Inoceramus (Platyceramus) cf. platinus Logan, 1898

Remarks

• Photographed by:  Keith Minor
• Formation:            Austin Group, Hutchins Chalk
• Location:               Dallas County, TX

• The one in the left image is about 1 meter across.  They get up to 2 meters!
• The platinus's on outcrop image was photographed by Prof. Norm King, Univ. So. Indiana.

I. (P.) platinus on outcrop.  Mancos Sh, Smoky Hill Sh equiv., CO.

General Info

Stratigraphic Occurrence

• Austin Group, Atco Limestone of north Texas

• Austin Group, Bruceville Marl north Texas

• Austin Group, Hutchins Chalk of north Texas

• Niobrara Group, Fort Hays Limestone of western Kansas

• Niobrara Group, Smoky Hill Chalk of western Kansas

• Niobrara Formation, Smoky Hill Shale Member of Colorado

• Mancos Shale, Smoky Hill Shale equivalent of Colorado

Age

• Inoceramus (Platyceramus) platinus Logan ranges from about the Peroniceras (Peroniceras) westphalicum (Schluter) zone to the Scaphites hippocrepis (DeKay) form II Cobban zone, middle Coniacian to the lower Campanian Stage (~87–82 mya).

Geographic Occurrence

• Archuleta County, CO

• Dallas County, TX

• Ellis County, TX

• Gove County, KS

• Logan County, KS

• Pueblo County, CO

Remarks

         For identification, descriptions, and ranges, see:

• Caldwell, W. G. E.; Kauffman, E. G. 1993. Evolution of the Western Interior Basin. Geological Association of Canada Special Paper 39, 397–434.
• Hattin, D. E.  1982.  Stratigraphy and Depositional Environment of Smoky Hill Chalk Member, Niobrara Chalk (Upper Cretaceous) of the Type Area, Western Kansas.  Kansas University Geological Survey Bulletin 225.1–108.
• Logan, W. N.  1898.  The Invertebrates of the Benton, Niobrara, and Fort Pierre Groups.  Kansas University Geological Survey 4, 431–518.
• Scott, G. R.; Cobban, W. A.  1964.  Stratigraphy of the Niobrara Formation at Pueblo, Colorado.  United States Geological Survey Professional Paper 454-L, L1–L27.