|
Inoceramus (Cremnoceramus) crassus inconstans (Woods, 1912)
 
 
 
Remarks
-
Collector: Prof. Norm King, University of Southern Indiana
-
Formation: Niobrara Group, Smoky Hill Shale
-
Location: Eastern Colorado
-
These Ino's fit Woods's type specimen very well (and Wood's cotypes).
-
Look closely the top right images. Inoceramus (Cremnoceramus) inconstans (Woods) has a peculiar habit of starting out as a "normal looking" inoceramid, compressed with concentric ribs and fine ribs in between, then making a sudden change in angle (almost 90 degrees!). This abrupt change in shell shape is accompanied by replacement of the concentric ribs by irregular growth folds. Weird, but cool! This is presumably the origin of the species name "inconstans".
-
This species is actually the type for the genus Cremnoceramus.
General Info
Synonyms (older names in the literature)
- 1822 Inoceramus sp. Mantell
- 1912 Inoceramus inconstans Woods
- 1955 Inocermus inconstans Woods; McAnulty
- 1969 Inoceramus (Cremnoceramus) inconstans Woods; Moore
- 1969 Inoceramus (Cremnoceramus) inconstans Woods; Hattin & Cobban
- 1977 Cremnoceramus inconstans (Woods); Kauffman
- 1978 Cremnoceramus inconstans (Woods); Kauffman et al.
- 1987 Cremnoceramus inconstans (Woods); Smith
- 1990 Cremnoceramus inconstans inconstans (Woods); Kopaevich & Walaszczyk
- 1992 Cremnoceramus inconstans (Woods); Walaszczyk
- 1997 Mytiloides incertus (Jimbo); Leckie et al.
- 2000 Cremnoceramus crassus inconstans (Woods); Walaszczyk & Cobban
- 2002 Cremnoceramus inconstans Woods; Akers & Akers
Stratigraphic Occurrence (not even close to being a comprehensive list of occurrences!)
- Lower Austin Group, Upper Atco Formation of north and central Texas
- Terlingua Group, Boquillas Limestone of Trans-Pecos Texas (inferred, based on geographic location and stratigraphic position)
- Niobrara Group, Basal Shale Member of the Smoky Hill Chalk of Colorado
- Niobrara Group, uppermost Fort Hays Limestone of Colorado
- Colorado Group, Marias River Shale of northern Montana
- late Early Coniacian rocks of the Czech Republic
- late Early Coniacian rocks of France
- late Early Coniacian rocks of Germany
- late Early Coniacian rocks of Poland
- late Early Coniacian rocks of Romania
- late Early Coniacian rocks of Russia
- late Early Coniacian rocks of Spain
- late Early Coniacian rocks of the Ukraine
- The Upper Chalk of Lewes, England
Age
Geographic Occurrence (not an all-inclusive list)
- Boulder County, CO
- Brewster County, TX
- Czech Republic
- Dallas County, TX
- El Paso County, CO
- France
- Fremont County, CO
- Germany
- Otero County, CO
- Poland
- Pueblo County, CO
- Romania
- Russia
- Southern England
- Spain
- Toole County, MT
- Ukraine
Remarks
For identification, descriptions, and range see:
- Kauffman, E. G. 1977. “Illustrated Guide to Biostratigraphically Important Macrofossils, Western Interior Basin, U. S. A.”. In: Kauffman, E. G., ed. Field Guide: North American Paleontological Convention II. Cretaceous Facies, Faunas, and Paleoenvironments Across the Western Interior Basin. The Mountain Geologist 14 (3-4), 225–274.
- Kauffman, E. G.; Sageman, B. B.; Kirkland, J. I.; Elder, W. P.; Harries, P. J.; Villamil, T. 1993. "Molluscan Biostratigraphy of the Cretaceous Western Interior Basin, North America". In: Caldwell, W. G. E.; Kauffman, E. G., eds. Geological Association of Canada Special Paper 39, 397–434
- Walaszczyk, I.; Cobban, W. A. 2000. Inoceramid Faunas and Biostratigraphy of the Upper Turonian-Lower Coniacian of the Western Interior of the United States. Palaeontological Association, Special Papers in Palaeontology 64.
See especially:
- Woods, H. 1911. Inoceramus (continued). A Monograph of the Cretaceous Lamellibranchia of England 2 (8), 285–291, plate LI, fig's 1–4.
|
