KEGION liJORTH OF GRANITE MOUNTAIN. 711 



west side of the fold. The summit of Dun Glen Pass is formed of a highly 

 altered quartzose rock, with a strike of north 10° east and a dip of 75° to 

 80^ to the west, which is overlaid by heavy beds of dark bluish-gray 

 limestone, still dipping west, but with a much less angle of inclination. 

 From here westM^ard, the structure in places is very obscure and complicated, 

 the beds showing considerable displacement, but in general possessing a 

 westerly dip, with much the same series of strata exposed as seen in Willow 

 and Inskip Canons, together with the overlying slates and fissile shales of 

 the Jurassic strata. North of Rose Canon, and near its head, the Triassic 

 limestones are well developed, lying at a gentle angle, and exposing several 

 hundred feet of Star Peak beds. South of Dun Glen Pass, these same 

 limestones form the summit of the ridge, with a dip of 80° to the westward. 

 The only organic remains procured from the Pah-Ute Range were 

 found in dark limestones in the region of Dun Glen Pass, and to the south- 

 ward for one and one-half to two miles, along the main ridge. 



The following forms, collected by our parties, have been described by 

 Prof. R. P. Whitfield: 



Pentacrinites asteriscus. 



Spiriferina Homfrayi. 



Spirifera (Spiriferina?) alia, n. sp 



Terehratula Humholdtensis. 



JEdmondia Myrina, n. sp. 



Of these forms, P. asteriscus is generally regarded as a well-defined 

 Jurassic species, at least in the Rocky Mountain region east of the Wah- 

 satch Range, but here it is associated with Spiriferina Homfrayi and Tere- 

 hratula Humholdtensis, species clearly recognized as belonging to the Star 

 Peak beds in the West Humboldt Range. It should be stated also that 

 these disks of Pentacrinites found in the Dun Glen limestone vary somewhat 

 from the type-specimens, and are all of larger size, reaching one-fourth of 

 an inch in diameter, while those of Jurassic age scarcely reach one-fifth of 

 an inch. Professor Whitfield suggests that the Dun Glen variety may 

 possibly be a new species. 



This association of a Jurassic form with those of Triussic age is of special 

 interest, because the Spirifera alia, also found here, is, in some respects, 



