148 ENVIRONMENT OF VERTEBRATE LIFE, ETC. 



3. Shale, red-brown, argillaceous, and thin cross-bedded, like grass or stems of reeds arranged in 



masses; contacts not exposed 16 



4. Sandstone, chocolate-colored to red, calcareous, extremely fine 3 



5. Shale, brown and maroon, arenaceous and calcareous, ripple-marked and mud-cracked 2 



6. Sandstone, red-brown, massive, extremely fine-grained, micaceous 2 



7. Shale, banded chocolate-colored and red-gray, arenaceous, becoming argillaceous at the top; tiny 



veins of gypsum 1 1 



8. Sandstone, red-brown, with white band at top, composed of extremely fine quartz grains with 



flakes of muscovite; plant impressions 3 



9. Shale like No. 27 8 



10. Sandstone, chocolate-colored, fine-grained, micaceous, thin-bedded at top; forms bench 6 



11. Shales, banded red of various shades and gray-green, arenaceous, argillaceous, calcareous 26 



12. Sandstone, thin-bedded, ripple-marked I 



13. Shale, red-brown, with streaks of purple and green-gray and blotches of white; includes lenses of 



sandstone ; bedding planes sun-baked 20 



14. Sandstone, red-brown, thin-bedded, cross-bedded, marked by ripples, mud cracks, and worm 



casts; muscovite on bedding planes; plant impressions on lumpy uneven surfaces include 

 striated and radiating groups 2 



15. Shale, banded chocolate-color, red, gray, and green, arenaceous and calcareous at bottom, argilla- 



ceous at top, ripple-marked, mud-cracked, lenticular 10 



16. Sandstone like No. 14 2 



17. Shale like No. 15 12 



1 8. Sandstone in 3-inch beds, wavy, irregular, lenticular, cross-bedded, ripple-marked 4 



19. Shale, red-brown, arenaceous, calcareous, banded and lenticular; shows worm casts, sun-baked 



surfaces, and impressions of plants 7 



20. Sandstone, red-brown, thin-bedded lenticular, with bands of argillaceous and calcareous shale; 



mud-cracked, and ripple-marked; plant impressions 2 



21. Shale, banded dark red, light red, and purple, with elliptical blotches of green-white, yellow- 



green, and ash-gray, calcareous, argillaceous, and arenaceous 18 



22. Sandstone like No. 20 2 



23. Shale like No. 21 ; bands of color one-half inch to 3 inches thick 5 



24. Sandstone like No. 20 2 



25. Shale like No. 21 2 



26. Sandstone, chocolate-colored, highly calcareous, with scattered limestone pebbles 3 



27. Shales, chocolate-colored to red, with gray and lavender lenses; arenaceous, imbricated, ripple- 



marked; 15 feet from the bottom is a 6-inch bed of sandstone, and thin sandstone lenses 

 occur throughout; the top 10 feet is dark-red argillaceous shale in regular beds traversed by 

 veins of gypsum, probably of secondary origin 40 



28. Sandstone, chocolate-red, with streaks of maroon and purple; fine-grained quartz with calcareous 



cement; cross-bedding both angular and tangential; fine to medium grained; size of grain 

 varies with each lamina. Near middle of bed are lenses of conglomerate, 2 inches to 12 feet 

 wide, 6 inches to 100 feet long, highly irregular in shape, and composed of chunks and slabs of 

 argillaceous shale, sandy shale, and sandstone; muscovite abundant on bedding plane; 

 forms vertical cliff 52 



29. Shales, chocolate-colored with white bands; arenaceous and micaceous strata, thin as cardboard 



or 2 to 3 inches thick; show ripple-marked, mud-cracked, sun-baked surfaces, curled disks, 

 tiny folds, and faults 100 



389 



(Page 25.) "The bedding is very irregular throughout. Strata of shale and 

 sandstone appear and disappear along the strike, and individual laminae within 

 the beds are markedly discontinuous. Arenaceous beds prevail, typical clay 

 shales are very rare, and pure limestone is absent. Mr. Heald noted that the 

 strata became increasingly calcareous upward until bed No. 3 is reached. 

 Gypsum in tiny horizontal and vertical seams is common. A large part of it, 

 perhaps all, is secondary. Several small unconformities were noted, but no 

 hiatus that necessarily involved a long period of corrasion or of weathering. 

 Part of the color banding- appears to be genetically related to conditions of deposi- 

 tion ; much of it is better explained as due to leaching by ground water. Frequent 

 exposure to the atmosphere as the Moenkopi beds were forming is indicated by 

 the almost universal presence of sun-baked surfaces and ripple-marks. Plant 

 impressions are common and appear to represent several different species." 



