PE.VLE.] DESCRIPTIVE GEOLOGY BEAE RIVER AREA. 577 



the climate is somewhat cold. The western boundary of the valley is 

 the Boundary Eange, a range of comparatively low hills eroded from the 

 east edge of the Bear Lake Plateau. These hills are comi)osed of the 

 variegated Wahsatch conglomerates antl sandstones, bright red colors 

 predominating. They are rounded in outline, and rise some 1,000 to 

 1,400 feet above the valley, increasing in height toward the north. They 

 will be referred to again under the head of the Bear Lake Plateau. 



The western side of the broad valley is covered with gravel outside of 

 the immediate river-bottom. This gravel is derived from the weather- 

 ing of the conglomeritic sandstones of the A¥ahsatch Group. There are 

 few settlements in the Upi)er Bear Eiver Valley in our district. South 

 of our district, however, there are sevei'al towns, Eandolph and Wood- 

 ruff being tlie principal ones. 

 if 



smith's fork of bear eiver. 



Smith's Fork enters the Bear Eiver Valley from between two high 

 biittes in a valley less than half a mile wide. Side by side with it is a 

 small creek (Spring Creek) that rises in the ridge east of the bend of 

 Smith's Fork. Just below the point where the two streams come out 

 into the valley there is a small settlement called Coketown. The bufcte 

 on the south side of the gap was named Station Butte. Station 37 was 

 located on its summit. It is composed of Carboniferous limestones, rep- 

 resenting the axis of an anticlinal, which is v/ell shown in the opposite 

 butte, which was named Coketown Butte. The latter is really the south 

 end of the Sublette Eange. The strike is north, or perhax)s a little west 

 of north. The Carboniferous limestones are very sharply folded, stand- 

 ing on end in the centre of the fold and dipping 80° to the westward on 

 the west side. The foUomiig general section was made from the butte 

 eastward to the coal outcrop. The relations will be better appreciated 

 by a reference to the accom])anying j)late, where the section from Bear 

 Eiver eastward across the bend of Smith's Fork to the range is given. 



Section 24, on north side of Smith's Fork. 



1. Massive grayish-blue limestones ) 



2. Blue limestones > 800 feet. 



These two layers comprise a thickness of EOO to 800 feet ) 



3. Space covered ^ 



4. Brown shales, calcareous 



5. Bluish-gray limestones, containing fragments of an indistinct 



Productus 



5. Gray limestones and calcareous shales near the top. The fol- } 500 to GOO feet. 



lovv^ing fossils were found: Aviciilopecten idahoensis, Osirea | 



-; ? Lingula Irevirostris? Mjiaciics ? They were | 



all fragmentary and identified w ith some doubt 



6. Grayish-brown limestones J 



7. Space covered with reddish debris ^ 



8. Blue limestone, containing the following fossils: Eumicrotis 



cnrtaf Lingula hrevirostris f Aviciilopecten f 



9. Covered space 



10. Grayish limestones 



11. Space covered by red and gray debris 



12. Greenish-gray sandstones 



13. Laminated grajy sandstones, with black slates 



14. Greenish-gray sandstones 



15. Coal 



1,500 to 1,800 feet. 



Total 2, 800 to 3, 200 feet. 



In bed ISTo. 14, which is rather a poor quality of coal, a shaft has been 

 sunk and a tunnel opened into the bed from below. The former is 80 

 feet deep and 7 feet in width. The tunnel is inclined and has penetrated 

 37 G s 



