94 ON THE GEOLOGY AND NATURAL HISTORY 
distributed somewhat sparingly throughout the bed of sandstone. It also contains some fine impressions Be 
of dicotyledonous leaves. 
2. Dark indurated carbonaceous clay, . : ; : i : : : ‘ ‘ ‘ : . ae 
3. Lignite, of an average degree of purity, ‘ 
4, Indurated clay with a reddish tinge containing much iii istics: ‘ 
5. Light yellow clay with seams of carbonaceous matter disseminated through it, a sort of fine Gast 4 feet 
exposed above the water-level. 
Thirteen miles above Fort Clark, at Red spring, on the right side of the Missouri, are a 
long series of nearly perpendicular bluffs, exposed by the river. This is the best locality 
for the collection of fossil plants I have yet seen. They are finely preserved, occur in 
great profusion, and belong nearly all to dicotyledonous trees. The following is a vertical 
section of the different beds in descending order, as they appear in this range of hills: 
Feet. 
. Ferruginous marl, . ; ; : : ‘ ‘ : vo oe 
Variegated bands of argillaceous seit ; : : aS : : é ‘ ‘ : . 380 
Seam of impure reddish lignite, 2 inches. 
. Yellowish gray grit, with numerous concretions, in hecteardal layers, filled with beautiful i impressions of 
leaves, . : . ee 
5. Seam of lignite, 2 TS 
6. Yellowish gray sand with argillo-calcareous concretions, laden with impressions of dicotyledonous leaves, 10 
7. Earthy lignite, 3 inches. 
8. Yellow and drab clay and sandstone, containing argillaceous concretions with vegetable impressions, . 15 
9. Dark reddish earthy lignite, 4 inches. 
10. Yellow argillaceous grit, . 5 : 20 
11. Alternate layers of lignite aad clay varying in inet at different localities within a disdanis of ‘tr 
miles, : . : . a 
12. Heavy-bedded friable asks, very inion varying in ii deci yaltoni to gray sia yellowish gray. 
Same bed, I think, as seen at Fort Clark and on the summit of Square hills, containing so many fossils. 
Here we have Melania Nebrascensis, Puludina multilineata, and Corbula matriformis, eae 
13. Seam of lignite, 2 inches. 
14. Gray argillaceous grit, . : ‘ : P : . ‘ : : : ; ; : Sie 
15. Lignite of excellent quality, : : x : ‘ : : : : Cane | 
16. Bluish gray clay, slightly arenaceous, . . . ; : . : ; 3 : : fee 
17. Lignite near water’s edge, quite pure, . ‘ ; : 7 . ‘ ‘ 3 to 4 
Beneath bed 17 may be seen at low water a oe bedded gray sandstone. 
In speaking of lignite as of a good quality, I mean, that it contains a small amount of 
earthy material, but I have not yet seen any of it that would be of much value for economi- 
cal purposes.* Specimens from this locality and from Fort Berthold, forty miles above, 
* T am satisfied that some of the beds of lignite, especially those on the Yellowstone, can be used for fuel, when 
the country is sufficiently settled to induce a demand for it, There are some excellent beds of lignite on the North 
