Ancient Lakes of Wisconsin. 151 



ANCIENT LAKES OF WISCONSIN. 



BY HON. J. G. KNAPP, MADISON. 



Few persons liave reflected — probably because their atten- 

 tion has not been directed to the subject — upon what barri- 

 ers have been cast across the courses of our rivers ; and how 

 they have been removed by the action of water and drift, in 

 the long periods of the past ; what immense tracts were once 

 covered with water, forming fresh water lakes, where now men 

 plow, hoe and tend crops, and human habitations stand. To 

 enlarge or particularly define any locations is not intended, 

 but to call attention to a subject scarcely noted. 



The Mississippi dam may be located just below the mouth 

 of the Wisconsin, where the strata of rocks rise on each side of 

 the river in unbroken series, several hundred feet. If these 

 strata were carried across the river, and the supposition is not 

 violent, since the strata are nearly horizontal, and there is no 

 evidence of violent teiTemotal action at this point to break 

 down the strata since their deposition, then both streams would 

 be backed up and made to cover their present valleys ; the 

 Mississippi to the Falls of St. Anthony and the Wisconsin to 

 the Baraboo bluffs. This barrier is out of the drift region, 

 and has been broken down by the action of water. If the next 

 supposition be warranted, the Wisconsin river was much smaller 

 than at present. 



The Baraboo barrier next deserves attention. This elevation 

 was united with the high lands on the east of the Wisconsin in 

 the southern towns of Columbia county, thus forming a large 

 lake into which the Wisconsin, Baraboo, Duck creek and Fox 

 rivers emptied, and which then belonged with the Wolf river 

 to the Lake Michigan watershed, as the Fox yet does. The 



