Plesiosaur Tooth in Matrix Claw about 500 miles north-northwest of

about 500 miles north-northwest of Buenos Aries

Mosasaurs had huge

while dinosaurs are placed with modern reptiles and birds in the group Sauropsida

signifying the end of the Olenellus lineage

The Hell Creek Formation is an intensely-studied division of Upper Cretaceous to lower Paleocene rocks in North America

Plesiosaur Tooth in Matrix Claw about 500 miles north-northwest ofZarafasaura oceanis Late Cretaceous (~70 million years ago) Phosphate Deposits Oulad Abdoun Basin, Morocco Tooth approx. size: 1. 5" Matrix approx. size: 3" x 2. 5" x 2. 25" Plesiosaurs were marine reptiles that appeared in the Triassic and died out along with the dinosaurs at the end of the Cretaceous period. They had a broad flat body and a short tail. Their limbs were four powerful flippers that made a flying movement to propel the plesiosaur