508 Noble — Geology of the Grand Canyon, Arizona. 



Character Thickness 



25. Thin-bedded, crystalline, white limestone 5' 6" 



26. Gnarled and nodular, white, cherty limestone.. 7' 



27. Very hard, dense layer of flint forming small 



cliff 5" 



Total 105' 2" 



d. Blue slate and white limestone. 



1. Soft, purple shale 3' 6" 



2. Hard, blue slate forming small cliff _ 1 ' 



3. Fissile, blue slates with fine partings _ 7' 



4. Thin-bedded, purple, crystalline limestone 1' 2" 



5. Dense, purple, crystalline limestone forming a 



small cliff „ 7" 



6. Same as 4 __ 2' 2" 



7. Same as 5, forming small cliff 8" 



8. Thin-lamellar, spotted, blue slate 6' 6" 



9. Gnarly layers of fine-lamellar, blue calcareous 

 slate with a very coarse concretionary struc- 

 ture. Irregular nodules of chert occur in the 

 middle portion __ _ 33' 



10. Dense, blue, crystalline limestone forming small 



cliff 2' 3" 



11. Thin-bedded, platy, white limestone _ 2' 6" 



1 2. Very thin-lamellar, fissile, blue slate 3' 



1 3. Calcareous, blue slate forming a cliff 3' 



14. Thin-bedded t platy white limestone ._ _ _ 4' 6" 



15. Fissile, blue slate _ 7' 



16. Dense, lumpy, white crystalline limestone 2' 



17. Pinkish-green, fissile, siliceous slate of a jaspery 

 appearance forming a cliff _. 5' 



18. Layers of dense, white, crystalline limestone 



separated by thin bands of pale-green, talcose 

 material . 10' 



19. Dense, red and black-banded jasper, weathering 

 green between the layers and forming a cliff. 

 The layers contain shrinkage cracks and ripple 



marks . 11' 4" 



20. Layers of dense, white, crystalline limestone 



separated by bands of pale green, talcose 

 material 2' 



Total 108' 2" 



Synopsis of second member of the JJnkar. 



a. Basal white limestone 6' 



b. Argillaceous and calcareous red shale and limestone 85' b" 



c. White limestone 105' 2" 



d. Blue slate and white limestone. _ 108' 2" 



Total thickness 304' 9" 



