THE CRETACEOUS RIM OF THE BLACK HHLS. 255 



sil plants were found and a small collection made. They bore 

 no resemblance whatever to the flora of the Dakota Group, but 

 consisted chiefly of ferns with a few coniferous twigs and possi- 

 bly cycadean remains. In short the flora, so far as I could 

 judge, was rather that of the Lower Cretaceous. 



Fig. 3. — Section across the divide between Red Valley and Minnekahta Creek. 



1. Red Beds. 12. A, Cycad Bed. B, Fossil Forest. 



2-7. Jurassic. 13. Equivalent of Quarry Sandstone in Section No. II. 



9. Plant Bed. 



The entire section, from the Red Beds at the bottom of the 

 canon to the summit of the crest forming the divide, was care- 

 fully measured, the position of the fossil forest bed, the cycad 

 bed, and the plant bed, fixed as nearly as the circumstances 

 would permit, and all the variations in the nature of the strata 

 indicated. The section, as determined on the spot, is as follows : 



SECTION NO. I. 

 Dakota of Newton. 275 Feet. 



13. Massive pinkish sandstone approaching a quartzite locally 75 feet 



12. Grayish white sandstone with silicified wood and cycads 30 feet 



II. Pinkish and yellowish soft sandstone 75 feet 



10. Clays with indications of coal 20 feet 



9. Soft pink and gray sandstone with ferns and other plants 25 feet 



8. Reddish, pinkish, and yellowish brown massive cross-bedded sandstone. . 50 feet 



Jurassic. 220 Feet. 



7. Olive gray clay and sandstone shales 50 feet 



6. Light red soft sandstone 60 feet 



5. Olive gray clays and gray sandstone shales 40 feet 



4. Olive drab clay 20 feet 



3. Yellow sandstone shales 20 feet 



2. Olive drab clay 30 feet 



Red Beds {Trias\ 

 I. Red marls, conformably exposed at bottom of canon 20 feet 



This section may be represented diagrammatically in Fig. 3. 



