THE FLORA OF THE DAKOTA GROUP. 11 



school explain this fact and make it conform to the theory of Evolution if they 

 can. 



Another proof of the richness of the vegetation during the Dakota epoch, 

 is found in the fact that nearly all the sandstone laid down during that time, is 

 strongly impregnated with iron, showing that it had been first accumulated by 

 plants. There are also beds, of considerable extent, of impure coal, that is 

 mined and used by people for fuel in western Kansas. In addition to the sand- 

 stone, are beds of shales and various colored clays. Some of them contaian 

 iron pyrites, crystals of gypsum and alum. I once found a spring flowing from 

 a bed of shale that contained so much alum that the taste was quite perceptible. 

 Scattered through the formation are enormous sandy concretions, often twenty 

 feet in diameter, circular in shape, flattened above and below; two or three are 

 often joined together. They sometimes rest on softer rock, which has been 

 washed into pillar-like supports, and they resemble large mushrooms. The rocks 

 of the formation are estimated to be about 200 feet thick. I have traced the 

 same formation in Texas, near Weatherford, where they top the limestone of the 

 Permian. In one place I saw an escarpment of red sandstone thirty feet thick ; 

 it contained fragments of sassafras cretaceuni. 



In searching for fossil-plants, there is nothing to indicate their presence. 

 The sandstone is all the same, and one may look at every exposure with no 

 results for miles, and perhaps suddenly stumble upon a rich locality in the same 

 kind of rock. The sandstone makes fine building material. 



In this formation, I have found a locality of fine white sand which I use in 

 making a scouring soap. The deposit is eighty feet long, twenty feet thick, and 

 extending into the blufTs. The surface features of this group are a broken, hilly 

 country, often so rough, in fact, as to be unfit for farming, though it makes a good 

 range. Fine springs of pure water gush out of the hill-sides that do not freeze 

 in the coldest weather. These springs are sometimes utilized in milk-houses, 

 and the water allowed to flow around the sides of the milk-pans, keeping them 

 at an even temperature. In Kansas the formation is about sixty miles wide, 

 except along the Arkansas, where it extends to the western boundary of the State. 



That the rocks are of marine origin, is proved by the presence of sea shells. 

 They are quite abundant south-east of Brookville. No animal remains have been 

 found, unless the theory of Prof. Cope is correct. He claims that all the won- 

 derful remains of dinosaurs found in Colorado, belong to this formation. Some 

 of these enormous reptiles reach a height of twenty-five feet, and length of sixty 

 feet. They are the largest known land animals and were herbivorous in habit, 

 feeding on the branches of trees. Prof. Marsh places the deposit in the Jurassic 

 age. Whether fossil plants have been found associated with the bones or not I 

 am unable to say, neither can I give the data from which Prof. Cope forms his 

 conclusions. 



A vast territory in the Dakota group remains still unexplored and promises a 

 rich harvest of things, new and old, to the ones who will be enabled to give the 

 whole formation a careful examination. I trust it will be done at an early date. 



