FLORA OF LAKOTA OF BLACK HILLS. 323 



Feet. 



30. Light-colored clayey sand rock .' 15 



29. Ledge of grayish to dark mud rock . 8 



28. Band of shale. 



27. Light-colored sandstone .5 



26. Shale ..\ 20 



25. Light-colored clayey sand rock a little more indurated than No. 23 6 



24. A clayey layer 15 



23. Fragile light-colored sand rock 15 



22. Dark shale 30 



Note. — Nos. 22, 24, and 26 seem to have been due to similar conditions of deeper water alternating 

 with those forming the sandstone layers Nos. 23, 25, and 27. 



21. A layer of rock much like Nos. 17 and 19, but forming a sharper ledge 6 



20. A shale talus - 50 



19. Grayish sand rock tending to form a ledge 5 



18. Shaly sandy material, yellowish and more clayey above 25 



17. Much hke No. 19 5 



16. Dark-colored shales. 15 



15. Heavy ledge of drab sandstone 15 



14. Soft rock or shale, followed above by a well-marked shale or clay iO 



13. Ledge of sand rock 10 



12. Soft rock weathering out rather gray and shalj' 15 



11. Light-colored ledge of sand rock with obscure plant impressions and frequent remains of dinosaurs 



[Stegosaurus and others] and silicified wood. As noted in the field, i\o. 11 is 80 or 90 feet above 



No. 3 8 



10. Shaly layer 3 



9. Soft flesh-colored sand rock. 8 



8. Shale 1 



7. Rather soft sand rock forming a ledge 12 



6. White sandstone, very soft, or else in places splitting into small and irregular blocks. 12 



5. Soft sandstone or shales 15 



4. A layer of sand rock sometimes forming a continuous ledge with No. 3 12 



3. Cross-bedded sandstone with silicified wood and frequent dinosaurian remains, especially in the lower 



part, somewhat conglomeratic. Forms a distinct ledge 12 



2. Light-colored to white sandstone with some banding, ochreous in places ,50 



1. Highly colored sandstone of the Calico Canyon quarry 60 



Total ; 613 



Note. — Nos. 1 and 2 constitute Darton's Unkpapa. They are very variable in thickness. No. 2 is some- 

 times followed by shale instead of sandstone. Whether or not this shale corresponds to that bearing dinosau- 

 rian remains, as at Piedmont, Sturgis, and other points, is a question, though such may be the fact. I am 

 unable to place the Piedmont and Minnekahta cycad horizon in this section, though it must be present some- 

 where above No. 11, the uppermost of the two dinosaur horizons. 



With regard to the horizon of the Minnekahta cycads much has 

 been said, but the following section includes some additional facts. In 

 it Nos. 3-6 are in the general position of the Beulah shales. 



Red Canyon Creek section {South Basin), 4 vales southwest of Minnekahta, taken at a point about one-fourth 



mile south of Matties Peal. 



Feet. 



13. A series of rocks nearly repeating the character of Nos. 6 and 9 of this .section, with some silicified wood, 



though too much covered by talus to be readily divided 80 



12. Light flesh-colored sandstone, in places reddish, containing silicified wood and probably some cycads. 20 



11. Characteristic red to yellowish sandstone, with cycads and large silicified tree trunks, which may in 



part be Araucarioxylons, also fragments of saurian bones 20 



