The Smoky Hill Chalk Member of the Niobrara Chalk formation is a Cretaceous

Cretaceous

The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

 conservation Lagerstätte

Lagerstätte

A Lagerstätte is a sedimentary deposit that exhibits extraordinary fossil richness or completeness.Palaeontologists distinguish two kinds....

, or fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 rich geological formation, known primarily for its exceptionally well-preserved marine reptile

Marine reptile

Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semi-aquatic life in a marine environment.The earliest marine reptiles arose in the Permian period during the Paleozoic era...

s. The Smoky Hill Chalk Member is the uppermost of the two structural units of the Niobrara Chalk. It is underlain by the Fort Hays Limestone Member; and the Pierre Shale

Pierre Shale

The Pierre Shale is a geologic formation or series in the Upper Cretaceous which occurs east of the Rocky Mountains in the Great Plains, from North Dakota to New Mexico....

 overlies the Smoky Hill Chalk. The Smoky Hill Chalk outcrop

Outcrop

An outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. -Features:Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial deposits are covered by a mantle of soil and vegetation and cannot be...

s in parts of northwest Kansas

Kansas

Kansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...

, its most famous localities for fossils, and in southeastern Nebraska

Nebraska

Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....

. Large well-known fossils excavated from the Smoky Hill Chalk include marine reptiles such as plesiosaur

Plesiosaur

Plesiosauroidea is an extinct clade of carnivorous plesiosaur marine reptiles. Plesiosauroids, are known from the Jurassic and Cretaceous Periods...

s, large bony fish

Osteichthyes

Osteichthyes , also called bony fish, are a taxonomic group of fish that have bony, as opposed to cartilaginous, skeletons. The vast majority of fish are osteichthyes, which is an extremely diverse and abundant group consisting of over 29,000 species...

 such as Xiphactinus

Xiphactinus

Xiphactinus was a large, 4.5 to 6 m long predatory bony fish that lived in the Western Interior Sea, over what is now the middle of North America, during the Late Cretaceous. When alive, the fish would have resembled a gargantuan, fanged tarpon...

, mosasaur

Mosasaur

Mosasaurs are large extinct marine lizards. The first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764...

s, flying reptiles or pterosaur

Pterosaur

Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...

s (namely Pteranodon

Pteranodon

Pteranodon , from the Late Cretaceous geological period of North America in present day Kansas, Alabama, Nebraska, Wyoming, and South Dakota, was one of the largest pterosaur genera and had a maximum wingspan of over...

), flightless marine birds such as Hesperornis

Hesperornis

Hesperornis is a genus of flightless aquatic birds that spanned the first half of the Campanian age of the Late Cretaceous period . One of the lesser-known discoveries of the paleontologist O. C. Marsh in the late 19th century Bone Wars, it was an important early find in the history of avian...

, and turtle

Turtle

Turtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield...

s. Many of the most well-known specimens of the marine reptiles were collected by dinosaur hunter Charles H. Sternberg and his son George

George F. Sternberg

George Fryer Sternberg was a paleontologist best known for his discovery in Gove County, Kansas of the "fish-within-a-fish" of Xiphactinus audax. He was the son of Charles Hazelius Sternberg and nephew of Brig. Gen. George M. Sternberg...

. The son collected a unique fossil of the giant bony fish Xiphactinus audax with the skeleton of another bony fish, Gillicus arcuatus

Gillicus arcuatus

Gillicus arcuatus was a relatively small, 2-metre long ichthyodectid fish that lived in the Western Interior Seaway, in what is now central North America, during the Late Cretaceous. Like its larger relative, Ichthyodectes ctenodon, G...

inside the larger one. Another excellent skeleton of Xiphactinus audax was collected by Edward Drinker Cope

Edward Drinker Cope

Edward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen...

 during the late nineteenth century heyday of American paleontology and its Bone Wars

Bone Wars

The Bone Wars, also known as the "Great Dinosaur Rush", refers to a period of intense fossil speculation and discovery during the Gilded Age of American history, marked by a heated rivalry between Edward Drinker Cope and Othniel Charles Marsh...

.

External links

• Everhart, M., nd, Oceans of Kansas Paleontology web page
• Everhart, M., nd, Remains of young mosasaurs from the Smoky Hill Chalk
• Everhart, M., nd, Marine turtles from the Smoky Hill Chalk and Pierre Shale