Trace fossils are used in deposystem analysis of Late Devonian–Early Mississippian nearshore facies in the north-central Appalachian Basin. These nearshore facies resulted from separate transgressions during latest Devonian (Cleveland Shale) and earliest Mississippian (Sunbury Shale) time. Emphasis is placed on a well-exposed section at Rowlesburg, West Virginia, where the Oswayo, Cussewago Sandstone, and Riddlesburg Shale Members of the Price Formation are exposed.

The Oswayo Member at Rowlesburg preserves an offshore-to-lower shoreface transition in a complex of euryhaline, protected-bay, lagoon, and possible estuarine facies. Cruziana is common and occurs along with Arthrophycus, Bifungites, Chondrites, Planolites, Palaeophycus, Rhizocorallium, Rosselia, Rusophycus, and Skolithos in intensely bioturbated mudstone, siltstone, and sandstone. These lithologies were deposited below fair-weather wave base and grade upsection to upper shoreface facies comprised of thick, horizontally-laminated sandstones with thinner, burrowed mudstone interbeds. Upper shoreface traces consist of Arenicolites, Cruziana, Diplocraterion, Dimorphichnus, Planolites, Thalassinoides, and Skolithos. Skolithos “pipe rock” sandstones occur at the toe of upper shoreface facies. Eastward the Oswayo Member grades into a restricted-bay facies and finally into beach and tidal flat facies near its stratigraphic wedge-out in eastern West Virginia and western Maryland. The Cussewago Sandstone Member at Rowlesburg overlies the Oswayo and is bounded at the top by a disconformity. The Cussewago contains Arenicolites, Isopodichnus, Phycodes, Planolites, and Skolithos in upper shoreface sandstones possibly related to deposition in deltaic or tidal channel systems.

Regionally, the Riddlesburg Shale records a range of euryhaline environments in shallow-shelf, open-bay, and probable estuarine facies. The Riddlesburg Shale Member at Rowlesburg is comprised of dark-grey silty shales, siltstones, and hummocky cross-stratified sandstones. Trace fossils include Bergaueria, Bifungites, Fustiglyphus?, Helminthopsis, Planolites, and Skolithos. Lithofacies of the Riddlesburg Shale in West Virginia were markedly influenced by a syndepositionally active basement feature, the West Virginia Dome. Riddlesburg-age shoreface sandstones deposited on the crest of the Dome contain apparent omission surfaces with common Rhizocorallium and Arenicolites, Cruziana?, Planolites, and Skolithos.

The late Namurian Hindostan Whetstone beds are among the oldest Pennsylvanian strata recognized in the Illinois Basin. Trace-fossil holotypes of Haplotichnus indianensis, Plangtichnus erraticus, and Treptichnus bifurcus were first described and illustrated from these nonmarine strata with line drawings without reference to scale in a relatively obscure work by S. A. Miller (1889). These holotypes are refigured and redescribed in this paper. Based on examination of holotype collections, the Ordovician “Feather-stitch Trail” of Wilson (1948) is judged not to be congeneric with Treptichnus. The ichnogenus Ancorichnus, which is present in the Hindostan Whetstone beds, superficially resembles Haplotichnus; however, Haplotichnus lacks the internal meniscae characteristic of Ancorichnus.

Paleobiological studies of early metazoan evolution are critically dependent on the accurate stratigraphic subdivision and correlation of uppermost Proterozoic and Lower Cambrian sequences. Planktonic microfossils evolved rapidly during this period and are widely distributed and abundant in Vendian and Lower Cambrian rocks; therefore, they provide what is potentially one of the best means of correlating successions of this age. In Ny Friesland, Spitsbergen, tillite-bearing detrital rocks of the uppermost Proterozoic Polarisbreen Group are overlain without apparent unconformity by the Tokammane Formation, a tripartite lithologic sequence consisting of quartzarenites (Blårevbreen Member) overlain by dark shales with subordinate sandstone (Topiggane Member) and dolomites (Ditlovtoppen Member). Salterella, hyoliths, and other invertebrate remains occur in the upper part of the Tokammane succession; trace fossils are found in the Tokammane quartzarenites and shales, as well as in the uppermost few meters of the Polarisbreen sequence. Planktonic microfossils occur throughout the succession. They indicate that the Polarisbreen Group is Vendian in age and that a hiatus corresponding in time to the latest Vendian and (perhaps) earliest Cambrian coincides with the Polarisbreen/Tokammane boundary. Lower Topiggane shale samples contain acritarchs comparable to those found in the sub-Holmia Lontova Beds of Eastern Europe. Upper Topiggane samples contain diverse acritarch assemblages that indicate a late Holmia or Protolenus age, suggesting the presence of a second hiatus within the Tokammane Formation. Planktonic microfossils allow biostratigraphic correlation with other sequences both within (East Greenland) and between (East European Platform) paleocontinents. Like those from other areas, diversity trends exhibited by late Proterozoic and Early Cambrian acritarchs from Spitsbergen indicate a major Vendian episode of extinction followed by Early Cambrian rediversification of planktonic microfossils.

Collections of four Ordovician bryozoan species from habitats of differing levels of taxonomic diversity were examined in order to assess the effect of environmental conditions on intraspecific and interspecific morphologic patterns. Up to 20 morphometric characteristics were measured for each species from populations in both high-diversity and low-diversity settings. Character means and the levels of character variability differ between populations in different diversity zones. Across species, mean character values differ significantly in 41 percent of the total comparisons, permitting intraspecific and interspecific multivariate discrimination of populations from the two diversity zones.

The partitioning of clonal morphologic variability into within-colony (nonheritable) and among-colony (potentially heritable) components reveals that habitat conditions favoring high diversities appear to promote a greater proportion of potentially heritable genetic variation both within- and among-species than do low-diversity settings wherein a larger percentage of variation is ecophenotypic, or nonheritable, plasticity. Although the actual percentages vary from species to species, this pattern is obtained for representatives of four different trepostome bryozoan families and therefore is robust. Variability of this sort, if unrecognized, could lead to taxonomic oversplitting along ecologic gradients. These local, facultative adjustments to environmental conditions may be indicative of processes involved in the reactions of populations to selective pressures.

Analyses such as this, coupled with examinations of character covariances, may permit the recognition not only of environmentally-induced morphologic plasticity and the proportions of potentially heritable and nonheritable variability, but also provide evidence for intraspecific changes in the rates and timing of developmental events (i.e., across-population or facultative heterochrony).

North American and Chinese lower and middle Paleozoic representatives of the hyolith order Orthothecida are here placed in the families Orthothecidae Syssoiev, Novitatidae Syssoiev, Decorithecidae Syssoiev, Chelsonellidae n. fam., ?Isitithecidae Syssoiev, and ?Tchuranithecidae Syssoiev. The Orthothecidae is redefined, and the Decorithecidae is in part synonymized with the Novitatidae.

Re-examination of type specimens of some species formerly included in the order Hyolithida requires placement of these species in the order Orthothecida. The type suite of Hyolithes newsomensis Foerste from the Middle Silurian of Tennessee is divided into two species, and is used as a basis for the new genus Foersteotheca; the species F. merryi is new. Hyolithes richardi Clarke from the Lower Devonian of New York is designated as the type species of the new genus Devoniotheca. Orthotheca cyrene Walcott from the Middle Cambrian of China is now included under Decoritheca. Foersteotheca, Devoniotheca, and Decoritheca are here placed in the redefined family Novitatidae. Hyolithes vanuxemi Walcott is assigned to the new genus Chelsonella in the new family Chelsonellidae. The types of Hyolithes newtoni Walcott from the Upper Cambrian of South Dakota and Hyolithes canalis from the Middle Cambrian of China are both included under Decoritheca with question.

Recognition of orthothecid hyoliths in the Cambrian of North America and China provides a more accurate record of the geographic and stratigraphic distribution of this group. The discovery of Foersteotheca and Devoniotheca constitutes the first known middle Paleozoic orthothecid occurrences from North America. In addition, reports of Tchuranithecidae and Isitithecidae in North America, if authentic, are the first occurrences of these forms in North America. The discovery in North America of hyolith taxa previously known only from the Soviet Union and China raises the possibility of intercontinental correlation using these fossils.

Large palaeotrochid gastropods of the genera Floyda Webster (1905a) and Turbonopsis Grabau and Shimer (1909) occur in the late Frasnian Lime Creek Formation of Iowa. Floyda concentrica was designated as the type species of Floyda by earlier workers (Webster, 1905a; Knight, 1941), but is a junior synonym of F. gigantea (Hall and Whitfield, 1873). Three of five species and subspecies of Floyda described from the Lime Creek (Floyda concentrica, F. concentrica multisinuata, and F. gigantea depressa) are considered synonyms of the type species F. gigantea; the fifth species, F. gigantea hackberryensis, is here reassigned to the closely related genus Turbonopsis. Both F. gigantea and T. hackberryensis are redescribed using the original types and additional hypotype material from the collections of Charles Belanski.

Floyda, first known from late Givetian rocks of the Rhenish Slate Mountains in Germany, is widespread in the United States Midcontinent and western North America by early Late Devonian time. Turbonopsis was endemic to the Appohimchi Subregion of the Eastern Americas Realm prior to the Taghanic Onlap, and appears to have remained so until late Frasnian time when it migrated to western North America.

Eustatic sea-level highstands during the Middle and Late Devonian are thought to have breached barriers to migration, allowing both Floyda and Turbonopsis to disperse by prevailing oceanic currents from the United States Midcontinent into western North America during the late Frasnian. The expected oceanic current patterns of the Middle and Late Devonian paleogeographic reconstructions of Heckel and Witzke (1979, figs. 3, 5) adequately account for the known distribution and dispersal of Devonian palaeotrochid gastropods.

The Palaeotrochidae underwent extinction prior to the latest Frasnian. Floyda, Turbonopsis, and Westerna became extinct during the onset of the last eustatic deepening event prior to the close of the Frasnian. The extinction of the palaeotrochid gastropods as well as other invertebrate groups may have been the result of restriction or near elimination of shallow warm-water, well-oxygenated shelf habitats by the onlap of cold anoxic bottom waters prior to latest Frasnian time.

A newly discovered ammonoid, Mimagoniatites nearcticus n. sp., is described from upper Zlichovian–lower Dalejan (Lower Devonian) strata in the Canadian Arctic Archipelago. This species is distinguished primarily by its extremely narrow profile and high degree of whorl involution. It is the most gracile species so far known in the genus, and displays possible kinship to Parentites praecursor Bogoslovsky. This record constitutes the first definite occurrence of a Lower Devonian ammonoid from the Canadian Arctic Archipelago.

Familial groupings of two upper Paleozoic superfamilies of Goniatitina, Marathonitaceae and Cyclolobaceae, are reviewed. It is concluded that the Marathonitidae gave rise to the Hyattoceratidae and together constitute the Marathonitaceae. Eohyattoceras n. gen. is the Lower Permian ancestral hyattoceratid, and is represented by two new species, the type, E. gerthi from the Roadian of Timor, and E. leei from the Sakmarian of Nevada. An advanced marathonitid from the Lower Permian (Roadian) of Timor is described as Cardiella martodjojoi n. sp.

Two lineages within the exclusively Permian family Cyclolobidae are recognized as the subfamilies Kufengoceratinae and Cyclolobinae. Type designations proposed herein fix usage of Demarezites Ruzhentsev (1955) as referring to ancestral Cyclolobinae, and D. oyensi (Gerth, 1950) and D. lidacensis (de Roever, 1940) are redescribed from the Lower Permian (Roadian) of Timor. The Cyclolobidae are derived from the Vidrioceratidae and together constitute the Cyclolobaceae.

Calceocrinids are unique crinoids with the crown movably hinged to a recumbent stem. The crown was raised for feeding by closing the hinge and bending the proximal stem. While resting, the crown lay parallel to the stem with the hinge opened. Allometric equations for four species reflect a combination of ontogeny, adult body size, phylogeny, habitat, and functional morphology. The hinge of most adult calceocrinids is extended into ear-like projections which made the crown more stable on the seafloor. For the hinge moment versus the effective weight of the crown, positive allometry characterized taxa that lived in agitated environments, whereas isometry was adequate for quiet-water species. The adult body size provides a secondary effect on the data for crinoids from the same type of environment. Here, the initial intercepts are transposed so that larger animals functioned like smaller ones. The equations are independent of phylogenetic position. All species exhibit positive allometry of the length and number of plates in the arms. The food-gathering capacity of a crinoid is estimated by the number of food-catching tube-feet multiplied by the width of the food grooves, whereas the soft parts that must be fed are proportional to the crown volume. The ratio of food-gathering capacity to crown volume is either fixed or decreases slightly in larger crinoids. Statistical tests reveal that all species follow a single developmental pattern for these two parameters. However, some of the evolutionary changes in the arms permitted calceocrinids to retain an adequate food-gathering capacity into larger adult body sizes.

Isorophid edrioasteroids representing a new genus and two new species are described from the Chesterian (Upper Mississippian) of Illinois and Maryland. Neoisorophusella lanei occurs in the Kinkaid Limestone of Johnson County, Illinois, and N. berryi occurs in the Greenbrier Limestone of Garrett County, Maryland. The problematic edrioasteroid species Hemicystites? carbonarius Bassler, 1935, from the Chesterian of southern West Virginia, is questionably assigned to Neoisorophusella.

A new species of Brissus is described from the lower Oligocene (Rupelian–Vicksburgian) Bridgeboro limestone of southwestern Georgia. Brissus bridgeboroensis n. sp. most closely resembles the Recent Brissus unicolor (Leske) of the West Indies and the Gulf of Mexico, but it differs primarily in features of the posterior paired petals. Brissus bridgeboroensis is the oldest known member of the genus from continental North America.

The well-exposed and fossiliferous Permian carbonates in China have yielded Early and Late Permian species of the Sweetognathus complex that permit worldwide stratigraphic evaluation of members of the group. The sporadic appearance of species of Sweetognathus and related genera throughout the Permian in western North America and Iran, in particular, may represent iterative evolution and homeomorphy. The pectiniform element morphologies of the several species are interpreted as most important for evolutionary studies and document a partial Permian biostratigraphy in China that aids in the interpretation of less complete sequences elsewhere. A new genus, Pseudosweetognathus, and four new species, Pseudosweetognathus costatus, Sweetognathus subsymmetricus, S. paraguizhouensis, and Iranognathus nudus, are described.

Additional fossil material from the Valentine Formation in Knox and Brown Counties, Nebraska, has allowed for the recognition of three new species of rodents, a heteromyid (Perognathus brevidens), a geomyid (Parapliosaccomys annae), and a zapodid (Schaubeumys cartomylos). The specimens referred here to P. brevidens were previously identified as P. furlongi, those of S. cartomylos were identified as S. grangeri, and those of P. annae were previously recognized as Lignimus cf. L. hibbardi. It is evident that Lignimus Storer should be restricted to the type species L. montis, and the remainder of the species referred to this genus are referred to Parapliosaccomys Shotwell. Parapliosaccomys is recognized as the earliest member of the subfamily Geomyinae based on its dental morphology, which extends the range of this subfamily into the Barstovian. The fauna from Annie's Geese Cross Quarry (Knox County) is recognized as being late Barstovian based on comparison with the older Norden Bridge Quarry (Brown County).

Systematically diverse assemblages of fossil plants have been collected in late Miocene strata at seven sites in northern Antelope County, Nebraska. Fossils were found in several members of the Valentine and Ash Hollow Formations of late Barstovian to medial Clarendonian (13–10 MYBP) age and unnamed members of the Ash Hollow Formation of late Clarendonian to early Hemphillian (9.5–8.0 MYBP) age. Seeds, fruits, and leaf-sheath fragments of 18 species from the families Equisetaceae, Cyperaceae, Gramineae, Boraginaceae, Juglandaceae, and Ulmaceae are described. These occurrences represent a 200 mile (322 km) eastward extension of the known geographic range of all of the taxa during the Miocene. The occurrence of Juglandaceae is the first reported from widespread Miocene strata of the Ogallala Group in central North America.