During the late Trentonian the New York State region experienced gentle crustal subsidence which preceded the onset of the Hudson Valley phase of the Taconic Orogeny. The lower and middle Steuben Limestone represents several shallow-water facies: a protected shoal, a wave dissipation zone and a shallow shelf. Overlying strata of the upper Steuben and the Hillier limestones represent progressively deeper water facies. After a short period of uplift, which produced a minor unconformity, black shales began to bury the Trenton carbonate platform.

Three fossil communities are found in the upper Trenton Group. Each had been present on the Trenton bank since it first formed. The Liospira Community existed on the shallow protected shoal facies of the Steuben Limestone. Its assemblages are dominated by brachiopods, gastropods, bryozoans, and crinoids. The Encrinurus Community was found in the wave dissipation zone and on the shelf facies. This diverse community was dominated by brachiopods, bryozoans, and crinoids. The Trematis Community is found in the deeper shelf deposits of the Hillier Limestone. It was a very heterogeneous community with brachiopods, crinoids, gastropods, trilobites, and conodonts all represented.

These communities have now been traced through a minimum of eight million years of their history and it is now possible to evaluate their patterns of community evolution. At the species level these communities were quite changeable. Between 45% and 55% of the species which were present in the lower Trenton Group were replaced by the late Trentonian. Despite this changeover, the communities maintained a remarkably familiar look because there was great stability at higher taxonomic levels and the same proportions of brachiopods, bryozoans, crinoids, etc., were maintained throughout the Trentonian. Community trophic group structure also seems to have been quite stable throughout the Trentonian. If these patterns are representative, then these invertebrate communities appear to be genuinely stable entities. Evolution changes the cast of characters but the play is the same!

A diverse, previously unknown fauna with Skenidioides and other small brachiopods, ostracodes, trilobites, and corals has been dated as gronbergi Zone on coexisting conodonts. Conodonts date the Leptocoelina globosa fauna as serotinus Zone. Cymostrophia seca, Strophodonta luxor, and Atrypa kobar are new species. These assignments and new occurrences allow retabulation of most Emsian brachiopod ranges in Nevada.

Plotting of provincial, endemic, and cosmopolitan brachiopod genera on a time vs. percent graph shows that the shift through time of Nevada faunas from Eastern Americas Realm to Old World Realm took place gradually during Emsian transgression. Endemic genera were prominent during early phases of Devonian transgression.

The small, distinctive, glyptorthinine brachiopod Ptychopleurella Schuchert and Cooper is widely distributed in rocks of early Ordovician to late Silurian age. Several species are known from the Barr and Ardmillan successions (middle-upper Ordovician) of the Girvan district, S.W. Scotland, one of which, ‘Orthis Lapworthi’ Davidson, has not been described in modern terms as there has been some confusion concerning its true identity. Recognition of this species of Ptychopleurella permits comparison with congeners elsewhere, strengthens the correlation of this part of the Girvan Succession with the middle Ordovician of North America, and provides a more complete record of this genus in the slope sedimentary facies of the northwestern margin of the Iapetus Ocean.

Five new species of mollusks are described from the early Eocene Maniobra Formation, northeastern Orocopia Mountains, southern California. The new species are from the basal part of the formation, and the fauna is indicative of the West Coast provincial molluscan early Eocene “Capay Stage.” The mollusks are shallow-marine forms that were transported a short distance into slope/upper submarine-canyon deposits.

Chedevillia saltonensis n. sp. and Eocypraea? maniobraensis n. sp. resemble Eocene species from Paris Basin, France. Phalium (Semicassis) louella n. sp. is the earliest North American species of Semicassis. Volutilithes orocopiaensis n. sp. is the earliest North American species of this genus and resembles V. muricinus from Paris Basin. Glossus (Meiocardia) susukii n. sp. is the earliest reported species of Meiocardia on the West Coast of North and South America.

Galeodea gallica, a species previously only known from lower Eocene strata in the Anglo-Paris Basin, is tentatively identified from the Maniobra Formation. Campanilopa dilloni, previously only known from south-central California, is present in the formation. Supplementary descriptions and illustrations are given for these two species.

The Maniobra species described have a close relationship to species characteristic of the Eurasian Tethyan paleobiogeographic province. The age of the Maniobra mollusks permits greater resolution of the timing of the westward migration of the Eurasian species, indicating that much of it occurred during early Eocene and/or late Paleocene time.

Denticle number per unit of length in the (P) element of contemporaneously occurring Ozarkodina excavata (Branson and Mehl) and O. tuma Murphy and Matti is a characteristic that shows that these taxa belong to two discrete species. Their morphological ranges with respect to this character do not overlap.

Ozarkodina tuma has a short range within the delta Zone (Lower Devonian) of the central Great Basin and is useful in intrabasin correlation.

Three distinct trilobite associations can be recognized in the Chouteau Formation (Tournaisian, Early Carboniferous) of central Missouri. These associations appear to be lithologically and environmentally sensitive. Association A, the stratigraphically lowest association, contains six genera and is among the most diverse Carboniferous trilobite associations known in North America. This association is dominated numerically by Proetides colemani and exhibits a restricted geographic and stratigraphic distribution. The association is found only in the basal 20 cm of the Chouteau Formation at one locality, in strata representing transgressive subtidal deposits. Association B is found within subtidal and open shelf lithologies and is dominated by two trilobite species, Breviphillipsia sampsoni and Breviphillipsia? swallowi. Breviphillipsia sampsoni, an apparently eurytopic species, is found in both shaly and carbonate strata but is predominately recovered from the shaly partings and interbeds. Breviphillipsia? swallowi, a more stenotopic species, occurs primarily in the more carbonate-rich intervals. In addition, five trilobite species, subordinate in numbers, are only locally common in Association B. The sparse trilobite fauna of Association C is dominated numerically by Namuropyge? armata, and is contained within open shelf sediments that interfinger with mud biostrome lithologies.

Early Carboniferous adaptive radiation of trilobites resulted from the creation of new ecospace by transgression. This allowed initially eurytopic trilobites to move into and occupy certain niches that may have been unavailable to them prior to the Frasnian extinctions. With continued deepening, niche-specialized associations developed in more offshore settings.

Murthya, a new ostracode genus of Cytherinae, is proposed for the species previously described as Leptocythere chadopadiensis Lyubimova and Guha from the Lower Miocene beds of Kachchh District, India. The genus also occurs in the Lower Miocene beds of Saurashtra, Quilon, and Thanjavur.

Patelliocrinus planus n. sp. (Patelliocrinidae), Manticrinus exaitos n. gen., n. sp. (Marsupiocrinidae), and Clematocrinus ohioensis n. sp. (Hapalocrinidae) are described from southwestern Ohio. These new Early Silurian crinoids are from the upper lower or middle Llandoverian Brassfield Formation. Patelliocrinus planus is the oldest member of this genus. It was originally designated as Platycrinid(?) by Foerste (1919) and, subsequently, Brower (1973) placed it in the Hapalocrinidae. Manticrinus is placed in the Marsupiocrinidae, previously a monogeneric family, and is the oldest member of this family. Manticrinus is judged to have evolved from Macrostylocrinus.

Species assignments are clarified between Clematocrinus and Hapalocrinus. These genera are distinguished by character of the arms, primibrachial number, and presence of cirri. Clematocrinus ohioensis is the oldest member of this genus and perhaps of the Hapalocrinidae.

Three new species of inadunate crinoids of Early Mississippian age from the Ramp Creek Formation along Indiana Creek, southern Montgomery County, Indiana, are described. Poteriocrinites amplus n. sp. is the first correctly identified record from North America of this long-ranging Old World genus. Poteriocrinites macropleurus and P. doris from the Burlington Limestone are here reassigned to Springericrinus. Interchange of Mississippian crinoid genera between Europe and North America is rare, many genera being endemic. Springericrinus sacculus n. sp. is the youngest reported species of this North American counterpart of Poteriocrinites. This new species exhibits two advanced features: presence of only one, rather than three, anal plate, and presence of 3 or 4, rather than 1 or 2, primibrachial plates per ray. The third species, Decadocrinus stellatus n. sp., presents an interesting blend of characters usually used as generic discriminators between Decadocrinus and Histocrinus. The specimen could possibly be considered to be an intermediate between these two genera that are currently placed, incorrectly we believe, in two separate superfamilies.

Ophiolancea swartkopensis n. gen. and sp. is the first ophiuroid to be described from the Lower Cretaceous (Valanginian) Sundays River Formation, South Africa. Ophiolancea is distinguished by lanceolate lateral arm shields which occur on the distal portions of the arms. Associated fauna and stratigraphic evidence suggest that the specimen was buried in an intertidal mud flat.

A new genus and species of amynodontid rhinoceros, Rostriamynodon grangeri, from the early Late Eocene of Inner Mongolia, People's Republic of China, is the most primitive amynodontid recognized to date. Rostriamynodon exhibits the major diagnostic characteristics of amynodontids: quadratic M3, preorbital fossa, and loss of upper and lower P1. It differs from more advanced members of the family in its long preorbital region and lower cheek tooth morphology. Comparisons with other Eocene ceratomorphs show the crucial position Rostriamynodon has in determining phylogenetic relationships between rhinocerotoids and tapiroids. Evidence is presented for the monophyly of the Rhinocerotoidea, including amynodontids.

Fossil land mammals were collected by G. G. Simpson in 1933–1934 at and near the Tapera de López in central Chubut Province, Patagonia, southern Argentina, from rocks now mapped as the Sarmiento Formation. These fossils are assigned to land mammal faunas of Casamayoran (Early Eocene), Mustersan (Middle Eocene), and Deseadan (late Early Oligocene through Early Miocene) age.

40K-40Ar age determinations of eight basalt and two tuff units associated with the Deseadan age local fauna at Scarritt Pocket establish a geochronologic framework that calibrates the biostratigraphic record at this locality. The radioisotope dates obtained at Scarritt Pocket range from 23.4 Ma to about 21.0 Ma, and equate with earliest Miocene time. The Scarritt Pocket local fauna is the youngest dated Deseadan age fauna yet known in South America.

Seven other localities have, or were reputed to have, local faunas of Deseadan age associated with dated volcanic units. Six of these localities are in Argentina (Gran Barranca, Cerro Blanco, Valle Hermoso, Pico Truncado, Cañadón Hondo, Quebrada Fiera de Malargüe) and one in Bolivia (Estratos Salla in the Salla-Luribay Basin). The stratigraphic relationships of the volcanic units with these local faunas is discussed, and the taxonomic content of each is reassessed.

The Deseadan Land Mammal Age is defined by the earliest record of the land mammal genus Pyrotherium, which is from below a basalt dated at 33.6 Ma at Pico Truncado. Other early records of Pyrotherium occur below basalts dated at about 29 Ma at the Gran Barranca and Valle Hermoso, and from a 28.5 Ma level of the Estratos Salla. Thus, the lower boundary for Deseadan time is about 34 Ma.

The youngest record of Pyrotherium is in the upper levels of the Estratos Salla dated at about 24 Ma. However, the Scarritt Pocket local fauna, which lacks Pyrotherium, permits placement of the upper boundary for Deseadan time at about 21.0 Ma. Late Deseadan time is surely, and the end of Deseadan time is apparently, marked by the last record of such groups as Proborhyaeninae (Proborhyaena), Rhynchippinae (Rhynchippus), Archaeohyracidae (Archaeohyrax), and the genera Platypittamys (Octodontidae), Scarrittia (Leontiniidae), Propachyrucos and Prohegetotherium (Hegetotheriidae), and Argyrohyrax (Interatheriidae), as these taxa are recorded in the Scarritt Pocket local fauna. Thus, Deseadan time extends from about 34.0 Ma to about 21.0 Ma, making it the Land Mammal Age with the longest known duration in South America.

Palynostratigraphic study of the Bear Gulch Member of the Heath Formation, central Montana, indicates an Upper Mississippian age for the deposit corresponding to Carboniferous palynofloral zone TK (ammonoid zone E2b, Namurian A). The palynoflora contains a diverse spore assemblage, including the Mississippian index Tripartites vetustus. In addition, the Bear Gulch Member contains an abundant and diverse acritarch assemblage. The age assignment is consistent with age determinations from studies of the ammonoid, conodont, and bryozoan faunas.

Interfacial methods are a group of newly emerging techniques for recovering phosphatic microfossils from disaggregated sediment residues by exploiting the lipophilic surface properties of apatite (Freeman, 1982). When a sediment residue is placed in a two-phase mixture of water and a water-insoluble organic liquid, the organic liquid wets the phosphate particles in preference to the gangue minerals, most species of which are wetted by the water instead.

Micropaleontologists can benefit from measurements of microfossil morphology in studies of taxonomy, stratigraphy, and evolution. Morphometric data can be used to clarify evolutionary relationships, increase biostratigraphic resolution within lineages, and identify ecophenotypes. Morphometric data also provides a means for objectively reporting and summarizing large numbers of microscopic observations.

Delthyris sculptilis Hall, 1843, from the Middle Devonian Hamilton Group of New York and equivalent rocks elsewhere in eastern North America, has long been assigned to the genus Delthyris or, in certain older studies, to the genus Spirifer. Recent restudy of this brachiopod shows that it belongs to the genus Megakozlowskiella Boucot, 1962. This extends the upper limit of Megakozlowskiella from the Eifelian (Southwood Stage, Onondaga Limestone in New York) to the Givetian (Tioughnioga Stage, Moscow Formation of the Hamilton Group in New York).

The genus Ardea includes all living species of large herons. Brodkorb (1963) listed five fossil species of Ardea, and only one fossil species has since been described. Of these six, only two are unquestionably members of the genus Ardea. Ardea brunhuberi von Ammon, 1918, from the Upper Miocene Brown Coal Formation, Württemburg, Germany, was moved by Brodkorb (1980) to the Phalacrocoracidae as Phalacrocorax brunhuberi. Brodkorb (1980) considered A. lignitum Giebel, 1860, from the Sarmatian Brown Coal of Rippersroda, Thuringia, Germany, to be a large owl in the genus Bubo. Olson (1985) similarly regards A. perplexa from the Astaracian of Sansan, France, to be a large owl, possibly in the genus Bubo. The type of Ardea aureliensis Milne-Edwards, 1871, from the Oreleanian of Suevres, France, has never been illustrated or restudied and its affinities need to be confirmed (Olson, 1985). The valid fossil species are Ardea polkensis Brodkorb, 1955, from the late Hemphillian Bone Valley Mining District, Florida, and A. howardae Brodkorb, 1980, from the Plio/Pleistocene Shungura Formation, Omo Basin, Ethiopia. A large species of Ardea is also known from the late Clarendonian Love Bone Bed local fauna, Florida, but is based on material too fragmentary for specific identification (Becker, 1985). This note reports the earliest certain occurrence of Ardea now known.