|Geologic age||Lower Silurian|
|Comments||part of the Clinton Group 150-325 ft. (40-100 m). Descriptions from USGS Lexicon website (ref. NY046) and references NY018 and NY033: The Willowvale Shale is exactly equivalent to the Williamson Shale because both are bounded by the same biostratigraphically-dated discontinuity surfaces. Earlier correlations of the upper Willowvale with the Irondequoit are in error. The Williamson-Willowvale sequence records a major marine transgression with at least one major regressive subcycle. New litho- and biostratigraphic data support Gillette's (1947) original contention that the underlying Westmoreland Hematite is genetically related to the Willowvale. Age of both units is Early Silurian (late Llandoverian) (Lin and Brett, 1988). New biostratigraphic data suggest that unit is the same age (late Llandoverian) as the overlying Willowvale Shale and is zonally distinct from the underlying Sauquoit Shale. Westmoreland is laterally equivalent to Second Creek Bed, a new name for a phosphatic quartz pebble bed with abundant pyrite at the base of the Williamson Shale (Lin and Brett, 1988).|
|Primary rock type||shale|
|Secondary rock type||sandstone|
|Other rock types||chemical; conglomerate|
Sedimentary > Clastic > Mudstone > Shale
Sedimentary > Clastic > Sandstone
Sedimentary > ChemicalKirkland Hematite, Westmoreland Hematite
Sedimentary > Clastic > Conglomerate
NYS Museum, NYS Geological Survey, NYS Museum Technology Center, 1999, 1:250,000 Bedrock geology of NYS, data is distributed in ARC/INFOr EXPORT format (with ".e00" extension) in 5 seperate files based on printed map sheets, http://www.nysm.nysed.gov/gis.html.
D. W. Fisher; Y. W. Isachsen, L. V. Rickard, 1970, Geologic Map of New York State, consisting of 5 sheets: Niagara, Finger Lakes, Hudson-Mohawk, Adirondack, and Lower Hudson, New York State Museum and Science Service, Map and Chart Series No. 15, scale 1:250000.