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Home , Atrasado Formation, Bursum Formation, Gray Mesa Formation, Madera Group, Sandia Formation

The Late (Missourian) index fusulinid Eowaeringella in the Manzanita Mountains of central Bruce D. Allen1 and Spencer G. Lucas2 1New Mexico Bureau of Geology and Mineral Resources, New Mexico Institute of Mining and Technology, Socorro, NM 87801; [email protected] 2New Mexico Museum of Natural History, Albuquerque, NM 87104; [email protected] Abstract The boundary between Middle and Upper Pennsylvanian strata in central New Mexico is generally considered to coincide with the contact between the Gray Mesa and the overlying Atrasado formations. This perception was advanced in the by D.A. Myers, who reported the early Missourian fusulinid Eowaeringella near the top of the from a single locality in Gotera Canyon at the northern end of the range. The Gotera Canyon locality was re-examined and the Eowaeringella horizon recovered, together with additional strata 20 to 25 meters higher in the section that contain early forms of Triticites, including T. cf. pygmaeus, T. wellsi, and T. cf. planus. Thus, at Gotera Canyon, the Eowaeringella Zone is present 50 meters above the top of the Gray Mesa Formation, near the base of the Tinajas Member of the . The overlying Triticites-bearing strata appear to be common in the lower part of the Tinajas Member, from as far south as the Gotera Canyon locality northward to the . Introduction Strata of the Pennsylvanian System in New Mexico consist of marine and marginal-marine deposits that are widely exposed in mountain ranges along the flanks of the Rio Grande rift (Fig. 1). Deposition of these strata occurred during a period of regional, Late Paleozoic orogenic activity, resulting in a complex succession of lithofacies across New Mexico. Pennsylvanian strata are subdivided in central New Mexico into three Figure 1. Map showing location of the Gotera Canyon section in the Manzanita Mountains. formation-rank units. These are the Blue shaded areas indicate the surface extent of Pennsylvanian rocks. Localities mentioned in the text include Barton (B), Cedro Peak (CP) and Kinney Brick Quarry (KBQ). See Figure 4 , which contains for a 1:24,000-scale map of the Gotera Canyon locality. a comparatively large proportion of sandstone and (generally 100 m thick or less), followed by the Gray Mesa Formation, Here, we report on lower Upper Pennsylvanian largely (generally 100 to 300 m thick), and the fusulinid-bearing strata from a locality in the Manzanita Atrasado Formation, consisting of alternating intervals Mountains, Gotera Canyon (Fig. 1), where Myers of slope-forming clastic deposits and limestone-domi- (1969, 1988) reported an early Missourian fusulinid nated ledges and cliffs (generally 200 to 300 m thick). (genus Eowaeringella) from the top of the Gray Mesa The boundary between Middle and Upper Pennsylvanian Formation. The overall lithostratigraphic architecture of strata, corresponding with the Desmoinesian-Missourian the Pennsylvanian sequence in the vicinity of the local- Stage boundary (ca. 306 Ma), is generally considered to ity is typical of exposures encountered in mountains coincide with the top of the Gray Mesa Formation. and uplifts bordering the Rio Grande from Socorro to

Fall 2018, Volume 40, Number 2 New Mexico Geology 35 Albuquerque. A measured section through the lower part data from the Cerros de Amado, approximately of the Atrasado Formation is presented, and the com- 100 km to the south of the Manzano Mountains, also mon forms of fusulinids recovered from the locality are suggest an early Desmoinesian age for much of the Gray described and illustrated. These forms include a species of Mesa Formation, and indicate that the Desmoinesian- the early Missourian genus Eowaeringella, and late-early Missourian boundary there lies within strata of the over- to middle Missourian Triticites from 20–25 meters higher lying Atrasado Formation, at the stratigraphic level of the in the section. Amado Member (Lucas et al., 2009; Barrick et al., 2013). Therefore, Myers’ (1988) report of the early Missourian Background fusulinid Eowaeringella near the top of the Gray Mesa Formation at Gotera Canyon seemed anomalous, and As summarized above, Pennsylvanian rocks are presently merited re-evaluation. assigned to three formations in central New Mexico— the Sandia, Gray Mesa, and Atrasado formations. The Sandia Formation typically rests on , The Gotera Canyon section and transitional Pennsylvanian– strata above The base of Myers’ (1969) section in Gotera Canyon is the Atrasado Formation are assigned to the Bursum in strata of the Gray Mesa Formation near the road that Formation. Before the early 2000s, the Gray Mesa and runs along the floor of the drainage, and traverses the Atrasado formations east of the Rio Grande were com- steep hillslope to the northeast. Bedding is inclined a few monly referred to as the lower and upper members of degrees to the east-northeast along the traverse. Near the Madera Limestone (Read and Wood, 1947). Myers the road at the base of the section, in the Gray Mesa (1973), who had been mapping and conducting fusulinid Formation, a several-meter thick channel-fill deposit in the Manzano Mountains, formally consisting of coarse-grained pebbly sandstone and con- introduced the names Los Moyos Limestone and Wild glomerate is present. Although comparatively thin sand- Cow Formation to replace “lower” and “upper” Madera stone beds are present in the Gray Mesa Formation, the in the area (before that, Myers had used lower and upper thick channel sand near the base of the Gotera Canyon Madera on his maps). Across the Rio Grande to the west, section is unusual and noteworthy. Above the sandstone, in the Lucero uplift, these lithostratigraphic units had the Gray Mesa Formation contains beds of fossiliferous been named the Gray Mesa and Atrasado members of the wackestone, packstone and some carbonate mudstone, Madera Limestone by Kelley and Wood (1946). Following with short covered intervals that for the most part proba- the suggestion of Kues (2001), the names proposed by bly represent fine-grained siliciclastic deposits. Limestone Kelley and Wood in the Lucero uplift are now used to beds are commonly cherty, which is typical of the Gray delineate Pennsylvanian formations over a large portion of Mesa Formation. The steep hillslope levels off somewhat, central New Mexico, replacing lower and upper Madera approximately 75 meters above the road, marking the top as well as the nomenclature proposed by Myers for the of the Gray Mesa Formation and the base of the Atrasado Manzano Mountains (e.g., Nelson et al., 2013a, b). The Formation. The graphic section depicted in Figure 2 Atrasado Formation has subsequently been divided into begins at the top of the Gray Mesa Formation near this eight members, which have been described and discussed change in slope. in detail elsewhere (e.g., Lucas et al., 2009, 2014, 2016). The basal unit of the overlying Atrasado Formation The units of interest to this study are the Bartolo Member (Bartolo Member base) is up to four meters of coarse- at the base of the Atrasado Formation, characterized by grained, arkosic, trough-crossbedded, pebbly sandstone. a relative abundance of siliciclastic deposits, followed by This laterally discontinuous but widespread sandstone at the Amado Member, largely consisting of limestone beds, the base of the Bartolo Member is the Coyote Sandstone and the overlying Tinajas Member, characterized again by Bed (Lucas et al., 2014), a term that dates back to Herrick’s a relative abundance of siliciclastics (Fig. 2). (1900) early discussions of the rocks of the Pennsylvanian In his monograph on fusulinids from the Manzano System in the vicinity of the Manzanita–Sandia Mountains. Mountains, Myers (1988) assigned a late Desmoinesian At Gotera Canyon, the Coyote Sandstone is overlain by an age to the upper part of the Gray Mesa Formation (his Los additional 29 meters of Bartolo Member strata expressed Moyos Limestone), placing it in his assemblage subzone mainly as covered intervals (shale) with a few decimeter- of Beedeina sulphurensis. Rare specimens of the fusulinid to meter-scale exposures of limestone and a single Wedekindellina ellipsoides were reported by Myers (1988, reddish- and greenish-gray sandstone bed. plate 5) from the upper part of the Gray Mesa Formation The overlying Amado Member forms the first prom- near Sol se Mete Peak, approximately 10 km to the north- inent limestone outcrop above the Gray Mesa Formation. east of Gotera Canyon, suggesting correlation of those At Gotera Canyon, the Amado is approximately 18 meters deposits with uppermost lower Desmoinesian (Cherokee thick, consisting of meter-scale beds of both cherty and ) strata of the Midcontinent (e.g., Wahlman, 2013). non-cherty bioclastic wackestone to packstone. Also pres- In a more recent study of calcareous microfossils from ent are meter-scale intervals consisting of thinner beds Cedro Peak, about 15 km to the north of Gotera Canyon, of wackestone to carbonate mudstone intercalated with Vachard et al. (2013) suggested a late early Desmoinesian thin shale interbeds and partings. The top of the Amado age for the youngest age-diagnostic assemblages they exam- is 1.2 meters of cherty limestone (unit 21 in Fig. 2). Here, ined from the Gray Mesa Formation, although diagnostic the hillslope along the traverse levels off again, forming from the uppermost part of the formation were not a bench that is underlain by interbedded limestone and obtained. Thus, available evidence from the Manzanita shale. Thin carbonate beds in these strata on the gentler Mountains suggests that much of the upper part of the slope above the Amado Member top contain the Gray Mesa Formation may be early Desmoinesian in age. fusulinid Eowaeringella, apparently corresponding to

36 New Mexico Geology Fall 2018, Volume 40, Number 2 lithology m unit 31 Triticites 30 29 mudstone/wackestone with shale breaks

Tinajas Mbr. (lower part) Triticites 70 26 very cherty mudstone/wackestone

25 cherty wackestone

24 60 phylloid-algal wackestone 23

fusulinid wackestone/packstone 22 Eowaeringella crinoidal wackestone/packstone 50 21 20 conglomeratic, arkosic sandstone (pebbles Amado Mbr. are quartz; Coyote SS is trough crossbedded) 19

arkosic sandstone 40 18 17 covered (shale/mudstone?) 16

13 12 lithostratigraphic units age 30 11 Wolfcampian

10 Moya Mbr. Del Cuerto Mbr Virgilian 9 Story Mbr. Bartolo Mbr. 20 Burrego Mbr.

Council Spring Mbr. 7 Missourian

Tinajas Mbr.

10 5 Amado Mbr. Atrasado Formation

Bartolo Mbr. 3

2 Coyote SS Bed Atrasado Fm. Desmoinesian 0 Gray Mesa 1 Gray Mesa Fm. Formation

mudstone wackestone Sandia Formation Atokan packstone

Figure 2. Stratigraphic section of the lower part of the Atrasado Formation at Gotera Canyon. Inset chart summarizes Pennsylvanian lithostratigraphy for central New Mexico, with age estimates for the southern Manzano Mountains (Priest Canyon) provided by Lucas et al. (2016).

Allen and Lucas Fig. 2 Fall 2018, Volume 40, Number 2 New Mexico Geology 37 Myers’ (1988) fusulinid locality f10177 in the “NW1/4 and 41 μm in thickness for the first through the seventh NW1/4 section 20, T. 8 N., R. 6 E.” volution. Septa are essentially planar across most of the At Gotera Canyon, the next prominent limestone shell, becoming irregularly folded in the polar extremities. interval above the Amado Member is 3.2 meters of The average septal count for the first through the seventh phylloid-algal wackestone, overlain by 3.3 meters of volution is 11, 16, 18, 20, 21, 24 and 26, respectively. medium- to coarse-grained pebbly sandstone (unit 24). Chomata are discrete mounds with steep to overhanging It could be argued that the top of the Amado Member tunnel sides and more gently inclined poleward sides, and at Gotera Canyon corresponds with the algal limestone are generally present in all but the final volution. Axial beneath this sandstone. However, the cherty limestone filling is insignificant. The tunnel occupies one half to two of unit 21 is an equally justifiable Amado top, and that thirds the height of the chamber and its path is generally option is presented here (Fig. 2). The important observa- straight, although it appears to wander somewhat in the tion, regardless of where the Amado–Tinajas contact is inner volutions of some specimens. The tunnel angle for chosen, is that the Eowaeringella horizon lies well above the first through the sixth volution averages 15, 20, 26, the top of the Gray Mesa Formation. 29, 34 and 44 degrees, respectively. The unit 24 sandstone in the lower part of the Tinajas Remarks—The tight coiling, planar septa becoming Member is overlain by a covered interval (4.1 meters; folded in the polar extremities, well-developed chomata probably mostly shale), followed by another prominent and the wall structure, in particular, help distinguish algal wackestone. This unit is overlain by a thin shale Eowaeringella from most other genera of fusulinids unit, 1.5 meters of thinly bedded mudstone to wacke- commonly found in central New Mexico. The relatively stone containing very small Triticites, another 1.3 meters large size, elongate shape and large proloculus of the Gotera of poorly exposed shale, followed by 1.5 meters of Canyon forms are consistent with assignment to E. hueco- fusulinid wackestone to packstone (unit 31). Tinajas ensis. Myers (1988) assigned Eowaeringella specimens from Member strata above this unit were not examined. In the Gotera Canyon locality to E. cf. E. joyitaensis Stewart, addition to fusulinids, unit 31 contains an abundance of but that species is significantly smaller and has a smaller other invertebrate fossils, including smaller foraminifers, proloculus than the specimens recovered in this study. and skeletons and fragments of and . Occurrence—Stewart’s (1968) type locality for Species of fusulinids recovered from the Gotera Canyon Eowaeringella huecoensis is in the Hueco Mountains of section are described below; illustrated specimens are El Paso County, Texas. E. huecoensis is present at Gotera reposited at the New Mexico Museum of Natural History Canyon in thin-bedded, pale-gray algal wackestone (unit and Science (NMMNH). 22 in Fig. 2), a few meters above a prominent cherty lime- stone assigned here to the top of the Amado Member of Paleontology the Atrasado Formation. Eowaeringella has been found in Pennsylvanian-aged strata in several mountain ranges Genus Eowaeringella Skinner and Wilde in New Mexico (Stewart, 1968; Wilde, 2006); it has Eowaeringella huecoensis Stewart been reported in the Manzanita Mountains only from Figs. 3.1–4, Table A1 the Gotera Canyon locality (Myers, 1988). The presence of this genus indicates correlation with early Missourian Eowaeringella huecoensis Stewart, 1968, Cushman strata of the Midcontinent (e.g., Wahlman, 2013). Foundation for Foraminiferal Research, Special Publication 16, p. 16–17, pl. 2, figs. 6, 8–10, table 5. Genus Triticites Girty Triticites cf. pygmaeus Dunbar and Condra Referred specimens—NMMNH P-55930 (two Figs. 3.5–8, Table A2 specimens; figs. 3.1, 3.3), NMMNH P-55931 (fig. 3.2), NMMNH P-55932 (fig. 3.4). Triticites cullomensis var. pygmaeus Dunbar and Condra, Description—The test is elongate-fusiform with con- 1928, Nebraska Geological Survey, Bulletin 2, Series vex to nearly straight to concave lateral slopes, rounded 2, p. 95–96, pl. V, figs. 3, 4. to bluntly pointed polar ends, and attains a length of Triticites pygmaeus Dunbar and Skinner, 1937, University 5.5 to 7.2 mm and a width of 1.4 to 1.8 mm in 6.5 to 8 of Texas Bulletin 3701, p. 614–616, pl. 48, figs. 13–26. volutions. The axis of coiling is typically straight, but is curved in some specimens. Early volutions are fusiform Referred specimens—NMMNH P-55934 (fig. 3.5), and somewhat inflated, expanding evenly, and gradually NMMNH P-55935 (fig. 3.6), NMMNH P-55936 become more elongate in succeeding whorls. The form (fig. 3.7), NMMNH P-55933 (fig. 3.8). ratio for mature individuals ranges from 3.4 to 4.1. Description—A small species of Triticites with a fusi- Morphometric data (Table A1) were obtained from form test and rounded to bluntly pointed ends, attaining four axial and three sagittal sections. The chambers are a length of 2.5 to 3.7 mm and a width of 1.0 to 1.4 mm nearly uniform in height across the central two thirds of in five to six volutions. The form ratio ranges from 2.3 to the shell. The height of successive whorls averages 58, 54, 2.6. The axis of coiling is generally straight; the lateral 78, 96, 123, 165, and 167 μm for the first through the slopes are typically evenly convex, but are nearly straight seventh volution. The diameter of the proloculus ranges to slightly concave in some individuals. The first volu- from 100 to 125 μm, averaging 116 μm. Average form tion is subspherical, with successive volutions becoming ratios for the first through the seventh volution are 1.9, increasingly elongate, typically progressing from elliptical 2.6, 2.9, 3.2, 3.4, 3.6 and 3.9, respectively. The spiroth- to fusiform in the outer whorls. eca consists of a tectum, a thicker diaphanotheca and an Measurements were obtained from seven axial and inner tectorium. The wall averages 18, 21, 24, 31, 34, 36 four sagittal sections (Table A2). The chamber height

38 New Mexico Geology Fall 2018, Volume 40, Number 2 varies little across the central portion of the shell, but tunnel averages 42, 53, 78, 118, 174, 229 and 254 μm increases notably toward the polar ends in the outer whorls for the first through the seventh volution. The spirotheca of mature specimens. The height of successive volutions in consists of a tectum and keriotheca, with alveoli evident the tunnel area averages 54, 65, 102, 138 and 178 μm for in the outer whorls. Wall thickness averages 13, 17, 23, the first through the fifth volution, respectively. The diam- 28, 38, 46 and 46 μm for the first through the seventh eter of the proloculus ranges from 96 to 140 μm, averaging volution. Septa are planar to gently undulating across 120 μm. Average form ratios for the first through the fifth the central part of the shell and seem rather widely volution are 1.3, 1.8, 2.2, 2.5, and 2.6. The spirotheca is spaced, with average septal counts for the first through thin, averaging 16, 19, 21, 25, 31, and 35 μm for the first the sixth volution of 9, 13, 15, 17, 18 and 19, respectively. through the sixth volution, and consists of a tectum and Chomata are asymmetrical mounds with comparatively keriotheca with alveoli becoming apparent in the outer steep faces toward the tunnel and gentler sides toward the whorls. Septa are nearly planar across the central part poles, and are generally present in all but the last whorl. of the shell, becoming irregularly fluted toward the ends. The tunnel is relatively low, and the tunnel angle for the Septal pores are readily apparent. Average septal counts first through the fifth volution averages 17, 26, 32, 46, and for the first through the fourth volution are 9, 16, 16 and 59 degrees, respectively. 18. Chomata are well-developed asymmetrical mounds Remarks—The elliptical outline of the test, thin with steep tunnel sides and sloping poleward sides, and walls, minimal septal fluting and modest size distinguish are generally present in the penultimate whorl. The tun- Triticites wellsi from most other species of Triticites nel widens through successive volutions, and its path is reported from central New Mexico. irregular in some specimens. The tunnel angle for the first Occurrence—Triticites wellsi is common in unit 31 through the fifth volution averages 23, 28, 39, 44 and (Fig. 2) of the Tinajas Member of the Atrasado Formation, 49 degrees, respectively. about 25 meters above the top of the Amado Member. Remarks—This small species of Triticites is similar Topotype specimens of T. wellsi collected from Needham’s to other small, relatively simple Missourian species, (1937) locality east of Barton in Santa Fe County occupy such as T. burgessae Burma and T. canyonensis Wilde. a similar stratigraphic position, approximately 15 meters The Gotera Canyon specimens possess a spirotheca that above the Amado Member at that locality. is quite thin, but most other morphometric parameters are quite similar to T. pygmaeus. The diameter of the Triticites cf. planus Thompson and Thomas proloculus, in particular, is significantly larger than in Figs. 3.12–14, Table A4 comparable species. Occurrence—Triticites cf. pygmaeus is common in Triticites planus Thompson and Thomas, 1953, The thin, wavy-bedded wackestone, a few meters below the Geological Survey of Wyoming, Bulletin 46, p. 31–34, main Triticites-bearing horizon at Gotera Canyon, in pl. 3, figs. 1–19, (?) pl. 4, figs. 1–10. the lower part of the Tinajas Member of the Atrasado Formation (unit 29 in Fig. 2). Referred specimens—NMMNH P-55939 (fig. 3.12), NMMNH P-55937 (fig. 3.13), NMMNH P-55938 (fig. 3.14). Triticites wellsi Needham Description—Tests are elongate fusiform to subcylin- Figs. 3.9–11, Table A3 drical in shape, with irregular lateral slopes and rounded to blunt ends in mature specimens. Lengths range from Triticites wellsi Needham, 1937, New Mexico Bureau of 5.7 to 7.5 mm and widths are 1.4 to 2 mm in 6 to 6.5 Mines and Mineral Resources, Bulletin 14, p. 37–38, volutions, resulting in form ratios ranging from 3.9 to 4.8. pl. VI, figs. 1–3. Volutions are tightly coiled and fusiform, with bluntly pointed ends in the juvenarium, becoming increasingly Referred specimens—NMMNH P-55940 (fig. 3.9), elongate in successive volutions. After about the fourth NMMNH P-55942 (fig. 3.10), NMMNH P-55941 (fig. 3.11). volution the axis of coiling tends to become irregular in Description—Elongate elliptical tests commonly most specimens and the ends more rounded. attain a length of 5 to 5.5 mm and a width of 1.4 to 1.8 Measurements (Table A4) were obtained from seven mm in six to seven volutions, with a straight to curved axial and three sagittal sections. The average form ratios axis of coiling and rounded ends. Lateral slopes are typ- for the first through the sixth volution are 1.6, 2.2, 2.5, ically convex, but may be straight or somewhat concave 3.0, 3.5 and 3.9, respectively. The proloculus ranges in in specimens with a curved axis. Overall the shell bears diameter from 62 to 116 μm in diameter, averaging 90 μm. a loosely coiled appearance. The form ratio of mature The chambers are lowest in the central part of the test and specimens ranges from 2.8 to 3.2. increase in height in the polar areas. The height of succes- Measurements were obtained from four axial and sive volutions above the tunnel averages 45, 58, 89, 140, three sagittal sections (Table A3). Early volutions are fusi- 202 and 242 μm in the first through the sixth volution. form and somewhat inflated with bluntly pointed ends, The spirotheca consists of a tectum and keriotheca and becoming progressively more elliptical after the fourth is relatively thin, averaging 13, 16, 21, 29, 40 and 45 μm or fifth volution. Averages of the form ratios for the first for the first through the sixth volution. Septa are nearly through seventh volutions are 1.5, 1.8, 2.0, 2.3, 2.6, planar across the central two thirds of the shell, becoming 2.8 and 2.8, respectively. The proloculus ranges in diam- irregularly folded in the polar extremities. Average septal eter from 60 to 110 μm, averaging 96 μm. The chambers counts for the first through the fifth volution are 8, 13, are uniform in height across much of the shell, with a 16, 18 and 21. Chomata in the inner few volutions appear relative increase in height in the polar extremities of some to extend to the ends of the shell in some specimens. In specimens. The height of successive volutions above the later volutions the chomata are small, nearly symmetrical

Fall 2018, Volume 40, Number 2 New Mexico Geology 39 Figure 3. Fusulinids from the lower part of the Tinajas Member (NMMNH P-55934, NMMNH P-55936, NMMNH P-55933), axial at Gotera Canyon in the Manzanita Mountains. All images sections. 6 (NMMNH P-55935), sagittal section. 9–11. Triticites 15X magnification. 1–4. Eowaeringella huecoensis Stewart. 1, wellsi Needham. 9, 10 (NMMNH P-55940, NMMNH P-55942), 4 (NMMNH P-55930a, NMMNH P-55932), axial sections. 2 axial sections. 11 (NMMNH P55941), sagittal section. 12–14. (NMMNH P-55931), sagittal section. 3 (NMMNH P-55930b), Triticites cf. planus Thompson and Thomas. 12, 14 (NMMNH tangential section of an adolescent specimen with a curved coiling P-55939, NMMNH P-55938), axial sections. 13 (NMMNH P55937), axis. 5–8. Triticites cf. pygmaeus Dunbar and Condra. 5, 7–8 sagittal section.

40 New Mexico Geology Fall 2018, Volume 40, Number 2 mounds. The tunnel widens from about 25 degrees in the from 19 localities in the U.S., including 9 localities in first volution to 65 degrees in the sixth. New Mexico. As discussed by Stewart (1968), the fusul- Remarks—A number of slender, subcylindrical, inid genus Eowaeringella is an important Pennsylvanian relatively simple forms of Triticites have been reported index , occupying a narrow stratigraphic interval from central New Mexico (e.g., T. ohioensis Thompson) between the Middle Pennsylvanian fusulinid Zone of that are similar to the Gotera Canyon specimens dis- Beedeina below and the Upper Pennsylvanian Zone cussed here. The comparatively modest septal fluting of Triticites above. Thus, following the demise of the together with other characteristics of the Gotera Canyon Desmoinesian Beedeina fauna, Eowaeringella was the specimens (e.g., lower form ratios relative to T. ohioensis) first biostratigraphically diagnostic fusulinid to appear, suggest assignment to T. planus. The presence of such and its presence in strata is considered diagnostic of an forms indicates correlation with Missourian (Kansas early Missourian age. City Group) strata of the Midcontinent (Thompson and The stratigraphic position of Eowaeringella in Thomas, 1953). the Tinajas Member at Gotera Canyon suggests a Occurrence—Triticites cf. planus is common in the Desmoinesian age assignment for some portion of the Gotera Canyon section in bedded bioclastic wackestone 50 meters of Atrasado strata underlying the Tinajas. We to packstone in the lower part of the Tinajas Member of are unaware of any diagnostic fusulinid data from the the Atrasado Formation (unit 31 in Fig. 2). It is associated lower two members of the Atrasado Formation in the with Triticites wellsi Needham, together with a small, Manzanita Mountains; Lucas et al. (2016) reported a spe- less common species (?T. nebraskensis Thompson) that is cies of Plectofusulina from the upper part of the Amado not discussed here because inadequate oriented sections Member at Priest Canyon in the southern Manzano were obtained. Triticites planus has been reported from Mountains, which may indicate an early Missourian the Manzanita Mountains near the Kinney Brick Quarry, age. Myers (1969) noted the presence of an unidentified 10 km north of the Gotera Canyon section, also in the species of the Desmoinesian genus Fusulina (=Beedeina) lower part of the Tinajas Member (Lucas et al., 2011). approximately 15 meters below what is considered here to be the top of the Gray Mesa Formation at the Discussion Gotera Canyon locality. Thus, taking the available data The Pennsylvanian section has recently been described in at face value suggests that the Desmoinesian–Missourian detail at Priest Canyon at the southern end of the Manzano boundary lies somewhere within ~65 meters of section Mountains and at Cedro Peak in the Manzanita Mountains extending from 15 meters below the top of the Gray at the northern end of the range (Lucas et al., 2014, 2016; Mesa Formation upward through 50 meters of Atrasado Fig. 1). The overall architecture of strata assigned to the strata comprising the Bartolo and Amado members. As Pennsylvanian System appears to be similar across the mountain block, and the lithostratigraphic terminology in current use for the Pennsylvanian System in central New Mexico is clearly applicable at the Gotera Canyon locality, at least for the part of the section that was examined. In particular, the base of the Atrasado Formation is readily distinguished from the underlying Gray Mesa Formation by the presence of approximately 30 meters of slope-forming clastic deposits of the Bartolo Member. Although Myers (1988) reported that the Eowaeringella horizon at Gotera Canyon is at the top of the Gray Mesa Formation, and depicted it as such on his graphic section for the locality (Myers, 1969), his geologic map (see Fig. 4) places the top of the Gray Mesa Formation well below the Eowaeringella-bearing measured section (Fig. 2) horizon, in close agreement with 500 m Myers (1969) section the obvious lithologic change Eowaeringella horizon T8N, R6E, sec. 17 & 20 from limestone to sandstone marking the top of the formation Figure 4. Geologic map of the Gotera Canyon locality (from Myers, 1969; red dashed lines are at this locality. structure contours), annotated to show the Figure 2 measured-section traverse and Eowaeringella Stewart (1968) described locality. Green map unit ( ml – lower Madera Limestone) and blue/purple unit ( mu – upper several species of Eowaeringella Madera Limestone) correspond to the Gray Mesa and Atrasado formations.

Fall 2018, Volume 40, Number 2 New Mexico Geology 41 noted above, conodont biostratigraphy from the Cerros Tinajas Member Triticites horizon helped to establish a de Amado east of Socorro (Barrick et al., 2013) suggests Missourian age for the strata comprising that import- that the Desmoinesian-Missourian boundary there lies ant fossil locality, an age assignment confirmed by within the Amado Member. conodont biostratigraphy (Lucas et al., 2011). The limestone beds containing abundant fusul- inids 25 meters above the Eowaeringella horizon are Conclusions important for two reasons. First, the forms of Triticites Lower Missourian fusulinids (Eowaeringella) present that are present indicate an early to middle Missourian at the northern end of the Manzano Mountains in Gotera age for these strata. Second, similar conditions that led Canyon are readily assignable to strata of the Atrasado to significant accumulations of Triticites in the lower Formation, 50 meters above the top of the Gray Mesa part of the Tinajas Member at Gotera Canyon appear Formation, and not at the top of the Gray Mesa as to have occurred over a large area encompassing previously reported. Early forms of Triticites are the Manzanita Mountains northward to the Sandia present in abundance 75 meters above the base of the Mountains. Indeed, examination of dozens of outcrops Atrasado Formation at Gotera Canyon. This distinc- of the Amado–Tinajas interval in this area has shown tive fusulinid horizon appears to be widespread across that limestone beds containing an abundance of early the Manzanita–Sandia Mountains, where it consistently forms of Triticites are usually present in the lower part occupies a similar stratigraphic position within the of the Tinajas Member, a short distance above the lower part of the Missourian Tinajas Member of the prominent Amado Member of the Atrasado Formation. Atrasado Formation. This fusulinid marker horizon in the lower part of the Tinajas Member was an important factor in deter- mining the age of strata comprising the Kinney Brick Acknowledgments Quarry Lagerstätte in the Manzanita Mountains, which Assistance gaining access to Gotera Canyon by person- is located approximately 10 km north of the Gotera nel with the Public Services Department, Isleta Pueblo, Canyon locality. For many years, it was thought that is gratefully acknowledged. We thank Merlynd Nestell, strata exposed at the Kinney Brick Quarry were Virgilian Daniel Vachard and Gregory Wahlman for their construc- in age (see articles in Zidek, 1992). Recognition that the tive reviews, and Shari Kelley for editorial supervision. quarry is in close stratigraphic proximity to the lower

References Lucas, S.G., Krainer, K., Allen, B.D., and Read, C.B, and Wood, G.H., Jr., 1947, Vachard, D., 2014, The Pennsylvanian Distribution and correlation of Pennsylva- Barrick, J.E., Lucas, S.G., and Krainer, section at Cedro Peak: a reference section nian rocks in Late Paleozoic sedimentary K., 2013, of the Atrasado in the Manzanita Mountains, central New basins of northern New Mexico: Journal of Formation (uppermost Middle to Upper Mexico: New Mexico Geology, v. 36, p. Geology, v. 55, p. 220–236. Pennsylvanian), Cerros de Amado region, 3–24. Stewart, W.J., 1968, The stratigraphic and central New Mexico, U.S.A.: New Mexico Lucas, S.G., Krainer, K., and Vachard, D., phylogenetic significance of the fusulinid Museum of Natural History and Science, 2016, The Pennsylvanian section at Priest genus Eowaeringella, with several new Bulletin 59, p. 239–252. Canyon, southern Manzano Mountains, species: Cushman Foundation for Foramin- Herrick, C.L., 1900, The geology of the White New Mexico: in Frey, B.A., Karlstrom, iferal Research, Special Publication no. 10, Sands of New Mexico: Journal of Geology, K.E., Lucas, S.G., William, S., Ziegler, K., 29 p. v. 8, p. 112–128. McLemore, V., and Ulmer-Scholle, D.S., Thompson, M.L, and Thomas, H.D., 1953, Kelley, V.C., and Wood, G.H., Jr., 1946, eds., The Geology of the Belen Area, New Systematic paleontology of fusulinids from Lucero uplift, Valencia, Socorro, and Mexico Geological Society, 67th Annual the Casper Formation: The Geological Bernalillo counties, New Mexico: U.S. Geo- Field Conference, Guidebook, p. 275–301. Survey of Wyoming, Bulletin 46, Part II, p. logical Survey, Oil and Gas Investigations Myers, D.A., 1969, Geologic map of the 15–56. Preliminary Map 47, scale 1:63,360. Escabosa quadrangle, Bernalillo County, Vachard, D., Krainer, K., and Lucas, S.G., Kues, B.S., 2001, The Pennsylvanian System New Mexico: U.S. Geological Survey, 2013, Pennsylvanian (Late ) in New Mexico—overview with suggestions Geologic Quadrangle Map GQ-795, scale calcareous microfossils from Cedro Peak for revision of stratigraphic nomenclature: 1:24,000. (New Mexico, USA): Part 2. Smaller New Mexico Geology, v. 23, p. 103–122. Myers, D.A., 1973, The Upper Paleozoic foraminifers and fusulinids: Annales de Lucas, S.G., Krainer, K., and Barrick, J.E., in the Manzano Mountains, Paléontologie, v. 99, p. 1–42. 2009, Pennsylvanian stratigraphy and New Mexico: U.S. Geological Survey, Wahlman, G.P., 2013, Pennsylvanian to Lower conodont biostratigraphy in the Cerros de Bulletin 1372-F, 13 p. Permian (Desmoinesian-Wolfcampian) Amado, Socorro County, New Mexico: in Myers, D.A., 1988, Stratigraphic distribution fusulinid biostratigraphy of Midcontinent Lueth, V., Lucas S.G., Chamberlin, R.M., of fusulinid from the Manzano North America: Stratigraphy, v. 10, p. eds., Geology of Chupadera Mesa, New Mountains, New Mexico: U.S. Geological 73–104. Mexico Geological Society, 60th Annual Survey, Professional Paper 1446, 65 p. Wilde, G.L., 2006, Pennsylvanian-Permian Field Conference, Guidebook, p. 183–211. Nelson, W.J., Lucas, S.G. and Krainer, K., fusulinaceans of the Big Hatchet Moun- Lucas, S.G., Allen, B.D., Krainer, K., Barrick, 2013[a], The Atrasado and Bar B formations tains, New Mexico: New Mexico Museum J., Vachard, D., Schneider, J.W., DiMichele, (Middle-Upper Pennsylvanian) in central of Natural History and Science, Bulletin 38, W.A., and Bashforth, A.R., 2011, Precise and southern New Mexico: New Mexico 331 p. age and biostratigraphic significance of the Museum of Natural History and Science, Zidek, J., ed., 1992, Geology and paleon- Kinney Brick Quarry Lagerstätte, Pennsyl- Bulletin 59, p. 123–142. tology of the Kinney Brick Quarry, Late vanian of New Mexico, USA: Stratigraphy, Nelson, W. J., Lucas, S. G., Krainer, K. Pennsylvanian, central New Mexico: New v. 8, p. 7–27. and Elrick, S., 2013[b], The Gray Mesa Mexico Bureau of Mines and Mineral Formation (Middle Pennsylvanian) in Resources, Bulletin 138, 242 p. New Mexico: New Mexico Museum of Natural History and Science, Bulletin 59, p. 101–122.

42 New Mexico Geology Fall 2018, Volume 40, Number 2 Table A2. Measurements of Triticites cf. pygmaeus Dunbar and Appendices Condra. Specimens A, I, B, and E are illustrated in text Figs. 3.5, 3.6, Table A1. Measurements of Eowaeringella huecoensis Stewart. 3.7, and 3.8, respectively. Specimens A, E, and C are illustrated in text Figs. 3.1, 3.2, and 3.4, respectively. Half length (mm) Volution Half length (mm) Specimen 1 2 3 4 5 6 Volution A 0.167 0.332 0.616 0.987 1.312 — Specimen 1 2 3 4 5 6 7 8 B 0.146 0.322 0.704 1.289 1.817 — A 0.159 0.324 0.612 0.968 1.520 2.129 2.915 3.800 C 0.156 0.351 0.556 1.012 1.537 — B 0.316 0.651 1.089 1.607 2.064 2.812 — — D 0.138 0.253 0.440 0.828 1.485 — C 0.162 0.305 0.532 0.837 1.209 1.816 2.628 3.305 E 0.154 0.322 0.648 1.061 1.440 — D 0.162 0.319 0.497 0.814 1.270 1.790 2.664 — F 0.102 0.205 0.382 0.684 1.147 1.815 G 0.126 0.279 0.467 0.711 1.066 1.583 Radius vector (mm) Volution Radius vector (mm) Spec. 0 1 2 3 4 5 6 7 8 Volution A 0.058 0.105 0.157 0.222 0.305 0.414 0.556 0.703 0.883 Specimen 0 1 2 3 4 5 6 B 0.063 0.135 0.190 0.284 0.390 0.531 0.747 — — A 0.053 0.088 0.152 0.242 0.360 0.539 — C 0.063 0.099 0.155 0.224 0.320 0.433 0.583 0.762 0.958 B 0.061 0.103 0.156 0.256 0.406 0.657 — D 0.050 0.074 0.115 0.184 0.271 0.383 0.508 0.652 — C 0.062 0.142 0.216 0.313 0.485 0.674 — E 0.060 0.153 0.217 0.303 0.398 0.508 0.680 0.867 — D 0.059 0.119 0.165 0.236 0.359 0.513 — F 0.058 0.131 0.189 0.276 0.382 0.535 0.721 0.898 — E 0.070 0.112 0.166 0.258 0.394 0.563 — G 0.055 0.117 0.193 0.279 0.375 0.503 0.633 0.808 0.988 F 0.048 0.103 0.145 0.219 0.317 0.459 0.662 G 0.050 0.085 0.132 0.198 0.302 0.440 0.608 Thickness of spirotheca (μm) H 0.070 0.137 0.237 0.362 0.533 — — Volution I 0.065 0.131 0.215 0.378 0.553 — — Specimen 1 2 3 4 5 6 7 8 J 0.063 0.107 0.180 0.317 0.446 0.644 — A 16 26 20 37 36 40 30 30 K 0.055 0.118 0.193 — — — — B 18 18 26 24 40 39 — — C 13 18 24 29 25 28 35 39 Thickness of spirotheca (μm) D 14 17 19 28 30 33 40 — Volution E 25 24 28 44 34 43 50 — Specimen 1 2 3 4 5 6 F 26 21 28 32 38 39 51 — A 12 15 18 30 37 — G 16 21 27 25 32 32 40 31 B 21 23 30 40 38 — C 25 27 28 32 42 — Tunnel angle (deg.) D 17 17 19 20 29 — Volution E 16 20 22 27 34 — Specimen 1 2 3 4 5 6 7 F 15 15 14 14 15 38 A 17 21 23 28 25 38 44 G 11 11 13 15 22 33 B 14 23 33 33 43 — — H 11 19 19 25 — — C 15 18 20 23 30 44 39 I 17 20 25 32 — — D 13 19 26 31 36 49 — J 12 17 23 19 34 K 16 23 — — — Septal count Volution Tunnel angle (deg.) Specimen 1 2 3 4 5 6 7 8 Volution E 13 17 19 22 24 30 28 — Specimen 1 2 3 4 5 F 12 15 19 19 21 22 27 — A 24 30 36 41 — G 9 15 16 18 18 21 23 24 B 28 39 52 42 — C 28 29 46 — — D 21 28 33 46 — E 22 29 45 36 — F 13 10 31 52 55 G 25 30 27 44 42

Septal count Volution Specimen 1 2 3 4 5 H 10 18 14 16 — I 9 16 17 21 — J 8 16 18 18 19 K 9 14 — — —

Fall 2018, Volume 40, Number 2 New Mexico Geology 43 Table A3. Measurements of Triticites wellsi Needham. Specimens D, Table A4. Measurements of Triticites cf. planus Thompson and B, and G are illustrated in text Figs. 3.9, 3.10, and 3.11, respectively. Thomas. Specimens D, H, and A are illustrated in text Figs. 3.12, 3.13, and 3.14, respectively. Half length (mm) Volution Half length (mm) Specimen 1 2 3 4 5 6 7 Volution A 0.084 0.186 0.380 0.741 1.277 1.80 2.633 Specimen 1 2 3 4 5 6 B 0.143 0.310 0.510 0.890 1.484 2.18 2.725 A 0.134 0.302 0.540 1.056 1.898 3.094 C 0.141 0.262 0.394 0.635 0.938 1.68 2.186 B 0.103 0.230 0.427 0.933 1.744 3.021 D 0.086 0.177 0.397 0.650 1.109 1.74 2.676 C 0.200 0.459 1.006 1.791 3.129 — D 0.212 0.386 0.646 1.340 2.183 3.139 Radius vector (mm) E 0.121 0.316 0.651 1.176 2.029 3.497 Volution F 0.147 0.332 0.566 1.108 1.840 2.881 Spec. 0 1 2 3 4 5 6 7 G 0.108 0.214 0.393 0.760 1.517 3.046 A 0.055 0.085 0.131 0.201 0.304 0.439 0.643 0.877 B 0.053 0.080 0.136 0.219 0.344 0.528 0.754 0.998 Radius vector (mm) C 0.052 0.071 0.133 0.210 0.294 0.413 0.586 0.788 Volution D 0.053 0.081 0.132 0.199 0.310 0.464 0.705 1.039 Specimen 0 1 2 3 4 5 6 E 0.036 0.106 0.149 0.218 0.332 0.491 0.767 — A 0.047 0.080 0.139 0.225 0.330 0.508 0.768 F 0.030 0.091 0.141 0.229 0.376 0.623 0.880 — B 0.036 0.062 0.105 0.171 0.294 0.447 0.684 G 0.055 0.109 0.169 0.258 0.398 0.615 — — C 0.053 0.111 0.187 0.304 0.509 0.818 — D 0.058 0.103 0.168 0.282 0.444 0.700 0.962 Thickness of spirotheca (μm) E 0.055 0.083 0.141 0.221 0.382 0.589 0.845 Volution F 0.037 0.094 0.160 0.240 0.381 0.588 0.903 Specimen 1 2 3 4 5 6 7 G 0.031 0.084 0.125 0.209 0.328 0.486 0.673 A 13 20 29 29 35 42 40 H 0.040 0.088 0.139 0.234 0.365 0.533 0.710 B 13 18 27 36 51 44 46 I 0.048 0.102 0.167 0.254 0.397 0.602 — C 9 18 22 22 38 46 46 J 0.045 0.092 0.146 0.232 0.346 0.529 — D 8 18 23 27 33 46 51 E 15 12 13 21 27 44 — Thickness of spirotheca (μm) F 18 21 25 34 45 55 — Volution G 16 15 20 24 41 — — Specimen 1 2 3 4 5 6 A 11 19 17 25 44 48 Tunnel angle (deg.) B 9 14 18 24 34 46 Volution C 18 21 22 42 54 — Specimen 1 2 3 4 5 6 D 11 14 31 34 41 47 A 14 21 33 45 59 55 E 12 17 28 33 48 44 B 14 31 39 52 54 — F 15 17 17 22 34 40 C 21 24 28 42 64 — G 12 12 22 30 31 43 D 17 29 26 43 57 — H 16 19 21 28 40 45 I 15 17 22 31 40 — Septal count J 10 14 18 24 36 — Volution Specimen 1 2 3 4 5 6 Tunnel angle (deg.) E 8 12 14 18 20 19 Volution F 8 12 15 16 17 19 Specimen 1 2 3 4 5 G 10 14 16 18 16 — A 20 33 45 56 69 B 28 26 34 48 50 C 23 37 54 50 — D 27 32 40 51 64 E 31 39 54 75 — F 26 35 44 65 — G 11 20 31 45 69

Septal count Volution Specimen 1 2 3 4 5 6 H 8 14 15 19 19 17 I 8 11 15 18 22 — J 8 14 17 18 22 —

44 New Mexico Geology Fall 2018, Volume 40, Number 2