FLORA OF LAKOTA OF BLACK TITLLS. 325 



numbered hy tlie colleetofs. It shows llic iiniiieiise lahoi- which yet 

 remains to he (lon(> in conipletin'r and re\isin<i the geological histoiy 

 of the Black Hills rini. 



Section froni ■■linn IIiili li" at Alinli/iii , Ifi/'i.. Iift/inniiuj linn tin has, ,if th, AlliixtiiKdniii.y .v/(f;/<.v. irhlrk nidij 



here he 100 feet Ihid-. 



Feet. 



5. Gray saiul 41; 



7. "'Black Jack" (cail)i)nai-C(>iis or nin-staincd clay and sand ) 2 



6. Brown sandstone (contains two hard and sliarp ledfccs ) :5() 



5. Red sandstones 7 



4. Gray sandstones j22 



3. Dark slialy cla\ . or I lie coal horizon lyin}; over the Atlanlosiinnis shales proper 4 



2. Green shaly clay of the Atlantosaunis shale proper (57 



1. Xodular bed, also sanrian-hearinf; t'nkpapa sandstoni- 20 



The latest contribution to the stibjecl now under considei-ation that 

 I am able to record is the elaborate papei' of Mr. N. H. Darton," pul)lished 

 in 190i and giving the results of his work in the Black Hills, mainly in 

 the seasons of 1898 and LS99. The hydrographic part of this paper 

 does not, of course, concern us here, and in his geological work Mr. Dai'ton 

 has paid little attention to paleontology, especially to paleobotany, but 

 there are certain facts relating to fossil plants that he could not wholly 

 ignore. He has not, however, contributed anything new to this subject, 

 unless it be a sketch (pi. Ixxvi, facing p. 526) of the large silicified trunk 

 and stump described on page 552 of my paper on the Black Hills.'' If the 

 sketch is correct it would seem that a number of large segments from the 

 middle portion have been removed since I was there. Mr. Darton has 

 reproduced my plate Ixxx (op. cit.) illusti'ating the most beautiful of the 

 cycadean ti'unks, Cycadeoidea pulcherrima, which forms his plate Ixxx'ii, 

 but he does not give the name of the species or state to what gemis these 

 trunks belong. 



The only interest, therefore, that this paper possesses for the paleo- 

 botanist is its geological part. It is here that for the first time he describes 

 the Lakota formation, named by him in 1899 (see p. 315). This 

 formation is treated on pages 526-529, but out of the Lower Cretaceous 

 included in my sections, and extending from the Jurassic to the Dakota, 

 he makes three formations, viz, the Lakota, the Minnewaste limestone, 



a Preliminary description of the freolofiy and water resources of the sontliern half of the Black Hills and 

 adjoining regions in South Dakota and Wyoming, by Nelson Horatio Darton: Twciity-tirst Ann. Kept. U. S. 

 Geol. Surv., Pt. IV, 1(X)1, pp. 4.S9-.59!), pi. Iviii-cxii. 



*J Nineteeiuh Atui. Rep. U. S. Geol. Surv., Pt. II, 1899. 



