A low-diversity shelly fauna occurs in the Deep Spring Formation of the White–Inyo Mountains of eastern California and in Esmeralda County, Nevada. Although poorly preserved, specimens can be recovered through acid digestion of the limestone matrix. The fauna is composed of three tubes of uncertain affinities and a hyolith. Nevadatubulus dunfeei n. gen. and sp., a distinctive, randomly curved and annulated tube, is abundant and far outnumbers the remaining three elements: Coleoloides inyoensis n. sp., Sinotubulites cienegensis McMenamin, and the hyolith Salanytheca sp. The original composition of the faunal elements appears to have been calcite or aragonite, but recrystallization has destroyed any ultrastructure. No phosphatic elements occur with the fauna nor have phosphatic fossils been recovered from the underlying Wyman and Reed Formations or the other members of the Deep Spring Formation.

The fauna occurs 1,500 meters below the first trilobite body fossils and may be coeval with faunas from the basal Cambrian Tommotian Stage of the Siberian Platform. Wyattia, the only previously described pre-trilobite shelly fossil from the region, occurs in approximately the same stratigraphic interval but was not recovered in our samples.

The Upper Cliff coal interval (Early Pennsylvanian) of northern Alabama consists of sandstone, siltstone, shale, and coal deposited within a southwestward prograding deltaic complex as previously defined using paleobotanical and sedimentological evidence. The paleoecology of two invertebrate-bearing lithofacies was studied within this context. A lower shaley-siltstone lithofacies records the inundation of the Upper Cliff #1 peat-accumulating swamp/marsh by fresh-water influenced brackish to restricted marine deposits. The fauna is dominated by the inarticulate Orbiculoidea and the trace fossil Planolites. As inundation continued, an interdistributary bay developed. Diversity and abundance of taxa increased with the establishment of a molluscan dominated Pteronites-Pianolites assemblage. The assemblage consists of a low diversity and low abundance fauna of bivalves and trace fossils that suggest soft substrates with abundant organics.

The overlying sandstone lithofacies consists of a basal shell-bed (Schizophoria zone) composed of rare indigenous Pteronites and Wilkingia and a transported component of open marine epifaunal brachiopods, gastropods, and trilobite fragments. The Schizophoria zone thins to the northeast, suggesting open marine conditions to the southwest. Directly above this bed, the fauna of the sandstone lithofacies is composed entirely of Zoophycos. Higher in the section, rare Pteronites and Wilkingia occur, thus this lithofacies preserves a Wilkingia-Pteronites-Zoophycos assemblage of low abundance and diversity reflecting mobile organic-poor substrates. The sandstone lithofacies is interpreted as a migrating sand body with a basal shell-bed, initially formed probably as a result of storm activity.

Early Cambrian Leptomitus zitteli Walcott, 1886, is a tubular, double-walled, demo-sponge from the Parker Slate of Vermont and is one of the few intact sponges of that age known. It occurs with skeletal fragments of ?Protospongia hicksi Hinde, 1887. Hazelia walcotti (Resser and Howell, 1938) is a thin-walled, tubular sponge with crudely clustered oxeas in a thatched skeleton. It is known from the Kinzers Formation of Pennsylvania. Early occurrences of Leptomitus and Hazelia indicate that at least these two lineages had diverged by the latter part of the Early Cambrian. The impression described as Leptomitus minor by Resser and Howell (1938) lacks spicules and is not a sponge.

The Upper Chesterian Pitkin Formation of the Ozark Dome region contains a large and diverse, yet highly endemic, coral fauna consisting of 10 genera of rugose corals and three of tabulate corals. Coral distribution within the formation is affected by stratigraphic, paleoecologic, and possibly paleogeographic controls. Although it is impossible at this time to fully evaluate the importance of stratigraphic controls on the coral distribution, the occurrence of two types of carbonate bioherms within the formation provides substantial paleoecologic control on the distribution of certain corals. Despite the high endemism and facies restriction, the coral fauna has proven to be biostratigraphically sensitive, correlating with middle and upper Chesterian coral zones in the Western Interior Province of North America. Among the Pitkin corals herein described are the new genera: Lesliella n. gen. (L. amplexa n. sp., type species) and Parvaxon n. gen. (P. minutum n. sp., type species). Other newly described species are: Amplexizaphrentis browni n. sp., Barytichisma clubinei n. sp., B. ozarkana n. sp., and Leonardophyllum arkansanum n. sp., which represents the first reported occurrence of the genus in strata below the Pennsylvanian boundary.

The septate, lamellose, spiriferacean brachiopod genus Tylothyris North, 1920, is considered to be a delthyridid of the subfamily Tylothyridinae Carter, 1972. Herein, the diagnosis of the Tylothyridinae is emended to include forms with micro-ornament, and with a myophragm or median septum on the floor of the pedicle valve.

For the first time, Tylothyris is formally reported from the Traverse Group rocks of Michigan, Givetian through early Frasnian in age. Two species of the genus occur in the Traverse Group. The first, T. subvaricosa (Hall and Whitfield, 1872), previously described by Stainbrook (1943) from the Cedar Valley Limestone of Iowa, is also known from the Milwaukee Formation of Wisconsin and the Mineola Limestone of Missouri. Tylothyris randalia Stainbrook, 1943, also from the Cedar Valley Limestone, is considered to be synonymous with T. subvaricosa. In the Traverse Group, T. subvaricosa occurs in the Bell Shale, Rockport Quarry Limestone, Ferron Point Formation, Genshaw Formation, Alpena Limestone, Gravel Point Formation, Norway Point Formation, and Potter Farm Formation. The second species, T. rockportensis n. sp., occurs only in the Rockport Quarry Limestone, and appears to be endemic to the Michigan Basin.

Tylothyris is considered to have originated in the Illinois area during the late Eifelian, then to have migrated to the Michigan area by the early Givetian. With the onset of Taghanic Onlap during the late Givetian, the genus dispersed from its Illinois–Michigan area of origin, becoming distributed across much of North America during the Frasnian and Famennian, and becoming essentially cosmopolitan in distribution during the Tournaisian. Tylothyris apparently became extinct by the end of the Visean.

The pelecypod genera Slava and Rhombopteria are reported for the first time from Canada, where they occur in a limestone concretion within the Cape Phillips Formation, Cornwallis Island, Arctic Archipelago. These genera are characteristic of Silurian rocks in Bohemia, Czechoslovakia. Graptolites from the same concretion indicate the Monograptus ludensis Zone (uppermost Wenlockian); this age is substantiated by associated conodonts, trilobites, vertebrates, and pelecypods but with less precision. It is difficult to explain the occurrence of Slava and Rhombopteria in the middle of Laurentia on the basis of some map reconstructions of the Wenlockian world.

The Canadian material of Slava novaterra n. sp. and Rhombopteria cf. R. mira (Barrande) is described. Leptodesma (Leptodesma) sp. A and an indeterminate grammysiid pelecypod from the same concretion are illustrated. Information is provided to show that Newsomella Foerste, from Wenlockian–Ludlovian rocks of Illinois, Wisconsin, and Tennessee, is not a subgenus of Rhombopteria Jackson.

Thirty localities in the Upper Paleozoic (Mississippian–Permian) of North America have yielded more than 1,000 cephalopod mandibles preserved as carbon films, pyrite/limonite internal molds, and as nuclei in phosphate, carbonate, and ironstone concretions. With occasional exceptions, cephalopod mandibles, as part of either the microfauna or macrofauna, are rare despite the fact that co-occurring cephalopods may be extremely abundant. Without exception, the mandibles recovered co-occur with ammonoids and very frequently with bactritoids. Localities containing only nautiloids, either coiled or orthoconic, have not yet yielded cephalopod mandibles. Also, nekroplanktic accumulations of cephalopods have not yielded mandibles. Except for Lagerstätten deposits (two occurrences), the cephalopod mandibles were always recovered from molluscan-dominated communities; these communities have been interpreted as being in relatively offshore, “deeper” water in normal marine salinities with relatively low to anoxic oxygen conditions.

Although enrollment has long been recognized as an important, perhaps advantageous, life posture in certain trilobites, some aspects of this phenomenon are poorly understood. Taphonomic evidence indicates that the preservation of enrolled trilobites is a two-stage process involving: 1) factors that evoked enrollment; and 2) depositional and geochemical factors that resulted in preservation of the trilobites in an enrolled condition.

The Alden Pyrite Bed, Ledyard Shale Member, Ludlowville Formation (Middle Devonian, Givetian) of western New York, a well-known stratigraphic marker bed, is formally described herein. This bed yields an extraordinary number of enrolled phacopine trilobites. This study suggests that trilobites, like certain modern arthropods, enrolled in response to inhospitable conditions, including environmental toxicity and/or rapid sediment influx. Frequency of occurrence data from the Alden Pyrite Bed and underlying and overlying beds of the Ledyard Shale indicate that the trilobites Greenops boothi (Green) and Phacops rana (Green) both enrolled in response to adverse conditions at the sediment-water interface. Prolonged adversity compelled the trilobites to remain, and eventually die, in an enrolled state. Rapid and deep burial within a fine-grained sediment precluded scavenger dismemberment and favored geochemical conditions which culminated in pyritization and preservation.

A new calappid crab, Prehepatus werneri n. sp., is described from the Upper Maastrichtian of Limburg, The Netherlands. This species represents the first European and youngest known member of the genus. The appearance of this species seems to correspond with an increasing Tethyan influence in the type-Maastrichtian area.

Four compsocrinine camerate crinoids are described from the Lower Silurian Brassfield Formation of southwestern Ohio. These late early or early middle Llandoverian crinoids are assigned to the Periechocrinidae and include Tirocrinus trochos n. gen. and sp., Ibanocrinus petalos n. gen. and sp., Acacocrinus anebos n. sp., and the taxon Dimerocrinites? vagans Foerste, herein referred to periechocrinid incertae sedis.

These Brassfield forms are the oldest known members of the Periechocrinacea and Periechocrinidae. Diagnoses of these supergeneric concepts are broadened to include the morphologic variability embodied within the Brassfield forms but not otherwise present in later periechocrinaceans.

Eight of the crinoids described by Rowley (1904) are redescribed and reclassified. This material is from northeastern and southeastern Missouri and was believed to include both Early Silurian and Middle Silurian material (Rowley, 1904). Reconsideration of this material changes considerably the interpretation of these fossils. All are assigned to a different genus with some assigned to a different order or subclass. Also, age assignments are clarified. Crinoids studied here that are considered to be probably Late Ordovician rather than Early Silurian are Calceocrinus alleni (previously Deltacrinus alleni), Ptychocrinus insperatus (previously Abludoglyptocrinus insperatus, Glyptocrinus insperatus, and G. insperatus var. carinatus of Rowley, 1904), Ptychocrinus pentagonus (previously Glyptocrinus insperatus var. pentagonus), Gnorimocrinus? problematicus (previously Gissocrinus? problematicus), and Glyptocrinidae genus unknown (previously Lampterocrinus? comptus). Two Middle Silurian (lower Ludlovian) crinoids that were described by Rowley are restudied, Thalamocrinus ovalis (previously Cyathocrinus? ovalis) and Clematocrinus dubius (previously Cordylocrinus? dubius).

The genus and species Johnognathus huddlei Mashkova, 1977, is synonymized with Distomodus staurognathoides (Walliser, 1964) on the basis of common occurrence, similar morphology, and the discovery of a complete S element of D. staurognathoides with a posterior process developed into a platform that is identical in morphology to specimens referred to J. huddlei.

This paper presents a morphometric study of the conodont genus Ancyrodelloides. It is one of a series of such papers whose goal is to increase the precision of correlation within the Lower Devonian by refining the taxonomic basis of its biostratigraphic units. Ancyrodelloides species are confined to the delta Zone and may be used to divide it into three parts. Morphometrics verify the species rank of A. eleanorae, A. limbacarinatus, A. trigonicus, and A. transitans. Ancyrodelloides delta and A. omus are retained as species on qualitative grounds, but need larger samples for statistical evaluation. Ancyrodelloides asymmetricus and A. kutscheri are classified as varieties, but lack adequate samples.

Baiotomeus is a new genus of ptilodontid multituberculate from the late Torrejonian Land-Mammal Age (late middle Paleocene) of western North America. Baiotomeus douglassi (Simpson), the type species, has been assigned, at one time or another, to Ptilodus, Mimetodon, and Neoplagiaulax. In addition, a second, new species, B. lamberti, from three localities in the Medicine Rocks area of southeastern Montana is reported here. The Medicine Rocks localities are tentatively assigned a latest Torrejonian age, younger than localities yielding B. douglassi and younger than previously suggested on the basis of plesiadapid primates.

Multituberculates appear to have attained their highest species richness during the Torrejonian Land-Mammal Age, but the discovery of B. lamberti illustrates that our knowledge of multituberculate diversity is incomplete from even that interval of time.

Four morphologically distinct tayassuid species are present in the marine strata of the lower Chesapeake Group in Maryland and Virginia. The oldest of these, an unnamed species, occurs in bed 2 of the Calvert Formation and is the only terrestrial mammal yet known from this unit. In the upper Calvert and lower Choptank Formations three tayassuid species resemble closely in size and morphology taxa known from the middle and upper Miocene Olcott and Valentine Formations in Nebraska. “Cynorca proterva” and “Prosthennops” xiphidonticus are present in beds 10 and 14, respectively, of the Calvert Formation. “Prosthennops” niobrarensis occurs in bed 17 of the Choptank Formation. These taxa, considered together with the other known terrestrial mammals from the Chesapeake Group, indicate the following correlations with land mammal faunas from western North America: bed 2, ?late Arikareean or early Hemingfordian; bed 10, late Hemingfordian or early Barstovian; bed 14, early late Barstovian; bed 17, late late Barstovian. These correlations are largely concordant with micropaleontogical correlations for the Chesapeake Group, but the age indicated for bed 17 is younger than an age estimate based on diatoms.