Paleontological studies at Florissant have been ongoing for more than 13 decades. As the focus of these studies has shifted through this time, the site has provided important insights into the evolution of paleontology as a science from its beginnings in the nineteenth century through its subsequent development. Early studies focused on the description of new taxa from collections that were being made by the early scientific surveys of the American West, particularly the Hayden Survey during the early 1870s and an expedition from Princeton in 1877. The first studies and descriptions of these fossils were by Leo Lesquereux on the fossil plants, S.H. Scudder on the fossil insects, and E.D. Cope on the fossil vertebrates. At the beginning of the twentieth century, T.D.A. Cockerell conducted field expeditions in 1906–1908, and subsequently published ∼130 papers on fossil plants, insects, and mollusks. Work by these early researchers was the first to consider the implications of the Florissant fossils for evolution, extinction, biogeography, and paleoclimate. Even greater emphasis on these broader implications began when H.D. MacGinitie made excavations during 1936–1937 and published a comprehensive monograph on the fossil flora in 1953, including numerous taxonomic revisions and detailed interpretations of stratigraphic context, paleoecology, paleoclimate, paleoelevation, biogeography, and taphonomy. Other workers during the late 1900s initiated the first studies on pollen, dicotyledonous woods, and multiple organ reconstructions of extinct plant genera, and developed more quantified methods for determining paleoelevation and paleoclimate. Current work emphasizes plant-insect interactions, the use of diatoms as fresh-water paleoen-vironmental indicators and as agents in macrofossil taphonomy, and the use of insects as terrestrial environmental indicators.

Abstract This field trip in the vicinity of the Florissant fossil beds includes five stops that examine the Precambrian Cripple Creek Granite and Pikes Peak Granite, and the late Eocene Wall Mountain Tuff, Thirtynine Mile Andesite lahars, and Florissant Formation. The Cripple Creek Granite and Pikes Peak Granite formed in balholilhs ca. 1.46 and 1.08 Ga, respectively. Uplifted during the Laramide Orogeny of the Late Cretaceous and early Tertiary, the Precambrian rocks were exposed along a widespread erosion surface of moderate relief by the late Eocene. The late Eocene volcanic history of the Florissant area is dominated by two separate events: (1) a caldera eruption of a pyroclastic flow that resulted in the emplacement of the Wall Mountain Tuff, a welded tuff dated at 36.73 Ma; and (2) stratovolcanic eruptions of tephra and associated lahars from the Guffey volcanic center of the Thirtynine Mile volcanic field. This volcanic activity from the Guffey volcanic center had a major influence on the development of local landforms and on sedimentation in the Florissant Formation, which was deposited in a fluvial and lacustrine setting and is dated as 34.07 Ma. The Florissant Formation contains a diverse flora and insect fauna consisting of more than 1700 described species. Most of these fossils are preserved as impressions and compressions in a diatomaceous tuffaceous paper shale and as huge petrified trees that were entombed in a lahar deposit.

ABSTRACT Florissant fossil beds ranks among the best documented Cenozoic fossil deposits in the world in number of scientific publications and named species. The history of geoscience research on the Upper Eocene Florissant Formation spans nearly one and a half centuries. New excavations and transfers of historic collections have spread Florissant fossils to nearly 30 natural history museums during that period. The history of acquisition, conservation, and taxonomic study of each museum’s collection is unique, so Florissant collections provide examples of how taxonomic diversity, physical conservation, and public exhibition of collections vary with provenance. Dispersal of fossils among museums, including separation of type specimen parts and counterparts, has led to a variety of challenges for research on Florissant fossils. First, an exploratory, quantitative analysis of taxonomic diversity in four collections of fossil insects from Florissant uncovers a pattern of identification bias. Some taxonomists preferentially identify common taxa or consistently misidentify rare taxa, for instance. In light of this result, it is recommended that researchers vet any set of identifications made by multiple researchers or, ideally, identify specimens anew. Second, observations of Florissant specimens at different museums show that a large number of fossils have been lost, damaged, or destroyed due to actions such as travel on loan, display in exhibits, or application of non-archival conservation techniques. Through the digitization process, including cataloging and imaging specimens, curatorial staffs have discovered the extent of uncatalogued or missing material. Digitization has mitigated some of the challenges associated with dispersion of specimens. Collaborative projects across museums have led to rediscovery of lost specimens or discovery for the first time of parts and counterparts that correspond to the same fossil but are housed at different institutions. Online databases that serve specimen images allow researchers to assign new taxonomic determinations, controlling for bias from earlier researchers, or to examine fossils remotely from photographs, reducing the need to handle and ship fragile material for loans. Moreover, providing public access to museum specimen records through collaborative digitization projects expands the opportunities to exhibit and develop specimen-based educational curricula.

Using available shape characters we conducted an outline morphometric analysis to make family-level identifications of fossil spiders from the Florissant Formation in Colorado. In this analysis we used carapace shape because it is a character that can be observed on most fossil spiders, and we also used linear leg characters. All measurements were first made on 202 modern spiders from eight families found in localities similar to the fossil lake environment. A multiple discriminant analysis (MDA) of the eigenshape axes was used to predict family placement among the modern data set to test the accuracy of the predictions. The modern spider families that were predicted correctly most often were the Salticidae (91.2%), Linyphiidae (80%), Dictynidae (76.5%), Tetragnathidae (68.2%), Clubionidae (66.7%), and Araneidae (65.5%). Families that produced less successful results were the Agelenidae (46.7%) and the Lycosidae (39.1%). Forty-three fossil spiders from Florissant were then added to the model to determine their family placement. All fossils were placed into modern families with varying degrees of accuracy. Only 42% of our identifications agree with those made by previous authors, but it is likely that these specimens were originally misidentified. With the addition of more taxa and characters, we believe that an outline morphometric approach shows great promise for helping to identify fossil taxa that are lacking traditional taxonomic characters.

A detailed survey of collections and publications for the Florissant fossil beds (Colorado, USA) forms the basis for developing a new relational database and Web site that documents information that had become widely scattered following 130 years of scientific study at Florissant. More than 1700 species that remain valid, mostly of plants, insects, and spiders, had been described in more than 300 publications, and these published specimens had been dispersed among ∼15 museums. Some of these specimens were not well documented in original publications and many of the type specimens had never been illustrated. Catalog data were compiled on-site at museums, specimens were photographed, and all of the publications referring to Florissant specimens were located. Taxonomic classification of the fossils was updated to modern concepts. A relational database incorporates the data into five core tables for specimens, bibliography, references to specimens in publication, taxonomy, and images. The database allows for complex searches to interrelate these categories, enabling new research and facilitating collections management. Examples show that the largest number of scientific publications and new species descriptions appeared from 1890 to 1920 and that most of the originally described insect species, but only about half of the plant species, still remain valid and unrevised. Digital images of the fossils and digital files for pre-1923 publications form an archive that is linked to the data records. A Web site makes the database publicly accessible for technical use, and also provides a less complex application for the layperson as well as a new college-level curriculum.

Abstract In 1901, Charles Van Hise asked Samuel Emmons and Whitman Cross to organize a grand excursion across Colorado as part of the combined meeting of the American Association for the Advancement of Science, GSA, and the Colorado Scientific Society (CSS). This trip replays part of that 10-day excursion across Colorado. Shortened to three days, this trip takes in some of the same sites as the 1901 trip, plus adds others of interest along the route where CSS members are reinventing geological interpretations. The trip will follow the precedent set in 1901; CSS members will serve as “site or stop hosts” in addition to the trip leader and drivers. While walking in the steps of the most famous of our profession we will also see some of the most magnificent scenery of Colorado.