5.4" Fossil Turtle (Toxochelys) Femur - Smoky Hill Chalk

This is a 5.4" long femur of the Cretaceous aged, marine turtle Toxochelys from the Smoky Hill Chalk of Kansas. It's still embedded in the chalk matrix in which it was found.

Toxochelys is an extinct genus of marine turtle from the Cretaceous period It is the most commonly found fossilized turtle species in the Smoky Hill Chalk, in western Kansas. Toxochelys was about 2 m (6 ft) in length. There are five known species in the genus: Toxocheys bauri, Toxochelys browni, Toxochelys latiremus, Toxochelys weeks, and Toxochelys moorevillensis. Phylogenetic analysis shows that Toxochelys belong to an extinct lineage of turtles transitional between modern sea turtles and other turtles.

The Smoky Hill Chalk Member of the Niobrara Chalk formation is a Cretaceous conservation Lagerstätte, or fossil rich geological formation, known primarily for its exceptionally well-preserved marine reptiles. It outcrops in parts of northwest Kansas, its most famous localities for fossils, and in southeastern Nebraska. Large well-known fossils excavated from the Smoky Hill Chalk include marine reptiles such as plesiosaurs, large bony fish such as Xiphactinus, mosasaurs, flying reptiles or pterosaurs (namely Pteranodon), flightless marine birds such as Hesperornis, and turtles. Many of the most well-known specimens of the marine reptiles were collected by dinosaur hunter Charles H. Sternberg and his son George.