Two hundred and thirty six calcitic brachiopod shells, covering the entire Silurian Period ($\sim$30 Ma), were collected at high temporal resolution from stratotype sections on Anticosti Island (Canada), in Wales (UK), in the Oslo region (Norway), on Gotland (Sweden), and in Podolia (Ukraine), Estonia, Latvia and Lithuania. Data from petrography, scanning electron microscopy (SEM), cathodoluminescence, isotopes and trace elements all confirmed excellent preservation in most shells, thus ensuring retention of primary isotope signals. The only exceptions were samples from the Oslo region. The $\delta\sp $O and $\delta\sp $C values for the well preserved samples range from $-$3 to ${-}6.5\perthous$ and from -1 to 7.5$\perthous$ (PDB), respectively. In terms of temporal trends, oxygen- and carbon-isotopes vary in parallel, with an overall decrease with decreasing age of ${\sim}1\perthous,$ through the Silurian. Superimposed on these general trends are short-term variations that are negatively correlated with sea-level changes. Three successive positive $\delta\sp $O shifts in early Aeronian, latest Aeronian and early Wenlock correlate with sea-level lowstands and with glacial diamictite deposits in the Amazon Basin and in Africa. The $\sp‡$Sr/$\sp†$Sr values range from 0.707930 $\pm$ 0.000011 to 0.708792 $\pm$ 0.000017, increasing with decreasing age. This may indicate increasing riverine flux of radiogenic Sr into the ocean from weathering of continental sialic rocks due to progressive global warming. The Sr-isotope curve shows distinct inflexion points in the earliest Wenlock and in mid-Pridoli These can be used to correlate the Llandovery/Wenlock boundary in the U.K., on Gotland and in Lithuania and for the Kaugatuma/Ohesaare boundary in the Baltic states and Podolia. Partial linear regressions for Sr-isotope data form a pattern that climbs stepwise with decreasing age, with local drops around the Llandovery/Wenlock boundary and in the latest Ludlow. The slopes of the partial regression lines can be used for reliable age estimates with a resolution of about $\pm$2 biozones ($\sim$1.5 to 2 Ma).

The microherpetofaunas recovered from the Kaiparowits Plateau, Utah, are described. Small reptiles and amphibians from 16 families and at least 22 genera were obtained from the Cenomanian Dakota, Turonian to Santonian Straight Cliffs, the early Campanian Wahweap, and the Campanian (Judithian) Kaiparowits Formations. A new genus and species of polyglyphanodontine, Manangyasaurus saueri, is described. The function of the unusual teeth of polyglyphanodontines is uncertain, but may have been related to frugivory. The polyglyphanodontines, in the restricted sense, appear to be confined to the western localities of the "southern communities" in the Judithian and Lancian. The early occurrence (Turonian) of Paraglyphanodon in the Straight Cliffs Formation suggests that the polyglyphanodontines may have been widespread during earlier Ages, permitting their dispersal to or from Asia. The genus Albanerpeton is best considered a member of the Order Caudata and its provisional assignment to the Family Prosirenidae is reasonable. The Polyglyphanodontidae, as presently defined, consists of a holophyletic group consisting of Polyglyphanodon, Paraglyphanodon, Manangyasaurus, and Cherminsaurus, and a poorly defined group consisting of the Asian "Macrocephalosauridae" Peneteius may also be a polyglyphanodontine, as the subfamily is presently defined.

Marine upwelling occurs when surface currents diverge or are deflected. Deeper water, often nutrient-rich, rises and generates a cascade of biological effects including elevated productivity and a unique assemblage of organisms. Macrofaunal characteristics of upwelling provide key evidence for oxygen-minimum zones, upwelling of cool water, and high productivity and are potentially useful indicators of ancient upwelling. The Upper Triassic Luning Formation in Nevada contains abundant, large ichthyosaurs and was deposited in a back-arc basin that could have experienced upwelling conditions. Luning Formation rocks at West Union Canyon were analyzed for sedimentological, geochemical, and paleontological upwelling indicators. Abundant suspension feeders, lack of corals and calcareous algae, modest total organic carbon and minor element concentrations in deeper marine facies, abundant cosmopolitan molluscs but no taxa restricted to low latitudes, and abundant fecal pellets and clotted fabrics in most facies suggest that upwelling could have influenced Luning deposition. Moderate-scale upwelling likely contributed to eutrophic conditions and ichthyosaur abundance at West Union Canyon. Marine reptiles might have had ties to upwelling areas to provide food, as do modern whales. A relational database containing 817 locality records and 1365 taxon-localities was assembled for ichthyosaurs, plesiosaurs, and mosasaurs. Marine reptile localities were compared with model-predicted upwelling and with upwelling-related lithologies (organic-rich rock, biogenic silica, phosphorite, and glauconite). Marine reptile occurrences intersected predicted upwelling more often than expected by chance for the Upper Cretaceous, Callovian, and Norian stages, and for all of the data together (P = 0.05). For age-restricted data, occurrences of Mosasauridae, Pliosauridae, and Plesiosauria intersected upwelling more often than expected by chance (P = 0.05). Average shortest distances between reptile fossil and upwelling lithology occurrences were smallest (one grid cell adjacent or smaller) for the Pliensbachian and four of five Cretaceous stages. Analytical biases and other aspects of reptile ecology may have affected the results, but overall, upwelling could have influenced marine reptile distribution, particularly for the Upper Cretaceous. Multiple radiations into the high-productivity, top-predator niche over the Mesozoic are suggested by the dominance of different taxa in grid cells containing upwelling lithologies: ichthyosaurs (early Mesozoic), plesiosaurs (middle Mesozoic), and finally mosasaurs (late Mesozoic).

About 2,500 specimens of small mammal fossils were collected from 10 localities in the Pliocene Panaca Formation in Meadow Valley, southeast Nevada. The most common taxa are cricetid and heteromyid rodents, and lagomorphs. Twenty-seven species, including five new species, were recognized from the fauna. A new genus of microtine rodent, Nevadomys, including three new species, N. fejfari, N. lindsayi, and N. downsi, is recognized. Nevadomys was probably derived from the Hemphillian Paramicrotoscoptes. Repomys minor n. sp. is another new species of high-crowned cricetid that was detected in the Panaca local fauna. With abundant upper and lower third molars of Repomys, it was possible to amend the diagnoses of genus Repomys. The fifth new species recognized from the fauna is a shrew, Paranotiosorex panacaensis n. gen. and sp. Enamel microstructure of molars of the microtine rodents Mimomys panacaensis and Nevadomys n. gen. from the fauna were examined under the scanning electronic microscope. Mimomys panacaensis shows the same schmelzmuster among different populations. Nevadomys has a more primitive schmelzmuster compared to Mimomys panacaensis. Both its leading and trailing edges are entirely composed of radial enamel. The assemblage of small mammal fossils suggests that the Panaca local fauna represents the early Blancan land mammal age. The first appearance datum of Mimomys panacaensis is suggested as the beginning of Blancan land mammal age, and the absolute age of the lowest stratigraphic datum of M. panacaensis in the Panaca Formation is interpolated from magnetostratigraphy and is considered as the age of the Hemphillian-Blancan boundary. The magnetostratigraphy of the Panaca Formation in Meadow Valley is established based on four sections in the basin. The ash in the Rodent Hill section was dated at 4.64 +/- 0.03 Ma, which constrains the correlation of the reversed polarity magnetozone in the Rodent Hill section to the C3n.2r in the Geomagnetic Polarity Time Scale (GPTS). The other three sections are correlated to the Rodent Hill section based on the ashes. The Panaca Formation in Meadow Valley was deposited from 4.50--5.30 Ma, and the Hemphillian-Blancan boundary is around 4.95 Ma, close to the termination of Thvera Subchron in the GPTS.

This study considers the ontogeny and phylogeny of branchiosaurids and amphibamids, small dissorophoid amphibians from the Upper Carboniferous and Lower Permian. Both clades play a central role in the discussion of the controversial relationships and origins of the three modern amphibian groups from among possible Paleozoic antecedents. An extraordinary fossil record comprising hundreds of specimens and many ontogenetic stages distinguishes branchiosaurids. This allowed for a detailed study of the ossification sequence of the limb skeleton in the branchiosaurid Apateon, which revealed that branchiosaurids share the unique preaxial dominance in limb development with modern salamanders. A detailed revision of the literature on ossification patterns in the limbs of extant and fossil tetrapods formed the basis for this investigation by showing that ossification sequence in the limbs of tetrapods indeed traces general patterns of early skeletogenesis. Furthermore, the excellent preservation of ontogenetic stages in branchiosaurids facilitated the identification of two distinct life history pathways in branchiosaurids, neoteny and metamorphosis. The vast majority of branchiosaurid taxa is neotenic, but members of the species Apateon gracilis were recognized that clearly metamorphosed into terrestrial adults. Events associated with metamorphosis took place in a very short period of time, which represents the first evidence of a condensed metamorphosis outside the modern amphibian groups. Contrary to branchiosaurids, amphibamids represent terrestrial animals with well-ossified limbs and braincase elements. A new genus and species of amphibamid from the Fort Sill fissure fills is described. An updated phylogenetic analysis of amphibamids including all known amphibamid taxa reveals two distinct clades within Amphibamidae, one comprising more plesiomorphic taxa and a second clade with derived members of the clade. Finally, a comprehensive analysis of dissorophoid relationsh / Cette étude envisage l'ontogénie et la phylogénie des branchiosaurides et amphibamides, des petits amphibiens dissorophoïdes du Carbonifère supérieur et du Permien inférieur. Les deux clades jouent un rôle central dans le débat qui considère les liens et les origines des trois groups d'amphibien modern parmi les possibles antécédents du Paléozoïque. Les branchiosaurides possèdent un record exceptionnel de fossiles comportant des centaines de spécimens et plusieurs étapes ontogéniques. Ceci a permis une étude détaillée à propos de la séquence d'ossification des membres du branchiosauride, Apateon. Ce dernier montre que les branchiosaurides partagent avec les salamandres modernes la caractéristique unique d'une dominance préaxiale dans le développement des membres. Une révision détaillée de la littérature concernant les différentes formes d'ossification des membres chez les tétrapodes, modernes et fossilisés, forme la base pour cette investigation. Ceci est réalisé en montrant que la séquence d'ossification parmi les tétrapodes marque le patron général de la squelettogenèse dans les premières étapes du développement. En outre, la préservation spectaculaire des étapes ontogénétiques parmi les branchiosaurides simplifie l'identification de deux cycles biologique, la néoténie et la métamorphose. La plupart des branchiosaurides sont néoténique, pourtant quelques membres de l'espèce, Apateon gracilis, ont été reconnus comme étant complètement métarmorphosés en adultes terrestres. Cette métamorphose a eu lieu durant une courte période de temps, et elle représente la première évidence d'une métamorphose condensée, hors des groups d'amphibien modern. Contrairement aux branchiosaurides, les amphibamides comportent des tétrapodes terrestres qui possèdent une bonne ossification des membres et de la boîte crânienne. Un nouveau genre et nouvelle espèce d'un amphibamide de la fissure de Fort Sill sont ici dé

This study investigates the abundance and dispersal of pollen in an urban area with a view to making accurate predictions of daily pollen counts. Two-hourly pollen counts of more than 60 different pollen types have been recorded over four complete growing seasons in the heavily urbanized area of North London and this is interpreted in relation to meteorological conditions, local pollen source areas, topography and the urban morphology. The analysis and forecasting of airborne pollen concentrations has relevance within three subject areas. Hayfever sufferers are able to use the forecasts to avoid times of high pollen counts; and this is of particular importance as the incidence of allergic respiratory diseases is higher in urban than in rural areas, and the incidence is believed to be increasing. The research has relevance also for Quaternary palynologists as an increased understanding of modern day pollen dispersal can aid in the interpretation of fossil pollen stratigraphies, as well as to the dispersal of particulate pollutants in urban areas. An initial investigation of pollen abundance illuminates seasonal, daily and two-hourly variations in concentration which are examined in detail in relation to both past and present meteorological conditions. Three pollen taxa (Gramineae, Betula and Platanus) are selected for further analysis to develop various models which are able to predict average daily pollen concentrations of these taxa two or three days in advance. The forecasting models are based upon a multiple regressional analysis of pollen counts and twelve meteorological variables and attain levels of explanation approaching S6%. An attempt is made also to predict the severity of the Gramineae pollen season by examining the average daily temperatures in the months preceding the start of the season. This research is novel in the level of detail of the analysis of pollen concentrations as well as in attempting to predict pollen counts using a variety of methods, especially in the use of accumulated values of maximum daily temperature and sunshine hours.

This study attempts to show that cluster groupings of rock samples based on spore/pollen content in the Weald Clay represent particular palaeoenvironments.

This study investigates the variations in the start and severity of the grass and birch pollen seasons at a network of sites in the United Kingdom. Daily grass and birch pollen concentrations have been monitored during the course of the study (1992-1994) at the University of North London site. Retrospective pollen data of up to 30 years in length at London, Cardiff and Derby has been incorporated into the database, along with between 2 and 7 years of retrospective data from 7 other European Aeroallergen Network(UK) sites. Annual grass and birch pollen concentrations, start of season dates and seasonal severities have been identified and analysed in relation to meteorological conditions and local pollen source areas. Variations have been found at the individual sites from year to year, and between the different sites in the same year. Multiple regression analysis has been used on the long term data sets at London, Cardiff and Derby to produce forecast models to enable the prediction of the start of the season and total seasonal grass and birch pollen concentrations at the 3 sites. Data from the other EAN(UK) sites has been incorporated into these models to assess their use on a regional basis. This research has relevance within many subject areas. The long term data sets on which a large part of the thesis is based are of great interest to Aerobiologists in the identification of long term trends in pollen data. The research has relevance to Quaternary palynologists interested in the influence of the source area on the pollen catch. The influence of climate on the seasonal variation of grass species will be of interest to Agriculturalists, Ecologists and Biogeographers. Finally, through the accurate forecasting of the start and severity of the grass and birch pollen seasons, hayfever sufferers are able to have increased knowledge, and therefore may be able to avoid the amount of medical consultation required by means of prophylactic treatment. The research is unique in that it is the first study to be conducted on the UK pollen databank. It is also unique research in that data sets of this length do not exist anywhere else in Europe and probably the world, and therefore this study poses an important piece of research both on a national and an international level.

This thesis presents the results of a research project designed to reconstruct the Holocene vegetation history of eastern Liguria. The study area lies within the northern Apennines, a region from which few detailed late Quaternary palaeoenvironmental records had boon published and prior to this study no radiocarbon-dated pollen profiles had been reported. Presented hare are the results of pollen-stratigraphical investigations (including pollen concentration and pollen preservation data) from six Holocene peat sites, augmented by twelve radiocarbon dates. The data provide a first regional assessment of the mid- and late Holocene vegetation succession in Liguria as well as a detailed examination of the problems of sampling and interpretation encountered. The sites are situated at a range of altitudes between 831 m to 1481 m and consist of both infilled basins within drift deposits as well as shallow shelf sites. However most of the peat sequences began to form only 4000 to 5000 years ago. At three sites there are strong indications that peat formation only occurred after major disruption of local soils which locally may have been initiated by human (Chalcolithic) forest disturbances. Nevertheless there is also a lack of known early Holocene peat or lake sediments in much of northwestern Italy suggesting widespread climatic conditions inimical to peat development during that period. The biostratigraphical data indicate that Abies forests were common at altitudes of over 1000 a during the mid-Holocene but these declined from approximately 2000 BP and subsequently, woodlands were dominated by Fagus. Certain types suggest that these changes in forest composition could have been related to human activity, although forest clearance appears to have been restricted. The evidence overall suggests that there was major disruption of local soils during the mid- and late Holocene and it is suggested, therefore, that changes in soil moisture regimes possibly as a result of human disturbance, may have led to permanent changes in the vegetation cover.

This dissertation has two overall objectives: first, to demonstrate the utility of paleozoological data for ongoing and future mussel-conservation efforts in Texas and second, to evaluate whether simple measures of habitat (e.g., water depth, velocity and particle size) are important for demonstrating the within-habitat spatial separation of mussels. Although these topics may seem disparate, both are important for increasing our understanding of unionid ecology and biogeography. Chapters 1 through 3 examine the use of paleozoological data for mussel conservation. Although these types of data are not new they have rarely been used in mussel conservation efforts within Texas. This is unfortunate because paleozoological data can provide an excellent record of the mussel fauna prior to wide-scale modern impacts and in areas where historical survey data are lacking. Chapter 4 examines whether assessments of microhabitat for mussels using simple measures of habitat (e.g., water velocity, depth and particle size) are useful. Recent studies have suggested that these measures do not explain the mussel distribution in flowing streams. If this is correct, instream flow studies using this approach need to be revised. Results of Chapter 4 indicate that mussels in the lower Brazos River basin are constrained in distribution by the availability of heterogenous substrate. Appendix A, details the first account of a living population of Truncilla macrodon, which is a candidate species for the Endangered Species Act (ESA). The population was found while conducting mussel instream flow studies in the lower Brazos River basin.