BIG SPRING PRAIRIE. 57 



from the evaporation of the water, which overflowed 

 the surface of soil in vicinity of Ox Spring, and in part 

 to the shells of fresh water mollusks inhabiting same. 



The water from this spring, and in fact from all 

 wells in vicinity of ridges is heavily charged with lime. 

 This marly soil effervesces briskly when treated with 

 liydrochloric acid. The surface muck to the east of 

 this section is of a deep black color, but at the depth 

 of 3 or 4 feet it is of a brown color, resembling in this re- 

 spect peat from a Sphagnum swamp. A microscopic ex- 

 amination of this brown soil reveals the fact that over 

 nineteen-twentieths of it is composed of purely vege- 

 table matter, the cellular structure being well pre- 

 served. This lower stratum has the appearance, and 

 slightly also the odor of well-rotted cow-manure. This 

 Tdtowu muck when first exposed possesses a slight am- 

 monia odor, which it soon loses. One form of plant 

 remains consists of a wavy stem with ^ inch inter- 

 nodes. The interior is well-rotted; the bark forms a 

 l)rownish layer, wliich, after drying, crumbles under the 

 least touch. It is this brown water-charged muck 

 which gives that extreme spongy character to the soil. 

 It would be interesting, if it were possible to determine 

 whether this brown muck were due to the remains of 

 Philotria, Ceratophyllum, Utricularia, Myriophyllum, 

 etc , or to Typha, Juncus, Phragmites, Carex, etc. 



As before mentioned this vicinity possesses the 

 deepest muck. Fig. 11 represents this natural meadow 

 as viewed northward from the divide. The ditch 

 represented is about 5 feet deep, and flows northward. 

 By a close inspection of the illusrtation, the surface 

 along each side of the ditch is seen to slope toward it; 

 this slope is due to the settling of soil incident to drain- 

 age and aeration. Between this ditch and the western 

 margin of prairie, especially in the vicinity of the 

 springs there occurs a plant society of the Heath type, 

 three of whose species are quite characteristic of peat 



