8 (1KOLOGY OF ILLINOIS. 



away fields of ice and icebergs, loaded with the debris and 

 stones collected in the downward journey. 



Similar phenomena, perhaps in a modified form, were 

 once displayed over all the regions traversed by the drift. 

 The ice gradually melted away, commencing south and 

 disappearing up to the arctic regions. In process of time 

 the waters gave place to the dry land, and our northern 

 prairies remain, moulded into gentle undulations by the 

 fingers of the retiring waves. 



The startling theory of the Tee Period in Xorth America., 

 announced by Professor AGASSFZ in the Atlantic Monthly 

 for July, 1864, at that time was almost too much for the 

 jfaith or credulity of scientific men. Xow, a large portion 

 of the scientific world accepts the theory then announced. 

 In his recent expedition in Brazil and up the Amazon, the 

 traces of a great glacier, filling the whole valley of lhat 

 large river, were discovered. "When such a sea of ice ex- 

 isted under the very tropic skies, this world must indeed 

 have been in the midst of a glacial winter, where snows, 

 and frost, and ice held supreme sway. We wonder if, then, 

 the progenitors of the mound builders and ancient copper 

 miners and workers, built their snow and ice huts, and 

 moved about in their light kiyaks, as the Esquimaux of 

 to-day do in frigid Greenland ! 



The influence of these glacial drift forces upon soils is 

 worthy of a passing thought. They changed the surface of 

 the earth from its conditions during the Carboniferous ages ; 

 and made soils, by the processes above enumerated, fit to 

 produce grasses, grains, fruits, and hard wood trees. They 

 prepared the earth for civilized man. 



In this part of the State, in attempting to classify soils 

 and earths thus mingled and made, there is 110 end to the 

 distinctions and classifications. Soils are light or heavy, 

 warm or cold, dry or wet, compactor porous, fine or coarse, 

 hungry, leachy, loamy, sour, sweet, clayey, sandy, limey, 

 marshy, peaty, and various combinations of these, too nn- 



