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Map showing publication footprint
  • Usage in publication:
    • McMillan formation
  • Modifications:
    • Named
  • Dominant lithology:
    • Shale
    • Limestone
  • AAPG geologic province:
    • Cincinnati arch
Publication:

Bassler, R.S., 1906, A study of the James types of Ordovician and Silurian Bryozoa: U.S. National Museum Proceedings, v. 30, p. 1-66.


Summary:

McMillan formation proposed to encompass the Bellevue, Corryville, and Mount Auburn, here reduced to members as they are closely related and not of sufficient importance to be separately mapped. Along McMillan Street in Cincinnati, 85 ft of strata composing this formation are fairly well exposed. Overlies Fairview formation and underlies Richmond group. Age is Late Ordovician. [According to Wilmarth (1938, US geologic names lexicon, USGS Bull. 896), at the time of publication McMillan was treated as upper formation of Maysville group (reference not given).]

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • McMillan group
  • Modifications:
    • Revised
  • AAPG geologic province:
    • Cincinnati arch
Publication:

McFarlan, A.C., 1943, Geology of Kentucky; Celebrating the 75th anniversary of the University of Kentucky: University of Kentucky, 531 p.


Summary:

McMillan used at group rank in KY. Includes Bellevue, Corryville, and Mount Auburn formations as exposed in region around Cincinnati. In southern Blue Grass region, the Tate, Gilbert and Mount Auburn occupy the same interval.

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • McMillan formation
  • Modifications:
    • Revised
  • AAPG geologic province:
    • Cincinnati arch
Publication:

Sweet, W.C., Turco, C.A., Warner, Earl, Jr., and Wilkie, L.C., 1959, Eden conodonts from the Cincinnati region of Ohio and Kentucky; [Part 1] of The American Upper Ordovician standard: Journal of Paleontology, v. 33, no. 6, p. 1029-1068.


Summary:

Pg. 1029-1030. McMillan formation of Covington group. Uppermost formation of Covington group. Overlies Fairview formation; underlies Arnheim formation. Fairview and McMillan formations constitute standard for a medial Cincinnatian Maysville stage.

Source: US geologic names lexicon (USGS Bull. 1200, p. 2309-2310).


Map showing publication footprint
  • Usage in publication:
    • McMillan Formation*
  • Modifications:
    • Areal extent
  • AAPG geologic province:
    • Cincinnati arch
Publication:

Weir, G.W., Greene, R.C., and Simmons, G.C., 1965, Calloway Creek Limestone and Ashlock and Drakes Formations (Upper Ordovician) in south-central Kentucky, IN Contributions to stratigraphy, 1965: U.S. Geological Survey Bulletin, 1224-D, p. D1-D36.


Summary:

McMillan Formation not used in area of report. Replaced by Tate, Gilbert, and Stingy Creek Members of Ashlock Formation.

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • McMillan Formation
  • Modifications:
    • Areal extent
  • AAPG geologic province:
    • Cincinnati arch
Publication:

Peck, J.H., 1966, Upper Ordovician formations in the Maysville area, Kentucky, IN Contributions to stratigraphy, 1966: U.S. Geological Survey Bulletin, 1244-B, p. B1-B30.


Summary:

Upper contact of McMillan Formation is not lithologically definable in its type area. On the basis of this and the restriction of the McMillan from south-central KY by Weir and others (1965), the unit is no longer valid in KY and the equivalent beds in the Maysville area are assigned to the Grant Lake Limestone.

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • McMillan Formation
  • Modifications:
    • Overview
  • AAPG geologic province:
    • Cincinnati arch
Publication:

Velbel, D.B., 1985, Ichnologic, taphonomic, and sedimentologic clues to the deposition of Cincinnatian shales (Upper Ordovician), Ohio, U.S.A., IN Curran, H.A., Biogenic structures; their use in interpreting depositional environments: Society of Economic Paleontologists and Mineralogists Special Publication, Symposium, Denver, CO, June, 1980, no. 35, p. 299-307.


Summary:

Stratigraphic column illustrates continued usage of the McMillan Formation in southwestern OH, where it includes Bellevue, Corryville, and Mount Auburn Members. Overlies Fairview Formation; underlies Arnheim Formation. Age is Late Ordovician (Cincinnatian).

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • McMillan Formation†
  • Modifications:
    • Abandoned
  • AAPG geologic province:
    • Cincinnati arch
Publication:

Tobin, R.C., 1986, An assessment of the lithostratigraphic and interpretive value of the traditional "biostratigraphy" of the Upper Ordovician of North America: American Journal of Science, v. 286, no. 9, p. 673-701.


Summary:

McMillan Formation (of Bassler, 1906) is here abandoned in southwestern OH [type area]. Its rocks are assigned to Corryville Formation, raised in rank. Lithologic homogeneity of McMillan is not up to the 1983 Code, according to author.

Source: GNU records (USGS DDS-6; Reston GNULEX).


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For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates published by U.S. Geological Survey authors.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

Slash (/) indicates name does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).