudstone, calcareous, limestone interbeds •••••••••••••••••• 3.0 grayish orange, massive; 21. Limestone (fine-grained contains indistinct limestone calcarenite or calcisiltite) clasts ••••••••••••••••••••••••••••••• 2.5 silty; one bed ••••••••••••••••••••••• 0.3 4. Limestone (fine-grained 20. Hudstone, calcareous ••••••••••••••••• 0.8 calcarenite or calcisiltite); one bed •••••••••••••••••••••••••••••• 0.4 19. Limestone, medium gray; one bed (Bouma Tab); grades from 3. Hudstone, calcareous, purplish gray •• 0.7 coarse-grained echinodermal 2. Limestone conglomerate, bioclastic, calcarenite at base to laminated medium gray; one ungraded bed calcisiltite at top; well sorted ••••• 1.5 (Bouma Ta); contains micritic 18. Covered interval ••••••••••••••••••••• 1.0 limestone clasts to 6 em in diameter and broken fasciculate rugose 17. Limestone (fine-grained calcarenite corals; clasts tightly packed and and calcisiltite) (60 percent) and strongly imbricated •••••••••••••••••• 0.6 mudstone (40 percent); in alternating beds. Limestone, silty, 1. Limestone (40 percent) and medium to dark gray, very fine to mudstone (60 percent), as in 17. fine grained; in beds 10 to 55 em Limestone, in beds 10 to 60 em thick; mean bed thickness about thick. Mudstone, in beds 10 to 30 em; generally plane laminated 70 em thick •••••••••••••••••••••••••• 4.1 24 Pennsylvanian and Permian Stratigraphy, Northern Argus Range and Darwin Canyon Area, California Section 2: Lower Permian--Continued Section 2: Lower Permian--Continued Darwin Canyon Formation--Continued Darwin Canyon Formation--Continued Millers Spring Member--Continued Millers Spring Member--Continued Unit 4--Continued Thickness Unit 4--Continued Thickness meters meters Incomplete thickness unit 4...... 47.6 9. Limestone, medium gray; one bed (Bouma Tab); grades from Incomplete thickness Millers Spring coarse-grained echinodermal Member.. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 165.4 calcarenite at base to laminated fine-grained calcarenite at Incomplete thickness Darwin Canyon top •••••••••••••••••••••••••••••••••• 1.0 Formation.. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 165.4 8. Mudstone, calcareous ••••••••••••••••• 0.2 Base of section covered. 7. Limestone (calcarenite), echinodermal, fine grained; one ungraded bed (Bouma Ta) •••••••••••••• 0.1 Section 2A. Unit 1 (incomplete); type section of units 2-4, Millers Spring Member. 6. Limestone and calcareous mudstone; one massive bed, grades from Thickness well-sorted echinodermal calcarenite meters in lower 3 m to pinkish-gray calcareous mudstone in upper 11 m; Top of section faulted. mudstone contains scattered diffuse Darwin Canyon Formation (Lower Permian) rounded clasts of medium-gray (incomplete): micritic limestone ••••••••••••••••••• 14.0 Millers Spring Member (incomplete): Unit 4: 5. Mudstone, calcareous, pink, 16. Limestone, dark gray; one bed massive; lenticular •••••••••••••••••• 10.0 (Bouma Tab); grades from 4. Limestone conglomerate, bio- coarse-grained bioclastic clastic; one crudely graded bed calcarenite at base to (Bouma Ta); contains micritic laminated fine-grained limestone clasts that decrease calcarenite at top; contains in maximum diameter from 5 em fusulinids. Section faulted at base to less than 1 em at immediately above this bed, top, broken fasciculate rugose which is correlated with the corals, and fusulinids; clasts uppermost bed in unit 4 of the loosely to tightly packed •••••••••••• 6.0 Millers Spring Member in section 2B...... 1.1 Minor fault; small amount of section probably missing. 15. Limestone (fine-grained calcarenite 3. Limestone (fine-grained calc and calcisiltite) (50 percent) arenite and calcisiltite) (70 and mudstone (50 percent); in percent) and cover (30 percent). alternating beds. Limestone, Limestone, silty; in beds 10 to medium gray, silty; in beds 15 40 em thick; plane and convolute to 40 em thick, all with lamination common •••••••••••••••••••• 1.4 pervasive plane lamination and 2. Mudstone, calcareous, pink, massive; many with convolute lamination; contains scattered clasts of bedding surfaces sharp. Mudstone, medium-gray micritic limestone; calcareous, yellowish brown; in clast borders diffuse, blending beds 5 to 50 em thick...... 4.2 with matrix; may grade up from 14. Mudstone, calcareous, yellowish underlying limestone ••••••••••••••••• 4.5 brown, light gray, and 1. Limestone, medium gray; one bed pinkish gray; indistinctly bedded.... 1.4 (Bouma Ta); grades from 13. Limestone (fine-grained coarse-grained bioclastic calcarenite or calcisiltite); calcarenite at base to medium one bed; crosslaminated and grained echinodermal calcarenite convolute laminated...... 0.4 at top; contains fusulinids. Fusulinid collection DC8: 12. Mudstone, calcareous...... 1.0 Schwagerina spp., 11. Limestone, medium gray; one bed Eoparafusulina cf. ~· (Bouma Tab); grades from linear is . ..••....•...... ••....•. 2.7 coarse-grained echinodermal Total thickness unit 4 •••••••••••••••••••• 60.9 calcarenite at base to laminated calcisiltite at top...... 1.0 Unit 3: 10. Limestone (fine-grained calcarenite 14. Sandstone (65 percent) and and calcisiltite), silty, medium mudstone (35 percent); in to dark gray; in beds 25 to 50 em alternating beds. Sandstone, thick; plane laminated and quartzose, variably calcareous crosslaminated; poorly exposed; and calcarenitic, gray to brown subordinate gray to brown calcareous on weathered surface, very fine mudstone occurs mainly as float...... 11.9 grained; in beds 15 em to 2.1 m Measured Sections 25 Section 2: Lower Permian--Continued Section 2: Lower Permian--Continued Darwin Canyon Formation--Continued Darwin Canyon Formation--Continued Millers Spring Member--Continued Millers Spring Member--Continued Unit 3--Continued Thickness Unit 3--Continued Thickness meters meters thick; mean bed thickness about Sandstone in beds 10 to 70 em 60 em; commonly plane laminated thick; mean bed thickness about and crosslaminated, less commonly 30 em. Mudstone in beds 5 em convolute laminated; bedding to 1.4 m thick, poorly exposed...... 6.0 surfaces sharp. Mudstone, light gray, in beds 10 to 90 em Total thickness unit 3...... 55.7 thick; mean bed thickness about 35 em •••••••••••••••••••••••••• 7.4 13. Mudstone and siltstone, calcareous, Unit 2: light gray, thin bedded •••••••••••••• 2.5 9. Mudstone, calcareous, conglom 12. Sandstone (55 percent) and eratic, light gray, grayish mudstone (45 percent), as in 14. orange, and grayish pink; Sandstone, strongly calcarenitic; one massive bed; contains in beds 20 to 55 em thick; abundant matrix-supported contains well-developed convolute clasts that include micritic lamination. Mudstone in beds 40 limestone clasts to 50 em in to 45 em thick ••••••••••••••••••••••• 2.9 diameter, broken fasciculate rugose corals, fusulinids, 11. Covered interval ••••••••••••••••••••• 2.0 echinodermal debris, and other 10. Sandstone (65 percent) and mudstone bioclasts; limestone clasts have (35 percent), as in 14. Sand sharp borders...... 17.0 stone in beds 10 em to 2.5 m 8. Sandstone, very fine grained, thick; mean bed thickness about and calcareous siltstone; 70 em. Mudstone in beds 5 em thin bedded and laminated; to 1 m thick; mean bed thickness poorly exposed...... 3.0 about 35 em •••••••••••••••••••••••••• 14.6 7. Mudstone, calcareous, light gray 9. Limestone, medium gray; one bed to grayish pink, massive; contains (Bouma Tab), grades from large rounded micritic limestone coarse-grained bioclastic clasts with diffuse borders; may calcarenite at base to laminated grade up from underlying limestone... 12.0 fine-grained calcarenite at top; contains fusulinids •••••••••••••••••• 0.3 6. Limestone (calcarenite), bioclastic, medium gray; one graded bed 8. Sandstone (45 percent) and (Bouma Ta); contains fusulinids. mudstone (55 percent), as in 14. Fusulinid collection DC3: Sandstone in beds 5 to 85 em Schwagerina spp., thick; mean bed thickness about Pseudoschwagerina sp...... 3.5 20 em. Mudstone in beds 2 to 40 em thick; mean bed thickness about 25 em•••••••••••••••••••••••••• 10.4 5. Mudstone, calcareous, light gray; one massive bed; 7. Limestone, medium gray; one bed contains medium-gray micritic (Bouma Tabe); grades from limestone clasts with diffuse coarse-grained bioclastic borders in basal 1.0 m; lenticular... 7.0 calcarenite at base to micrite at top ••••••••••••••••••••••••••••••• 0.7 4. Limestone; one bed (Bouma Tab); grades from medium-gray 6. Mudstone, calcareous, light gray ••••• 0.5 limestone-granule conglomerate 5. Covered interval ••••••••••••••••••••• 2.5 at base to laminated light-gray calcisiltite at top...... 1.2 4. Sandstone, quartzose, brown, very fine grained (lower 50 em); grades 3. Limestone-pebble conglomerate, upward into light-gray calcareous medium gray; one graded bed (Bouma siltstone and mudstone Ta); clasts strongly imbricated...... 0.8 (upper 1. 6 m) •••••••••••••••••••••••• 2.1 2. Limestone, medium gray; one bed 3. Limestone, medium gray; one bed (Bouma Ta); grades from bioclastic (Bouma Tab); grades from limestone conglomerate at base to coarse-grained bioclastic echinodermal calcarenite at top; calcarenite at base to laminated contains micritic limestone clasts calcisiltite at top •••••••••••••••••• 0.8 to 4 em in diameter and broken fasciculate rugose corals...... 1.2 2. Mudstone, calcareous, light gray; contains scattered unsorted 1. Mudstone, calcareous, dark-gray limestone clasts to yellowish brown; one massive bed; 30 em in diameter; largest clasts contains large fragments of are in upper part of bed •••••••••••• 3.0 medium-gray bioclastic limestone and limestone conglomerate...... 5.0 1. Sandstone (40 percent) and mudstone (60 percent), as in 14. Total thickness unit 2...... 50.7 26 Pennsylvanian and Permian Stratigraphy, Northern Argus Range and Darwin Canyon Area, California Section 2: Lower Permian--Continued Section 3: Lower Permian--Continued Darwin Canyon Formation--Continued Darwin Canyon Formation--Continued Millers Spring Member--Continued Panamint Springs Member--Continued Thickness Thickness meters meters Unit 1 (incomplete): echinodermal debris, and chert 3. Sandstone (55 percent) and clasts to 3 mm in diameter. mudstone (45 percent); in Fusulinid collection I1300 from 25 m alternating beds. Sandstone, above base of interval: Schwagerina cf. quartzose, variably calcareous ~· crebrisepta, Schwagerina and calcarenitic, brown to diversiformis, Pseudoschwagerina reddish brown on weathered convexa, Chalaroschwagerina sp... 29.0 surface; in beds 10 em to 8. Shale, moderate pink...... 3.0 1.5 m thick, generally plane laminated and and crosslaminated, 7. Siltstone and very fine grained less commonly convolute laminated. sandstone, as in 12; a few thick Mudstone, gray to purplish gray; graded calcareous beds contain in beds 10 to 60 em thick...... 5.8 fusulinids, echinodermal debris, chert clasts, and occasional 2. Limestone, medium gray; one bed limestone clasts to 6 mm in (Bouma Tab); grades from diameter ••••••••••••••••••••••••••••• 143.3 coarse-grained bioclastic calc arenite at base to laminated calci- 6. Siltstone, calcareous, siltite at top; contains fusulinids.. 0.9 moderate orange to grayish orange pink; contains nodules of medium- 1. Sandstone (60 percent) and gray limestone 15 to 25 em long...... 9.1 mudstone (10 percent), as in 3; covered intervals (30 percent) 5. Limestone, medium light gray, probably represent unexposed fine grained; contains about 40 mudstone intervals. Sandstone percent dark-gray elongate to in beds 40 em to 1.4 m thick. spherical limestone nodules...... 21.3 Hudstone in beds 10 to 30 em thick...... 5.8 4. Siltstone, medium light gray and grayish orange...... 3.0 Incomplete thickness unit 1...... 12.5 3. Limestone, medium gray, massive; contains dark-brown siliceous layers Incomplete thickness Millers Spring Hember...... 179.8 and nodules•••••••••••••••••••••••••• 29.0 2. Sandstone, quartzose, calcareous, Incomplete thickness Darwin Canyon medium light gray to grayish orange, Formation.. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 179.8 very fine grained; in beds 50 em to 1m thick•••••••••••••••••••••••••••• 16.8 Base of section covered. Incomplete thickness Panamint Springs Hember not including basal limestone unit. 405.4 Section 3. Unit 6B (incomplete) and units 6C-7, Millers Spring Member, and Panamint Springs Member (incomplete) of the Basal limestone unit: Darwin Canyon Formation. Measured in the hills south of 1. Limestone, medium dark gray; pink Darwin Canyon in June 1981. shale; and grayish-orange to moderate-yellowish-brown silty Thickness limestone; in beds 30 em to 1 m meters thick; felsic dike 1 m thick Section ends at axis of syncline. present 6 m below top of interval •••• 86.9 Darwin Canyon Formation (Lower Permian) Total thickness basal limestone unit...... 86.9 (incomplete): Panamint Springs Member (incomplete): Incomplete thickness Panamint 13. Limestone, medium gray, and Springs Member••••••••••••••••••••••••••• 492.3 light-brown siltstone •••••••••••••••• 9.1 12. Siltstone and very fine grained Millers Spring Member (incomplete): sandstone, light brown; in thin Unit 7: graded beds that commonly have Sandstone, quartzose, calcareous, parallel and convolute lamination •••• 35.1 medium gray to moderate brown, very fine grained; in beds 15 to 11. Limestone, medium gray, and 60 em thick•••••••••••••••••••••••••• 44.2 light-brown siltstone; subordinate pink shale••••••••••••••••••••••••••• 13.7 Total thickness unit 7...... 44.2 10. Siltstone and very fine grained Unit 6E: sandstone, as in 12 •••••••••••••••••• 93.0 2. Mudstone, mottled grayish pink to 9. Limestone, light gray, and moderate pink and medium light gray; light-brown siltstone. Limestone contains limestone clasts and in graded beds as thick as 30 em; fusulinids. Fusulinid collection contains fusulinids, coarse Ia-305 from 1 m above base of MeasuredSections 27 Section 3: Lower Permian--Continued Section 4: Lower Permian--Continued Darwin Canyon Formation--Continued Darwin Canyon Formation--Continued Millers Spring Member--Continued Millers Spring Member--Continued Unit 6 E --Continued Thickness Unit 6E--Continued Thickness meters meters interval: Schwagerina aculeata, of interval: Schwagerina cf. ~· Schwagerina aff. ~· thompsoni, eolata, Pseudoschwagerina Schwagerina sp, Chusenella sp ••••••• 21.4 convexa •••.••.••••••••••••••..•.•.. 15.3 1. Limestone, light to medium gray; 1. Limestone, medium light gray; in in beds 60 em to 1.5 m thick; some graded beds averaging about 3 m thick; beds contain fusulinids and some contains medium-light-gray limestone contain clasts of fine- to clasts to 5 em in diameter and medium-grained limestone to 15 em coral fragments...... 15.3 in diameter. Fusulinid collection Total thickness unit 6E...... 30.6 Ia-295 from 2 m below top of interval: Schwagerina elkoensis, Chalaroschwagerina sp., Unit 6D: Sandstone, quartzose, calcareous, Pseudoschwagerina uddeni ••••••••••••• 18.3 very fine grained; and dusky-brown, Total thickness unit 6E •••••••••••••••••••• 39.7 medium-light-gray, and grayish-orange silty limestone; in beds as much as Unit 6D: 1.5 m thick; convolute Sandstone, as in unit 7 •••••••••••••• 29.0 lamination common ••••••••••••••••••••• 44.2 Total thickness unit 6D •••••••••••••••••••• 29.0 Total thickness unit 6D ••••••••••••••••••••• 44.2 Unit 6C: Limestone, light to medium gray; in Unit 6C: graded beds 60 em to 1.5 m thick; 2. Limestone, medium gray; in thick some beds contain clasts of fine- to graded beds; contains rounded medium-grained limestone to 15 em in medium-gray limestone clasts to diameter ••••••••••••••••••••••••••••• 9.2 8 em in diameter; one bed contains imbricated clasts and coral Total thickness unit 6C...... 9.2 fragments •••••••••••••••••••••••••••• 10.7 Unit 6B (incomplete): 1. Limestone, medium light gray; one Sandstone, as in unit 7...... 35.1 graded bed; contains fusulinids and coarse echinodermal debris at base ••• 4.8 Incomplete thickness unit 6B...... 35.1 Total thickness unit 6C •••••••••••••••••••• 15.5 Incomplete thickness Millers Spring Member ••••••••••••••••••••••••••••••••••• 157.2 Unit 6B: Incomplete thickness Darwin Canyon 3. Limestone, silty, grayish orange, Formation...... 649.5 dusky brown, and light gray; convolute lamination common •••••••••• 9.2 Base of section covered. 2. Sandstone, quartzose, calcareous, very fine grained; in beds 1 to 1.5 m thick; forms ridge...... 16.8 Section 4. Unit 4 (incomplete), units 5-6, and unit 7 (incomplete), Millers Spring Member of the Darwin Canyon 1. Sandstone, quartzose, calcareous, Formation. Measured in the hills south of Darwin Canyon in very fine grained; and grayish-orange, June 1981. dusky-brown, and light-gray silty limestone; in beds 30 em to 1.5 m Thickness thick; convolute lamination common; meters outcrops resistant with blocky fracture...... 16.8 Top of section faulted. Darwin Canyon Formation (Lower Permian) Total thickness unit 6B...... 42.8 (incomplete): Millers Spring Member (incomplete): Unit 7 (incomplete): Unit 6A: Sandstone, quartzose, calcareous, Limestone, medium gray; one bed; medium light gray to grayish orange, grades upward into laminated, very fine grained, thick bedded; medium-light-gray silty limestone; convolute lamination common •••••••••• 36.6 contains rounded limestone clasts to 1 em in diameter and abundant Incomplete thickness unit 7 •••••••••••••••• 36.6 fusulinids and echinodermal debris. Fusulinid collection 1500 from base Unit 6E: of interval: Schwagerina cf. S. 2. Mudstone, moderate pink, massive; crebrisepta, Schwagerina contains medium-light-gray limestone elkoensis, Schwagerina cf. clasts to 5 em in diameter, coral ~ wellsensis, Stewartina sp. 13.7 fragments, and fusulinids. Fusulinid collection I975 from 4 m above base Total thickness unit 6A •••••••••••••••••••• 13.7 28 Pennsylvanian and Permian Stratigraphy, Northern Argus Range and Darwin Canyon Area, California Section 4: Lower Permian--Continued Section 5. Unit 1 (incomplete), units 2-6, and unit 7 Darwin Canyon Formation--Continued (incomplete), Millers Spring Member of the Darwin Canyon Millers Spring Member--Continued Formation. Measured in the hills south of Darwin Canyon in June 1981. Thickness Thickness meters meters Top of section covered. Total thickness units 6A-6E •••••••••••••••• 146.8 Darwin Canyon Formation (Lower Permian) Unit 5: (incomplete): 3. Sandstone, quartzose, calcareous, Millers Spring Member (incomplete): grayish orange, dusky brown, and Unit 7 (incomplete): light gray, very fine grained; and Sandstone, quartzose, calcareous, medium-dark-gray, fine-grained light gray, grayish orange, and limestone; in graded beds 1 to grayish brown on weathered surface, 1.5 m thick; some beds contain very fine grained; thick bedded, fusulinids. Fusulinid collection laminated; convolute lamination I410 from 14 m above base of con:unon • •••••••••••••••••••••••••••••• 40.0 interval: Schwagerina aculeata, Incomplete thickness unit 7...... 40.0 Schwagerina diversiformis, Pseudoschwagerina uddeni, Unit 6E: Pseudoschwagerina sp., 2. Mudstone, calcareous, moderate Parafusulina sp. ••••••••••••••••••• 41.2 pink; contains fusulinids, coral 2. Sandstone, quartzose, grayish red fragments, and rounded medium to dusky red, very fine grained, gray limestone clasts to 2 em massive; forms resistant outcrops in diameter. Fusulinid with blocky fracture...... 12.2 collection 1I1605 from 1 m below top of interval: 1. Sandstone, quartzose, calcareous, Schwagerina SPP•••••••••••••••••••••• 7.6 very fine grained; and grayish-orange, dusky-brown, and light-gray silty 1. Limestone, medium gray; in thick, limestone; in beds 30 to 60 em thick; graded beds; contains rounded parallel and convolute lamination medium-gray limestone clasts to common... • • • • • • • • • • • • • • • • • • • • • • • • • • • • 30.5 5 em in diameter and abundant coral fragments; tops of beds fine Total thickness unit 5...... 83.9 grained and plane laminated...... 12.2 Total thickness unit 6E •••••••••••••••••••• 19.8 Unit 4 (incomplete): Unit 6D: 3. Limestone, medium to dark gray, Sandstone, as in unit 7 ••••••••••••••• 27.4 in graded beds as much as 60 em thick; consists mainly of Total thickness unit 6D...... 27.4 fine-grained echinodermal debris; fusulinids present in some beds; Unit 6C: parallel and convolute lamination Limestone, medium gray; in graded present in some beds...... 30.5 beds 1 to 3 m thick; contains fusulinids, coral fragments, 2. Limestone, silty, grayish pink and and gray limestone clasts to medium light gray; grayish-pink 5 em in diameter; clasts beds have convolute lamination and strongly imbricated in some beds..... 19.8 contain spherical nodules of medium light-gray, fine-grained limestone Total thickness unit 6C...... 19.8 to 15 em in diameter; medium-light gray beds are graded, average about Unit 6B: 30 em thick, and have convolute Sandstone, as in unit 7...... 47.3 lamination••••••••••••••••••••••••••• 29.0 Total thickness unit 6B...... 47.3 1. Limestone, medium light gray; in graded beds 45 em to 1 m thick; Unit 6A: contains rounded limestone clasts Limestone, medium gray; in thick to 5 em in diameter, echinodermal graded beds; contains rounded, debris, fusulinids, and corals •••••.•••• 9.2 medium-gray limestone clasts to 1 em in diameter, fusulinids, Incomplete thickness unit 4 ••••••••••••••••• 68.7 coral fragments, and coarse echinodermal debris. Fusulinid Incomplete thickness Millers Spring collection 1I1220 from 4 m below Member • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 336 • 0 top of interval: Schwagerina aculeata, Schwagerina sp...... 19.8 Incomplete thickness Darwin Canyon Formation •••••••••••••••••••••••••••••••• 336.0 Total thickness unit 6A...... 19.8 Base of section faulted. Total thickness units 6A-6E •••••••••••••••• 134.1 Measured Sections 29 Section 5: Lower Permian--Continued Section 5: Lower Permian--Continued Darwin Canyon Formation--Continued Darwin Canyon Formation--Continued Millers Spring Member--Continued Millers Spring Member--Continued Thickness Unit 3--Continued Thickness meters meters Unit 5: 5. Siltstone, grayish brown to graded beds 25 em to 1 m thick. brownish black; contains nodules Sandstone and silty limestone, and lenses of fine-grained gray yellowish brown to grayish orange limestone 8 to 30 em long; on weathered surface; in laminated subordinate medium-gray limestone beds to 1 m thick; convolute in graded beds containing lamination common •••••••••••••••••••• 21.3 fusulinids (2 beds present). Total thickness unit 3 ••••••••••••••••••••• 88.4 Fusulinid collection II1150 from base of interval: Unit 2: Schwagerina cf. ~· 3. Mudstone, calcareous, moderate pink; crebrisepta, Schwagerina one massive bed; contains rounded to elkoensis •••••••••••••••••••••••••••• 6.1 subangular, light- to medium-gray 4. Sandstone, quartzose, brownish gray, limestone clasts to 75 em in brownish black, and pale reddish diameter and fusulinids, corals, brown on weathered surface, very and echinodermal debris •••••••••••••• 25.0 fine grained; in beds as much as 2. Limestone, shaly, moderate pink •••••• 4.6 1.5 m thick; forms ridges; crosscutting dike present 15 m 1. Limestone, medium gray; in thick below top of interval •••••••••••••••• 45.7 graded beds; contains rounded, 3. Covered interval ••••••••••••••••••••• 10.7 medium-gray limestone clasts, fusulinids, and coral fragments; 2. Limestone, medium gray, fine grained, clasts imbricated. Fusulinid thin to medium bedded; plane and collection II155 from 12 m above convolute laminated; some graded beds base of interval: Schwagerina contain coarse echinodermal debris elkoensis?, Chusenella and fusulinids ••••••••••••••••••••••• 4.6 compacta, Paraschwagerina sp., 1. Sandstone, as in 4 ••••••••••••••••••• 6.1 Pseudoschwagerina uddeni, Pseudoschwagerina sp., Total thickness unit 5 ••••••••••••••••••••• 73.2 Stewartina? spp.; fusulinid collection II175 from Unit 4: 18 m above base of interval: Limestone, medium gray, fine grained, Schwagerina cf. S. eolata, thin to medium bedded; beds commonly Schwagerina aff .-i.-t'iiOiiiPsoni, graded. One 2-m-thick graded bed Chusenella compacta, 46 m above base of interval contains Stewartina moranensis, medium-gray limestone clasts to 1 em Stewartina sp. • • • • • • • • • • • • • • • • • • • • • • 32 .o in diameter, fusulinids, and coral fragments. Fusulinid collection Total thickness unit 2...... 61.6 II850 from this bed: Schwagerina aculeata, Chusenella compacta, Unit 1 (incomplete): Pseudofusulina? aff. Sandstone, quartzose, calcareous, ..!:· loringi, Cuniculinella spp. 70.1 very fine grained, and pale yellowish-orange-weathering silty Total thickness unit 4 ••••••••••••••••••••• 70.1 limestone; in laminated beds as much as 75 em thick; convolute Unit 3: lamination common...... 35.1 2. Sandstone, quartzose, calcareous, very fine grained, and Incomplete thickness unit 1...... 35.1 yellowish-brown- to grayish-orange weathering silty limestone; in Incomplete thickness Millers Spring laminated beds as much as 1 m Member.. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 502.5 thick; convolute lamination common ••• 67.1 Incomplete thickness Darwin Canyon 1. Limestone, silty limestone, and Formation •••••••••••••••••••••••••••••••• 502.5 quartzose sandstone. Limestone, medium gray, medium grained; in Base of section covered. 30 Pennsylvanian and Permian Stratigraphy, Northern Argus Range and Darwin Canyon Area, California GPO 785-048/48043