578 EEPOET UNITED STATES GEOLOGICAL SURVEY. 



nearly 100 feet. There are several beds alongside of tlie main bed. 

 They stand almost on end, dipping slightly toward the east. In some 

 of the coaly slate I obtained fragments of Unio VetusUis, and a nnmber 

 of undeterminable shells which warrant reference to the Laramie Group. 

 There are tw^o claims located on the bed on the north side of the valley 

 and several on the south side. There is scarcely any doubt that this 

 coal-bed is the same as the one of Twin Creek, and that it should be 

 referred to the Laramie Group. The fossils obtained below are Jm^assic, 

 and there would appear to be but a small thickness of Cretaceous pres- 

 ent, if any, as the greenish-gray sandstones just above appear to be a 

 portion of the Laramie. Going farther east we find red conglomerates 

 outcropping on Smith's Fork above the bend, with an eastern dip. These 

 sandstones and conglomerates disappear beneath a broad terrace which 

 rises 241 feet above the level of the stream. Back of this terracQ, between 

 it and the hogbacks that extend along the range, there is a broad valley, 

 evidently one of the old river-beds for Smith's Fork. South of the bend 

 of the river this terrace does not exist, and the beds that underlie it 

 form a series of eastward-dipping hogbacks. These hogbacks are form ed 

 ©f the teddish and gray sandstones that outcrop farther north in the 

 valley of Smith's Fork. Beneath the sandstones are blue limestones 

 which rise on the range ; in one layer a large number of Camptonectes 

 Stygius, f were observed. These limestones are probably above those in 

 which fossils were obtained west of the coal opening. Below them are 

 the following beds forming the range : 



Blue limestones. 



Dark-red sandstones. 



Light-red sandstones. 

 - Eed limestones. 



Eed sandstones. 



Covered space reaching to the level of Pine Creek. 



Carboniferous limestones. 



The latter are on the east side of Pine Creek. The latter stream rises 

 east of the hogbacks, between them and the main ridge, which is the 

 continuation of the ridge east of Eock Creek. It joins Smith's Fork at 

 the bend. From the bend of Smith's Fork northward to the Forks is 

 about nineteen miles. The course from the Forks is somewhat west of 

 south. In the lower part of the valley, as we have seen, the river is 

 west of the synclinal. As we follow up the river we soon find it oc- 

 cupying the axis of the depression, and it flows between hogbacks 

 which have rather rounded outlines. The few outcrops noted are of 

 gray sandstones. To the westward are high, rolling hills and spurs from 

 the Sublette Eange. The only fossils found in the beds underlying the 

 hills nearest to the river were of the Bear Eiver Laramie Group. Just 

 below the Forks the course of the river is somewhat eccentric. After the 

 two forming streams unite, the river flows to the northwest for about 

 half a mile, when it turns to the southwest and comes out into the valley 

 that continues southward. The two branches join in a canon. Follow- 

 ing uj) this cailon we cross, first, the sandstones that form the hogback 

 along the east side of Smith's Fork. Below the sandstone are shales 

 with a coaly layer. Below are more sandstones and shales, and then a 

 conglomerate somewhat metamorx^hosed, or seemingly so. It is quartz- 

 itic and dark colored, with red and lighter colored pebbles. It has con- 

 siderable resemblance to the conglomerate of the Dalvota Cretaceous. It 

 dijjs to the westward at an angle of about 30°. E"o fossils were found 

 near it, neither just above it nor just below, so that its age remains 

 doubtful. Below there is a considerable thickness of shales and sand- 



