Work in the Dakota Group 15 



But, although I should like to recall more of the 

 incidents connected with the opening up of a new 

 country, time presses, and I must pass on to an ac- 

 count of my work as a fossil hunter. 



I had not been long in this part of the country 

 before I found that the neighboring hills, topped 

 with red sandstone, contained, in isolated places, 

 from a few feet to a mile in diameter and scattered 

 through a wide expanse of country, the impressions 

 of leaves like those of our existing forests. 



The rocks consisted of red, white, and brown 

 sandstone, with interlaid beds of variously-colored 

 clays; while here and there, scattered through the 

 formation, were vast concretions of very hard flint- 

 like sandstone, often standing on softer rocks that 

 had been weathered away into columns, the whole 

 giving the effect of giant mushrooms, as seen in 

 the cuts (Figs. 1-3). 



This formation, resting unconformably on the up- 

 per carboniferous rocks, belongs to the Dakota Group 

 of the Cretaceous Period. The sedimentary rocks 

 were laid down during the Cretaceous Period, the 

 closing period of the " Age of Reptiles," in a great 

 ocean, whose shore line enters Kansas at the mouth 

 of Cow Creek on the Arkansas River, and extending 

 in a northwesterly direction in the vicinity of Bea- 

 trice, Nebraska, touches Iowa, and passes on to 

 Greenland. 



