One of the earliest discoveries of Permo-Carboniferous terrestrial vertebrates in North America occurred in 1875 along Horseshoe Bend, a cutbank on the Salt Fork of the Vermilion River west of Danville, Vermilion County, east-central Illinois. The discovery was soon eclipsed by the description of similar but much more complete remains from the Lower Permian of Texas in 1878. The deposit itself was obliterated by slumping and erosion in the earliest 1900s and has not been collected since despite repeated efforts. Previously unreported outcrop records and subsurface data indicate that the deposit originated as a paleochannel fill in the Inglefield Sandstone Member of the Patoka Formation, which underlies the Macoupin Limestone Member (early Missourian Stage of the Midcontinent, early Kasimovian Stage of global Carboniferous time scale). In addition to aquatic to terrestrial tetrapods, teeth of lungfishes (Sagenodus Owen, 1867, Conchopoma Cope, 1877a, Gnathorhiza Cope, 1883a) and teeth, occipital spines, and coprolites of a xenacanth shark (Orthacanthus Agassiz, 1838) are known from Horseshoe Bend. The teeth of the marine petalodont shark Janassa M & uuml;nster, 1839, also are present in the collection but presumed to have been derived from one of the beds on the cutbank that produced brackish to marine invertebrate fossils. Alhough not diverse, the tetrapod assemblage is significant in that it contains the oldest diplocaulid amphibian (Diplocaulus salamandroides Cope, 1877a), fragmentary remains of the oldest diadectid and limnoscelid stem reptiles, and possibly the oldest captorhinid eureptile, all of which have not been adequately described. The ophiacodontid synapsid Clepsydrops Cope, 1875, is the most common fossil at Danville, which could be an artifact of primitive collecting methods that did not promote the recovery of articulated material. An accurate stratigraphic placement of the Horseshoe Bend deposit and a review of other late Carboniferous tetrapod localities reveals that this important Illinois locality combines an overlooked vanguard of terrestrial taxa regarded as Permo-Carboniferous (Kasimovian-Asselian) and amphibious to aquatic forms known from older, Moscovian deposits.

The youngest Paleozoic vertebrate-bearing continental deposits of North America are Middle Permian (Guadalupian) in age and occur in the Chickasha Formation (El Reno Group) of central Oklahoma and the lithostratigraphically lower San Angelo Formation (Pease River Group) of North-Central Texas. Although regarded originally as Guadalupian, these deposits have been assigned recently to the Early Permian on the basis of marine fossils and questionable lithostratigraphic correlations between marine and continental strata. A review of ammonoid genera recovered from the Blaine Formation, which overlies both the Chickasha and San Angelo in Oklahoma and Texas, shows that they range globally in age from the Early to Late Permian, but most occur in the Guadalupian or Middle Permian. A modest but intensively studied paleobotanical record of compression fossils from the San Angelo, as well as palynomorphs in rocks associated with the Chickasha, presents an unquestionably Middle to Late Permian flora dominated by voltzian conifers. The Chickasha and San Angelo vertebrate assemblages are overwhelmingly dominated by large caseid synapsids and indicate a biostratigraphic signal of early Guadalupian. The occurrence of the tupilakosaurid temnospondyl Slaugenhopia , the parareptile Macroleter , and the eureptile Rothianiscus suggests a Roadian age (lowermost Guadalupian) given the global records of closely related forms. These plant and vertebrate assemblages contrast sharply with those of underlying Cisuralian rocks of the Hennessey Formation of Oklahoma and the Clear Fork Formation of Texas, both of which are much more fossiliferous than those of the Guadalupian in the region. A barren interval of up to 300 m in thickness separates these fossil-bearing intervals. This true void in the late Kungurian was first reported a half century ago but has not been recognized in recent biochronology studies. Our findings, as well as those of other vertebrate paleontologists who have evaluated the San Angelo and Chickasha data by other means, strongly refute the current notion of “Olson’s Gap” as spanning most of the Roadian.

A small temnospondyl skull from the upper Carboniferous Allegheny Group of Five Points, Ohio, is referred to a new dissorophoid, Palodromeus bairdi n. gen n. sp. The complete skull with mandibles is preserved in counterparts. It is characterized by, (1) elongated slit-like choana; (2) postfrontal, postorbital, and supratemporal bearing a distinct ridge; and (3) reduced parietal only two-thirds the length of the frontal. Phylogenetic analysis confirms a dichotomy between amphibamiforms and olsoniforms and places Palodromeus bairdi n. gen. n. sp. at the base of the olsoniforms, revealing an early stage in the evolution of that clade. UUID: http://zoobank.org/3871e443-7888-4439-a7c1-9463bc4d87ab

Fossil floras have been recovered from a unique deposit of early Permian age in North-Central Texas. The site, Kola Switch, preserves three distinct floras in different lithofacies, in a succession from a single outcrop. The sedimentary environment appears to be a floodplain channel fill of primarily siltstones and claystones. The lowermost flora, preserved in a kaolinitic siltstone, indicates active water flow. It is dominated by plants typical of well-drained substrates, dominated by Sphenopteris germanica , and contains no wetland elements. The middle flora is from a finely laminated carbonaceous claystone and is dominated by marattialean tree ferns, with no elements from habitats typical of seasonal moisture availability. It contains no roots and appears to have formed as a floating peat mat. The upper flora is a mixed assemblage of wetland taxa and those typical of well-drained soil environments or a seasonal rainfall regime. Unlike the two lower floras, it has a relatively even distribution of dominance and is the most diverse of the three assemblages. Palynofloras also were recovered from each of these beds. The palynofloras, although varying between and even within the beds, indicate a common background species pool during the time interval sampled, suggesting that these distinct floras reflect local changes in microhabitat conditions under a constant climatic background. The palynoflora from each bed has characteristics in common with the macroflora of that bed, but also distinct differences. Together, the macroflora and microflora provide an unusually broad picture of this site through time. Kola Switch compares favorably with the recently described flora from the nearby Sanzenbacher Ranch site of approximately the same age and also with floras of Rotliegend age from Central Europe.

Plant macrofossils and palynofossils occur in lower Permian (Wolfcampian) mudstones and very fine grained sandstones on the Sanzenbacher Ranch, Clay County, in north central Texas. Three macrofossil collections made by different field parties about 20 years apart contain a total of about 740 specimens. Macrofloras and palynofloras were assessed quantitatively. The macrofloras consists of about 36 whole-plant-proxy taxa, 12 of which are represented by a single specimen (32%). Two macrofloral collections are dominated by the callipterid, Autunia conferta; the other is codominated by A. conferta and the conifer Walchia sp. Other prominent elements in one or more of the collections include Sphenopteris germanica, marattialean foliage, Neurodontopteris auriculata, Odontopteris subcrenulata, and calamitalean stem remains (associated with Annularia spicata). Fourteen taxa (39%) occur in only one collection. The palynoflora is dominated by Vesicaspora, likely from callipterids, with subdominant abundances of pteridosperm and conifer pollen and marattialean tree fern spores. At least 65 morphotaxa of pollen and spores are present in a 900-grain count. The less common palynotaxa represent primarily Pennsylvanian wetland "holdovers". Thus, the palynofloras and macrofloras display similar dominance-diversity profiles.

Donald Baird (1926–2011), an influential and innovative vertebrate paleontologist with a scientific career spanning nearly 50 years, had an exceptional breadth of expertise in the study of late Paleozoic and Mesozoic vertebrates and their life traces. Beginning in 1956, Baird conducted fieldwork in the Carboniferous and Triassic-Jurassic of Nova Scotia, making a total of 21 trips in 30 years. His many scientific contributions include the discoveries of important assemblages of Carboniferous vertebrates as well as an unexpectedly diverse record of early Mesozoic tetrapods and their trackways in the province. Baird also encouraged and supported fieldwork by other vertebrate paleontologists as well as amateurs in Nova Scotia and elsewhere. His career-long commitment to the vertebrate paleontology of the province was instrumental in establishing it as an important source of fossils of Carboniferous and early Mesozoic continental vertebrates.RÉSUMÉDonald Baird (1926–2011), paléontologiste des vertébrés influent et novateur dont la carrière scientifique s’est échelonnée sur près de 50 ans, a acquis un savoir-faire exceptionnel dans l’étude des vertébrés du Paléozoïque tardif et du Mésozoïque et des vestiges de leur vie. À partir de 1956, M. Baird a mené des études sur le terrain du Carbonifère et du Trias-Jurassique en Nouvelle-Écosse, où il s’est rendu au total 21 fois en 30 ans. Ses nombreuses contributions scientifiques comprennent notamment les découvertes d’importants assemblages de vertébrés du Carbonifère ainsi que d’un nombre étonnamment diversifié de tétrapodes du Mésozoïque inférieur et de leurs traces dans la province. M. Baird a en outre encouragé et soutenu les études sur le terrain d’autres paléontologistes des vertébrés et d’amateurs du domaine en Nouvelle-Écosse et ailleurs. Pendant toute sa carrière, il s’est consacré à la paléontologie des vertébrés de la province, ce qui a contribué à la réputation de la Nouvelle-Écosse en tant que source importante de fossiles de vertébrés continentaux du Carbonifère et du Mésozoïque inférieur.

Coal samples from a coalbed methane exploration well in northern Zavala County, Maverick Basin, Texas, were characterized through an integrated analytical program. The well was drilled in February, 2006 and shut in after coal core desorption indicated negligible gas content. Cuttings samples from two levels in the Eocene Claiborne Group were evaluated by way of petrographic techniques and Rock-Eval pyrolysis. Core samples from the Paleocene-Eocene Indio Formation (Wilcox Group) were characterized via proximate-ultimate analysis in addition to petrography and pyrolysis. Two Indio Formation coal samples were selected for detailed evaluation via gas chromatography, and Fourier transform infrared (FTIR) and C-13 CPMAS NMR spectroscopy. Samples are subbituminous rank as determined from multiple thermal maturity parameters. Elevated rank (relative to similar age coal beds elsewhere in the Gulf Coast Basin) in the study area is interpreted to be a result of stratigraphic and/or structural thickening related to Laramide compression and construction of the Sierra Madre Oriental to the southwest. Vitrinite reflectance data, along with extant data, suggest the presence of an erosional unconformity or change in regional heat flow between the Cretaceous and Tertiary sections and erosion of up to >5 km over the Cretaceous. The presence of liptinite-rich coals in the Claiborne at the well site may indicate moderately persistent or recurring coal-forming paleoenvironments, interpreted as perennially submerged peat in shallow ephemeral lakes with herbaceous and/or flotant vegetation. However, significant continuity of individual Eocene coal beds in the subsurface is not suggested. Indio Formation coal samples contain abundant telovitrinite interpreted to be preserved from arborescent, above-ground woody vegetation that developed during the middle portion of mire development in forested swamps. Other petrographic criteria suggest enhanced biological, chemical and physical degradation at the beginning and end of Indio mire development. Fluorescence spectra of sporinite and resinite are consistent and distinctly different from each other, attributed to the presence of a greater proportion of complex asphaltene and polar molecules in resinite. Gas chromatography of resinite-rich coal shows sesquiterpenoid and diterpenoid peaks in the C14-17 range, which are not present in resinite-poor coal. Quantities of extracts suggest bitumen concentration below the threshold for effective source rocks [30-50 mg hydrocarbon/g total organic carbon (HC/g TOC)]. Saturate/aromatic and pristane/phytane (Pr/Ph) ratios are different from values for nearby Tertiary-reservoired crude oil, suggesting that the Indio coals are too immature to source liquid hydrocarbons in the area. However, moderately high HI values (200-400 mg HC/g rock) may suggest some potential for naphthenic-paraffinic oil generation where buried more deeply down stratigraphic/structural dip. Extractable phenols and C20+ alkanes are suggested as possible intermediates for acetate fermentation in microbial methanogenesis which may, however, be limited by poor nutrient supply related to low rainfall and meteoric recharge rate or high local sulfate concentration. Published by Elsevier Ltd.

This publication is the fifth in a searies of reports by the U.S. Geological Survey on the assessment of the quantity and quality of the nation's coal deposits that potentially can be mined during the next few decades. For eight years (1995-2003), geologic, geochemical, and resource information was collected and compiled for the five major coal-producing regions of the United States. This volume contains the assessment results for the Gulf of Mexico Coastal Plain region. The contents of this volume were compiled mainly during the 8-year period mentioned above. However, every effort has been made to update the references and text to incorporate new work that has been completed since the original compilation period.

This publication is the fifth in a searies of reports by the U.S. Geological Survey on the assessment of the quantity and quality of the nation's coal deposits that potentially can be mined during the next few decades. For eight years (1995-2003), geologic, geochemical, and resource information was collected and compiled for the five major coal-producing regions of the United States. This volume contains the assessment results for the Gulf of Mexico Coastal Plain region. The contents of this volume were compiled mainly during the 8-year period mentioned above. However, every effort has been made to update the references and text to incorporate new work that has been completed since the original compilation period.

This publication is the fifth in a searies of reports by the U.S. Geological Survey on the assessment of the quantity and quality of the nation's coal deposits that potentially can be mined during the next few decades. For eight years (1995-2003), geologic, geochemical, and resource information was collected and compiled for the five major coal-producing regions of the United States. This volume contains the assessment results for the Gulf of Mexico Coastal Plain region. The contents of this volume were compiled mainly during the 8-year period mentioned above. However, every effort has been made to update the references and text to incorporate new work that has been completed since the original compilation period.

The Wilcox Group (Paleocene to Eocene) of the Sabine uplift, a structural arch in northeastern Texas and northwestern Louisiana (Figure 1), has lignite zones that approach subbituminous rank (see Chapter 4, this publication). These coals are among the highest quality resources known within the Gulf Coastal Plain because of their low ash yield and sulfur content. The surface expression of the Sabine uplift is defined by the contact between coal-bearing rocks of the Wilcox Group and overlying fluvial rocks of the Carrizo Sand, which is the basal unit of the Claiborne Group (Figures 2, 3). The Sabine uplift study area includes parts of Harrison, Marion, Nacogdoches, Panola, Rusk, Sabine, San Augustine, and Shelby Counties in Texas and Bossier, Caddo, De Soto, Natchitoches, Red River, and Sabine Parishes in Louisiana (Figure 1). Adjacent counties and parishes that include the subsurface Wilcox Group extend the regional Sabine uplift area. TheWilcox in the subsurface is underlain by the Midway Group (Figure 3), a mudstone-dominated marine sequence of Paleocene age. Quaternary alluvium and terrace deposits overlying the Wilcox Group at the surface are limited to areas of modern drainage. The total thickness of the Wilcox Group within the Sabine uplift area ranges from approximately 400 ft on outcrop to 2500 ft in subsurface (Kaiser, 1990). In a few places, the contact between the overlying Carrizo Sand andWilcox Group is erosional, but in other places, the contact is gradational. Where the Carrizo Sand directly overlies sandstones of the Wilcox, the contact is approximated because they cannot be differentiated. In the central Texas assessment area, the Wilcox Group consists of three formations: the Hooper, Simsboro, and Calvert Bluff (Figure 3). Separate formations are not differentiated in the Wilcox Group in the Sabine uplift area of Texas because the Simsboro, a predominantly fluvial sandstone unit, is not mappable. In west-central Louisiana, where marine beds interfinger within the Wilcox, numerous formations (Figure 3) have been described (Murray, 1948; Andersen, 1960, 1993). However, these subdivisions do not persist regionally beyond Louisiana. The Texas Bureau of Economic Geology has published estimates of coal resources in the Texas Sabine

This publication is the fifth in a searies of reports by the U.S. Geological Survey on the assessment of the quantity and quality of the nation's coal deposits that potentially can be mined during the next few decades. For eight years (1995-2003), geologic, geochemical, and resource information was collected and compiled for the five major coal-producing regions of the United States. This volume contains the assessment results for the Gulf of Mexico Coastal Plain region. The contents of this volume were compiled mainly during the 8-year period mentioned above. However, every effort has been made to update the references and text to incorporate new work that has been completed since the original compilation period.

This publication is the fifth in a searies of reports by the U.S. Geological Survey on the assessment of the quantity and quality of the nation's coal deposits that potentially can be mined during the next few decades. For eight years (1995-2003), geologic, geochemical, and resource information was collected and compiled for the five major coal-producing regions of the United States. This volume contains the assessment results for the Gulf of Mexico Coastal Plain region. The contents of this volume were compiled mainly during the 8-year period mentioned above. However, every effort has been made to update the references and text to incorporate new work that has been completed since the original compilation period.

This publication is the fifth in a searies of reports by the U.S. Geological Survey on the assessment of the quantity and quality of the nation's coal deposits that potentially can be mined during the next few decades. For eight years (1995-2003), geologic, geochemical, and resource information was collected and compiled for the five major coal-producing regions of the United States. This volume contains the assessment results for the Gulf of Mexico Coastal Plain region. The contents of this volume were compiled mainly during the 8-year period mentioned above. However, every effort has been made to update the references and text to incorporate new work that has been completed since the original compilation period.

This publication is the fifth in a searies of reports by the U.S. Geological Survey on the assessment of the quantity and quality of the nation's coal deposits that potentially can be mined during the next few decades. For eight years (1995-2003), geologic, geochemical, and resource information was collected and compiled for the five major coal-producing regions of the United States. This volume contains the assessment results for the Gulf of Mexico Coastal Plain region. The contents of this volume were compiled mainly during the 8-year period mentioned above. However, every effort has been made to update the references and text to incorporate new work that has been completed since the original compilation period.

Thermal maturity was determined for about 120 core, cuttings. and outcrop samples to investigate the potential for coalbed gas resources in Pennsylvanian strata of north-central Texas. Shallow (<600 m; 2000 ft) coal and carbonaceous shale cuttings samples from the Middle-Upper Pennsylvanian Strawn, Canyon, and Cisco Groups in Archer and Young Counties on the Eastern Shelf of the Midland basin (northwest and downdip from the outcrop) yielded mean random vitrinite reflectance (R-0) values between about 0.4 and 0.8%. This range of & values indicates rank from subbituminous C to high volatile A bituminous in the shallow subsurface, which may be sufficient for early thermogenic gas generation. Near-surface (<100 m; 300 ft) core and outcrop samples of coal from areas of historical underground coal mining in the region yielded similar R. values of 0.5 to 0.8%. Carbonaceous shale core samples of Lower Pennsylvanian strata (lower Atoka Group) from two deeper wells (samples from similar to 1650 m; 5400 ft) in Jack and western Wise Counties in the western part of the Fort Worth basin yielded higher & values of about 1.0%. Pyrolysis and petrographic data for the lower Atoka samples indicate mixed Type II/Type III organic matter, suggesting generated hydrocarbons may be both gas- and oil-prone. In all other samples, organic material is dominated by Type III organic matter (vitrinite), indicating that generated hydrocarbons should be gas-prone. Individual coal beds are thin at outcrop (<1 m; 3.3 ft), laterally discontinuous, and moderately high in ash yield and sulfur content. A possible analog for coalbed gas potential in the Pennsylvanian section of north-central Texas occurs on the northeast Oklahoma shelf and in the Cherokee basin of southeastern Kansas, where contemporaneous gas-producing coal beds are similar in thickness, quality, and rank. Published by Elsevier B.V.

The U.S. Geological Survey and the Texas Bureau of Economic Geology are engaged in an ongoing collaborative study to characterize the organic composition and thermal maturity of Upper Paleozoic coal-bearing strata from the Eastern Shelf of the Midland basin and from the Fort Worth basin, north-central Texas. Data derived from this study will have application to a better understanding of the potential for coalbed gas resources in the region. This is an important effort in that unconventional resources such as coalbed gas are expected to satisfy an increasingly greater component of United States and world natural gas demand in coming decades. In addition, successful coalbed gas production from equivalent strata in the Kerr basin of southern Texas and from equivalent strata elsewhere in the United States suggests that a closer examination of the potential for coalbed gas resources in north-central Texas is warranted. This report presents thermal maturity data for shallow (<2,000 ft; <610 m) coal and coaly shale cuttings, core, and outcrop samples from the Middle-Upper Pennsylvanian Strawn, Canyon, and Cisco Groups from the Eastern Shelf of the Midland basin. Data for Lower Pennsylvanian Atoka Group strata from deeper wells (5,400 ft; 1,645 m) in the western part of the Fort Worth basin also are included herein. The data indicate that the maturity of some Pennsylvanian coal and coaly shale samples is sufficient to support thermogenic coalbed gas generation on the Eastern Shelf and in the western Fort Worth basin.