NO. I LOWER EOCENE MAMMALIAN FAUNAS — GAZIN 7 



The foregoing, together with a recent decision (Feb. 24, i960) of 

 the Geologic Names Committee of the U. S. Geological Survey to 

 recognize "Wasatch formation" in preference to "Knight formation" 

 for the concerned beds in southwestern Wyoming, has led me to re- 

 vise usage in this paper from that adopted in my 1952 and 1959 reports 

 on the faunas, complying to this extent with nomenclature henceforth 

 to be used by the U. S. Geological Survey. The term Knight, how- 

 ever, I have retained in this study to designate a member of the 

 Wasatch formation. It is restricted from my earlier usage in the Green 

 River and Washakie Basins to include only the lower Eocene portion 

 of the Wasatch that is beneath the Tipton tongue (see fig. 2), exclud- 

 ing the Cathedral Bluffs tongue of the Wasatch and its equivalent 

 New Fork tongue. 



The type section of the Knight, as defined by Veatch, is in the Fossil 

 Basin; and the unit in this general area has been demonstrated to 

 include beds from lowest Eocene to at least as high as Lysite, but 

 whether or not strata of Lost Cabin equivalence are present has not 

 been shown. The sequence does involve these later beds in the Green 

 River and Washakie Basins and hence does not appear to be en- 

 tirely equivalent. Nevertheless, the two sequences are essentially con- 

 tinuous to the east of Evanston and there would seem to be no logical 

 reason for separate designation in any of the complex of adjoining 

 basins having contiguous early Eocene deposition in the southwestern 

 part of the State. 



Wasatchian. — Although recognizing the term "Wasatch" to be 

 variously misused and adopting it only as a group term, the Society 

 of Vertebrate Paleontology's committee on Nomenclature and Cor- 

 relation of the North American Continental Tertiary in 1941 (Wood, 

 et al.) proposed and defined the term "Wasatchian" as an arbitrary 

 time or age designation to include the lower part of the Eocene, older 

 than Bridgerian or middle Eocene. The term "Wasatchian" is clearly 

 limited by definition to the Eocene and is not intended to include the 

 Paleocene portion of time that seems evident for earlier strata that 

 might be included in the Wasatch formation. 



Green River formation. — W. H. Bradley in 1959 revised the strati- 

 graphic nomenclature of the Green River formation in Wyoming. 

 Recognizing that the "Laney" of the Bridger Basin interfingered with 

 the Cathedral Bluffs tongue northeast of White Mountain and was 

 hence stratigraphically older than the type Laney in the Washakie 

 Basin which overlies the type Cathedral Bluffs, he gave the new name 

 "Wilkins Peak" member to the "Laney" of the Bridger Basin. At 



