434 Marsh — Jurassic formation on the Atlantic Coast. 



The Atlantosaurus Beds. 



The extensive fresh-water deposits of Jurassic age, that lie 

 over the marine strata at Como, I have called the Atlantosaurus 

 beds, from a gigantic Dinosaur especially characteristic of the 

 horizon. Other Dinosaurs, large and small, and a great num- 

 ber and variety of vertebrate fossils, — mammals, birds, reptiles, 



and fishes, I have, likev^^ise secured from this locality and at 

 several other points in the same horizon, chiefly in Wyoming 

 and Colorado. Among these extinct forms, the gigantic 

 Saurojpoda, the largest of all land animals, are the most won- 

 derful, and are known only from the Jurassic. They are 

 therefore of special value as evidence of geological age. 



