Stratigraphic range: Lower Carboniferous (early Osagean)
Logan Formation exposed in Wooster, Ohio.
|Unit of||Waverly Group|
|Sub-units||Berne, Byer, Allenville, Vinton|
|Overlies||Cuyahoga Formation; Black Hand Sandstone|
|Thickness||0 to 40 m|
|Primary||sandstone, siltstone, conglomerate|
|Extent||Ohio, West Virginia|
|Named for||Logan, Ohio|
|Named by||Andrews, 1870|
Stratigraphy and paleoenvironment
The Logan Formation was named by Andrews (1870) and originally described as a "buff-colored, fine-grained sandstone" above the Waverly Formation and below the Maxville Limestone. Bork and Malcuit (1979) concluded that the Logan Formation was deposited on a shallow marine shelf in a generally transgressing sea. The age of the Logan Formation has been established as early Osagean (Tn3) by the occurrences of brachiopods, ammonoids, conodonts and miospores (Clayton et al., 1998; Matchen and Kammer, 2006).
- Andrews, E.B. (1870). "Report of progress in the second district, Part II, IN Report of progress in 1869". Ohio Division of Geological Survey Report of Progress, 2nd series: 1091–1094.
- Bork, K.B.; Malcuit, R.J. (1979). "Paleoenvironments of the Cuyahoga and Logan Formations (Mississippian) of central Ohio". Geological Society of America Bulletin 90: 89–113.
- Clayton, G.; Manger, W.L.; Owens, B. (1998). "Mississippian (Lower Carboniferous) miospores from the Cuyahoga and Logan Formations of northeastern Ohio, USA". Journal of Micropalaeontology 17: 183–191.
- Matchen, D.L.; Kammer, T.W. (2006). "Incised valley fill interpretation for Mississippian Black Hand Sandstone, Appalachian Basin, USA: Implications for glacial eustacy at Kinderhookian-Osagean (Tn2-Tn3) boundary". Sedimentary Geology 191: 89–113. Bibcode:2006SedG..191...89M. doi:10.1016/j.sedgeo.2006.02.002.
The bivalve Aviculopecten subcardiformis from the Logan Formation in Wooster, Ohio (external mold).
Schizodus medinaensis; a bivalve from the Logan Formation in Wooster, Ohio (internal mold).
Syringothyris sp.; a spiriferid brachiopod from the Logan Formation in Wooster, Ohio (internal mold).
Helminthopsis ichnosp.; a trace fossil from the Logan Formation in Wooster, Ohio.
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