Petrified Pennsylvanian Age Plants of Eastern Ohio1
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PETRIFIED PENNSYLVANIAN AGE PLANTS OF EASTERN OHIO1 GAR W. ROTHWELL, Department of Botany, Ohio University, Athens, Ohio 45701 Abstract. The recent (1975) discovery of coal-ball petrifactions in the Duquesne and Ames coals of the Conemaugh Group provides an opportunity to make detailed studies of abundant and well preserved Pennsylvanian age fossil plants. Material from these beds was collected at a single location west of Steubenville, Ohio. Remains assignable to all the major groups of coal swamp plants were present, with the psaroniaceous tree ferns and medullosan seed ferns most abundantly represented. To date, 50 distinct taxa of plant remains have been discovered. OHIO J. SCI. 76(3): 128, 1976 Pennsylvanian age plants, preserved by calcareous cellular permineralization (coal balls), are among the most valuable of Paleozoic fossils. At localities where Duquesne large quantities of material are available for study, features such as anatomical structure and plant habit can often be thoroughly examined (e.g. Dennis, 1974). In instances where preservation is espe- cially good, developmental sequences and even reproductive mechanisms sometimes can be interpreted (e.g. Millay and Eg- gert, 1974). Unfortunately, known col- lecting localities of coal balls are few in number. In the Appalachian Basin only six discoveries have thus far been re- ported (Cross, 1967; Schopf, 1961); in- cluding two in Ohio (Good, personal communication; Good and Taylor, 1974). It is therefore of considerable importance that two new Ohio coal-ball localities are described. LOCALITIES AND STRATIGRAPHY Two coal seams were exposed in a road cut on the south side of Ohio Route 22 (NE M SE K SE 14, Sec. 6, Wayne Township, Jefferson County), approxi- mately five miles west of Steubenville, FIGURE 1. Stratigraphic column of collecting Ohio. Coal balls were present within locality. Coals are black (with both seams 1,000 m west of the highway white coal balls). Clays are white bridge over Cross Creek. Separation of and the remaining strata are indi- the seams by the Ames limestone (fig. 1) cated by standard lithologic sym- suggests that they are the product of bols. Numbers at left indicate thickness of individual units in Manuscript received November 17, 1975 and meters. Based on Ohio Division in revised form March 26, 1976 (#75-70). of Geological Survey section #13643. 128 No. 3 PENNSYLVANIAN AGE PLANTS 129 two separate depositional sequences, and (table 1). The greatest volume of plant therefore probably represent distinct remains is assignable to the Psaroniaceae. floristic habitations of the area. The Most of this consists of Psaronius free upper seam occurs approximately 1.5 m roots, but several stems also have been above the Ames limestone, from which it discovered. The specimen illustrated in is separated by zones of clay and shale. This is the Duquesne coal (Duquesne TABLE 1 Cyclothem), which is 0-38 cm thick at Presently known flora of the Duquesne this exposure and in localized areas con- and Ames Coals tains lenses of isolated or aggregated coal balls. In some areas coal from the bot- Duquesne Ames tom or top zone of the seam is replaced Plant Coal Coal by coal-ball material and in other areas the seam consists primarily of coal balls Alethopteris sp. X* X separated by narrow coal stringers. In Amyelon sp. X X the latter areas the seam is expanded to Anachoropteris involuta X X as much as 1.3 m. The smaller coal balls Arthropitys sp. X X Asterophyllites sp. X — are elipsoidal masses less than 3 cm in Biscalitheca musata X — diameter and larger coal balls range to Botryopteris sp. X X 1 m. Most of the material is light brown Bowmanites sp. X — or beige in color with plants that are Calamocarpon sp. X — Calamodendron sp. X — easily seen on weathered surfaces. Other Calamostachys sp. X — coal balls are chocolate brown with more Callistophyton poroxyloides X X crushed plant remains. The surrounding Callospermarion sp. X X calcareous matrix is usually a translucent Cardiocarpus sp. X — Cardiocarpus sp. X — white, but in places a gray limestone Conostoma cf. platyspermum X — (probably marine in origin) replaces the Conostoma cf. quadratum X X other constituents. Cordaianthus sp. X X The second coal seam lies directly be- Cordaites sp. X X Cyathotrachis sp. X X low the Ames limestone (fig. 1) and is Dolerotheca cf. formosa X — more difficult to identify. In Ohio, coal cf. Eoangiopteris sp. X — that occurs 0-7 m below the Ames lime- Etapteris sp. X X stone is of sporatic occurrence and has Heterangium sp. X — cf. Hexapterospermnm sp. X — traditionally been regarded as the Harlem cf. Idanothekion sp. (or coal (e.g. Stout el al, 1923). In Athens Callandrium, sp.) X — County, the Harlem coal is separated cf. Mazocarpon sp. X — from the Ames limestone by several Medullosa sp. X X meters of shale and sandstone, and by a Mesoxylon sp. X X cf. Mitrospermum sp. X — coal seam that directly underlies the Myeloxylon sp. X X Ames limestone. This coal seam has Neuropteris sp. X — been designated the Ames coal, and is Pachytesta berryvillensis X X considered to be equivalent to the Cri- Pachytesta cf. hexangulata X — Pachytesta cf. stewartii X — noidal or Friendsville coal of Maryland Paurodendron sp. X X (Sturgeon, 1958). The lower coal seam Pecopteris sp. X — of this report is therefore considered to Psaronius chasei X (?) be the Ames coal (Ames Cyclothem). Scolecopteris sp. X X Sermaya sp. X — This seam is 20-76 cm thick and contains Sigillaria sp. X X isolated, dark brown, elipsoidal coal balls. Sigillariophyllum sp. X — They are round to oval, 15-70 cm in Sphenophyllum sp. X X greatest length and typically contain Stephanospermum sp. X — Stigmaria sp. X X crushed plant parts. Stipitopteris sp. X X Tedelia sp. X — SYSTEMATIC DESCRIPTION Triletes X X Tubicaulis sp. X — From approximately five hundred Du- Zygopteris berryvillenis X — quesne coal balls, 46 genera and 50 spe- cies of fossil plants have been identified indicates presence of species. 130 GAR W. ROTHWELL Vol. 76 figure 2 is assignable to P. chasei Morgan phyton stems and leaves, Callospermarion (1959). Frond segments (i.e., Stipito- ovules and Idanothekion or Callandrium pleris) and the fertile pinnules of Scole- pollen organs (fig. 9). Medullosan pteri- copteris, Cyathotrachis, and possibly dosperms were undoubtedly the most Eoangiopteris are extremely abundant. abundant seed plants. Medullosa stems, Of particular interest is the frequent Myeloxylon petioles and Neuropteris pin- occurrence of the coenopterid fern Zygop- nules of medullosan origin are extremely teris berryvillensis (fig. 6) Dennis (1974) common. Alethopteris pinnules (fig. 7) and associated Etapteris foliar fragments. of probable medullosan affinities are also The zygopterid fructification Biscalitheca represented. Ovules include at least musata Mamay (1957) is also excep- three species of Pachytesta (fig. 3), tionally well represented (fig. 5). Arbo- Stephanos per mum, and possibly Hexapte- rescent lycopsids appear to be entirely rospermum. sigillarian in nature. These include The number of available coal balls branches assignable to Sigillaria, Sigil- and quality of plant preservation in the lariophyllum leaves and Sligmaria root- Ames coal are below those described ing structures. Several large, lycopsid above. The Psaroniaceae is represented cone fragments, isolated megasporangia primarily by fragments of the bound and micro sporangia are frequently en- root zone, with only a few crushed free countered. The articulates are repre- roots present in most coal balls. Stems, sented by several taxa of vegetative and foliar fragments and fertile material are fertile organs assignable to the Calami- also occasionally encountered. Remains tales and Sphenophyllales. These in- of the Medullosaceae make up a large clude Ar thro pity s, C alamo dendr on and percentage of the flora. These include Sphenophyllum (fig. 8) stems, and Aster o- mostly crushed fragments of the outer phyllites and Sphenophyllum leaves. "sclerenchymatous" cortex from stems Sphenopsid cones have been identified and petioles, but some intact organs are as Calamostachys, Calamocarpon and Bow- also present. The Calamitales and Cor- manites. Gymnospermous remains are daitales are most abundantly represented assignable to the Cordaitales and Pterido- by root material. Fertile structures of spermales. Mesoxylon stems, Cordaites all groups occur with a lower frequency leaves, Amyelon roots, Cordaianthus pol- than in the Duquesne material. len strobili, and at least two species of the isolated ovule Cardiocarpus (fig. 10) DISCUSSION were present in approximately 10% of Coal balls are now known from four the cut coal balls. Ovules tentatively stratigraphic levels in the Conemaugh assignable to Mitrospermum were also and Monongahela Groups of Ohio. These present. Among the pteridospermales, include in ascending order the Anderson Heterangium stems and Conostoma ovules (?) coal (Good, C. W., personal communi- (fig. 4) are abundant. The Callisto- cation), the Ames coal, The Duquesne phytaceae is represented by Callisto- coal and the Pittsburgh or Redstone coal EXPLANATION OF FIGURES 2 TO 10 FIGURE 2. Psaronius chasei stem, somewhat flattened. O.U. coal ball 413 E Top. XI.5. FIGURE 3. Pachytesta berryvillensis ovule in oblique transverse section. O.U. coal ball 554 C Top. X7. FIGURE 4. Conostoma cf. quadratum in longitudinal section. O.U. coal ball 588 E(i) Top. X25. FIGURE 5. Biscalitheca musata sporangia in various planes of section. O.U. coal ball 407 A Bot. X13. FIGURE 6. Zygopteris berryvillensis stem in transverse section. O.U. coal ball 413 E Top. X8. FIGURE 7. Alethopteris sp. pinnule of medullosan affinities in transverse section. O.U. coal ball 613 D Bot. X12. FIGURE 8. Sphenophyllum sp. stem at nodal level showing the origin of three branches. O.U. coal ball 591 E Bot. X5. FIGURE 9. Idanothekion or Callandrium type pollen organs attached to Callistophyton foliage. O.U. coal ball 391 B Bot. X26. FIGURE 10.