1 6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 98 



One species, Kootenia bearensis, is described from the isolated 

 outcrop of the Langston formation in Laketown Canyon (loc. I9x). 



THE LANGSTON FORMATION 



The Ptarmigania fauna was regarded as fully representative of the 

 Langston formation until Deiss (1938) questioned the validity of 

 Walcott's determination of the Spence shale in Blacksmith Fork and 

 the correlation of the thin fossiliferous limestone in the Two Mile 

 Canyon and Liberty sections, immediately under the Spence shale, 

 with the Langston at its type locality. If it were not for the great 

 difference in thickness no question concerning the identity of the 

 Ptarmigania beds with the Langston formation would have been 

 raised. As the matter now stands two alternative interpretations are 

 possible. First, we may assume as Walcott did, that the Langston 

 formation is discontinuous but that it appears in the known sections, 

 at some places attaining a thickness of 670 feet. The second alternative 

 assumes that the Langston is absent in the northern part of the region 

 and that the thin fossiliferous limestones occupying its stratigraphic 

 position are lenses or bioherms in the base of the Ute, closely 

 associated in origin with the Spence shale, or in the top oi the 

 Brigham. Determination of which is the more satisfactory interpre- 

 tation requires careful field work, with tracing of the formation at 

 least far enough to find out whether thickening of the fossiliferous 

 limestone takes place southward. Pending field examination, and in 

 preparation for it, we can examine the faunal evidence bearing on the 

 problem. 



All observers agree that the basal quartzite is the same formation 

 throughout the region. However, if the Langston is absent in the 

 northern part of the area, then the quartzite there may be somewhat 

 younger, at least in part. All observers also agree that the Ute forma- 

 tion extends over the entire region, and everywhere has the same 

 lithologic expression, and is characterized by the same faunas. There- 

 fore, as previously stated, the question is whether the 6 to 30 feet of 

 fossiliferous limestone in Two Mile Canyon and on Mill Creek near 

 Liberty are thin equivalents of the Langston formation, which is 

 from 500 to 650 feet thick in Blacksmith Fork and 375 feet near 

 Garden City. Locally it does not make any difference how this 

 question is determined but its proper understanding does have wide 

 significance for precise correlation beyond the immediate region. 



Lithology is without significance because the crystalline limestones 

 containing the Ptarmigania fauna are of types common in typical 





