Platycarpus ictericus, mosasaur skull Kentrosaurus William Winkley discovered Pachycephalosaurus in

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

Saltasaurus Sauropod Dinosaur Egg

The life span for these three lakes was over 17 million years for Lake Uinta about 6 million years for Lake Gosiute

all in the Ischigualasto Basin

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