40 



GEOIvOGY OF IvA SAI^LE COUNTY. 



beds of such rock in this part of our country, and 

 to find such we must travel from 150 to 400 miles 

 to the north, where we find in southern Wisconsin 

 some beds similar to some of these frao-ments, and 

 on the south shore of lake Superior the ledges 

 from which others must have come. The limestone 

 blocks found in the same position are all of one 

 kind, the ruins of the Niag-ara beds which once 

 extended farther south, but a considerable section 

 of which along- the southern margin has been 

 broken up and crushed and a part g-round to powder. 

 Hence our drift clays contain more or less lime. 

 These clays, sands, g^ravels and smoothed and 

 rounded rocks have been so deposited as to form 

 g-reat ridg-es, long- hills, resembling" a boat turned 

 bottom up, and round hills with funnel-shaped 

 basins between them, and to their arrang-ement is 

 due the present face of the country, in larg-e part 

 the scenery of our county. How was this mate- 

 rial prepared, transported and deposited where we 

 find it? 



It is evident that the movement of this g'reat 

 mass of matter was due in part to the action of 

 water, but the transportation for long- distances of 

 heavy blocks of stone and the smoothing- and shap- 

 inof them cannot be ascribed to its action, for we 

 find no such effects produced, where we can be 

 sure that water is the only ag-ent concerned in the 

 work. Water moves rock of considerable weig-ht, 

 for they can be lifted much more easily in water 

 than when out of it ; it smooths by rubbing- ag-ainst 

 other rocks or sand, or b\^ rolling- these over rocks 

 which are fixed; it wears sinuous charnels in 

 rocks, but does not cut straig'ht and regfular 

 o-rooves : it mav smooth a surface, but does not re- 



