280 PROCEEDINGS OF THE ACADEMY OF 



locality from 150 to 200 miles distant. So with the determinations 

 from Weber River (Coalville) 200 miles, and Evanston and Sulphur 

 Creek 150 miles distant, on the opposite side of the Bridger Basin. 

 He did not regard these as determinations affecting the age of the 

 Bitter Creek Beds any more than they did of the Eocene coal of 

 Osino, 200 miles west of them. 



The only approximations to the point were made by Mr. Meek. 

 In King's Survey of the 40th Parallel (1. c. 462),- Mr. Meek's 

 nearest points of investigation were the shell beds of Sulphur 

 Creek (Bear River) ; of these he says, " While I am, therefore, 

 willing to admit that facts may yet be discovered that will warrant 

 the conclusion that some of these estuary beds should be included 

 rather in the Cretaceous than in the Tertiary, it seems to me that 

 such evidence must either come from included vertebrate remains, 

 etc." This is not very conclusive, and acknowledges in advance 

 the importance of the determination of vertebrates from the same 

 neighborhood (Evanston), and from Bitter Creek, above described. 

 Secondly, in Hayden's Survey, 18T0, p. 298, the only determina- 

 tion of the age of coal of the Bitter Creek area is tertiary (Hall- 

 ville). Thirdly, in Hayden's Survey Montana, etc. (1871, p. 375), 

 Mr. Meek enumerates three species from this region (Point of 

 Rocks) as cretaceous, every one with question as to the determi- 

 nation, which, therefore, decides little as to the age of the beds. 

 In the same way all his Coalville species are marked with question. 

 In his earliest investigation in connection with Mr. Engleman, in 

 Capt. Simpson's Report (1860), he expressly states that the age 

 of the Bitter Creek coal series is unknown. 



Thus it seems that a knowledge of the literature of the geology 

 of the Bitter Creek coal, shows : I. The Messrs. King and Emmons 

 on stratigraphic evidence referred the lower part to the cretaceous 

 and the upper to the tertiary. That on Palreontological grounds, 

 II. Mr. Lesquereanx regards them as tertiary; III. Mr. Meek's 

 evidence is doubtful; 1 and, IV. Dr. Hayden has believed in a 

 transition series. 



Hence it appeared to the speaker, that the explorations directed 

 by Dr. Hayden during the past season had contributed largely to 

 our knowledge, proving the existence of an interruption between 

 the cretaceous and tertiaiy formations ; less it is true than that 

 which exists elsewhere, and similar to that insisted on by Clarence 

 King's survey in the region of Bear River and the Wahsatch 

 country. 



Prof. Cope defined a genus of Saurodont Fishes from the 

 Niobrara Cretaceous of Kansas, under the name of Erisichthe. 

 He stated that it agreed with Portheus and Ichthyodectes in the 

 absence of nutritious dental foramina on the inner face of the 



1 This gentleman has stated in a letter to the writer that the Bitter Creek 

 Beds constitute a "new zone." 



