CRETACEOUS AND TERTIARY FORMATIONS 519 



contact of the Fort Union and Lance beds is well shown in the 

 following section, exposed in a high bluff of the river: 



Feet Inches 



15. Shale, light gray and yellow, to top of bluff 16 



14. Shale, chocolate brown . 1 6 



13. Shale, light gray 6 



12. Shale, light yellow, soft, and readily crumbled 6 



11. Shale, light gray 15 



10. Coal 4 2 



9. Shale, gray 23 



8. Coal 2 



7. Shale 1 6 



6. Coal 31 



5. Shale, sandy, light gray 10 



4. Coal 1 6 



3. Sandstone, light gray, cross-bedded 25 



2. Shale, sandy, brown, with much iron 4-6 



1. Sandstone, soft, yellow, with concretions and some thin limoni- 



tic streaks, exposed above river 50 



163 9 



Nos. 1,2, and 3 of the above section belong to the Lance for- 

 mation, while the other members are Fort Union. As is the case 

 at a number of points, a coal bed (No. 4) occurs at the contact, 

 and there are also two workable beds above this. The upper 

 sandstone of the Lance formation extends down the river seven 

 or eight miles below this section, forming in many places vertical 

 cliffs rising from the water's edge. Then a dark shale appears 

 beneath the sandstone as shown in the following section, which 

 is seen about ten miles below the previous one, in sees. 29 and 

 30, T. 133 N., R. 88 W.: 



Feet 



5. Sandstone, soft, yellow, to top of bluff 20 



4. Shale, dark gray to black, alternating with thin-bedded, shaly sand- 

 stone 15 



3. Shale, dark gray to black, when moist 70 



2. Sandstone, yellow, with hard ledge near top 20 



1. Shale, dark gray to black, sandy, exposed above river 25 



ISO 

 Only twenty feet of the upper sandstone of the Lance formation 

 appear at this point, and the bluffs are here formed largely of the 

 underlying black shale. 



