Trilobites Above Earth May Have

Scientists estimate that life on Earth may have begun as early as three billion years ago. For much of its history, however, life was confined to single-celled bacteria. Stromatolites, layered mounds of sediment trapped by mats of blue-green cyanobacteria, are the predominant fossils for nearly two billion years of geologic history. Finally, in the late Precambrian Ediacarian Period, about 570 million years ago, enigmatic soft-bodied forms of multicellular life first appeared as impressions in sandstone.

About 543 million years ago life made a further profound change in direction. A sudden burst of new organisms with hard skeletons in the fossil record has been called the "Cambrian Explosion." The earliest fossil skeletons were simple tubes, probably made by worms; shell material clearly made by complex living creatures such as mollusks appeared about 540 million years ago. Then, beginning about 520 million years ago, highly sophisticated skeletons of trilobites, early representatives of Earth's most abundant complex animals β€”the Phylum Arthro-poda β€” appeared in marine strata worldwide. The trilobites not only appeared dramatically in the fossil record but for millions of years they dominated it.

Trilobites are the quintessential archaic marine animals. Few if any other invertebrate fossils have attracted more attention from paleontologists and fossil collectors than these ancient arthropods, distant relatives of today's crustaceans and insects. Paleontologists have learned a great deal about trilobites because they were ubiquitous in the oceans and seas of the early Paleozoic Era and because they possessed readily preserved hard skeletons. In the mid to late 1800s lithographed images of trilobites became symbolic of the rapidly developing field of paleontology in New York State as well as in England, two hotbeds of early research by serious amateurs and professional scientists when interest in the nascent field of geology was first beginning to burgeon. The beautifully preserved, segmented exoskeletons of trilobites β€” in shades of saddle brown and blue gray to black β€” are truly spectacular objects, but perhaps above all it is the well-developed, commonly compound eyes of trilobites that have made them attractive to paleontologists and lay persons alike. Trilobites were certainly among the first organisms to form relatively clear images of their world.

New York State is and has long been a magnet for trilobite hunters. Historically, New York was of central importance in the study of Paleozoic fossils, and New York's trilobites were among the first illustrated fossils in North America. New York strata are the source of many specimens accepted worldwide as the best of their kind. These fossil remains are actively sought, studied, and traded. With its extensive shale deposits, New York is a particularly rich source of trilobites, many of which are shown for the first time in this volume. Many outstanding localities in New York State, from the majestic Ordovi-cian limestone bluffs of Trenton Falls to the Silurian beds in the great gorge of Niagara River to the Devonian shale cliffs of Lake Erie, continue to yield abundant and spectacular trilobite fossils. New York strata have also yielded more trilobites with preserved appendages and other "soft parts" than almost any other region of the world. The rarity and aesthetic beauty of complete outstretched or enrolled trilobites gives trilobite fossils special value to collectors. Spectacular, ornate trilobites from New York, ranging from a few millimeters to nearly a half-meter in length, are featured in museums all over the world; some extraordinary examples are prized by collectors and have been sold for thousands of dollars.

Yet despite the fame of New York State's trilobites, no recent text has attempted to document comprehensively these remarkable fossils. With a little effort one can find trilobites in New York State rocks ranging in age from the time of their earliest occurrence in the Early Cambrian up to their last time of major abundance in the Devonian Period, about 370 million years ago. Thus, although New York strata do not document the entire evolutionary history of trilobites, the abundant, high-quality material available in this area offers a rare opportunity to discover and study these intriguing representatives of early life history.

Trilobites of New York is intended to be a nearly complete compilation of the trilobite species found in New York: a review of the biology of the trilobite; insight into trilobite preservation in the rocks; a short course on the Paleozoic geology of New York, emphasizing trilobite-bearing strata; and a collection of high-quality images of representative New York trilobites. The book is not and was never intended to be a field guide or identifica tion matrix to trilobites. As such, there is no specific locality information, although many readers will find the photographs very useful in identification and in differentiating similar species.

This work started more than 20 years ago as an attempt by Tom Whiteley to compile illustrations of the trilobites found in New York. Although New York has a history of trilobite discovery and research since 1824, references on trilobites are scattered and often not available except in the libraries of large universities. The only collective works on New York trilobites were the classic volumes by James Hall, and the last of these was published in 1888. It soon became apparent that the New York Paleozoic exposures are too varied for one person to really understand all the trilobites and their locations. Hence, Gerald Kloc became involved with this project for his knowledge of the Silurian and Devonian exposures and their trilobites and for his contacts in the amateur community.

As in all research programs, background literature is an essential starting point. There are a few texts on trilobites that provide more in-depth information on the animal itself than we include. The works of Johnson (1985), Levi-Setti (1975), Ludvigsen (1979b), and Whittington (1992) are good references for additional reading. Every trilobite publication has references, and these references lead to other publications, which in turn lead to more references and so on. Hundreds of publications were examined, and the relevant ones were put into a database. Fieldwork was also carried out in the more promising exposures. However, this fieldwork resulting from literature surveys was limited and nowhere near the hours and days of work spent by many professionals and amateurs in the field collecting each individual specimen. Specimens of the quality illustrated in this book are uncommon, even rare. A number of the trilobite specimens are unique in their quality of preservation and preparation, and very few like them exist anywhere.

The trilobite collections in a number of major northeastern United States museums were examined carefully, and specimens that were unusual or of high quality were photographed and the accompanying information recorded. These museum collections represent the efforts of dozens of individuals over a period of more than 150 years. A number of amateur collectors made their specimens available for photography, which was helpful as the best and most complete material is often not in a museum. In a few cases research paleontologists made their photographs of uncommon material available for reproduction. The photographic procedures are provided in Appendix B, but in general the photographs were taken in a museum or in a laboratory environment. Often the specimens were whitened with ammonium chloride to bring out detail. The images were then scanned into a digital file, and all of the final preparation of images was done on computer. No information was added or subtracted from the digital image at any time. Of the thousands of photographs, only about 200 could be selected for the book. Selection was made on the basis of quality, rarity, and representation of the material present in the New York rocks.

Anyone who collects fossils of any kind understands that finding a choice specimen is only part of the process. Most trilobites are embedded in a matrix of shale or limestone, and to really appreciate their quality one must prepare them by removing the stone from the part of the trilobite that is to be displayed. Most of the illustrated specimens were prepared or "touched up" by Gerald Kloc. Even some museum specimens were worked on, with the museum's permission, to bring out the details concealed by matrix.

As work on this project progressed, it became clear that to compile data and images on trilobites was not enough. A listing of nearly 500 separate species, while interesting to a few specialists, is not very helpful to the collector or the student. To be really useful, we needed to include information on why the trilobites are found where they are and how their preservation comes about. To this end, Carlton Brett provided a review of trilobite taphonomy, as well as an overview of the geological history of the New York Paleozoic.

The remaining issue concerned the intended audience, or who is expected to read the book. Dr. Warren Allmon of the Paleon-tological Research Institution suggested that high-school earth science teachers represented the right level for content, as this level would provide information useful to the collector, teacher, and student. Dr. Allmon also made the first contacts with Cornell University Press.

As already mentioned, it was necessary in the course of this work to visit many of the major natural history museums in the northeast United States. The American Museum of Natural History, Museum of Comparative Zoology (Harvard), Peabody Museum (Yale), New York State Museum, National Museum of Natural History (Smithsonian), Rochester Museum and Science Center, Royal Ontario Museum, and Paleontological Research Institution were visited, some many times, and their collections carefully examined. The cooperation of the museums' management and their collections managers in particular was unreserved. Without their help, this work would not have been possible.

The cooperation and assistance of Fred Collier, Jan Thompson, Ed Landing, Niles Eldredge, Janet Waddington, Tim White, Wendy Taylor, Paul Krohn, Fredrick Shaw, Stephan Westrop, and George Mcintosh were all important to this work. Fred Collier, in particular, while at the United States National Museum, greatly influenced the early direction of these efforts with his professionalism and enthusiasm.

We gratefully acknowledge the collectors who made their specimens available for photography and in some instances donated these specimens to a museum. They are William Pinch, Kent Smith, Lee Tutt, Paul Krohn, James Scatterday, Gregory Jennings, Fred Barber, Kym Pocius, Sam Insalaco, Kevin Brett, Steve Pavelsky, Tod Clements, Douglas DeRosear, Fred Wessman, Gordon Baird, and William Kirchgasser.

Rolf Ludvigsen, Nigel Hughes, and George Mcintosh read early drafts of the book and made many valuable suggestions. Warren Allmon made the first contacts with Peter Prescott, science editor of Cornell University Press, who was instrumental in giving the book focus and helped turn what was a collection of information and pictures into something publishable. Alyssa

Sandoval, Lou Robinson, and Candace Akins also provided valuable assistance. To all we express our gratitude.

Thomas E. Whiteley Gerald J. Kloc Carlton E. Brett

T Trilobites of New York

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