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The Logan Formation is the name given to a Lower Carboniferous (early Osagean) siltstone, sandstone and conglomeratic unit exposed in east-central Ohio and parts of western West Virginia, USA.

Logan Formation
Stratigraphic range: Lower Carboniferous (early Osagean)
Logan Formation exposed in Wooster, Ohio.
Unit ofWaverly Group
Sub-unitsBerne, Byer, Allenville, Vinton
UnderliesMaxville Limestone, Pottsville Group, and Rushville Shale
OverliesCuyahoga Formation; Black Hand Sandstone
Thickness0 to 40 m
Primarysandstone, siltstone, conglomerate
RegionAppalachian Basin
CountryUnited States
ExtentOhio, West Virginia
Type section
Named forLogan, Ohio
Named byAndrews, 1870

Stratigraphy and paleoenvironmentEdit

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. doi:10.1130/0016-7606(1979)90<1091:potcal>;2.
  • 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. doi:10.1144/jm.17.2.183.
  • 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.