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State Fossils

Kansas was once covered by a shallow sea called the Western Interior Seaway. The warm ocean was home to many plants, huge fish, swimming birds, and reptiles. Some of the creatures found in the sea were as long as the width of a basketball court. Some fish had enormous mouths that opened 8 feet high. Evidence of the marine animal fossils can be found in Kansas rocks. Clams and oysters, fish and sharks, and even reptiles have been found in fossilized form.

On April 4, 2014, the Tylosaurus became the official state marine fossil and the Pteranodon the official state flying fossil.

Tylosaurus image courtesy Kansas Geological SocietyThe Tylosaurus is a giant mosasaur, which inhabited the sea that covered portions of Kansas during the Late Crestaceous period and grew to lengths of more than 40 feet. With a name meaning “large protuberance” or snout, it weighed as much as seven tons. The Tylosaurus dominated most other sea creatures. With its narrow and water dynamic body, the creature had a blunt and powerful head it used to ram into prey. The Tylosaurus was fitted with agile flippers, fins, and a long tail. In 1918 Charles H. Sternberg discovered a specimen in Logan County with the fossilized remains of an unidentified plesiosaur in its stomach.This large, predatory marine lizard is closely related to modern monitor lizards and to snakes.

Photo courtesy Sternberg Museum in Hays The Pteranodon is a great, winged pterosaur with a wingspread of more than 24 feet. Meaning “wing without tooth, this large creature flew the skies of Kansas during the Late Crestaceous period.These reptiles hadlarge heads and wingspans, but small bodies and tails.Most of the known Pteranodon remains come from the Smoky Hill Chalk of west Kansas. Paleontologists believe that these flying reptiles were either feeding on ocean creatures or were migrating across the sea. It would not be uncommon for the weak or old to die during a long flight.

We can trace of much of the early discoveries of fossils to the work of George F. Sternberg who came from a family of fossil hunters. When he was only nine years old he wandered away from his father’s excavation in Gove County and discovered a plesiosaur skeleton. One of Sternberg’s most famous discoveries is the Xiphactinus “fish within a fish” fossil.

The state statutes read:

73-3301. State marine fossil. Tylosaurus, a giant mosasaur which inhabited the great inland sea that covered portions of Kansas during the cretaceous period of the mesozoic era and grew to lengths of more than 40 feet, is hereby designated as the official marine fossil of the state of Kansas.

73-3401. State flying fossil. Pteranodon, a great, winged pterosaur with a wingspread of more than 24 feet, which flew the skies of Kansas during the cretaceous period of the mesozoic era, is hereby designated as the official flying fossil of the state of Kansas.

Entry: State Fossils

Author: Kansas Historical Society

Author information: The Kansas Historical Society is a state agency charged with actively safeguarding and sharing the state's history.

Date Created: April 2014

Date Modified: June 2021

The author of this article is solely responsible for its content.