Fossils

Swimming Reptiles: Mosasaurs / Plesiosaurs / Turtles

Flying Reptiles: Pteranodons

Bony Fish: Xiphactinus / Gillicus / Saurodon / Pentanogmius / Pachyrhizodus / Cimolichthys / Apsopelix / Enchodus / Ichthyodectes / Protosphyraena

Sharks: Cretoxyrhina / Squalicorax / Ptychodus / Rhinobatos

Invertebrates

Crinoids: Uintacrinus

Clams & Oysters: Inoceramus / Rudistes / Ostrea congesta

Cephalopods: Spinaptychus & Rugaptychus / Niobrarateuthis bonneri

Birds: Hesperornis / Ichthyornis

Other Niobrara fossils: Coprolites / Fossil Tree

Other Resources: Geology of Western Kansas / Bonner Fossil Hunters / Oceans of Kansas (off-site)

Origins of the Mosasaur

First found in the chalk of Maastrict, Netherland in 1778, this mosasaur was thought to be the gigantic skull of a crocodile, but later and subsequent research showed this was actually a representative from an extinct group of lizards. This specimen was the first fossil specimen to be described as an extinct creature—other fossil species had been found, but were erroneously described as animals still living.

W. D. Conybeare, an English geologist, first proposed the name mosasaur, meaning “marine serpent-like reptile.”

Mosa: Latin for Meuse river
Sauros: Greek for lizard

Drawing of Meuse River, location of the first mosasaur found.

Drawing of the Meuse River type specimen.

Soldiers collecting the specimen in the Meuse River cave.

Cave entrance in Maastrict.

Pictures from:

Histoire Naturelle de La Montagne de Saint-Pierre De Maestricht, by Faujas-Saint-Fond, Professor of Geology, National Museum of History Paris, 1799.

Thanks to William Ashworth and Bruce Bradley at the Linda Hall Library in Kansas City, Missouri for letting us hold, photograph, and turn the pages of this rare book.