REEXAMINATION OF THE ORDOVICIAN SNAKE HILL TYPE LOCALITY: SIGNIFICANCE OF FOSSILIFEROUS DEPOSITS BORDERING THE TACONIC FRONT, EASTERN NEW YORK STATE

"Snake Hill Shale" is a broadly applied term in eastern New York. It is often used to describe heavily deformed, unfossiliferous belts of shale-dominated tectonic mélange and broken formation associated with the Taconic Orogeny. In contrast, the Snake Hill type locality displays a long, ordered siltstone-sandstone dominated succession yielding a rich assortment of infaunal and epifaunal taxa. This study demonstrates that the Snake Hill type locality is faunally and stratigraphically uncharacteristic of what is commonly designated "Snake Hill Shale"; it is more suitable for describing fossiliferous facies rather than a grade of structural deformation. Faunal comparisons with the Martinsburg Formation in Pennsylvania and association with the Climactograptus spiniferus graptolite zone suggest that the Snake Hill fauna is Early Edenian Stage. Other benthonic faunas from Green Island and Waterveliet were examined; association with the Orthograptus ruedemanni zone indicates deposition during the slightly older, Middle-Late Shermanian Stage. The faunas of the Green Island/Waterveliet localities are interpreted as being distally resedimented from a more hospitable, shallower environment. There appears to be a progradational trend of biofacies associated with the incursion of coarse-grained sediment beginning,first, at the Green Island/ Watervliet localities, continuing through deposition of the Snake Hill type succession, and westward into the later Edenian Stage- Early Maysville Lorraine Group of central New York. Due to the rarity of benthonic fossils in the Upper Ordovician deformed belt of eastern New York within the Taconic Foreland Basin, it is recommended that the term Snake Hill Facies be used to describe any locality containing abundant non-transported benthonic fossils within the greater Austin Glen sedimentary complex.