Ilion Shale

Ilion Shale
State New York
Name Ilion Shale
Geologic age Upper Silurian
Lithologic constituents
Sedimentary > Clastic > Mudstone > Shale > Black-shale
Sedimentary > Carbonate > Dolostone
Comments part of Lockport Group 0-75 ft. (0-23 m). Secondary unit description from USGS Lexicon website (ref. NY046) and reference NY030: Farmers Mills Bed (new name) occurs in the uppermost Ilion [misspelled Illion] Formation, transitional into the overlying Vernon Formation of the Salina Group in eastern NY. The black shale horizon contains a rich eurypterid fauna identical to that found in the type region of the Pittsford Bed of the Vernon Formation, western NY. Author transfers this uppermost portion of the Ilion Formation to the Salina Group and suggests that perhaps the entire Ilion should be included in the Salina. . [Usage of the Ilion in this report is in conflict with Art. 28(b) of the NACSN, which states "* * * a formation or its parts may not be assigned to two vertically adjacent groups."] (Ciurca, 1990).

Fisher, D.W., Isachsen, Y.W., and Rickard, L.V., 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 1:250,000.

Ciurca, S.J., Jr., 1990, Eurypterid biofacies of the Silurian-Devonian evaporite sequence; Niagara Peninsula, Ontario, Canada, and New York, IN Lash, G.G., ed., Western New York and Ontario; field trip guidebook: New York State Geological Association Guidebook, no. 62, 62nd Annual Meeting, Fredonia, NY, p.Sat/Sun D1-D30.

USGS Geologic Names lexicon found at:

NGMDB product
Counties Herkimer - Oneida