EROSION AL HISTORY OF DRIFTLESS AREA 87 





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Fig. 20. A portion of the Elizabeth topographic ir.ap where tl.e Lancaster plain is 

 exceptional y well represented. 



Fig- 21. View of the Lancaster plain in Jo Daviess County, north of Stockton. Illi- 

 nois. The elevations in the distance are the "mounds" which are monadnocks on the 

 plain. Below the general siu-face, there are vaLeys more than 200 feet deep. 



