The Merchantville Formation of New Jersey, Maryland, and Delaware yields a distinctive assemblage of upper lower Campanian ammonites: Pachydiscus (Pachydiscus) sp., Pseudoschloenbachia cf. P. chispaensis Adkins, 1929, Placenticeras placenta (DeKay, 1828), Texanites (Texanites) sp., Menabites (Delawarella) delawarensis (Morton, 1830c), M. (D.) vanuxemi (Morton, 1830c), Menabites (Bererella) sp., Submortoniceras punctatum Collignon, 1948, S. uddeni Young, 1963, Cryptotexanites paedomorphicus n. gen. and sp., Glyptoxoceras sp., Chesapeakella nodatum n. gen. and sp., Baculites haresi Reeside, 1927, and Scaphites (Scaphites) hippocrepis (DeKay, 1828) III of Cobban, 1969. Elements of the fauna occur in the Gulf Coast and Western Interior regions of the United States, in Western Europe, and in Madagascar and provide a basis for correlation at this level.

Ophioxenikos langenheimi n. gen. and sp. (class Somasteroidea), Stibaraster ratcliffei n. gen. and sp., and Cnemidactis? macroadambulacralatus n. sp. (both class Asteroidea) are new stelleroid echinoderms described from Lower and Middle Ordovician strata of the western United States. Stibaraster clearly is at the asteroid grade of organization, although an early representative of the class. Ophioxenikos is the first fossil somasteroid recognized from beyond Europe. It is similar to Chinianaster and Villebrunaster, ambulacral characters of all three suggest affinities with ophiuroids. Cnemidactis? is recognized from North America; it is unusual in the presence of proportionately large marginal ossicles. An indeterminate species is unusual in its structural parallels with living taxa. In recent years, the possibility that edrioasteroids were ancestral to stelleroids has been revived. Supporting arguments for this hypothesis neglect important differences; ancestry of stelleroids remains uncertain.

A collection of small crinoids and crinoid debris from the Ashgill (Rawtheyan?) of Cnwce, near St. Clears, Dyfed, southwest Wales includes numerous crowns of Aithriocrinus strahani n. gen. and sp. incertae familiae, an indeterminate 10–armed camerate(?) and an indeterminate multiple-armed camerate. Aithriocrinus strahani was previously considered to be a cincinnaticrinid, but it is undoubtedly dicyclic and therefore a cladid. This is the only diverse fauna of complete crinoids known from the Welsh Ashgill.

The monobathrid camerate Xenocrinus S. A. Miller is easily recognized from its disarticulated columnals, which are square in outline. Xenocrinus columnals are now recognized from three Hirnantian localities in Wales. Xenocrinus became extinct during the Hirnantian and not at the Rawtheyan–Hirnantian boundary, as has been suggested on the basis of crown material.

The clypeasteroid echinoid Astrodapsis bajasurensis n. sp. is described from upper middle Miocene beds of the Isidro Formation near the mouth of Arroyo Mezquital on the Pacific coast of north-central Baja California Sur, Mexico. The new species is the first occurrence of Astrodapsis outside of California and extends the southern limit of the genus by 1,100 km.

Reticuloceras (Swintoceras) n. subgen. unites an early group of the mid-Carboniferous goniatite family Reticulocertidae, in which reticulate sculpture is weakly developed or lacking and the typically reticuloceratid suture has slightly expanded ventral prongs. The type species, Reticuloceras (S.) spiraloides (Bisat and Hudson, 1943), is a rare, poorly known species from the British Namurian. Two additional species, R. (S.) wainwrighti (Quinn, 1966) and R. (S.) tiro (Gordon, 1969), are common in the basal type Morrowan Series, Lower Pennsylvanian, of Arkansas. Swintoceras occurs with two distinctive, late forms of the ammonoid, Hudsonoceras: Hd. ornatum (Foord and Crick, 1897) in Britain and Hd. moorei Quinn and Saunders, 1968, in Arkansas. The cooccurrence of these taxa correlates the basal Morrowan in its type region with the Namurian Reticuloceras nodosum (R1b) Zone of Britain and thereby also dates the close of the Mid-Carboniferous Eustatic Event in the North American Midcontinent.

At the well-known fossil mammal locality of Fort Ternan in southwestern Kenya, radiometrically dated at about 14 million years old (middle Miocene), fossil grasses have been preserved by nephelinitic sandstone in place of growth above a brown paleosol (type Onuria clay). Large portions of grass plants as well as fragments of leaves have revealed details of silica bodies, stomates, and other taxonomically important features under the scanning electron microscope. The computer database for grass identification compiled by Leslie Watson and colleagues was used to determine the most similar living grass genera to the five distinct kinds of fossil found. Two of the fossil species are assigned to Cleistochloa kabuyis sp. nov. and C. shipmanae sp. nov. This genus includes one species from low fertility dry woodland soils of New South Wales and Queensland and a second species from “raw clay soils” in western New Guinea. A third fossil species, represented by a large portion of a branching culm, is assigned to Stereochlaena miocenica sp. nov. This genus includes five species of low-fertility woodland soils in southeastern Africa. Both Cleistochloa and Stereochlaena are in the supertribe Panicanae of the subfamily Panicoideae. A fourth species is assigned to Distichlis africana sp. nov. and provides a biogeographic link between the single species of this genus now living in coastal grasslands in southeastern Australia and the 12 species of dunes and deserts found throughout the Americas from Patagonia and the West Indies to the United States and Canada. A fifth species is, like D. africana, in the subfamily Chloridoideae, but its stomata were not seen and it could belong to Cyclostachya, Pogoneura, or Polevansia. This earliest known wooded grassland flora in Africa is taxonomically unlike the modern grass flora of fertile volcanic African landscapes, and may have been recruited from an archaic grass flora of Gondwanan desert and lateritic soils.

A new assemblage of thalattosaurs is described from the Lower to Middle Triassic Sulphur Mountain Formation of eastern British Columbia. The following new species are described: Thalattosaurus borealis n. sp.; Paralonectes merriami n. gen. and sp.; and Agkistrognathus campbelli n. gen. and sp. In addition, specifically indeterminate material is described. This assemblage extends the geographic range of the Thalattosauria to Canada and demonstrates that thalattosaurs were more taxonomically diverse and widely distributed than previously thought.

Carboniferous marine bivalves, especially those of early Late Carboniferous, are abundant and highly diversified in China. About 357 species, 76 genera in 29 families, of Carboniferous marine bivalves have been found from 103 localities throughout the country. This represents 83 percent of the genera (t = 92) and 85 percent of the families (t = 34) reported worldwide. These bivalve faunas are characterized by: 1) the high diversity of Aviculopectinidae and Myalinidae, in place of the highly diversified Pterineidae and Pterinopectinidae of the Devonian; 2) the presence of only three endemic genera (Cucullopsis, Palaeolucina, and Glyptoconcha); and 3) the endemic nature of most species, although some species are closely related to species in North America and Europe. The stratigraphic distribution of Carboniferous bivalves in the four faunal provinces of China is discussed stage by stage. All four faunal provinces of China had a close tie with the tropical to subtropical Tethys Realm during the Carboniferous. About 43.4 percent of the genera are epifauna with byssate attachment, which is almost four times more than the proportion present in living bivalve faunas.

Species of the late Osagean and early Meramecian advanced cladid crinoid genera (suborder Poteriocrinina) Abrotocrinus, Aulocrinus, Cromyocrinus. Decadocrinus, Dinotocrinus, Holcocrinus, Hylodecrinus, Lanecrinus n. gen., Pachylocrinus, Parascytalocrinus n. gen., and Stinocrinus from Illinois, Indiana, Iowa, Kentucky, and Missouri are redescribed and redefined from study of type material and museum collections. Nomenclatural and systematic acts include the following: 1) Abrotocrinus cymosus Miller and Gurley, 1890a, is a valid species and not a synonym of A. coreyi (Meek and Worthen, 1869); 2) A. coreyi is a senior synonym of Poteriocrinus orestes Worthen, 1882; 3) Scaphiocrinus manus Miller and Gurley, 1890a, is assigned to Abrotocrinus; 4) Abrotocrinus granulatus n. sp. is described; 5) S. bellus Miller and Gurley, 1890a, is assigned to Aulocrinus and is a senior synonym of Aulocrinus agassizi Wachsmuth and Springer, 1897; 6) S. orbicularis Hall, 1861a, is assigned to Cromyocrinus; 7) P. latidactylus Worthen, 1882, is assigned to Dinotocrinus; 8) S. gibsoni White, 1878, is assigned to Hylodecrinus with P. nauvooensis Worthen, 1882, questionably placed in synonymy; 9) P. briareus Worthen, 1882, is assigned to Hylodecrinus and is a senior synonym of S. lacunosus Miller and Gurley, 1890a, S. boonvillensis Miller, 1891b, S. constrictus Miller, 1891a, and S. arrosus Miller and Gurley, 1893; 10) S. bonoensis Miller and Gurley, 1890a, is assigned to Hylodecrinus; 11) Hylodecrinus robustus n. sp. is described; 12) P. validus Worthen, 1882, is questionably assigned to Hylodecrinus; 13) Lanecrinus n. gen. is described and the following species are assigned to this new genus: S. halli Hall, 1861 a, S. depressus Meek and Worthen, 1870, P. milleri Wetherby, 1881, P. fountainensis Worthen, 1882, S. repertus Miller and Gurley, 1890a, and Ramulocrinus consectatus Strimple and Watkins, 1969; P. otterensis Worthen, 1882, is questionably assigned to Lanecrinus; 14) Lanecrinus depressus is the senior synonym of P. ulrichi Worthen in Miller, 1889, and S. maniformis Miller, 1892; 15) Lanecrinus repertus is the senior synonym of S. gorbyi Miller, 1891a; 16) P. asper Worthen, 1882, is assigned to Pachylocrinus and is a senior synonym of S. extensus Wachsmuth and Springer, 1886; 17) Parascytalocrinus n. gen. is described and the following species are assigned to this new genus: Poteriocrinus hamiltonensis Worthen, 1882, and Scytalocrinus validus Wachsmuth and Springer, 1897; 18) Poteriocrinites mcadamsi Meek and Worthen, 1873, is questionably placed in synonymy with Parascytalocrinus hamiltonensis; and 19) Poteriocrinus burketi Worthen, 1882, nomen dubium and Zeacrinus dubius Miller and Gurley, 1890a, are placed in Incertae Sedis.

Cromyocrinus orbicularis is the oldest species of its genus extending the range of the genus downward from the Upper to the Lower Mississippian.

I he National Museum of Natural History (Smithsonian Institution), Department 01 Paleobiology, recently received the collection of invertebrate fossils (except Insecta and Patagonia material) formerly housed in the Princeton University, Department of Geological and Geophysical Sciences. This fine collection contains approximately 70,000 specimens; type and nontype specimens were stored together in taxonomic order. Current documentation for the entire collection consists of a card catalogue. Following curation, the specimens will be housed taxonomically in standing type and nontype collections. Lists of type specimens received will be published as they are isolated. Borrowers should return specimens to the Department of Paleobiology, National Museum of Natural History, upon completion of loans.

Black Mesa in northeastern Arizona exposes sediments of late Cenomanian–Turonian age deposited during the transgressive–regressive Greenhorn cyclothem. These sediments contain a diverse selachian fauna that consists of 21 taxa: Hybodus sp., Ptychodus whipplei, P. decurrens, P. cf. P. mammillaris, Chiloscyllium greeni, Chiloscyllium sp., Scapanorhynchus raphiodon, Cretodus semiplicatus, Cretolamna appendiculata, C. woodwardi, Cretoxyrhina mantelli, cf. Leptostyrax sp., Squalicorax falcatus, Rhinobatos sp., Pseudohypolophus mcnultyi, Protoplatyrhina hopii n. sp., Ischyrhiza schneideri, I. avonicola, Onchopristis dunklei, Ptychotrygon triangularis, P. rubyae n. sp., and five types of dermal denticles. Two selachian assemblages, a nearshore and a deeper water assemblage, are present in this fauna. Though there is some provincialism in North Africa, Europe, and North America during the Greenhorn marine cycle, the wide dispersion of some shark taxa and the great similarities between widely separated selachian faunas are striking.

The ecdysial style of Flexicalymene meeki (Foerste) from the Upper Ordovician of the Cincinnati arch (Ohio) is best characterized by a spectrum of configurations. Recurring patterns of displaced tergites and points of disarticulation indicate differential susceptibility of the exoskeleton to disarticulation during ecdysis. Specimens identified as exuviae are characterized by one or more of the following: thoracic segments displaced (unevenly spaced, disarticulated or telescoped); pygidia and/or cephala rotated away from the sagittal line; cephalon sharply bent ventrally at first thoracic segment; librigenae separated or folded ventrally along facial sutures; “extra” tergites (exuvia) superposed on the new exoskeleton; and missing elements, especially librigenae and hypostomae. The range of exuvial configurations suggests a variety of ecdysial behavior in this trilobite.

The genus Cirquella is erected for small, smooth nevadiid trilobites that lack genal spines. The type species, C. nummularia, is associated with taxa in the Dogtooth Mountains, British Columbia, that belong to the Nevadella Zone. A second species, C. espinata, is described from the southern Canadian Rocky Mountains, where it is associated with the new archaeaspid genus Geraldinella. Strata in the latter locality can be physically correlated to documented strata of the Nevadella Zone. The same zone in Nevada contains C. nummularia?.

Several heretofore undescribed fragmentary specimens of the horned dinosaur Pentaceratops sternbergii (Ornithischia: Ceratopsia) reveal previously unknown features of the skull and extend the known range of morphological variation in this species. Pentaceratops sternbergii possesses a well-developed postfrontal fontanelle and a braincase structure similar to that of other chasmosaurines. The posterior parietal margin bears a pair of upturned epoccipitals on either side of the midline, similar to the short hook-like processes in Anchiceratops. The stratigraphic range of Pentaceratops spans the Late Campanian to Early Maastrichtian but, contrary to previous reports, cannot reliably be extended into the Late Maastrichtian.

Primitive euconodont elements from the Upper Cambrian of Sweden are investigated histologically and compared with co-occurring elements of paraconodonts. The proposed close relationship between the two groups is confirmed. Typical euconodont and paraconodont elements are bridged by intermediate forms. The ontogenetic development of the early euconodont elements shows striking similarities to the evolutionary development from paraconodonts to euconodonts, suggesting that evolution generally followed a peramorphic pattern (“recapitulation”). The conodont crown originated through extension of the growth lamellae around the whole element, accompanied by stronger mineralization. The first denticulation in Proconodontus arose when a jagged posterior edge in juvenile specimens was enhanced by the subsequent deposition of growth lamellae, a process comparable to the regeneration of broken tips. The most primitive euconodont elements probably erupted from the epithelium earlier in ontogeny than in more advanced forms. After the appearance of the phosphatic crown, conodont elements underwent a very rapid morphological differentiation. Cordylodus may have arisen from Proconodontus serratus.

Cuticular features and details of fine venation are now widely relied upon in systematic and phylogenetic studies of fossil plants. Where fossil leaves are robust or adherent to the matrix, such features may be readily available, but should the remains be fragile and subject to damage or loss, it may be necessary to preserve their integrity immediately following recovery and during transport. Clays, shales, and fossil leaf compressions are particularly vulnerable to the drying environment; fossil specimens are commonly damaged or entirely lost due to spalling, cracking, and shrinking of the clays or due to exfoliation of the organic film caused by differential drying. In an attempt to eliminate these problems, a technique using a mixture of nitrocellulose lacquer and acetone to coat fossil leaf compressions was developed for use on freshly excavated specimens under a wide range of climatic conditions (subfreezing to warm, dry or wet) while in the field. Many other preservational techniques exist, but they are typically complex, expensive, time consuming, destructive, or were developed for use in a laboratory setting.

Pandorinellina? boucoti (Klapper) is based on material from the Lochkovian–Pragian (Devonian) section at Royal Creek, Yukon Territory, Canada, where it is found with species of the pesavis and sulcatus Zones. The species is also a rare element in the late Lochkovian–early Pragian faunas in the Toquima Range, central Nevada, where it is found within the same zones. Pandorinellina? boucoti has been recovered from 17 beds in sequence at the IK IV section in the McMonnigal Limestone and shows a morphologic change from a Pa element with a simple blade, small lateral lobes, and an enlarged triangular anterior denticle to a Pa element with ornamented pillars surmounting both platform lobes. The simple blade form is present in beds IK IV 21–16. The next overlying bed yields specimens with a single pillar-like enlargement of the larger platform lobe and a slight swelling on the smaller platform lobe. The following beds (IK IV 14–6) have only morphotypes with the pillar-like enlargement on both platform lobes.

This morphologic change effectively divides the upper pesavis Zone into two segments in the IK IV section. The rarity of this species, however, will probably limit the usefulness of the lineage in refined biostratigraphy and the sequence of morphotypes needs to be verified in other areas. Nevertheless, where present, P.? boucoti should improve the accuracy of correlation in the late Lochkovian and early Pragian.

The advent of readily available computer-based clustering packages has created some controversy in the micropaleontological community concerning the use and interpretation of computer-based biofacies discrimination. This is because dramatically different results can be obtained depending on methodology. The analysis of various clustering techniques reveals that, in most instances, no statistical hypothesis is contained in the clustering model and no basis exists for accepting one biofacies partitioning over another. Furthermore, most techniques do not consider standard error in species abundances and generate results that are not statistically relevant. When many rare species are present, statistically insignificant differences in rare species can accumulate and overshadow the significant differences in the major species, leading to biofacies containing members having little in common.

A statistically based “error-weighted maximum likelihood” (EWML) clustering method is described that determines biofacies by assuming that samples from a common biofacies are normally distributed. Species variability is weighted to be inversely proportional to measurement uncertainty. The method has been applied to samples collected from the Fraser River Delta marsh and shows that five distinct biofacies can be resolved in the data. Similar results were obtained from readily available packages when the data set was preprocessed to reduce the number of degrees of freedom. Based on the sample results from the new algorithm, and on tests using a representative micropaleontological data set, a more conventional iterative processing method is recommended. This method, although not statistical in nature, produces similar results to EWML (not commercially available yet) with readily available analysis packages. Finally, some of the more common clustering techniques are discussed and strategies for their proper utilization are recommended.

Specimens of the ostracode species Puriana pacifica Benson, 1959, from a modern assemblage from the Gulf of California can be sorted by visual inspection into five groups based on taphonomic condition. Characteristics used for sorting include: presence or absence of appendages; color and opacity of the valves; and evidence of abrasion, fragmentation, and boring. As measured by resistance to crushing force, members of the five groups show appreciable, progressive, postmortem weakening so that specimens in the poorest apparent condition are the weakest mechanically. The groups also differ in style of fracturing in response to crushing force. Fractures of valves of the freshest specimens are located quite consistently. Among specimens with progressively more damage, the location of fractures becomes less predictable. On valves of the most damaged specimens, typical fractures are short and likely to occur almost anywhere on the valve. These experimental results emphasize the importance of rapid burial in enhancing the likelihood of fossilization. Furthermore, they cast doubt on the ability of paleoecologists to use valves and carapaces of fossil ostracodes to interpret levels of wave and current energy in ancient environments because taphonomic weakening and subsequent destruction may effectively mask functional morphology.

Coccolithus crassus was described by Bramlette and Sullivan (1961) from the Lodo Formation of California. This species has a short stratigraphic range within the lower Eocene and its first occurrence is a marker for the CP10/CP11 zonal boundary in the widely used nannofossil zonation of Okada and Bukry (1980). Most nannofossil workers, however, do not report this index fossil, and the CP10/CP11 zonal boundary is often not determined. This is in contrast to the work of D. Bukry, who used the first occurrence of C. crassus for the CP10/CP11 boundary in virtually all lower Eocene DSDP cores that he examined (Figure 1). Apparently, there is considerable confusion about C. crassus. For instance, Romein (1979) considered C. crassus a junior synonym of Coccolithus eopelagicus (Bramlette and Riedel) Bramlette and Sullivan; Steinmetz and Stradner (1984, p. 741, Pl. 42, figs. 1 and 2) figured a specimen of Ericsonia subpertusa Hay and Mohler from Zone CP7 (upper Paleocene) as C. crassus; Perch-Nielsen (1985, p. 433, figs. 3.46 and 3.47, p. 504, figs. 58.12 and 58.13) mistook Toweius callosus Perch-Nielsen as C. crassus, as did Varol (1989, p. 302, Pl. 4, figs. 37 and 38). The main problem that prevents most workers from using this index fossil is that the species concept is largely unclear. It appears to be difficult to distinguish C. crassus from C. pelagicus or T. callosus based on the light micrographs of Bramlette and Sullivan (1961, Pl. 1, figs. 4a and 4c), and scanning electron microscope (SEM) photographs of this species have never been published except one specimen of the species was illustrated in Matter et al. (1974, p. 914, Pl. 4, fig. 8) under the name Ericsonia ovalis Black.