New Order of Gigantic Fossils. 9 



improbability, if not impossibility, of sponge-growth in waters 

 so laden with sediment. Besides, in a section, unmistakable 

 plant cells are shown, — which cannot, however, establish 

 their vegetable origin, since this slide alone out of six shows 

 any such structure ; and it is quite possible that modern root- 

 lets could have made their way into this particular specimen 

 sectioned. On the other hand, all the slides show certain 

 smooth, spindle-shaped rods, which are suggestive, at least, 

 of sponge spicules. Whether we accept the animal or vege- 

 table theory, the difficulties are about equal 



Fig. 6. — "Underground stem" of Daimonelix, showing greatly enlarged extremity. 



See . G, Fig. 3. 



Reference to the map of Sioux County, kindly furnished 

 me by Judge Barker of Harrison, shows the Devil's corkscrew 

 beds to cover an area equal to two or three hundred square 

 miles ; the eastern and western limits being in some doubt. 

 These beds, as the map (Fig. i) will show, follow the divide 

 between the White and the Niobrara rivers, which bound the 

 region on the north and south respectively. While my collec- 

 tions were made chiefly at Harrison at the extreme northern 

 limit, and comprise very large and excellent specimens, yet 

 some twenty miles south, at the well-known James Cook 

 ranch at Agate Springs, these corkscrews are far larger than 

 those found near Harrison. 



309 



