C. A. White — On the Bear River Formation, etc. 97 



fossils of that formation are so referred to as to convey the 

 idea of its equivalency to the Laramie. From the latter date 

 to the year 1891, as already indicated, no direct reference to 

 the taxonomic position of these strata seems to have been pub- 

 lished. 



During the preparation of a Review of the North American 

 Cretaceous- Formations which was published in 1891, I found 

 it necessary to discuss the Laramie formation in that connec- 

 tion. While reviewing the literature and paleontology of that 

 portion of my subject, in connection with the results of my 

 personal visits to Bear River valley, I became convinced that 

 the Bear River formation is older than the Laramie,* and that 

 it would somewhere be found overlain by Cretaceous strata. 

 This opinion I expressed on page 153 of the work referred to. 



In connection with my official duties upon the U. S. Geo- 

 logical Survey during the past season Mr. Stanton accompanied 

 me to Bear River valley where we together reviewed its geol- 

 ogy up to the point where my previous investigations had 

 ceased. It being then impracticable for me to continue field 

 work I left him to pursue his investigations alone, and the fol- 

 lowing article prepared by him is the result. I need only add 

 that I regard as correct his conclusion that the Bear River 

 formation is not equivalent to the Laramie, but that it occupies 

 a position beneath the greater part, if not the whole, of the 

 equivalent of the Colorado formation of the marine Cretaceous 

 series. That is, instead of overlying the equivalent of the 

 Fox Hills group, or No. 5, of Meek & Ha'yden's Cretaceous 

 section, the Bear River formation underlies the equivalent of 

 the Fort Benton, or No. 2, of that section. 



It is known that certain strata exist in southern Utah in 

 which several of the characteristic species of the Bear River 

 formation occur. Their investigation in the near future, and 

 in the light of the newly ascertained facts which have just 

 been stated and referred to, is contemplated ; but because of 

 present want of sufficient knowledge of the relation of those 

 strata to other formations in that district they have not been 

 considered in the foregoing remarks. 



of some associated forms hitherto known. Proc II. S. National Museum, vol. v, 

 pp. 94-99, plates 3 and 4. 



A Review of the Non-marine Fossil Mollusca of North America. Third Ann. 

 Rep. TJ. S. Geol. Surv., pp. 411-550, plates 1-32. 



Contributions to Invertebrate Paleontologv. No. 4 ; Fossils of the Laramie 

 Group. Twelfth Ann. Rep. U. S Geol. Surv. Terr., Part I, pp. 49-103, pi. 20-30. 



The genus Pyrgulifera Meek and its associates and Congeners. This Journal, 

 vol. zxix. pp. 277-280. 



•BnlL'U. S. Geol. Survey, No. 82. 



