112 T. W. Stanton — Stratigraphic Position 



supplements the preceding one as it shows the beds east of the 

 synclinal fold. 



Beginning at the river the following beds are exposed in 

 descending order. (See Section 4). 



Section" on the East Side of Smith's Fork. 



1. Bear River formation. 



Bluish argillaceous and calcareous shales with occa- 

 sional thin beds of gray sandstone. Fossils are 

 abundant especially in the upper half. There are 

 also a few fossils (a small Gasteropod and nutlets of 

 Chara) at the base. Dip 55° to 60° west. Thick- 

 ness about . 3000 ft. 



2. Dakota? 



Brown pebbly conglomerates and coarse sandstones 

 alternating with covered spaces. Total thickness 

 about 500 ft. 



3. Jurassic? 



A space nearly a mile wide that is mostly covered but 

 the surface debris and numerous small exposures 

 indicate that it is underlain by reddish brown sand- 

 stones and sandy shales. Dip 55° or 60° west. 

 Thickness.. 3000 ft. 



4. Jurassic. 



Greenish gray laminated calcareous sandstone 100 ft. 



Blue and gray calcareous shales. Thickness undeter- 

 mined. 

 No. 4 is the " Pentacrinus Beds" of Dr. Peale's general sec- 

 tion* of the Jura-Trias in this region. 



Five miles farther north a part of the section on the west 

 side of the stream was measured. The river is here in a syn- 

 clinal valley as it was at the preceding section, but it cuts 

 across the strata at a low angle so that near Cokeville it has 

 passed west of the syncline and cuts through an anticlinal as 

 we have seen. (See Section 5.) 



Section on West Side of Smith's Fork. 



1. Dakota? 



Brown conglomerate and coarse sandstone, partly cov- 

 ered. It crops out on the crest and eastern slope of 

 the divide betw/en Smith's Fork and Thomas' Fork. 

 Dip 55° east. Thickness 500 or 600 ft. 



2. Bear River formation. 



Covered. Farther north this space was seen to con- 

 sist principally of shales with obscui'e Gasteropod 

 casts near the base and with TInio vestustus and Cor- 

 bicula durkeei at the top. Thickness 900 ft. 



* llth Ann. Rept. IT. S. Geol. Surv. Terr., p. 623. 



