228 



GEOLOGY OF Tlll<: DENVEH BASIN. 



Ii i- probable thai tlu' lasl four species of this list occur also abun- 

 dantly in ilu' Arapahoe beds. ITrom this list il appears thai ven few species 

 oi % © restricted to either formation, even with the presenl imported knowledge 

 of thr fauna. 



Horuont from whui t»inod — All [he determinable species of verte- 



brates referred i<> above were found cither in the Arapahoe or Denver strata. 

 The better preserved ones came from thr Denver beds exposed in the 

 ravines tributary to tin' Platte River in <>r within a few miles of the city 

 <>\ Denver. Others wore found on the slopes of Green Mountain in the 

 outcrops ><\ the Denver beds, ami one at least came from Table Mountain. 



The io>siU assigned to the Arapahoe were neailv all obtained 1>\ Mr. 

 Eldridge, either direct!} embedded in the grits of this formation or in tho 

 gravel resulting from the surface disintegration of these Weds. The princi- 

 pal localities are north of Dear ('reek and west of the Platte Kiver. 



J n Since the description of the first repre- 



sentative of the Ceratopsidre 1>\ Professor Marsh, in L888, a large number 

 of allied dinosaurian forms and mauj associated vertebrate fossils of other 

 types have been discovered by him and grouped as the "Ceratops fauna." 

 It also appears that a number of tonus previously described l>\ ('ope 

 belong to this family of liorned dinosaurs. 



According to the statements of Pi'ofessor Marsh. Wyoming and Mon- 

 tana have yielded groat numbers of fossils assigned to the Ceratops fauna, 



In Wyoming most of the species were found in Converse Countv, near the 



eastern border oi die State, and in Montana the Judith River Basin has 

 produced a large number of the forms described 1>\ Marsh and Cope. 



As mentioned in describing the post-Laramio beds of the Animas 

 River, this region has yielded several dinosaurian types from strata not far 



below the I'uereo. These were described l>\ ('ope, as well as some similar 



forms from Bijou ('reek, aboul U> miles east of Denver, A representative 

 of the horned dinosaurs was also described in 1ST"-' 1>\ Cope, from Black 

 Butte, in Wyoming, under the name Agathaumas. This is now regarded 



l>\ both Cope and Marsh as allied to Ceratops. 



In association with the Ceratopsidre in these various localities are 

 representatives of Other dinosaurian families, and also crocodiles, turtles. 



