Judith River / White River Fossils

The Judith River and White River formations are two rich fossil bearing formations in North America.  The Judith River formation in Montana and Alberta is famous for its Cretaceous dinosaur fossils, while the White River formation in Nebraska and South Dakota is renown for its Oligocene mammal fossils. 

All the Judith River fossils were expertly identified by Joseph LeBlanc of Calgary, Alberta.    Joseph has offers to help others with identification as well.   I have included Joseph's excellent article from the January issue of Fossil News about the Identification of Cretaceous dinosaur teeth, courtesy Lynne Clos, editor/publisher of Fossil News..  Check out Fossil News for other interesting articles about amateur paleontology.

Personally, I am still amazed how our knowledge of quite a few dinosaur species is based on meager remains, in some cases not much more than teeth. Unlike mammals, most dinosaur skulls are lightweight, with many large openings. Iin many cases the bones comprising the skull are held together by ligaments; as the remains decay, the skull falls apart. So while the skulls and teeth of mammals are the most commonly preserved part of the animal, skulls of dinosaurs are rarely preserved.  .

Many people are surprised by  the small teeth of dinosaurs, particularly those of herbivorous dinosaurs.  All I've seen are less than an inch long.  The carnivorous dinosaurs had larger teeth, but even these are not huge.

We are fortunate to be living in a great age of discovery for dinosaurs.  This is driven largely by the public's insatiable interest in them.  But so much remains to be known.  Doubtless numerous species lie undiscovered and unstudied.   Controversy still surrounds their warm/cold bloodedness, activity level (how fast?), posture (could sauropods rear up on their rear feet?), skin covering (which, if any were feathered?), and extinction (was an asteroid the whole story?).  By contrast, the mammals of the White River formation were well studied more than a half century ago.

Special thanks to my graphic artist sister, Sue Schaeffer, for her wonderful pen and ink illustrations (all illustrations except those on the Dinosaur Identification page). The illustrations may be freely copied and used by the public providing credit is given to Sue Schaeffer and her e-mail address included.

Thanks to Janet Miller and Gina Robbins for use of their scanners.  The smaller fossils were scanned directly on Janet's Mustek scanner; photos of the larger items were scanned on Gina's Canoscan scanner.

Please send comments, questions, and suggestions to Don Schaeffer

This page was last updated on 02/04/00.