Mitchell’s Monster

Mitchell’s Monster – The Plesiosaur (Plee-see-uh-sawr)

Once upon a time, (80 -90 million years ago) all of Eastern Oregon including the area around Mitchell, was on the bottom of an ocean called the Cretaceous Sea.  There, below the surface, a giant 25 -40 foot monster was swimming and hunting in an underwater world –
the Plesiosaur, also called the Tiger of the Cretaceous Sea.

The Plesiosaur was a carnivorous aquatic reptile – a swimming Dinosaur – with a large body, long neck, shorter tail, and four flippers that it used like blades to cut through the water and propel itself forward. Recent studies of Plesiosaur paddles have shown that, instead of being pulled back and forth like oars on a rowboat, they were ‘flapped’ up and down much like the wings of a bird or the paddles of a marine turtle.  The plesiosaur seemed to have „ flown through the water like a modern penguin“ It had a U shaped jaw with ferocious backward curving teeth, each at least one inch in size perfect for attacking its prey. Its tail was probably used to stabilize the body and help navigate. With these anatomic features the Plesiosaur was well adapted for life in the ocean and was one of the most powerful predators of its times.

From the recent finding of a fossilized Plesiosaur with an intact 6 foot fetus inside it could be concluded that these giant sea creatures gave birth to one live offspring just like whales or dolphins, instead of laying eggs like other reptiles.

In 2003 evidence for the existence of the monster in this particular area of Eastern Oregon, a fossilized lower jaw-bone, was found a few miles out of Mitchell by two amateur paleontologists.

Fossils of different types of Plesiosaurs have been found on all continents making it a large and varied group with two distinct species, the longer necked small-headed plesiosaur and the shorter necked large-headed plesiosaur. The Mitchell Monster was one of the latter which was determined from the dug up fossil.


In 2009 a 12 foot sized replica of the Plesiosaur was build by metal artist Larry William together with students of the Mitchell High School in a special project coordinated and funded by the Oregon Paleo Lands Institute (OPLI) thru different grants. This remarkable sculpture is still exhibited in the OPLI in the city of Fossil, about 40 miles from Mitchell. At this time Mitchell’s chamber is planning to raise funds to create Mitch, a 6 foot cement replica of a Plesiosaur for their city park.

If you would like to learn more about Plesiosaurs head over to www.Plesiosauria.com