Platycarpus ictericus, mosasaur skull Kentrosaurus William Winkley discovered Pachycephalosaurus in

William Winkley discovered Pachycephalosaurus in 1938 on the family ranch outside of Ekalaka

The skull was set at an acute angle

Sinokannemeyeria fed by tearing plant material with the front of the snout

Baculites ("walking stick rock") is an extinct genus of cephalopods with a nearly straight shell

Saltasaurus Sauropod Dinosaur Egg

Platycarpus ictericus, mosasaur skull Kentrosaurus William Winkley discovered Pachycephalosaurus inMosasaurs were a group of predatory marine reptiles that were very successful during the Late Cretaceous Period. The first mosasaur fossils were found in the 1770's in a mine in the Netherlands, more than 50 years before the first dinosaur bones were found. Mosasaurs were among the first fossils recognized and scientifically described. "Mosasaur" means "reptile of the Meuse," a river near the quarry where mosasaurs were first found. Mosasaurs were