GEOLOGICAL SURVEY OF THE TERRITOEIES. 323 



Ft. In. 



1. Bottom sand-rock grayish-yellow, filled with concretions of red sandstone, 



sti-atified with red sandstone, decomposes easily into yellowish- white sand, 



with little grit, (exfoliating) 195 



2. Brown, very soft shale, (soapstone) 2 



3. Coal - 1 8 



4. Browu (chocolate-colored) very soft shale, (soapstone) 2 



5. Coal, separating in blocks by cleavage 4 2 



6. Brown, very soft shale, (like No. 4) 8 



7. Coal 1 foot to 1 4 



8. Shale lo 



9. Clay 2 6 



10. Coal 10 



11. Shale, with thin layers of argillaceous carbonate of iron 9 



12. Sand-rock 7 



13. Shale 3 



14. Sand-rock 33 



15. Shale, with thin layers of carbonate of iron 8 



16. Coal 2 2 



17. Slate 14 



18. Sand-rock 2 



19. Shale 2 



20. Coal 1 8 



21. Rock and shale 12 



22. Coal 2 8 



23. Rock and brown shale 25 



24. Coal 1 1 



25. Brown shale 1 lO 



26. Sand-rock 22 lO 



27. Slate 6 



28. Coal, (river-seam) 3 8 



29. Shale 10 



Then follows some 200 feet of sand-rock, containing three seams of coal, varying 

 from 10 to 20 inches, one of which yields pieces of cok^e. On the edge of the basin, the 

 coal-bearing strata are few in number ; toward the center they increase in number, 

 high bluffs continually appearing until, over the center of the basin, we find the high- 

 est geological rocks of the region. 



Mr. Clark still remarks : 



But in regard to the formation of the coal the regularity of the strata is wonderful. 

 It is true that, toward the north, the seams of coal are thinner, and the sandstone 

 much thicker, than to the south ; true, also, that at times the parting of the seams, 

 mostly of clay, varies somewhat in thickness, but over the whole extent of the 

 basin, some thirty-three square miles from outcrop to outcrop, the dip is conformable 

 to the center with a few unimportant exceptions, and the thickness of the seams and 

 the sand-rocks varies regularly. 



Mr. Clark's section has been carefully made from data obtained in 

 mapping and surveying the whole extent of this lignitic basin. I there- 

 fore consider it as a favor to have the privilege of substituting it for my 

 own, not only on account of its being more detailed, but because it 

 affords opportunity to consider here, as at the Eaton Mountains, the 

 essential characters of the Lignitic from observations presented under 

 different points of view. 



In the above section it is easy to recognize from its composition, its 

 color, its mode of disaggregation, the sandstone No. 1, about 200 feet 

 thick, as the equivalent of the lower fucoidal sandstone of the Lig- 

 nitic of the Eaton Mountains. The essential character taken from its 

 remains is not mentioned. But I had full opportunity to remark it, not 

 only in the lower beds under the coal worked by the Improvement Com- 

 jjany, but also where the same sandstone is exposed, together with the 

 upper Cretaceous strata, in the middle of the valley, half way between 

 Pueblo and Canon City. In my examination of the strata overlying 

 the lignite of the same basin, I found not only a number of dicotyledo- 

 nous leaves in the shaly sandstone, but in the intermediate beds of hard 



