Species: hatcheri HAY, 1901 (nomen dubium)
Etymology:

Holotype: CM 115

Locality: South side of Lance Creek, opposite of Dogie Creek, Converse County, Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material: Fragmentary shell.
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Species: marshi HAY, 1904 (nomen dubium)
Etymology:

Holotype: YPM 299

Locality: Between Buck and Lance Creeks, Converse County, Wyoming.

Horizon: Laramie Formation.

Biostratigraphy:

Age: Lancian Age, upper Maastrichtian Stage, uppermost Senonian Subepoch, Upper Upper Gulf Epoch, Late Cretaceous.

Material: Fragmentary shell.
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Species: collosa HAY, 1905 (nomen dubium)
Etymology:

Holotype: CM 330

Locality: Willow Creek, Gallatin County, Montana.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material: Imperfect carapace and the greater portion of the plasteron.
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Species: hayi GILMORE, 1916 (nomen dubium)
Etymology:

Holotype: USNM 6728

Locality: Lance Creek, Niobrara County (formerly a part of Converse County), Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material: A carapace and plastron.