same deposits. Numerous small mammals, also of ancient types, a few birds, and many fishes, are like- 

 wise entombed in this formation. Invertebrate fossils and plants are not uncommon in the same horizon 

 . . . -. (p. 203). Besides these there were still others related to the Jurassic Stegosaurs, among them the 

 NodosatiridcB, quadrupedal forms heavy dermal armor." 



These quotations show that the marine, fresh-water and terrestrial fauna, fishes, 

 plesiosaiirs, as well as stegosaurs were all included by Marsh in the Laramie fauna of the 

 " Ceratops Beds " in general, which name, in fact, he assigned from the Montana type, 

 Ceratops montanus. The eastern Wyoming (Converse county, where the great collection 

 of Triceratops skulls was made by Hatcher), the western "Wyoming (Bitter Creek) Laramie 

 (where Agathaumas, Cope, was found), the Colorado (Denver beds, where PoJyonax, 

 Cope and Ceratops alticornis were found), and the Montana (Judith Eiver and supposed 

 Fort Union), are all treated by this author as of the same age, namely. Upper Cretaceous. 



The confusion has been rendered greater in the early references of some of the Mon- 

 tana fossils to the Fort Union beds. A year after Cope's original description of his " Fort 

 Union " collection he transferred them to the Judith Eiver, in his paper on the " Geology 

 of the Judith River beds." The Ft. Union beds have been considered late Cretaceous or 

 on the border land between Cretaceous and Tertiary. In 1874-5, G. M. Dawson published 

 several papers expressing the opinion that they are Eocene. L. F. Ward referred the Ft. 

 Union beds to the Upper Laramie, from its flora ; on the same ground Newberry placed 

 it above the Laramie in the Tertiary. Quite recently Mr. Earl Douglas has made the 

 very fortimate discovery in these beds of basal Eocene mammals of Puerco (Thanetien 

 Montien) age. The reference of Montana dinosaurs to Fort Union beds is, therefore, an 

 error. 



It remains to be determined, therefore, whether all the fossils recorded from Montana 

 are actually from Judith EiA'er beds, or whether a portion at least of the beds described 

 and collected in as " Judith River " are not older than the Laramie. 



Provisional Correlation 



Fresh-water 



Brackish & fresh-water 



Paskapoo'^. 

 (No dinosaurs) 



Edmonton. 



Ft. Union-. 



Laramie & Judith 

 River. 



Triceratops, Torosaurus, 

 Dryptosaurus, Ornithomimus. 



Marine ... •< 



Pierre- Fox 

 Hills group. 



Fox Hills, 

 Fort Pierre. 









Fresh and brackish -water. . . 

 Sandy clays and sandstones. 



Belly River. 

 910 feet. 



Montana exposures 



in part. 

 (Niobrara). 



Stereocephalu.'s, Mouoclonius. 

 Ceratops, Trachodon, Deinodon, 

 Ornithomimus, Compsemys, 

 Ptilodus. 





Ft. Benton. 



Ft. Benton. 

 Dakota. 





'. Regarded by Tyrrell as the beginning of the Tertiary. 

 ". Mammals of Puerco type discovered by Douglas in 1901. 



