Devonian Conodonts in Arizona R

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Devonian conodonts in Arizona R. L. Ethington, 1962, pp. 72-76 in: Mogollon Rim Region (East-Central Arizona), Weber, R. H.; Peirce, H. W.; [eds.], New Mexico Geological Society 13th Annual Fall Field Conference Guidebook, 175 p.

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DEVONIAN CONODONTS IN ARIZONA R. L. ETHINGTON University of Missouri, Columbia

DEVONIAN STRATIGRAPHIC NOMENCLATURE a local facies of the Percha. Occurrence of Devonian rocks in southern Arizona was Devonian beds in the Swisshelm and Pedregosa Moun- reported by Williams (1903, p. 41), who compared fossils tains between Bisbee and the Chiricahuas contain a high found along Pinal Creek north of Globe with the already proportion of clastics. They were described as the Swiss- well known fauna at Rockford, Iowa. The following year helm Formation by Epis, Gilbert, and Langenheim (1957) the same author examined brachiopods collected from the who considered them to be equivalent to the Martin to the section at Bisbee by F. L. Ransome and correlated them with west, as well as to the combined Ohate, Sly Gap and Con- the Rockford fauna and fossils from the basal Chemung of tadero of New Mexico. Absence of fossils typical of the New York. He interpreted Theodossia [ Spirifer] hunger- Percha from the Arizona exposures was attributed to dif- forth, which is common at Bisbee, as having close affinities ference in facies. It was suggested that the Martin- with Spirifer anossofi, a Russian species which was then Swisshelm, the Oriate-Sly Gap-Contadero sequence, and considered to be contemporaneous with the Middle Devon- the Percha are arealy distinct facies of a contemporaneous ian index Stringocephalus in central Europe. Williams unit in which the Percha is a central basin deposit, whereas therefore believed the beds at Bisbee to be of Middle the others represent marginal phases. Devonian age. Ransome (1923) and Stoyanow (1936) Stoyanow (1936) believed that during late Devonian reevaluated this assignment in the light of more recent time central Arizona was occupied by a northeast-trending interpretations of the Russian species and decided upon an highland area of Precambrian rocks to which he gave the Upper Devonian age for the Arizona brachiopod fauna. name Mazatzal Land. According to his interpretation the Ransome (1904, p. 33) used the name Martin Lime- Martin sea advanced northwestward from southern Arizona stone for the Devonian beds of the Bisbee section. During toward this barrier only as far as the general vicinity of the ensuing years, equivalent strata have been found to be Roosevelt Lake. Devonian deposits near Payson, some 40 widely distributed in the mountain ranges of south-central miles farther to the north, were considered to be deposits Arizona between the Mogollon Rim and the Mexican border. laid down in another sea which transgressed from the north- The Martin Formation is principally a carbonate sequence in west toward Mazatzal Land. These strata were correlated the southern part of the state and maintains a relatively with the Devonian sequence near Jerome and given the uniform thickness of the order of 375 feet in the various name Jerome Formation. Stoyanow concluded that the ranges where it is exposed. Toward central Arizona an Martin Limestone, which he restricted to the portion of the increasingly high proportion of clastic material is admixed Devonian succession at Bisbee containing the T. hungerfordi with the carbonate. fauna, was equivalent to the fossiliferous upper part of his The brachiopod fauna, on which Upper Devonian age Jerome Formation. From a locality along the Verde River assignment was based, is restricted to the upper part of the about 12 miles north of Jerome, Stoyanow also described formation. Stoyanow (1936) reported the occurrence of 125 feet of strata containing a molluscan fauna which was Camarotoechia endlichi, a characteristic fossil of the Percha not developed in the Devonian in other areas, and applied Formation of New Mexico and the Ouray beds of the Four the name Island Mesa beds to them. It seems probable Corners region, above the strata containing Theodossia that only a local faunal zone within the Devonian sequence hungerfordi and Cyrtospirifer whitneyi in Peppersauce Can- is represented and that a distinct stratigraphic designation yon on the east side of the Santa Catalina Mountains near is not warranted. Tucson, and along Pinal Creek northwest of Globe. He Huddle and Dobrovolny (1952) and Anderson and suggested that these upper rocks be considered a separate Creasey ( 1958) rejected Stoyanows use of a separate for- formation which he named the Lower Ouray. Occurrence mational name for the Devonian rocks north of Mazatzal of Spirifer iowensis near the middle of the Devonian se- Land. They applied the term Martin Formation for all De- quence at Superior, Arizona, has been recorded by Stoya- vonian strata in central Arizona south of the Mogollon Rim. now. He also described abundant stromatoporoids from McNair (1951) equated the Muddy Peak Limestone of the approximately the same horizon in the Picacho de Calera Virgin Mountains in extreme northwestern Arizona with the hills near Rillito, Arizona. Correlation of this lower portion Devonian of the Jerome area. He considered these rocks of the Devonian strata of central Arizona with the Middle to be laterally gradational in a northeasterly direction into Devonian Cedar Valley Formation of Iowa was inferred, the Temple Butte Limestone of the Grand Canyon region. and Stoyanow proposed that these beds be set apart from DEVONIAN CORRELATIONS the upper part of the section as the Picacho de Calera Most authors have correlated the Martin Formation Formation. Most subsequent authors have rejected the Low- with the early Upper Devonian Lime Creek (Hackberry) er Ouray and Picacho de Calera of Stoyanow as formations, beds of northern Iowa owing to the common occurrence of and instead considered them to be faunal zones within the brachiopods, particularly Theodossia hungerfordi (Hall) Martin Formation. and Cyrtospirifer whitneyi (Hall), in both units. General Sabins (1957) described a carbonate and black shale equivalence to at least the lower part of the Chemung of sequence of Upper Devonian age which crops out along the New York has been reported (Cooper, et al., 1942). east flank of the Chiricahua Mountains in southeastern Ari- Merriam (1940) correlated the Martin strata containing the zona. The black fissile shale member in the lower half brachiopod fauna with the Cyrtospirifer zone of the Devils of the formation is suggestive of the basal part of the Gate Formation of Nevada. However, owing to the occur- Percha Formation, but , owing to the distance from the type rence of Pachyphyllum in the Martin, he considered it to be area of the latter, the name Portal Formation was applied only slightly younger than the lower zone of the Devils to the Arizona unit. Pye (1959) considered the Portal to be Gate. NEW MEXICO GEOLOGICAL SOCIETY n THIRTEENTH FIELD CONFERENCE 73

Correlation of the entire Martin is questionable be- crop, rock specimens were taken at every lithologic change cause the Theodossia-Cyrtospirifer fauna is restricted to to the base of the yellow shale . Thick units were sampled only a part of the carbonate sequence. In central Arizona, at intervals to provide representative material. A total of for example, it is found in only the upper fourth of the 31 samples were collected, of which 23 contained at least Martin strata. No fossils are known from the lower half some Devonian conodonts, although only four yielded any of the unit in this area. However, as stated above, Stay- significant number. anow based a correlation of lower Martin with the Cedar Material collected at the top of the yellow shale was Valley Formation on the reported occurrence of Middle disaggregated by kerosene treatment and proved to be Devonian spirifers and stromatoporoids just above the mid- barren. The overlying yellow dolomitic strata were dle of the formation. sampled at two-foot intervals and produced a few frag- Early reports I Ransome, 1916, 1923) considered the mented polygnathid conodonts. A thin, slabby layer, Martin fauna to suggest equivalence to the Percha Forma- about an inch thick, at the contact between the yellow tion of New Mexico and the Ouray Formation of south- beds and the overlying gray, crinoidal limestone produced western Colorado. Stoyanow has demonstrated that char- an abundance of somewhat crushed specimens of Siphono- acteristic Ouray-Percha species are present above lime- della. Limestone taken six inches higher in the Mississip- stones carrying the typical Martin brachiopods along Pinal pian rocks was barren. Creek northwest of Globe, and in Peppersauce Canyon 2.—A complete section of the Martin Formation is east of Tucson. That the Martin brachiopods are older well exposed on the north side of Queen Creek Canyon than those of the Percha is further substantiated by Stain- one-fourth mile east of Superior, Arizona. Material was brooks ( 1947) report of discovery of a Percha fauna collected at five-foot intervals from the top of the lowest above the brachiopod-bearing beds in the Martin at the quartzite near the middle of the formation to the base of type locality near Bisbee. the red fissile shale near the top of the unit. These strata The Portal Formation, described by Sabins in extreme comprise the Middle and Upper Members of the Martin southeastern Arizona, contains a high percentage of shale, Formation as described by Huddle and Dobrovolny. The particularly in the lower half of the unit. In this respect lower portion of the sampled sequence includes the upper it resembles the Percha Shale. However, G. A. Cooper beds which Stoyanow believed to be of Middle Devonian ( in Sabins, 1957) interpreted a sparse brachiopod fauna age. Conodonts were found in half of the specimens col- from near the top of the Portal as being slightly older than lected, although none of them produced any abundance. typical Percha forms. Sabins therefore concluded that The lower 165 feet of Devonian strata at this locality con- these strata are broadly equivalent to the Martin. stitute the Lower Member of the Martin of Huddle and DEVONIAN CONODONT LOCALITIES Dobrovolny, and the greater part of Stoyanows Lower Carbonate samples from Devonian rocks collected at Ouray Formation. These beds consist of gray, buff- a number of localities in Arizona have been processed in weathering, silty dolomitic limestone and are not known to acetic or formic acid and the residues examined for cono- contain fossils. Samples collected randomly through this donts. Quantity of conodonts recovered varied widely part of the section proved to be totally barren of conodonts. among the several localities, and at none of them could 3.—Lithologic material collected at Black Gap, three these fossils be considered to occur in abundance. In this miles southeast of Bisbee, near the type locality of the respect, the Arizona Devonian rocks differ markedly from Martin, was almost all unproductive. No conodonts were approximately contemporaneous formations in the mid- found in those strata containing the abundant brachiopod continent region in which abundant conodont faunas oc- and coral fauna on which correlation of the Martin strata cur. However, sufficient numbers were found at three of has been based. This region has been intensely mineral- the localities studied to provide representative conodont ized, and all of the megafossils are almost completely collections. In all cases the color of the specimens is jet silicified. Possibly conodonts were destroyed in the pro- black, apparently as a result of alteration . This may have cess, if they ever were present in these rocks. A number accompanied the sulphide mineralization which has af- of limestone blocks collected from exposures of fossilifer- fected the limestones at all of the localities which were ous Martin in road cuts in the Bisbee area also were totally examined. devoid of conodonts. Collecting areas were as follows: 4.—Sabins reported the occurrence of several cono- 1.—The Devonian section along the west side of dont genera in the lower member of his Portal Formation Pinal Creek, three miles northwest of Globe, is the one at Blue Mountain, on the east side of the Chiricahua Moun- from which Williams reported Devonian brachiopods in tains . Rock collected at two-foot intervals contained cono- Arizona. These strata were measured and described by donts only in the upper 36 feet of this member. The re- Stauffer (1928), who also recorded an extensive faunal mainder of the unit, which becomes increasingly shaly list. Stauffer placed the Mississippian-Devonian boundary toward its base, is barren as are the other three members at the base of a yellow, splintery shale. However, Stoy- of the Portal Formation at this locality. anow found Camarotoechia endlichi in the 18 feet of yel- 5.—Devonian corals are abundant in reddish, dolo- low-gray, sugary dolomitic limestone above the shale, and mitic limestone at the quarry a half mile north of the Dia- correlated the shale and overlying beds with the Ouray mond Point Fire Control Tower, 11 miles east of Payson, and Percha. Arizona. Lithologic material from this quarry did not pro- The lower part of the exposure consists of buff- duce conodonts. Random collections from the Martin ex- weathering, thick-bedded dolomitic limestones which be- posures on the slope north of Sycamore Creek, a mile west come increasingly sandy about 100 feet above the base of the East Verde River bridge on the Pine-Payson highway, of the section. These beds do not contain megafossils and were also unproductive. Possibly very systematic sampling were not sampled at this locality. Beginning at the base of the Devonian at the latter locality would provide a of Stauffers Unit 11, the fossiliferous portion of the out- conodont fauna. 74 NEW MEXICO GEOLOGICAL SOCIETY L THIRTEENTH FIELD CONFERENCE

CONODONTS OF THE MARTIN AND PORTAL FORMATIONS Bryantodus sp. Occurrences of conodonts seem to be rather sporadic Hindeodella sp. in the Devonian of Arizona. Only three of the collecting Icriodus symmetricus Branson Mehl sites from which samples were taken produced significant I. aff. I. cornutus Sannemann numbers of specimens . Frequency of occurrence varies Ligonodina delicata Branson Mehl considerably between successive lithologies within indivi- L. flexuosa Branson Mehl dual outcrops, and even within individual layers. Re- Lonchodina robusta Branson Mehl sampling of the more productive horizons determined by Neoprioniodus sp. the initial collection at the Pinal Creek locality in general Ozarkodina aff. 0. plans (Huddle) failed to produce additional specimens. It therefore 0. sp. appears that conodonts occur only locally within the strata, Palmatodella sp. rather than being uniformly distributed. Possibly local Palmatolepsis flabelliformis Stauffer current conditions on the sea floor at the time of deposi- Polygnathus aff. P. normalis Miller Youngquist tion resulted in such concentrations. Prioniodina powellensis (Stauffer) Faunal lists for the Martin and Portal Formations are P. sp. shown below. At each of the localities, species of Poly- Scutula? sp. gnathus exceed all other faunal elements combined in STRATIGRAPHIC EVALUATION OF THE CONODONTS number of specimens. The conodonts of the Martin Formation are best de- Martin Formation Along Pinal Creek North of Globe veloped in the Pinal Creek exposure, both in abundance of Ancyrodella aff. A . buckeyensis Stauffer specimens and total number of species. Although fre- Apatognathus aff. A. varians Branson Mehl quency of occurrence is much less and fewer forms are Bryantodus camurus Huddle present, the same fauna is represented at Superior . At B. multidens Ulrich Bassler both of these localities conodonts were found only in the Ctenopolygnathus brevilamina (Branson Mehl) upper half of the formation, and any inferences concern- C. iowaensis (Youngquist Peterson) ing age and correlation can be made only for those upper Falcodus secundus (Youngquist) strata. No positive evidence was found for a Middle De- Hindeodella acuta Branson Mehl vonian age for the lower Martin, as has been suggested by H. cf. H. subtilis Ulrich Bassler Stoyanow. The fossilife-ous beds (Middle Martin of Icriodus alternatus Branson Mehl Huddle and Dobrovolny) at Superior, on which he based Ligonodina falciformis Branson Mehl this interpretation, yielded only a few conodont specimens, Lonchodina projecta Ulrich Bassler all of which occur higher in the section associated with L. aff. L. discreta Ulrich Bossier species of unquestionable Upper Devonian age. Neoprioniodus sp. The total collection indicates that at least the upper Ozarkodina cf. 0. regularis Branson Mehl Martin beds were deposited during early Upper Devonian Palmatolepis sp. time, and represent part of the Manticoceras Stufe of the Polygnathus linguiformis Hinde standard European Devonian section. Many species are long-ranging forms and have little stratigraphic value. P. normalis Miller Youngquist Several forms are sufficiently restricted in their stratigraphic P. procera Sannemann ranges to permit comparison with conodonts collected from P. subserrata Branson Mehl other localities. P. unicornis Muller Muller The conodonts from Blue Mountain are very similar to P. sp. those from the Superior-Pinal Creek area, although only Polygnathus? angulosa Stauffer a few species occur at all localities. In particular, the Prioniodina prona (Huddle) occurrence of Palmatolepis subrecta in upper Martin at Roundya aurita Sannemann Superior, and the closely related Palmatolepis flabellifor- R. robusta (Branson Mehl) mis in the basal member of the Portal at Blue Mountain, R. tumida (Branson Mehl) together with the common presence of Ancyrognathus buck- Martin Formation at Superior eyensis, supports the correlation of these strata. Hindeodella acuta Branson Mehl As has been demonstrated by Stoyanow, upper Martin H. subtilis Ulrich Bassler of central Arizona is overlain by a thin unit which is the Icriodus sp. correlative of the Percha Shale of New Mexico . The few Lonchodina sp. conodonts found in these layers north of Globe are frag- Neoprioniodus alatus (Hinde) mented polygnathids. Although not sufficiently diagnostic Ozarkodina regularis Branson Mehl to permit precise temporal evaluation, these specimens Palmatolepis subrecta Miller Youngquist appear to be typical of long-ranging Devonian species. Polygnathus normalis Miller Youngquist Lack of abundance of conodonts is a character that seems P. procera Sannemann to be common to the Percha equivalents throughout the P. aff. P. semicostata Branson Mehl southwest. Material examined by the writer from the Prioniodina prona (Huddle) Chaffee Formation of central Colorado, and from the Ouray Roundya aurita Sannemann Formation of the Four Corners region, both of which con- R. laminata (Branson Mehl) tain a Percha brachiopod fauna, yielded no conodonts. Spathognathodus sp. Additional collections from the Box Member of the Percha Portal Formation at Blue Mountain Formation at a locality 17 miles east of Silver City, New Ancyrodella aff. A. buckeyensis Stauffer Mexico, produced only several polygnathids including Ancyrognathus amana Muller Muller P. linguiformis, a Spathognathodus, a Prioniodina and Avignathus? sp. Hindeodella. NEW MEXICO GEOLOGICAL SOCIETY THIRTEENTH FIELD CONFERENCE 75

No conodonts were found above the lower member indicate the base of the Mississippian. of the Portal Formation at Blue Mountain. However the Clark and Becker (1960) have established a cono- lithologies involved, a black fissile shale overlain by a dont zonation which they propose as a standard for the carbonate section, suggest that these units are continuous Great Basin. Presence of Palmatolepis subrecta, Ancyro- with the Percha which is typically developed 100 miles to della and Ctenopolygnathus among the upper Martin-lower the northeast in New Mexico. Although much thinner, the Portal conodonts indicates that these strata can be cor- same sequence of rock types is widespread at the top of related with their Zone A which includes the lower Pilot the Devonian in central Arizona. Correlation of these Shale of western Utah, as well as part of the Cyrtospirifer strata is indicated in Figure 1. Although the character- Zone of the Devils Gate Formation in Nevada. Palma- istic shale is lacking in the Devonian at Bisbee, Stainbrook tolepis constitutes nearly 60 percent of the Devils Gate (1947, p. 298) reported the occurrence near the top of conodonts, whereas it is only sparingly represented among the section of brachiopods which characterize the Percha. the forms at hand. No conodonts characteristic of Zone Stainbrook concluded that the Percha brachiopods indicate B of Clark and Becker were found in any of the Arizona Mississippian age. However, two specimens of Palma- collections. However, the presence of Palmatolepis rugo- tolepis rugosus, an Upper Devonian conodont which is in- sus near the top of the Devonian at Bisbee, and in the dicative of somewhat younger age than Palmatolepis sub- upper Pinyon Peak Limestone of Utah (Clark and Becker, recta which characterizes the Martin conodonts, were found footnote, p. 1667) suggests that the Percha and its cor- a short distance below the base of the Escabrosa Formation relatives are equivalent to their Zone C. at Black Gap near Bisbee. This is approximately the same Since it was first described, the megafauna of the horizon from which Stainbrook reported the Percha brachio- Martin Formation has been compared with the Upper De- pods. The few conodonts recovered from the Percha and vonian fossils of the Cyrtospirifer whitneyi Zone in the its equivalents near Globe do not suggest Mississippian age Lime Creek beds at Rockford, Iowa. Conodonts from the for these strata. Furthermore, along Pinal Creek the Percha Iowa unit have been described by Bjoraker (1955). His equivalent is immediately overlain by a thin layer rich in report, together with collections made at Rockford by the Siphonodella, a genus which Mehl (1960) considered to author, indicates that conodonts are considerably more

21mi 135mi 100mi SILVER CITY CHIRICAHUA MTS.

ESCABROSA LAKE VALLEY

SUPERIOR

PINAL CREEK R ESCABROSA 1 CONODONT ZONE C I I C I SCABROSA -r- H R A T FLISSELMAN

CONODONT ZONE A L 744

T EL PASO

Figure I.— Conodont Zones in Arizona Devonian TROY (lithologies generalized)

R. L. Ethington-1962 76 NEW MEXICO GEOLOGICAL SOCIETY % THIRTEENTH FIELD CONFERENCE

abundant in the shaly Lime Creek beds than they are in the REFERENCES Arizona carbonates. Furthermore, the average size of indi- Anderson, C, A. and Creasey, S. C., 1958, Geology and ore deposits of the Jerome area, Yavapai County, Arizona: U. S. Geol. Survey Prof. viduals in the Iowa fauna is larger than that of their Ari- Paper 308, 185 p., 13 pls. zona counterparts. Nevertheless the conodonts from the Bjoraker, R. W., 1955, Upper Devonian conodonts from the Lime Creek Formation of northern Iowa: State Univ. Iowa, Unpub. M. S. Thesis, two regions are quite similar and serve to reinforce the 67 p., 5 pls. long-standing correlation of the brachiopod-bearing part Clark, D. L. and Becker, J. H., 1960, Upper Devonian correlations in western Utah and eastern Nevada: Geol. Soc. America Bull., v. 71, of the Martin and the Lime Creek. p. 1661-1674, 2 pls. A conodont zonation for the Devonian section of New Cooper, G. A., et al., 1942, Correlation of the Devonian sedimentary for. mations of North America: Geol. Soc. America Bull., v. 53, p. 1729- York was described by Hass (1959). He reported Palma- 1794, 1 pl. tolepis subrecta to be a zonal index for the Chemung. Its Epis, R. C., Gilbert, C. M. and Langenheim, R. L., 1957, Upper Devonian Swisshelm Formation of southeastern Arizona: Am. Assoc. Petroleum occurrence in the Martin at Superior constitutes further evi- Geologists Bull., v. 41, p. 2243-2256. dence for a Chemung age for this portion of the Arizona Hass, W. H., 1959, Conodont faunas of the Devonian of New York and Pennsylvania (Abstract): Geol. Soc. American Bull., v. 70, p. 1615. Devonian. Huddle, J. W. and Dobrovolny, Ernest, 1952, Devonian and Mississippian rocks of central Arizona: U. S. Geol. Survey Prof. Paper 233, p. 67-112, pls. 11-13. CONCLUSIONS McNair, A. H., 1951, Paleozoic stratigraphy of part of northwestern Arizona: Am Assoc. Petroleum Geologists Bull., v. 35, p. 503-541. Early Upper Devonian conodonts characterized by Mehl, M. G., 1960, The relationships of the base of the Mississippian System in Missouri: Denison Univ. Jour. Sci. Labs., v. 45, p. 57-107. Palmatolepis subrecta, Ancyrodella, and an abundance of Merriam, C. W., 1940, Devonian stratigraphy and paleontology of the Polygnathus occur in the upper part of the Martin Formation Roberts Mountain region, Nevada: Geol. Soc. America Spec. Paper in central Arizona, and near the base of the Portal Forma- 25, 114 p., 16 pls. tion of the southeastern part of the state. Collectively these Pye, W. D., 1959, Silurian and Devonian stratigraphy, southeastern Arizona and southwestern New Mexico: Arizona Geol. Soc. Southern conodonts indicate that this is the same fauna which Clark Arizona Guidebook II, p. 25-30. and Becker designated as representing Zone A in the Upper Ransome, F. L, 1904, The Geology and ore deposits of the Bisbee Devonian of eastern Great Basin. The upper Martin-lower Quadrangle, Arizona: U. S. Geol. Survey Prof. Paper 21 , 168 p., Portal strata are overlain by a shale and carbonate se- 29 pls. , 1916, Some Paleozoic sections in Arizona and their quence which contains few conodonts, but which can be correlation: U. S. Geol. Survey Prof. Paper 98, p. 133-166, pls. correlated with the Percha Formation of New Mexico on 24-31 the basis of megafossils and similar lithologies. Occurrence , 1923, Description of the Ray Quadrangle: U. S. Geol. of the basal Mississippian index Siphonodella immediately Survey Geologic Atlas of the U. S., Folio 217, 24 p., 5 pls. Sabins, F. F., Jr., 1957, Stratigraphic relations in Chiricahua and Dos above these beds at Globe confirms their Upper Devonian Cabezas mountains, Arizona: Am. Assoc. Petroleum Geologists age. No conodonts are known to occur in the lower half Bull., v. 41, p. 466-510. of the Devonian sequence of central Arizona. Whether Stainbrook, M. A., 1947, Brachiopoda of the Percha Shale of New Mexico these rocks should be considered to also be of Upper De- and Arizona: Jour. Paleontology, v. 21, p. 297-328, pls. 44-47. vonian age, or assigned to the Middle Devonian as has Stauffer, C. R., 1928. The Devonian section on Pinal Creek, Arizona: Ohio Jour. Sci., v. 28, p. 253-260. been suggested, cannot be determined. The long-standing Stoyanow, A. A., 1936, Correlation of Arizona Paleozoic formations: correlations of the Martin megafossils with brachiopods Geol. Soc. America Bull., v. 47, p. 459-540, 1 pl. from the Lime Creek beds of Iowa and the Chemung of Williams, H. S., 1903, Devonian fossils of the Globe Quadrangle, Ari- New York are supported by comparison of the respective zona: in Ransome, F. L., Geology of the Globe Copper District, Arizona: U. S. Geol. Survey Prof. Paper 12, p. 40-42. conodonts.