92 C. A. White — On the Bear River Formation, etc. 



Bear River strata rest upon, or hold the same relation to, the 

 equivalent of the Fox Hills group of Meek & Hayden's Upper 

 Missouri section that the true Laramie is known to do. 



The object of this article, and of the immediately following 

 one by Mr. T. W. Stanton, is to show that the strata which 

 have hitherto been known as Bear River Laramie are not only 

 not referable to the Laramie formation but that they occupy a 

 lower position, being overlain by marine Cretaceous strata the 

 equivalents of which are known to underlie the true Laramie. 

 For this reason I shall in this, and in future writings, designate 

 these strata as the Bear River formation, omitting the term 

 Laramie in that connection as being wholly inapplicable. 



The following remarks are offered as a brief historical 

 account of the growth and prevalence of opinion concerning 

 this interesting group of strata, which is paleontologically so 

 different from any other known Xorth American formation. 



The first published account of these strata was given by 

 Messrs. F. B. Meek and Henry Engelmann jointly in I860 ;* 

 and later in the same year Mr. Meek published descriptions of 

 some of the fossils which characterize them.f In these publi- 

 cations both authors unhesitatingly assign the strata in ques- 

 tion to the Eocene Tertiary. 



J^o other publication concerning them seems to have ap- 

 peared until 1869, when Dr. F. Y. Hayden inserted a para- 

 graph concerning them in one of his official reports;}: upon 

 another region, in which he expressed the opinion that they 

 are of Tertiary age and proposed to group them together with 

 the coal-bearing strata of the Sulphur Creek section, those 

 near Evanston and those at Coalville, Utah, as constituting one 

 formation to which he gave the name of Bear River group.§ 



In 1870 Dr. Hayden published a short article containing a 

 minute description, accompanied by figures, of the non marine 

 strata originally discovered by Mr. Engelmann in which publi- 

 cation he continued to assign them to the Tertiary.|| 



In the same volume, and immediately following the article 

 of Dr. Hayden just mentioned, Mr Meek catalogued and de- 

 scribed a number of new species of fossils among which are 

 some that were obtained from the Bear River formation at and 

 near the originally discovered locality. These Mr. Meek as- 

 signed to the Tertiary without comment or qualification. 



*Proc. Acad. Nat. Sci. Philad , vol. xii, pp. 126-131. 



f Proc. Acad. Xat. Sci. Philad.. vol. xii, pp. 308-315. 



\ Preliin. Rept. U. S. Geol. Surv. Colorado and Xew Mexico, p. 91. 



§ The Bear River group as proposed by Dr. Hayden embraced strata belonging to 

 three separate formations. I retain the name for only those which pertain to one 

 of them. That is, for those to -which the name •' Bear River " has been most 

 generallv applied. 



|| Proc. Am. Philos. Soc, vol. xi, 1870. pp. 420-425, pi. 12. 



