UGA Stratigraphy Lab

The data is in the strata

• Fossils and Strata
  of the Sundance Seaway
• Fossils
• Stratigraphy
• References
• Acknowledgments

Cephalopoda

Ammonitida

Superfamily Stephanoceratoidea

Family Stephanoceratidae: Evolute, planulate, ribbed, with tubercles and branching ribs.

• Stephanoceras (Stephanoceras)
• Stephanoceras (Stemmatoceras)

Family Otoitidae: Evolute, strong primary ribs that bifurcate, with subdued tubercles.

• Normannites

Family Kosmoceratidae: Round whorled, mesovolute (Kepplerites) to evolute (Kosmoceras), with branching ribs

• Kepplerites
• Kosmoceras

Family Sphaeroceratidae: Sphaerocones and cadicones (very wide and squat); involute and highly inflated inner whorls. Ribs persist to end of growth. Dimorphs differ only in size.

• Chondroceras
• Eocephalites
• Parachondroceras
• Sohlites
• Warrenoceras
• Megasphaeroceras
• Paracephalites
• Lilloettia
• Xenocephalites

Family Cardioceratidae: Commonly dimorphic. Wide variation in shell inflation.

• Subfamily Arctocephalinitinae: involute, inflated, with rounded umbilical edge, sharp primary ribs that bifurcate.
• Arctocephalites
• Arcticoceras
• Subfamily Cadoceratinae: inner whorls compressed and involute, sharp ribs that bifurcate and strongly sweep forward toward venter, inflated with craterlike umbilicus
• Cadoceras
• Subfamily Cardioceratinae: keeled, at least on inner whorls, or with ribs that form angular chevrons on venter. Wide morphological variation in any horizon.
• Quenstedtoceras
• Cardioceras (Scarburgiceras)
• Cardioceras (Cardioceras)
• Cardioceras (Goliathiceras)
• Scoticardioceras
• Vertebriceras
• Cawtoniceras

Superfamily Spiroceratoidea

Family Spiroceratidae: Openly coiled, becoming loosely curved or straight, strongly ribbed.

• Spiroceras

Superfamily Perisphinctoidea

Family Perisphinctidae: Evolute and planulate, with ribbing that splits towards venter, not keeled.

• Procerites
• Grossouvria
• Perisphinctes (Prososphinctes)

Belemnitida

• Pachyteuthis

Comments or questions? Please contact Steven Holland at stratum@uga.edu

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.