Walchian Conifers from the Mid-Late Pennsylvanian Conemaugh Group in the Appalachian Basin: Stratigraphic and Depositional Context, and Paleoclimatic Signiﬁcance

Home , Annularia, Conemaugh Group, Cordaites, Samaropsis, Walchia

International Journal of Coal Geology 171 (2017) 153–168

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International Journal of Coal Geology

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Walchian conifers from the Mid-Late Pennsylvanian Conemaugh Group in the Appalachian Basin: Stratigraphic and depositional context, and paleoclimatic signiﬁcance

Ronald L. Martino

Department of Geology, Marshall University, Huntington, WV 25755, United States article info abstract

Article history: Walchian conifers are indicators of seasonally dry habitats of the Euramerican subtropics and tropics and are of Received 6 August 2016 considerable value in tracking both short term and long term Pennsylvanian-Permian paleoclimatic changes in Received in revised form 28 December 2016 central Pangea. Walchian conifer macrofossils ﬁrst appeared in North America during the Middle Pennsylvanian, Accepted 11 January 2017 but are rare in central Pangean coal basins until the Permian. An abrupt climate change occurred near the Available online 12 January 2017 Desmoinesian-Missourian boundary that was characterized by global warming, stronger seasonality, and shorter

Keywords: wet phases. This change coincided with the regional extinction of most tree lycopsids and the appearance of Walchia widespread, high chroma, calcic vertisols and aridisols. Only four occurrences of Walchia have been reported Paleoclimate from the Pennsylvanian of the Appalachian Basin: 1) 7-11 Mine of eastern Ohio, 2) Rennersville in southwest Cyclothems Pennsylvania, and 3) Charleston and 4) Cedar Run, both in southern West Virginia. This paper uses recently ac- Sequence stratigraphy quired outcrop data to more fully document and reevaluate the depositional and stratigraphic context of the West Virginia assemblages and their paleoclimatic and paleogeographic implications. The Cedar Run Walchia assemblage occurs in olive mudshale of an abandoned fluvial channel-fill 15.8–16.9 m above the base of the Ames Limestone, indicating an early Virgilian age. It consists of compressions and impres- sions of branches and branchlets of Walchia, Lepidophylloides, Cordaites, and rare neuropteroid pinnules. The channel-fill at this location is a component of the Grafton Sandstone incised valley-fill previously described from the study area. Correlation of paleosol-bounded, marine-cored cyclothems in the study area with their nonmarine cyclothem equivalents at Charleston, West Virginia indicates the Walchia previously reported at the Mahoning coal horizon, occurs between the Brush Creek and Bakerstown coals, and is therefore Missourian, not late Desmoinesian, and similar to the revised age for the 7-11 Mine Walchia reported from eastern Ohio. Late Pennsylvanian, upland (or dryland) conifer communities were comprised of Walchia, Cordaites,andSigillaria which produced a forest with seed ferns as an understory. The Cedar Run assemblage was probably transported into the valley from adjacent, well-drained coastal plain uplands formed during valley incision, and deposited within the early transgressive systems tract. It is also possible that Walchia expanded into the valleys when drainage became ephemeral during more arid climatic phases. The revised correlations of Appalachian Basin Walchia horizons indicate their appearance closely followed, rather than predated the abrupt climate change and extinc- tions at the Desmoinesian-Missourian boundary. © 2017 Elsevier B.V. All rights reserved.

1. Introduction DiMichele, 2014). Plant fossils provide a snapshot of paleoclimatic conditions. A full understanding of their spatial and temporal distributions The late Middle and Late Pennsylvanian strata of the Appalachian and their sedimentologic context is essential to the accuracy of interpre- Basin have been the focus of much attention because they record both tations regarding paleoclimate trends and cycles and evolutionary pat- short-term climate cycles related to glacioeustasy and longer term terns. The importance of their sequence stratigraphic context in trends related to 1) the northward drift of Pangea across the equator, accurate paleoenvironmental reconstructions has also become apparent 2) orographic effects of the rising Appalachian Mountains, and 3) possi- (e.g. Demko et al., 1998; Falcon-Lang et al., 2009; Gastaldo and Demko, bly atmospheric changes in carbon dioxide (Donaldson et al., 1985; 2010). The paleoenvironmental and paleoclimatic signiﬁcance of Cecil, 1990; Frakes et al., 1992; Heckel, 1994; Otto-Bleisner, 2003; Walchia has received much attention over the past three decades and the various interpretations have been recently been reviewed in detail by DiMichele (2014). Walchia was a primitive conifer represented by E-mail address: [email protected]. woody trees with small, helically arranged, needle-like leaves 1–5mm

http://dx.doi.org/10.1016/j.coal.2017.01.005 0166-5162/© 2017 Elsevier B.V. All rights reserved. 154 R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168 in length (Taylor, 1981). The xeromorphic traits of Walchia, like most 2. Geologic setting modern conifers (thick cuticle, needle like leaves with low ratio of surface area to volume), enabled it to retain moisture and inhabit well- Strata in the study area crop out in the Central Appalachian Basin at drained soils, and drier climates (Lyons and Darrah, 1989a). the southwest end of the Dunkard Basin Synclinorium (Spencer, 1964; Walchia is a key taxon and is widespread in Permian strata. In con- Merrill, 1988). Downwarp of the Dunkard Basin may have occurred dur- trast, relatively few occurrences are know from the Mid-Late Pennsylva- ing, as well as after, the deposition of the Conemaugh Group (Merrill, nian of North America. The term ‘Methuselah taxa’ was recently 1988). The Appalachian foreland basin extends from Quebec to Ala- suggested for sporadic, anomalous occurrences of genera, like Walchia, bama, covering an area of about 536,000 km2 (Ettensohn, 2008). During many millions of years older than their more temporally continuous, the Middle-Late Pennsylvanian, thrust-loading in the Appalachian established range (Looy et al., 2014). They are named for Methuselah, Orogen caused basin subsidence which helped provide sediment ac- the oldest man (929 years) in the book of Genesis in the Hebrew commodation space (Quinlan and Beaumont, 1984; Greb et al., 2008). Bible. Methuselah floras are typically found in seasonally dry facies in The rate of subsidence was greatest in eastern West Virginia and de- between vertically adjacent wetland floras. It has been postulated that creased northwestward toward the cratonic platform in Ohio and Ken- Methuselah floras may have first appeared in upland areas with low tucky. Transgressive-regressive cycles each lasting several million years, preservation potential, and periodically migrated into basinal lowlands referred to as tectophases, resulted from tectonic loading and relaxa- during seasonally drier portions of glacioeustatic climate cycles (e.g. tion. Higher frequency, glacioeustatic transgressive–regressive cycles Dolby et al., 2011; DiMichele, 2014; Looy et al., 2014). are superimposed on the tectophases (Busch and Rollins, 1984; Busch The earliest unequivocal walchian conifer macrofossils occur in Mid- and West, 1987; Heckel, 1994, 1995; Ettensohn, 2008; Greb et al., dle Pennsylvanian (middle Desmoinesian) strata of the North American 2008). During the Late Pennsylvanian the Central Appalachian Basin Illinois Basin (Plotnick et al., 2009; Falcon-Lang et al., 2009). Walchian was positioned within a few degrees of the equator (Blakey, 2007; pollen (Potonieisporites) has been reported from the Late Mississippian Rosenau et al., 2013). During the Middle and Late Pennsylvanian, rivers (early Namurian) of Britain and Nova Scotia (Bharwadjwa, 1964; flowed west and north across West Virginia, draining the Allegheny Neves and Belt, 1971; Mapes and Gastaldo, 1986). Walchia has been re- Orogen. Channel belts in the tropical coastal plain were flanked by ported from the Pennsylvanian of Colorado, Illinois, Oklahoma, and Kan- flood basin lakes and swamps during the wetter parts of glacial-inter- sas (Elias, 1942; Rothwell, 1982; Winston, 1983; Lyons and Darrah, glacial cycles (Arkle, 1974; Donaldson, 1979; Martino, 2004, 2015). 1989a, 1989b; Falcon-Lang et al., 2009). Only four occurrences have been reported from the Late Pennsylvanian of the Appalachian Basin: 3. Stratigraphic and depositional framework one in Ohio (7-11 Mine, McComas, 1988), one in Rennersville, Pennsyl- vania (Darrah, 1969, 1975) and two in West Virginia (Charleston: Lyons The late Middle to Late Pennsylvanian Conemaugh Group extends and Darrah, 1989a, 1989b; Cedar Run, Martino and Blake, 2001; Fig. 1). from the top of the Upper Freeport coal to the base of the Pittsburgh The stratigraphic context of the Ohio occurrence has recently been re- coal (Fig. 2). It was historically referred to as ‘the lower barren mea- vised (Easterday, 2004; Falcon-Lang et al., 2011; Belt et al., 2011), but sures’ because there are relatively few minable coals in this stratigraphic the West Virginia occurrences have yet to be clearly documented. The interval (Wanless, 1939). The Conemaugh Group does contain several objectives of this paper are to fully document the paleobotanical and high volatile bituminous coals with total sulfur of 1–3%. These are usu- stratigraphic context of the Cedar Run Walchia assemblage (Martino ally minable only in the northern Appalachian Basin (Repine et al., and Blake, 2001) and re-evaluate the stratigraphic correlations for the 1993). Where the Ames Limestone is present, the Conemaugh Group Charleston and 7-11 Mine occurrences and their paleoclimatic and pa- is divided into the Glenshaw and Casselman Formations; where absent, leogeographic implications. as is the case in the Charleston area of West Virginia, it is the

Fig. 1. Location map showing the four known Pennsylvanian-age Walchia occurrences in the Appalachian Basin of the eastern U.S. R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168 155

Fig. 2. Stratigraphic framework for the Conemaugh Group and composite stratigraphic section for the Cedar Run study area showing level of Walchia interval at Cedar Run relative to the Ames Limestone based on sections at locations 1–5(Figs. 3 and 7). Time scale is based on Davydov et al. (2010) and Richards (2013). The position of the Westphalian-Stephanian stage boundary is not accepted by some workers.

Conemaugh Formation. The Glenshaw Formation in Wayne County, The absence of Western European taxa in the Appalachian Basin and West Virginia and vicinity is 80 m thick. It consists mainly of fluvial, del- the apparent stratigraphic gap was subsequently interpreted to be the taic, and estuarine sandstones and flood basin mudrocks and occasional result of different paleobiogeographic and climatic factors between thin coals and marine limestone and shale (Martino et al., 1996; Western Europe and North America rather than a major unconformity Martino, 2004, 2015). The Casselman is 90 m thick and extends from (Blake et al., 2002; Falcon-Lang et al., 2011). The uplift and deformation the Ames Limestone to the base of the Pittsburgh coal. It is lithologically associated with the Allegheny-Hercynian Orogeny during the Late similar to the Glenshaw (Donaldson, 1979), except that it is predomi- Pennsylvanian fragmented the tropical floral belt. Biotic migration was nantly nonmarine. obstructed between Europe and North America causing increasingly en- The Conemaugh Group is late Desmoinesian to early Virgilian in age demic floras which hinder interregional correlations. Biostratigraphy is and recent workers have correlated it with the Westphalian D to further complicated by the alternation of wetland and dryland floras Stephanian B of Western Europe (Eble et al., 2009; Falcon-Lang et al., during cyclothems; during dryland phases extrabasinal forms can tem- 2011). Wagner and Lyons (1997) suggested the presence of a major un- porarily appear in lowland regions in place of the wetland taxa (e.g. conformity near the base of the Conemaugh based on the absence of Falcon-Lang et al., 2009; Falcon-Lang and DiMichele, 2010; Looy et al., plant megafossils found in Western Europe. They concluded that essen- 2014). Due to the current uncertainty regarding the relationship of the tially all of the Conemaugh was late Stephanian C or Autunian in age. Desmoinesian-Missourian boundary in North America to the 156 R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168

Westphalian-Stephanian boundary in Europe (Wagner and Lyons, and tree ferns were prevalent during humid to subhumid climates asso- 1997; Falcon-Lang et al., 2011), the regionally recognized stage names ciated with interglacial phases (late TST and HST). Gymnosperms in- for North America will be used going forward. cluding conifers, cordaitaleans and pteridosperms were widely The Glenshaw Formation in the study area contains nine, paleosol- developed during drier and more seasonal climate associated with gla- bounded allocycles averaging 8–9 m in thickness (Martino, 2004, cial maxima and associated lowstands of sea level (Falcon-Lang et al., 2015). Thick, mature, calcic vertisols and calcisols are interpreted to 2009; Falcon-Lang and DiMichele, 2010). Thus, in general, wetland have formed as interfluvial sequence boundaries (IFSBs) during falling floras developed at or near glacial highstands while ‘dryland’ floras stage systems tract (FSST), lowstand systems tract (LST) and early were prevalent and expanded into lowlands at or near glacial maxima transgressive systems tract (TST) during sediment bypassing and nega- (Falcon-Lang et al., 2011). The relatively uniform oxygen-18 and car- tive accommodation. Rising sea level/base level and wetter climatic con- bon-13 isotopic composition in growth layers of spiriferid brachiopods ditions caused rising water table and gley overprinting. The paleosols from the Ames Limestone indicates a consistently moist subtropical cli- are overlain by thin coals, and fresh, brackish and marine shales and mate with minimal seasonality existed during the Ames sea level limestones. Lakes and shallow seas filled with coarsening-upward se- highstand (Roark et al., 2015). quences during the HST. Incised valley-fills (IVFs) 20–35 m thick were cut during FSST and early LST and filled with multistory fluvio-estuarine channel facies during late LST and early TST. 5. Results and discussion The Grafton Sandstone along the Big Sandy River is a multistory, incised valley-fill up to 20 m thick (Martino, 2004). Individual channel- 5.1. Cedar Run Walchia assemblage fills commonly display epsilon cross-bedding with sets 7–9 m thick which indicate lateral accretion normal to the paleoflow direction. The Cedar Run Walchia assemblage was collected from a temporary Cross-stratification from several Grafton outcrops in the study area indi- excavation along a gas pipeline trench near the base of the Casselman cates average flow directions from 249 to 335 degrees. Paleohydraulic Formation. The exposure existed in May–June 1999 and was located ap- analysis of a Grafton paleochannel 9.4 km (5.85 miles) SSW of location proximately 15 m north of Cedar Run Road and 0.6 km (0.37 miles) 5 indicates a low gradient, suspended or mixed load meandering river northeast of its intersection with West Virginia Rt. 52 (location 1, Fig. (sinuosity = 1.9) with a width of 49 m and depth of 5.5 m in cross- 3). A total of 15.33 kg including 77 plant-bearing samples was recovered overs between meander bends (Martino et al., 1985). Similar results before the site was reclaimed in July. The Cedar Run flora occurs in pale were reported by Morton and Donaldson (1978) for a Grafton Sand- olive (Munsell Hue 5Y, Value 6/3), clayshale and mudshale. The facies is stone paleochannel in northern West Virginia. thin bedded and laminated. The flora consists of compressions and im- pressions of branches and branchlets of Walchia, grass-like leaves of 4. Paleoclimate and glacioeustasy Lepidophylloides, palm-like leaves of Cordaites and isolated neuropteroid pinnules. Lepidophylloides occurs as isolated pinnules and as clusters of During the Early to Middle Pennsylvanian, the tropical climate in the subparallel pinnules representing branchlets of the tree Sigillaria (Figs. central Appalachian Basin varied from perhumid (everwet) to wet sub- 4–7). Fieldwork in 2016 revealed Lepidophylloides and rare root traces humid (long wet season/short dry season; precipitation regime termi- in olive shale 1.1–1.5 m below the level of the Walchia horizon at loca- nology from Cecil, 2003). During the Late Pennsylvanian there was tion 1. significantly less rainfall, and the climate fluctuated between humid The stratigraphic position of the Cedar Run Walchia was originally subtropical to semiarid (Donaldson et al., 1985; Cecil, 1990). A sharp projected as 8.5 m above the Ames Limestone (Martino and Blake, change occurred near the Desmoinesian-Missourian boundary and 2001) based on its elevation compared to structural contours of was characterized by global warming, stronger seasonality, and shorter Merrill (1988) on the Ames Limestone; this position would put it in wet phases. It coincided with the regional extinction of most arbores- the paleosol-capping, lacustrine roof shale that directly overlies the cent lycopods and the appearance of widespread, high chroma, calcic Ames marine zone at nearby locations (Martino and Blake, 2001; vertisols and aridisols. Aridity was greatest during deposition of the Martino, 2004). Additional fieldwork at the Cedar Run location and Conemaugh Group (Donaldson et al., 1985; Cecil, 1990; Pfefferkorn et four nearby exposures in 2016 has helped clarify the stratigraphic and al., 2008). This paleoclimate change had a major impact on coal re- depositional context (Figs. 3, 8). The Ames marine zone of the Glenshaw sources. Coals of the Conemaugh Group likely formed under moist sub- Formation contains a distinctive, ledge-forming, calcareous crinoidal humid (wet-dry seasonal) climates and tend to be thinner, laterally sandstone facies in Wayne County, West Virginia and adjacent Boyd discontinuous, and higher in sulfur and ash than Early to Middle Penn- County, Kentucky (Merrill, 1988, 1993; Martino et al., 1996; Martino, sylvanian coals in the Appalachian Basin which formed under wetter 2004). At the Cedar Run locality, this marker bed is 1.1 m thick and its (humid-perhumid) climates (Cecil et al., 1985; Milici, 2005). Subregion- top crops out 5.5 m below Cedar Run Road along a steep embankment. al differences in paleotopography and subsidence rates likely influenced ThebaseoftheWalchia interval occurs 5.3 m above the road. This places where and how thick peat could accumulate (Lyons and Darrah, 1989a, the stratigraphic interval between the top of the crinoidal sandstone 1989b). and the Walchia floral zone 10.8 m at locality 1. The interval between Only the greater highstands (major cyclothems) invaded the Appa- the base of the Ames Limestone and the top of the crinoidal sandstone lachian Basin due to its high shelf position relative to midcontinent ba- is 5.0–6.1 m at locations 3 and 5. Using this interval, the Walchia horizon sins. The major cyclothems have an average duration of 400,000 years at location 1 occurs 15.8 to 16.9 m above the base of the Ames Limestone and resulted from glacioeustatic sea level cycles and climate variations (Figs.2,8), slightly higher stratigraphically than the 8.5 m initially con- associated with the eccentricity of the earth's orbit (e.g. Busch and cluded by Martino and Blake (2001). Rollins, 1984; Busch and West, 1987; Greb et al., 2008; Heckel, 1995, The Walchia horizon at locality 1 is recognized as occurring within a 2008). The amount of rainfall in tropical Pangea varied during paleochannel fill of the Grafton Sandstone IVF rather than in strata that cyclothems and impacted the composition of tropical vegetation. View- are truncated by the IVF because 1) the strata that are 15.8–16.9 m points vary as to what stage of the sea level cycle wetter and drier above the Ames Limestone at all nearby localities (Martino, 2004) are phases occurred (e.g. Falcon-Lang, 2004; Dolby et al., 2011; Horton et above the base of the IVF, and 2) the large scale, inclined bedding that al., 2012; DiMichele, 2014). In the Conemaugh, polygenetic paleosols in- occurs 3–5 m below the Walchia horizon (recently identified from a dicate that drier conditions were associated with falling sea level and construction site photograph) is similar to the epsilon cross-strata lowstands, whereas wetter conditions were associated with transgres- seen in paleochannels at the same stratigraphic level at locations 2 sions and highstands (Martino, 2004, 2015). Pteridosperms, lycopods and 4 which also contain plant fossils (Figs. 8, 9). R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168 157

Fig. 3. Topographic map showing outcrop locations 1–5. Contour interval = 20 ft. The Walchia assemblage from Wayne County was collected from bedrock that was temporarily exposed in a gas pipeline trench at Locality 1 (red star) in May and June of 1999. Rob Thompson, a civil engineer for Columbia Gas Transmission at the time, reported the location of the collection site; based on his description, the Walchia interval was 15 m (~50 ft.) north of Cedar Run Rd. at an elevation of 184.5–185.7 m (605–609 ft.) above sea level (latitude = 38.327421, longitude −82.563500). (For interpretation of the references to color in this ﬁgure legend, the reader is referred to the web version of this article.)

5.2. Flora of correlative Grafton Sandstone paleochannels

At location 2, 0.84 km (0.52 miles) west of the Cedar Run site at locality 1, a nearly complete 15.5 m section extending upward from the crinoidal sandstone was measured (Fig. 8). Using the 10.8 m interval between the top of the crinoidal sandstone and the Walchia horizon at location 1, the projected Walchia-equivalent interval occurs within a 6.75 m thick channel-fill. The lower 4.5 m consists of medium-coarse sandstone that grades up to very fine sandstone. Epsilon cross-beds en- close medium to large scale trough cross-stratification and ripple cross- lamination. Reactivation surfaces are common. This 4.5 m thick sandstone is overlain by a 2.25 m thick abandoned channel facies consisting of olive green shale/dark greenish gray mudstone. This channel-fill is truncated by another channel-fill sandstone, and both are part of the Grafton Sandstone IVF (Fig. 8). Calamites, Annularia stellata,and Pecopteris were found along a 5 cm thick interval in the shale (Fig. 9). At location 4, 1.51 km (0.94 miles) southwest of the Cedar Run Walchia locality, a complete section from 0 to 16.3 m above the crinoidal sandstone was measured and combined with the section through the Ames marine zone at location 3. Using the 10.8 m interval from the top of the crinoidal limestone to the Walchia horizon at locality 1, the projected Walchia-equivalent interval occurs within a 3.4 m thick, pale yellow mudstone (Fig. 8) in the upper portion of a channel-fill. The lower 4–5 m of the channel-fill consists of cross-stratified sandstone Fig. 4. Walchia piniformis frond showing branches with short, helically arranged, needle- and correlates with the Grafton Sandstone Member of the Casselman like leaves, Cedar Run site, locality 1. Formation. The paleochannel-fill is overlain by a 3.2 m thick red/olive 158 R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168

Fig. 5. Walchia piniformis from locality 1. A, C. Walchia fronds. B, D. Walchia branchlets. Scale bar is 5 mm. variegated hackly mudstone paleosol with abundant micritic limestone Conemaugh Formation in the Charleston area using traditional litho- nodules in the lower 40 cm. Plant fossils are restricted to a 10 cm thick stratigraphy. Furthermore, the Mahoning coal cannot be identified interval near the top of the channel-fill. Cordaite leaves are common and with confidence at Charleston because it is thin and discontinuous, Lepidophylloides is rare (Fig. 9). and the Mahoning coal horizon tentatively identified is usually truncated by the Upper Mahoning Sandstone (Windolph, 1987). 5.3. Flora from below the Grafton Sandstone incised valley-fill Recent work involving the correlation of paleosol-bound allocycles from Charleston downdip to Huntington and Flatwoods, West Virginia A second floral horizon occurs below the Grafton Sandstone IVF at indicates that the Twomile Limestone of I. C. White (1885) is likely locations 2 and 4. The flora are preserved in the lower part of a 2.2 m equivalent to the Upper Brush Creek Limestone (Martino, 2015). A com- thick, gray to dark gray shale. The shale occurs directly above a calcic posite section of the Conemaugh Formation from the north side of vertisol that overlies the Ames marine zone and it is truncated by the Charleston indicates that the Brush Creek coal horizon is present Grafton Sandstone IVF. At locality 2, this assemblage includes 7.5 m above the lowest redbeds (Fig. 11). This coal is discontinuous in Lepidophylloides, Cordaites, Pecopteris,andNeuropteris ovata.Atlocality the Charleston area. Kosanke (1988) reported the palynomorph 4, the shale contains Cordaites, Lepidophylloides,andPecopteris (Fig. Laevigatosporites globosus from carbonaceous shales at three horizons 10). This shale correlates with the Duquesne coal which in eastern north of Charleston that have been correlated to the Charleston section. Ohio is overlain by the marine Skelly Limestone (Sturgeon and Hoare, These horizons occur near interfluvial sequence boundaries 2, 5 and 6 in 1968). Fig. 10. Lycospora is absent in these beds and last occurs in the Mahoning coal (Fig. 2; Eble et al., 2009). The Brush Creek coal is distinguished from 5.4. Charleston Walchia the Mahoning coal below by the absence of Lycospora, and from the Bakerstown above by the presence of Laevigatosporites globosus and Walchia and Cordaites were reported by Lyons and Darrah (1989a, Punctatosporites granifer (Peppers, 1996; Eble et al., 2009). Since the 1989b) from a carbonaceous shale about 7.5 m above the lowest red first occurrence of L. globosus without Lycospora is ~20 m below the bed in the Conemaugh Formation at Charleston, West Virginia as de- Twomile Limestone and this first happens in the Brush Creek coal, the scribed by Englund et al. (1979). The exact location and stratigraphic Charleston Walchia reported by Lyons and Darrah (1989a, 1989b) section of the Charleston Walchia was not included. Lyons and Darrah must be above the Brush Creek coal and below the Bakerstown coal. If (1989a, 1989b) concluded that the Charleston Walchia occurred at the the first occurrence of L. globosus without Lycospora occurs between Mahoning coal horizon. However, the absence of minable coal and ma- the Mahoning and Brush Creek coals, it is possible that the Charleston rine units makes it difficult to confidently correlate within the Walchia may be associated with the Brush Creek coal horizon, but it R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168 159

Fig. 6. Walchia piniformis from locality 1. A. Walchia frond. B–D. Walchia branchlets. Scale bar = 5 mm. would still be Missourian in age and not Late Desmoinesian as postulat- Pennocereas seaman (Mapes and McComas, 2010) and the conodont ed by Lyons and Darrah (1989a, 1989b). Idiognathodus cancellosus confirm the correct correlation as Lower Brush Creek (Work et al., 2007; Falcon-Lang et al., 2011). The thin coal 5.5. 7-11 Mine Walchia beneath the walchian shale is limited to the valley-fill and therefore cannot be strictly lithostratigraphically correlated with the Brush Walchia was reported from a 1.5 m thick, dark gray-black shale at the Creek coal horizon. However, its position above a 2.7 m thick paleosol 7-11 Mine north of East Liverpool, Ohio (Mapes and McComas, 1984; with limestone nodules and directly beneath the Lower Brush Creek McComas, 1988). Wagner and Lyons (1997) reexamined this assem- transgressive sequence suggests the coal and overlying walchian shale blage and found abundant Walchia as well as Cordaites, Sigillaria brardii, are genetically related to the lower Brush Creek Cyclothem. The 7-11 and fern and pteridosperm fragments. Associated taxa reported by Mine Walchia interval is younger (early Missourian) than the late McComas (1988) included Lepidostrobophyllum, Sigillariostrubus, Desmoinesian Mahoning roof shale age presumed by Lyons and Annularia asteris, Calamites, Asterotheca, Pecopteris unita?, Ptychocarpus, Darrah (1989a, 1989b) when they correlated it with their Charleston Spiropteris, Alethopteris, Aphlebia, Cyclopteris orbicularis, Neuropteris Walchia horizon. ovata, Odontopteris aequalis, Cordaites, Gomphostrobus, Walchiostrobus, and Samaropsis. 5.6. Rennersville Walchia The Walchia-bearing shale has a thin coal at the base which was que- ried as the Brush Creek coal (McComas, 1988). The Walchia interval is Darrah (1969, 1975) reported four specimens of Walchia (Lebachia part of a fine-grained incised valley-fill up to 28 m thick that truncates sp.) from a fine grained sandstone at Rennersville southwest of Pitts- the Mahoning coal and overlying 18 m of strata (Easterday, 2004; burgh, Pennsylvania. The sandstone was located above the Clarksburg Falcon-Lang et al., 2011, Fig. 2; Belt et al., 2011, Fig. 13). Lycospora, Limestone in the upper Casselman Formation. The Walchia was consid- which is absent in this coal (Easterday, 2004), last occurs in the ered a rare component of the assemblage. Common taxa included Mahoning coal, which is consistent with the Brush Creek coal correla- Lescuropteris moorii, Pecopteris polymorpha, P. aborescens, Neuropteris tion. Both the flora and palynoflora associated with the lower 11 m of ovata and Sphenophyllum oblongifolium. Other taxa present were the IVF are early Missourian in age (Belt et al., 2011). The Walchia-bear- Callipteridium cf. pteridium?(questionedbyWagner and Lyons, 1997), ing shale is overlain by a fossiliferous shale identified as the Lower Brush Danaeites emersoni, Pecopteris feminaeformis, Sphenopteris minutisecta, Creek marine unit by McComas (1988). The presence of the ammonoid Alethopteris grandini, Odontopteris reichiana, Macroneuropteris 160 R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168

Fig. 7. Flora associated with Walchia from Cedar Run, locality 1. A, B, D: isolated neuropteroid pinnules. C, E. Strap-like Cordaites with Walchia branchlet. F: grass-like leaves of Lepidophylloides (foliage from Sigillaria). Scale bar = 5 mm.

scheuchzeri,andCordaites. The stratigraphic and depositional context of occurrences in the Casselman Formation are slightly younger, correlat- this assemblage is not known. The age is early Virgilian, but younger ing with the early Virgilian stage. These results provide a more coherent than the Cedar Run Walchia. picture of the timing of paleoclimatic changes in the Appalachian Basin and the migration of walchian conifers into this region. The first appearance of Walchia, instead of preceding other indicators of increasing dry- 5.7. Implications for revised correlation of Appalachian Basin Walchia ness (extinction of wetland-centered lycopods, first appearance of calcic vertisols), closely follows these events (Fig. 12). The first red beds are The previously reported and revised stratigraphic positions of the associated with the Mahoning coal horizon, and the earliest widespread four Walchia occurrences in the Appalachian Basin are shown in Fig. calcic vertisols occur below the Brush Creek coal (Martino, 2004, 2015); 12. The oldest occurrences from the Glenshaw Formation (Charleston, the Desmoinesian-Missourian boundary occurs between these two 7-11 Mine) were originally thought to be from the level of the coals. Thus, walchian conifers were already established in subtropical Mahoning coal and late Desmoinesian in age. From the preceding paleolatitudes and more western regions of the midcontinent during data, it appears that both are younger and correlate with the Brush the Middle Pennsylvanian (Lyons and Darrah, 1989a, 1989b), and mi- Creek coal roof shale or lower Brush Creek cyclothem making them grated to the Appalachian Basin as climate/sea level cycles involved lon- early Missourian in age. The Cedar Run and Rennersville Walchia ger dry seasons along the equator. R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168 161

Fig. 8. Stratigraphic sections from locations 1–5inFig. 3. Correlations are made across the study area using the top of the crinoidal sandstone as a datum, which was discovered at the Cedar Run Walchia locality in 2016. The crinoidal sandstone is a shallow marine facies found along the Big Sandy River that is developed in the upper part of the Ames marinezone.Acomposite section was constructed for locations 3 and 4 due to their close proximity and continuous exposure between them. The stratigraphic interval between the Walchia horizon and the regionally developed Ames Limestone was determined by adding the interval between it and the crinoidal sandstone at locality 1 to the interval between the top of the crinoidal sandstone and the base of the Ames Limestone at localities 3 and 5.

5.8. Paleoecology (Clement-Westerhof, 1988; Rothwell et al., 1997). Cordaites inhabited peat swamps, clastic swamps, upland/dryland regions, and slopes of The xeromorphic traits of most modern conifers (thick cuticle, nee- river valley walls. Its large, tough, strap-like leaves were fairly durable dle like leaves with low ratio of surface area to volume) enables them during transport (Falcon-Lang and Bashforth, 2004, 2005). Some to retain moisture, inhabit well-drained soils, and tolerate drier climates Cordaites had deep root systems that enabled them to inhabit mois- (Lyons and Darrah, 1989a). Walchia was restricted to seasonally dry ture-stressed clastic substrates (Bashforth et al., 2014). Lepidophylloides habitats in subtropical to tropical Euramerica (Ziegler et al., 2002)and includes the grass-like leaves arborescent lycopods (Gillespie et al., is considered to be an indicator of semiarid settings where only 1–2 1978), and Sigillaria is the only lycopod that survived into the Missouri- wet months occurred per year (DiMichele et al., 2010). Walchian coni- an and Virgilian. Though Sigillaria was typically associated with wet- fers may have occupied upland areas continuously, and expanded into lands, it was tolerant of seasonally drier conditions and lowered water lowland areas during the drier phase of the cyclothems (Phillips and tables due to deep-reaching adaptations in its stigmarian root system Peppers, 1984; Falcon-Lang et al., 2009; Dolby et al., 2011, DiMichele, (Phillips and DiMichele, 1992; Pfefferkorn and Wang, 2009). Sigillaria 2014). Their rarity in Late Pennsylvanian strata has been attributed to is often preserved in fluvial channel sandstones suggesting that some be due at least in part to the lower preservation potential of flora that species grew along stream margins, perhaps on levees (Gastaldo, inhabited well-drained soils (Looy et al., 2014). 1987; Phillips and DiMichele, 1992). Calamites was an arborescent The flora associated with the Cedar Run Walchia includes Cordaites, plant up to 30 m in height which inhabited lake margins and point Lepidophylloides and rare neuropteroid pinnules. Cordaites, like Walchia, bars of meandering rivers. The hollow stems of mature Calamites com- was a coniferophyte with well-developed xeromorphic features monly filled with mud forming pith casts (Gillespie et al., 1978; Mapes 162 R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168

Fig. 9. Flora from abandoned ﬂuvial channel-ﬁll mudstones at locations 2 (A–C) and 4 (D). Scale bar = 5 mm. A. Annularia carinata, Calamites,andPecopteris.B,C.Annularia carinata.D. Cordaites.

and Gastaldo, 1986). Annularia carinata represents foliage of Calamites 5.9. Plant taphonomy (Kerp and Fichter, 1985; DiMichele et al., 2010). Pecopteris and Neuropteris are seed ferns (pteridosperms) that included shrubs and Studies of modern depositional settings indicate that fossilized small trees. They are common elements in Pennsylvanian, tropical wet- plants may represent flora living at or near the site of deposition (i.e. au- land floras. Late Pennsylvanian swamps were dominated by tree ferns tochthonous/parautochthonous) or flora that were transported from and the lycopod Sigillaria, with pteridosperms as an understory upstream or upland locations (allochthonous; Gastaldo et al., 1987; (DiMichele, 2014). Gastaldo and Degges, 2007). Preservation potential is highest in fluvial, During the Late Pennsylvanian, Walchia, Cordaites,andSigillaria are upper delta plain, and lacustrine settings (Dodd and Stanton, 1990). Dif- often found together in what earlier workers interpreted as ‘upland as- ferent plant parts have highly variable floating times. For example, ex- semblages’ (Scott and Chaloner, 1983; Rothwell and Mapes, 1988; perimental work has shown that leaves may be saturated in a few Stewart and Rothwell, 1993), though more recent workers prefer the days to a few months (Spicer, 1981; Ferguson, 1985). Evergreen term ‘dryland’ (e.g. Looy et al., 2014). The branches and leaves of upland branches and needles often can float for several months, increasing trees may have been detached during storms and swept downstream the likelihood of sustained transport over a significant distance (Spicer during high rainfall and runoff, ultimately accumulated in abandoned and Greer, 1986). In the modern Mobile Delta of Alabama, fascicles of fluvial channels. Previous studies have documented allochthonous Pinus from upland pine savannah communities have been found in cre- Walchia assemblages in lowland lake and swamp facies (Rothwell and vasse splay channel deposits (Gastaldo et al., 1987). Mapes, 1988; Mapes and Rothwell, 1988) and even marine limestone (Leisman et al., 1988). In the Illinois Basin, Middle Pennsylvanian conifers including 5.10. Depositional model for the Cedar Run Walchia assemblage Walchia have been described from incised fluvial channel-fills, and are interpreted to have grown on the interfluves or within the channels During deposition of the Conemaugh Group, a low relief coastal plain themselves during dry conditions associated with glacial lowstand with poorly drained interfluves prevailed during late TST and HST (Falcon-Lang et al., 2009). Walchian conifers in growth position have (Martino, 2004, 2015). During FSST and LST, rivers incised their valleys been described from Missourian coastal facies in New Mexico (Falcon- (Fig. 13) creating relief on the order of at least 20–35 m based on the Lang et al., 2015). Limited palynologic sampling of Desmoinesian cyclic preserved thickness of IVFs. The total maximum relief is likely to have strata from Nova Scotia suggests that conifers including Walchia were been significantly greater than the preserved thickness of the IVFs, the dominant forms of vegetation on a well-drained interfluve and dry when sediment compaction is taken into account and also that the in- alluvial plain during lowstand and early transgressive systems tracts terfluves were being eroded as the valleys filled. The dryland/upland (Dolby et al., 2011). flora may have developed on well-drained interfluves, topographically R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168 163

Fig. 10. Flora from paleosol-capping shale facies a locations 2 and 4. Scale bar = 5 mm. A. Pecopteris.B.Pecopteris cf. oreiopteridia.C–E. Neuropteris ovata.F.largeCordaites.

higher areas of a dissected lowland (Fig. 14). A similar scenario is Looy et al. (2014) reviewed the taphonomic factors that controlled envisioned for conifer-dominated assemblages from the Mid-Late Penn- the preservation of plant fossils in Late Paleozoic strata, and concluded sylvanian Sydney Mines Formation of Nova Scotia (Dolby et al., 2011). that Methuselah occurrences of drought-tolerant plants such as The excellent preservation of the Cedar Run Walchia and lack of size walchian conifers likely represented normally extrabasinal (i.e. upland) sorting indicates minimal physical, biologic or chemical degradation. In- elements living above base level that migrated into the basinal lowlands terfluve runoff could have easily introduced coniferous vegetation into during drier parts of the climate cycle. Their model (Looy et al., 2014, rapidly filling valleys requiring transport of several km or less. Mass Fig. 2) was based on a static, flat coastal plain that persisted through wasting could also have played a role in transferring the conifers as wet and dry climatic phases. It overlooks the significant relief that de- the valleys were widened over time (e.g. Falcon-Lang et al., 2009; Fig. velops in coastal plains along the depositional strike due to fluvial inci- 14). A large, paleovalley wall slump block is preserved in the Glenshaw sion during FSST and persists during LST and early TST. During these Formation along Rt. 52 at Prichard, 5 km south study area (Martino, times, it is likely that walchian conifers inhabited well-drained upland 2004,Fig.17).TheCordaites and Sigillaria may have populated the wet- interfluves and valley walls adjacent to the river basins. Slope failure lands of the valley floor, but could also have coexisted with Walchia and flash flooding could have transported them as little as a hundred along the valley walls or interfluves. meters to the valley floor where they were quickly buried in standing 164 R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168 water, with rapidly increasing accommodation and rising water table valleys (Fig. 14) provides a very plausible alternative to the dryland- during TST enhancing their preservation potential. The juxtaposition lowland concept, particularly for rare, anomalous, Methuselah-type of well-drained upland or valley wall substrates within rapidly filling occurrences.

9 80

70 SM,O 8

60 7

L. globosus 50 6 IVF

40 SM,O Twomile Ls. 5 L. globosus

SM,O 4 Brush Cr. C. Walchia of Lyons and Darrah 30 7.5 m

lowest red bed 20

2 L. globosus

10 Mahoning Ss.

0 m IVF

Coal Shale 1-9 Interfluvial sequence boundaries

Silty shale, bedded mudstone Carbonaceous shale/claystone Cr Crinoid plates

Hackly mudstone Micritic limestone nodules Br Brachiopods

Bi Bivalves, marine Siltstone Siderite nodules G Gastropods, marine Ripple cross-lamination Root traces Cs Conchostracans Trough cross-stratification Parallel lamination SM Spirorbid Microconchids Compound cross-stratification Hummocky cross-stratification O Ostracods Limestone Burrows P Plants Argillaceous limestone Quartz pebbles T Shark Tooth

Fig. 11. Composite section of lower Conemaugh in the Charleston area with paleosol-bounded cyclothems which have been correlated with marine-cored cyclothems to the north and west of Charleston (modiﬁed from Martino, 2015). Lyons and Darrah (1989a, 1989b) reported Walchia from a carbonaceous shale 7.5 m above the lowest red beds at or above the Mahoning Sandstone which they believed to be the Mahoning coal horizon. R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168 165

Fig. 12. Stratigraphic position of Appalachian Basin Walchia occurrences and associated paleoclimatic data (red bed paleosols, calcic vertisols, extinction of most lycopods). Relative wetness curve is based on abundance of known bituminous coal resources from eastern U.S. coal basins (modiﬁed from Phillips et al., 1985). Stars show the four occurrences of Walchia in the Appalachian Basin (7-11 = 7-11 Mine, Ch = Charleston, CR = Cedar Run, R = Rennersburg). Dashed arrows point to revised stratigraphic positions based on this study.

6. Conclusions 2) The Cedar Run floral assemblage occurs 15.8–16.9 m above the base of the Ames Limestone and is early Virgilian in age. It includes Walchia, Cordaites, Lepidophylloides, and rare neuropteroid pinnules 1) The Cedar Run Walchia is only the fourth Walchia occurrence from preserved in an abandoned channel-fill mudstone that is part of Pennsylvanian strata of the Appalachian Basin, and only the second the Grafton Sandstone incised valley-fill. This is slightly higher occurrence to be accompanied by a detailed description of its strati- stratigraphically than was initially reported, and revises the flood graphic and sedimentologic context. basin lake interpretation of Martino and Blake (2001). 166 R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168

SEQUENCE STRA FACIES ASSOCIATIONS

MFS Valley incision, pedogenesis on interfluves LATE TST SB 2 IFSB under dry, seasonal climate. FSST/LST/EARLY TST Valley filled by stacked fluvial channels with fluvial-estuarine transition. Lake or sea filling by crevasse splays and deltas produces coarsening upward sequence locally truncated by crevasse and delta channels.

2 HST Interglacial sea level highstand.

IVF SB TST Rising water table with rising sea level and less seasonal, wetter climate gleys and drowns soils forming histosol + lakes, bays, and seaway. MFS LATE TST Valley incision, pedogenesis on interfluves SB 1 IFSB FSST/LST/EARLY TST under dry, seasonal climate. Onset and peak of of glaciation. Valley filled by stacked fluvial channels with fluvial-estuarine transition during deglaciation and rising sea level.

subhumid semiarid subhumid IVF TST inter fluve exposure- paleosols IFSB SB1 calcisol/calcic vertisol HST histosol HST valley incision late FSST valley late FSST TST filling TST

early early LST sea level water table

Fig. 13. Sequence stratigraphic model for paleosol-bounded, eccentricity-driven, fourth-order sequences in Conemaugh Group and related moisture regimes that affected vascular plants (modified from Martino, 2015). Sea level curves, systems tracts and water table conditions are shown. Symmetric sea level curve is used for simplicity, but is likely to be strongly asymmetric for glacioeustatic cycles since ice sheets melt more rapidly than they grow (Catuneanu, 2006). The Cedar Run Walchia is interpreted as mass wasting into an abandoned fluvial channel from an adjacent valley wall or upland as the Grafton Sandstone incised valley was filling during early TST.

Fig. 14. Paleoenvironmental model for origin of the Cedar Run Walchia assemblage in an abandoned fluvial channel. Interfluvial sequence boundaries occur at the top of thick, mature, well- drained paleosols (IFSB = interfluvial sequence boundary; SB 9, 10, and 11 from Martino, 2004, Fig. 12). A = Calamites, B = medulosan pteridosperms, C = tree ferns, D = walchian conifers, E = Cordaites,F=Sigillaria (modified from Falcon-Lang et al., 2009). Sigillaria and Cordaites could inhabit basin floor wetlands and well-drained coastal plain uplands, while Walchia was restricted to well-drained uplands. Topographic relief may have been 30 m or less. The occurrence of Walchia at a single location and the abundance of well-preserved fronds and branchlets make it more plausible that an entire tree fell into the channel via a slump block from the valley wall. Valley-fill sequence not to scale. The Grafton IVF downcuts to Harlem coal north of the present study area. R.L. Martino / International Journal of Coal Geology 171 (2017) 153–168 167

3) It is possible that Walchia, Sigillaria,andCordaites populated the Cecil, C.B., 1990. Paleoclimate controls on stratigraphic repetition of chemical and siliciclastic rocks. Geology 18, 533–536. drainage basin (lowland/dryland origin) when water tables were Cecil, C.B., 2003. The concept of autocyclic and allocyclic controls on sedimentation and seasonally low due to the semiarid climate during or near glacial stratigraphy, emphasizing the climatic variable. SEPM Spec. Publ. 77, 13–20. maximum. However, it appears more likely that it was derived Cecil, C.B., Stanton, R.W., Neuzil, S.G., Dulong, F.T., Ruppert, L.F., Pierce, B.S., 1985. fl Paleoclimate controls on Late Paleozoic sedimentation and peat formation in the Cen- from proximal, well-drained inter uves or valley walls through tral Appalachian Basin (USA). Int. J. Coal Geol. 5, 195–230. mass wasting associated with valley-widening. Clement-Westerhof, J.A., 1988. Morphology and phylogeny of Paleozoic conifers. In: Beck, 4) The flora of the lacustrine shale that caps the calcic vertisol directly C.B. (Ed.), Origin and Evolution of Gymnosperms. Columbia University Press, New – above the Ames marine zone consists of tree ferns and Cordaites. York, pp. 81 121. Darrah, W.C., 1969. Upper Pennsylvanian Floras of North America. Gettysburg Press (220 The rising water table associated with wetter climatic conditions p). and rising sea level drowned interfluvial paleosols forming lakes as Darrah, W.C., 1975. Historical aspects of the Permian flora of Fontaine and White. In: part of the TST. Barlow, J.A., Burkhammer, S. (Eds.), Proceedings of the First I. C. White Symposium, Morgantown WV. West Virginia Geological and Economic Survey, pp. 81–101. 5) The earliest reported occurrences of Walchia in the Appalachian Davydov, V.I., Crowley, J.L., Schmitz, M.D., Poletaev, V.I., 2010. High precision U-Pb zircon Basin from Charleston, West Virginia and the 7-11 Mine in Ohio age calibration of the global Carboniferous time scale and Milankovitch band cyclicity are early Missourian in age and not late Desmoinesian as previously in the Donets Basin, eastern Ukraine. Geochem. Geophys. Geosyst. 11, 1–22. Demko, T.M., Dubiel, R.F., Parrish, J.T., 1998. Plant taphonomy in incised valleys: implica- thought. The appearance of walchian conifers between the Brush tions for interpreting paleoclimate from fossil plants. Geology 26, 1119–1122. Creek and Wilgus coals follows the mass extinction of nearly all ar- DiMichele, W.A., 2014. Wetland-dryland vegetational dynamics in the Pennsylvanian ice borescent lycopods near the Desmoinesian-Missourian boundary age tropics. Int. J. Plant Sci. 175, 123–164. DiMichele, W.A., Cecil, C.B., Montanez, I.P., Falcon-Lang, H.J., 2010. Cyclic changes in Penn- and the earliest development of calcic vertisols and aridisols in the sylvanian paleoclimate and effects on floristic dynamicsin tropical Pangaea. Int. J. Coal Conemaugh Group of the Appalachian Basin. Geol. 83, 329–344. Dodd, J.R., Stanton Jr., R.J., 1990. Paleoecology – Concepts and Applications. second ed. John Wiley and Sons, New York (502 p). Acknowledgements Dolby, G., Falcon-Lang, H.G., Gibling, M.R., 2011. A conifer-dominated palynological assemblage from Pennsylvanian (late Moscovian) alluvial drylands in Atlantic Canada: I am greatly indebted to Robert D. Thompson for 1) bringing the Ce- implications for the vegetation of tropical lowlands during glacial phases. J. Geol. Soc. 168, 571–584. dar Run Walchia location to my attention, 2) facilitating the description Donaldson, A.C., 1979. Depositional environments of the Upper Pennsylvanian Series. In: of the Walchia location and stratigraphic interval, and 3) assisting in the Englund, K.J., Arndt, H.H., Henry, T.W. (Eds.), Proposed Pennsylvanian System recovery of additional fossils from the site. James Bowling and Robert D. Stratotype Virginia and West Virginia. American Geologic Institute, Selected Guide- book Series 1, pp. 123–132. Thompson, Jr. also helped in the collection of fossils. Elaine Martino rec- Donaldson, A.C., Renton, J.J., Presley, M.W., 1985. Pennsylvanian deposystems and ognized the potential significance of the fossils when they were first ex- paleoclimates of the Appalachians. Int. J. Coal Geol. 5, 167–193. cavated and was instrumental in their recovery and preservation. She is Easterday, C.R., 2004. Stratigraphy and Paleontology of Cemetery Hill (Desmoinesian– Missourian: Upper Carboniferous), Columbiana County, Eastern Ohio. The Ohio also due thanks for her patience and support throughout this project. State University, Columbus, Ohio (Unpublished M.S. Thesis, 505 p). Mitch Blake provided copies of field notes that helped correlate Eble, C.F., Blake Jr., B.M., Gillespie, W.H., Pfefferkorn, H.W., 2009. Appalachian basin fossil Kosanke's pollen-bearing horizons to the Charleston Walchia occur- floras. In: Greb, S.F., Chesnut, D. (Eds.), Carboniferous of the Appalachian and Black Warrior Basins. Kentucky Geological Survey Special Publication 10, pp. 46–58. rence. Paul Lyons provided input on the proposed Stephanian unconfor- Elias, M.K., 1942. Walchia associated with diagnostic Early Pennsylvanian forms in central mity in the Appalachian Basin and shared his current knowledge of the Colorado. Geol. Soc. Am. Bull. 53, 180. stratigraphic context and location of the Charleston Walchia occurrence. Englund, K.J., Arndt, H.H., Henry, T.W., 1979. Proposed Pennsylvanian system stratotype, William DiMichele provided encouragement and generously assisted Virginia and West Virginia. American Geological Institute Selected Guidebook Series 1(136p). with the identification of plant taxa. Annalisha Johnson provided invalu- Ettensohn, F., 2008. The Appalachian foreland basin in Eastern United States. In: Miall, able guidance on drafting illustrations. The clarity of this paper was signif- A.D. (Ed.), The Sedimentary Basins of the United States and Canada. Elsevier, The – icantly improved due to thorough and thoughtful reviews by William Netherlands, pp. 105 179. Falcon-Lang, H.J., 2004. Pennsylvanian tropical rain forests responded to glacial-intergla- DiMichele, Martin Gibling, and Stephen Greb. Various phases of this study cial rhythms. Geology 32, 689–692. were supported by the Petroleum Research Fund (PRF 34516-B8), the Falcon-Lang, H.J., Bashforth, A.R., 2004. Pennsylvanian uplands were forested by giant West Virginia Geological and Economic Survey, and Marshall University. cordaitalean trees. Geology 32, 417–420. Falcon-Lang, H.J., Bashforth, A.R., 2005. 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