244 DESCEIPTIVE GEOLOGY. 



Creek, by the red and chocolate beds of the Vermillion Creek series, with 

 no observed discrepancy of angle. 



From Quien Hornet Mountain eastward to Green River, the buff cal- 

 careous sandstones and limestones dip 5^ to the northward, with a non- 

 conformity of from 5° to 15° with the underlying Vermillion Creek Ter- 

 tiaries. These beds form the gateway of the canon of Green River, 

 at its entrance into the lower valley of Henry's Fork, dipping 5° to the 

 northward, while the underlying reddish sandstones and clays of the Ver- 

 million Creek series dip 10°. They are traced along the lower flat spurs 

 of Twin Buttes, between Green River and Henry's Fork, and, as exposed 

 in the valley of Henry's Fork, contain some lignitic seams, one of which is 

 of sufficient thickness to constitute a vein ef coal. To the west of Henry's 

 Fork, north of Deadman's Spring, they form low ridges, dipping 25° to 

 the north, made up of yellow sandstones and whitish limestones, carrying 

 casts of Goniohasis, and some interstratified shales. West of this point, they 

 are covered by the soft soil resulting from the decomposition of the Bridger 

 beds, no further outcrops having been observed on this side of the basin. 



On the western side of the basin, the beds of the Green River series have 

 been observed at comparatively few points. Near the railroad-station at 

 Piedmont are outcrops of white impure limestone and thin calcareous 

 shales, from which were obtained a few indistinct remains of fishes similar 

 to those found near Green River City. These outcrops are isolated by the 

 Quaternary accumulations of Muddy Creek ; but their geological horizon 

 is sufficiently indicated, both by their lithological character and their posi- 

 tion between the horizontal beds of the Bridger group, which form the 

 bluffs on the east of this valley, and the slightly-inclined chocolate and red 

 sandstones of the Vermillion Creek series, which rise to the west. They 

 are represented to the northward by light calcareous beds, to the west of 

 Carter's Station, which are immediately succeeded to the westward by the 

 same underlying red and chocolate sandstones. They extend to the north- 

 ward in a line of low ridges, having a bluff exposure to the westward, and 

 in the desert plains to the north, where, though not traced continuously, 

 they occupy approximately the line of outcrop indicated on the map. 



Bridger Eocene. — The beds of this formation are found in their 



