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Kansas Ammonites

(Cephalopoda: Ammonoidea)


Page created 04/18/2010; Last updated 08/04/2010

Copyright © 2010 by Mike Everhart


Definitely a work in progress.....



LEFT: An internal mold of a portion of the the outer coil of a large ammonite (Prionotropis hyatti) from the upper Blue Hill Shale of northeast Russell County, Kansas. Rock hammer is 41 cm (16 in) in length. Collected by Bruce Schumacher, April, 2010. 

The preserved shells and internal casts of ammonites are common occurrences in Mesozoic marine sediments around the world and are often used by paleontologists as stratigraphic markers. However, they are only rarely preserved  in the Smoky Hill Chalk Member of the Niobrara Chalk, and I have thus pretty much avoided saying much about them. Recently, however, I've had opportunities to collect fossils in other Cretaceous formations in north-central Kansas and have been able to collect several species of ammonites.  In addition, I co-authored a paper with Anthony Maltese about the first discovery of a heteromorph ammonite in the Smoky Hill Chalk (see photos below):

Everhart, M.J. and Maltese, A. 2010. First report of a heteromorph ammonite, cf. Glyptoxoceras, from the Smoky Hill Chalk (Santonian) of western Kansas, and a brief review of Niobrara cephalopods. Kansas Academy of Science, Transactions 113:(1-2):64-70.

In June, 2008, the partial internal mold of a small ammonite was discovered beneath a Tylosaurus nepaeolicus skull collected from the Clioscaphites vermiformis-C. choteauensis zone (early to mid-Santonian), Smoky Hill Chalk. in northern Lane County, Kansas by staff of the Rocky Mountain Dinosaur Resource Center. The specimen was collected and later donated to the Sternberg Museum of Natural History. The ammonite did not appear to be directly associated with the vertebrate remains. The mold preserves a trace of the siphuncle as distinct line visible for about 4 cm along near the outer edge of the specimen. Although incomplete, the specimen preserves the distinctive uncoiled form of a heteromorph ammonite, and appears to be quite similar to a species (Glyptoxoceras texanum) recently named from Santonian deposits in northeastern Texas. This specimen is the first known occurrence of a heteromorph ammonite in the Smoky Hill Chalk.

A brief background of Kansas ammonites from the Introduction of Everhart and Maltese, 2010:

"Cephalopods, including ammonites, occur in relative abundance in several Late Cretaceous formations in Kansas, but are seldom observed or collected from the Smoky Hill Chalk Member of the Niobrara Chalk due to the poor preservation of their aragonitic shells (Hattin, 1982). Among the first to mention Niobrara ammonites was Williston (1897, p. 242) who wrote that they “occur, though rarely, and almost always only impressions are found, with but little of the shell substance. Once or twice I have seen such impressions a foot in diameter.”

Logan (1898) does not mention the ammonite impressions noted by Williston, but does report on discovery of a new species of another cephalopod, a squid which he named Tusoteuthis longus” (corrected for gender to T. longa by Miller, 1968).  Several other species of squid were named by Miller (1968, 1969) and Green (1977), but these have since been synonymized with T. longa (Nicholls and Izaak 1987; Stewart and Carpenter 1990).

In his paper on the Kansas Niobrara, Williston (1897) also noted that baculites had never been collected from the chalk, but indicated that Baculites ovatus had been found in the overlying Pierre Shale near McAllister Butte in western Logan County. Morrow (1935, pl. 53, fig. 7) was the first to describe and figure the internal mold of a baculite (Baculites sp. cf. B. ovatus) from chalk of Trego County. Since that time the molds of baculites have been recognized by several authors (Miller 1968, 1969; Hattin 1982; Hasenmueller and Hattin, 1985; Stewart 1990).

Based on a single, damaged specimen in the University of Kansas collection, Jeletzky (1955) reported on the first belemnite from the Smoky Hill Chalk which he identified as Belemnitella praecursor. Two years later, Miller (1957) also described Belemnitella praecursor from 12 specimens collected by G.F. Sternberg and M.V. Walker. Those specimens apparently had not been available to Jeletzky. Following Miller’s publication, Jeletzky (1961) was able to examine the material in the collection of the Sternberg Museum, and subsequently redescribed them as belonging to the genus Actinocamax, including two new species, A. sternbergi and A. walkeri. Hattin (1982) mentions that belemnites are rare in the chalk, but did not figure them.

In his paper describing cephalopods from the Cretaceous of Kansas, Morrow (1935, pl. 53, fig. 1-2) briefly describes a large, unnumbered specimen (Ammonite sp., “close to Pachydiscus”) from the Smoky Hill Chalk in Logan County in the collection of the University of Kansas, and a nautiloid (Eutrephoceras) from the underlying Fort Hays Limestone of Phillips County. Morrow (ibid., p. 466, pl. 50, fig. 4a-d) also described and named a heteromorph scaphite (Scaphites carlilensis) from the Blue Hill Shale (Middle Turonian) in Mitchell County, Kansas. Miller (1968) assigned the unnumbered KU specimen reported by Morrow to “Brevahites? sp. A” and figured a similar specimen (FHSM IP-12029-2) in the Sternberg Museum collection that he called “Brevahites? sp. B” (subsequently referred to Submortoniceras sp. by Miller 1969). While most ammonite specimens have been collected from Gove and Logan counties, Miller (1969, p. 535) reported “abundant” ammonite remains from a fossiliferous locality in northwestern Rooks County, including several fragmentary molds of large ammonites. Another heteromorph ammonite, Didymoceras nebrascense Meek and Hayden 1856, has been collected from the overlying Pierre Shale in western Kansas (Kennedy, et al., 2000).

Internal molds of Clioscaphites vermiformis Meek and Hayden (1862) and C. choteauensis Cobban (1951) also occur in the middle Santonian Smoky Hill Chalk, and are used as stratigraphic markers (Hattin, 1982; Stewart, 1990). In at least one instance, several individuals have been collected in close proximity (MJE, pers. obs., 2007), suggesting a mass die-off. Although these two species of Clioscaphites occur in adjacent stratigraphic layers according to Kauffman, et al. (1993), Carpenter (2003) noted that Stewart (1990) had combined them into a single biostratigraphic zone in the Smoky Hill Chalk due to poor preservation. Hattin (1982, p. 70) suggests that cephalopods are rare in most of the Smoky Hill Chalk because of less-than-normal salinity, and that the occurrence of Clioscaphites may represent a time when salinity returned to normal marine levels.

The calcitic aptychi of ammonites (Everhart, 2005, fig. 3.4) are preserved occasionally at various stratigraphic levels in the chalk. Hattin (1982) noted that the remains of cephalopods belonging to the Collignoniceratidae are rare and mostly only represented by aptychi. Although there has been considerable debate over use of aptychi as ammonite opercula or jaws (Morton, 1981), more recently it has been suggested by Lehmann and Kulicki (2007) that they served as both operculum and cutting edges of the lower jaws. In his description of the Niobrara vertebrate stratigraphy, Stewart (1990) designated two of his biostratigraphic zones based on occurrence of “Spinaptychus n. sp.” and “Spinaptychus sternbergi,” and noted occurrence of a third form, “Rugaptychus sp.” in the Zone of Hesperornis (Early Campanian). Another aptychi form (“Spinaptychus n. sp. B”; J.D. Stewart, pers. comm. 1991) is present in the Zone of Protosphyraena perniciosa (Upper Coniacian; Everhart, 2005). None of these aptychi, however, has been described in association with identifiable ammonites although fragments of a pair of Spinaptychus n. sp. aptychi were discovered in association with the internal cast of an ammonite informally referred to as “Texanites” (J.D. Stewart, pers. comm. 1993; Everhart, 2005)."

That said, I know barely enough about these invertebrates to be dangerous. So bear with me and I will show some of the specimens that I have collected or seen collected from Kansas rocks in the last five years. We'll start with the youngest Cretaceous rocks in Kansas (Pierre Shale Group) and go down in time to the oldest - the Kiowa Formation:

Other ammonite related sites:

The Geology of Portsdown Hill  Ammonite page

Sharon Springs Formation (Pierre Shale Group) - Middle Campanian:

Ammonites occur rarely in the shales that overlie the Niobrara Formation in far-western Kansas. Baculites are more commonly collected there. I'll add pictures at a later date:

Smoky Hill Chalk Member of the Niobrara Chalk Formation - Upper Coniacian to Lower Campanian: 

FHSM IP-1484-01a.jpg (23378 bytes) LEFT: The piece of chalk that preserves an impression (internal mold) of a heteromorph ammonite (FHSM IP-1484). This is the first such specimen ever collected from the Smoky Hill Chalk. The specimen was collected by Anthony Maltese in northern Lane County.

RIGHT: A close-up of IP-1484 showing the dark trace that indicates the probable location of the siphuncle in the living ammonite. The siphuncle is a living tube that passes from the body of the ammonite through each chamber of the ammonite’s shell. It allows the extraction of water from and the injection of gas into the otherwise closed off older chambers of the shell. This enables the ammonite to adjust the amount of water in the hollow shell compartments and allows the animal to control its buoyancy to a certain extent. In this preservation, the structure in the circle may represent the terminus of the siphuncle where it enters the living chamber. See another example below.

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LEFT: The probable funnel shaped terminus of the siphuncle tube in FHSM IP-1484

RIGHT: An internal mold of Clioscaphites choteauensis from the middle of the Smoky Hill Chalk. According to Cobban, this is the only species of Scaphites found in the chalk. (About 4 in / 10 cm in diameter)

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LEFT: A portion of the internal mold a "Texanites" ammonite from the Smoky Hill Chalk collected by Duffer Mauck of Hoxie, Kansas. Note that a portion of an associated aptychus is also preserved laying the ammonite mold. Ammonite shells were composed aragonite and were generally dissolved before they could be fossilized. The smaller and thinner aptychi, on the other hand, were composed of calcite and preserve very well, sometimes with exquisite detail (below).

RIGHT: Another fragment of the same specimen.  Photos by Mike Everhart, courtesy of J.D. Stewart.

JDS-93520-2a.jpg (23011 bytes)
spinaptya.jpg (19090 bytes) Spinaptychus is the term used to describe the paired structures (aptychi) that probably served as jaw structures for the ammonite (similar to squid beaks). They look like the inside of a clam shell (smooth) on the inside while the outside is covered with numerous, short projections or spines. Several types of "Spinaptychi" are found in the chalk.

LEFT: Spinaptychus sp.: An ammonite aptychi specimen (FHSM IP-528) on exhibit in the Sternberg Museum. Note this publication is available on the web: Fischer, A.G. and  Fay, R.O. 1953. A spiny aptychus from the Cretaceous of Kansas. Bulletin Geological Survey Kansas. 102(2):77-92, 2 pl.

RIGHT: A large ammonite aptychus - FHSM IP-941

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LEFT: A pair of aptychi (EPC 1994-13) that I collected in 1994 from the lower chalk of Gove County (about 4 inches tall). This specimen was prepared by Neal Larson (Black Hills Institute). Close-up views of two other fragmentary specimens are HERE. Note that these structures are rather thin and delicate, with thickness that varies from 1 to 2 mm, except at the hinges where it is somewhat thicker. 

RIGHT: Another nice Spinaptychus sp. specimen (RMDRC 10-018) collected in 2010 from the lower chalk of Gove County by Anthony Maltese (Rocky Mountain Dinosaur Resource Center). This specimen was prepared, including minor reconstruction,  by Neal Larson (Black Hills Institute). 

Blue Hill Shale Member of the Carlile Shale Formation - Upper Middle Turonian:

The Blue Hill Shale ammonite fauna is pretty much dominated by the occurrence of a large ammonite called Prionotropis hyatti (formally Collignoniceras hyatti) - See picture at top of this page -

Prionotropis01a.jpg (22342 bytes) LEFT: The outer coil of a Prionotropis hyatti ammonite collected by Gail Pearson in March, 2010, from the Blue Hill Shale in southwestern Mitchell County, KS.

RIGHT: Part of the inner coil of a similarly-sized Prionotropis hyatti ammonite that I collected in March, 2010.  Note the distinctive suture formed between adjacent chambers of the ammonite.  Another example is shown HERE.

Unfortunately the larger outer coil was only partially preserved. However, this fragment preserves the terminus of the siphuncle on the upper edge, just below the keel. Several smaller ammonites were preserved in the concretion that formed around this ammonite.

P_hyatti-001a.jpg (16752 bytes)
P_hyatti-002a.jpg (17003 bytes) LEFT: Close-of the Prionotropis fragment showing the terminus of the siphuncle.

RIGHT: An anterior end view of one of the chambers, showing the terminus of the siphuncle just below the keel of the shell.

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Ammonite1a.jpg (14954 bytes) LEFT: The Blue Hill Shale also preserves smaller ammonites inside "mud balls", small gray concretions about the size of a baseball.   Sometimes cracking them open with a hammer will reveal an ammonite or other shell inside....

RIGHT: Another mud ball ammonite.

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Ammonite3a.jpg (13308 bytes) LEFT: Another ammonite preserved in a mud ball... these are actually limestone concretions that formed around the ammonite on the muddy bottom of the sea.

RIGHT: A small Prionotropis hyatti ammonite preserved partially inside a mud ball concretion. In this case, outer edge of the ammonite was visible before the concretion was cracked open.

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Scaphites_carlilensis-1a.jpg (23350 bytes) LEFT: A heterotroph ammonite and the counter-part that was broken off to reveal it. In this case the ammonite is a species which was discovered first in Kansas, called Scaphites carlilensis, for the Carlile Shale Formation. 

RIGHT: Another Scaphites carlilensis that still preserves some of the rainbow of colors in the nacre.

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Scaphites_carlilensis-3a.jpg (16160 bytes) LEFT: Still another Scaphites carlilensis with slightly different preservation. If you look at the right side of the shell, you can see that some of the sutures are preserved.

RIGHT: Another Scaphites carlilensis, but this one is preserved in the "red rock" layer that occurs about 3 m below the layer containing the mud balls. In this case, most of the original shiny nacre of the shell is preserved.

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Greenhorn Formation - Lower Turonian to Middle Cenomanian:

PfeiferAmmonite-a.jpg (17859 bytes) LEFT: The internal mold of a small, unidentified ammonite discovered in the Pfeifer Shale, the upper most member of the Greenhorn Formation. This specimen was collected about 1 m below the Fencepost Limestone during the dig on a plesiosaur in eastern Russell County, KS. The preservation (or lack thereof) is similar to ammonites in the Smoky Hill Chalk (above).

RIGHT: A badly weathered internal mold of an ammonite, probably Calyceras sp. from the Lincoln Limestone, the lowermost member of the Greenhorn Formation (Middle Cenomanian).  In this case, it was discovered at the site of a large elasmosaur collected by George Sternberg and M.V. Walker in 1930, near Holyrood, Kansas (Ellsworth County).

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Kiowa Formation - Upper Albian (Early Cretaceous):

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LEFT: An Engonoceras sp. ammonite from the Kiowa Shale of McPherson County, KS. Note the difference in the sutures compared to Prionotropis (above).

RIGHT: .... and for something a little different, an unidentified Pennsylvanian-age Ammonoid preserved in limestone from near Sedan, Kansas (Chautauqua County) ..... about 300 million years old.

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Carpenter, K. 2003. Vertebrate biostratigraphy of the Smoky Hill Chalk (Niobrara Formation) and the Sharon Springs Member (Pierre Shale). pp. 421-437 in Harries, P.J. (ed.), Approaches in High-Resolution Stratigraphic Paleontology, Kluwer Academic Publishers, The Netherlands.

Cobban, W.A. 1951. Scaphitoid cephalopods of the Niobrara Group. U.S. Geological Survey Professional Paper, 239, 42 pp.

Crampton, J.S. 2004. Shell composition, cryptic costae, complex composite molds and taphonomic chicanery in Mytiloides (Inoceramidae, Bivalvia). Journal of Paleontology 78(6):1091-1096.

Everhart, M.J. 2005. Oceans of Kansas - A Natural History of the Western Interior Sea. Indiana University Press, 322 pp.

Everhart, M.J. and Maltese, A. 2010. First report of a heteromorph ammonite, cf. Glyptoxoceras, from the Smoky Hill Chalk (Santonian) of western Kansas, and a brief review of Niobrara cephalopods. Kansas Academy of Science, Transactions 113:(1-2):64-70.

Green, R.G. 1977. Niobrarateuthis walkeri, a new species of teuthid from the Upper Cretaceous Niobrara Formation of Kansas. Journal of Paleontology 51(5):992-995.

Hattin, D.E. 1982. Stratigraphy and depositional environment of the Smoky Hill Chalk Member, Niobrara Chalk (Upper Cretaceous) of the type area, western Kansas. Kansas Geological Survey Bulletin 225, 108 pp.

Hasenmueller, W.A. and Hattin, D.E. 1985. Apatitic connecting rings in moulds of Baculites sp. from the middle part of the Smoky Hill Member, Niobrara Chalk (Santonian), of western Kansas. Cretaceous Research 6(4):317-330.

Jeletzky, J.A. 1955. Belemnitella praecursor, probably from the Niobrara of Kansas, and some stratigraphic implications. Journal of Paleontology 29(5):876-885, 1 fig.

Jeletzky, J.A. 1961. Actinocamax from the Upper Cretaceous Benton and Niobrara Formations of Kansas. Journal of Paleontology 35(3):505-531, pl. 72, 6 figs.

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Lehmann, U. and Kulicki, C. 2007. Double function of aptychi (Ammonoidea) as jaw elements and opercula. Lethaia 23(4):325-331.

Logan, W.N. 1898. The invertebrates of the Benton, Niobrara and Fort Pierre groups. The University Geological Survey of Kansas, Part VIII, 4:432-518, pl. LXXXVI-CXX.

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Stewart, J.D. and Carpenter, K. 1990. Examples of vertebrate predation on cephalopods in the Late Cretaceous of the Western Interior. pp. 203-208 in Boucout, A.J. (ed.), Evolutionary Paleobiology of Behavior and Coevolution. Elsevier, New York.

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