BLACKWELDER: new formations in WYOMING 419 



2. Limestone; buff to gray, weathering tawny brown; thin- 

 bedded, with uneven stratification 26 



1. Shale; gray micaceous shale, largely concealed by talus from 



above 95 



796 

 Flathead Sandstone 



Sandstone; with several beds of sandy shale in the upper 

 part about 200 



LEIGH DOLOMITE MEMBER OF THE BIGHORN DOLOMITE 



From the Teton Range eastward at least to the middle of the 

 Wind River Mountains and north into the Absaroka Range, the 

 massive member of the \vell-known Bighorn dolomite is overlain 

 by a thin but persistent layer which deserves special recognition. 

 In almost every section it is from 30 to 40 feet thick, and in 

 most, if not in all, localities it is I imited both above and below 

 by disconformities. A typical section from the west slope of 

 Dinwoody canyon, on the north side of the Wind River Range is 

 as follows: 



Darby formation (Devonian) 



Feet. 

 12. Basal laj^er a stratified breccia consisting of small bits of 

 cream-colored dolomite and pink chert in a gray dolomite 

 matrix. Base sharp and shghtly uneven 5.0 



Leigh dolomite memher of Bighorn dolomite 



11. Dolomite; pale gray, finely laminated. Contains ostracods 



and a few small moUusks 3.0 



10. Dolomite; thin lavender-gray. Surface checkered with 



cracks which are stained pinkish 5.6 



9. Dolomite; thin, lavender-gray. Rather massive. Contains 



a few ostracods 3.5 



8. Dolomite; massive and thin. Rather brittle and full of 



blind joints 5.1 



7. Shale; finely laminated, pink and maroon. Calcareous. ... 0.3 



6. Dolomite; pale gray, finely streaked and spotted with lav- 

 ender. Very brittle and full of cracka 0.9 



5. Shale; calcareous, light to dark red 0.2 



4. Dolomite; like No. 3, but Streaked and spotted with laven- 

 der ■ 4.0 



3. Dolomite; like No. 2, but beds 2 to 10 inches thick 3.5 



