THE MOLLUSCAN FAUNA OF THE DELLS OF 



WISCONSIN.* 



Frank Collins Baker. 



Contents. 



I. Introduction. 

 II. Topography of the region. 



III. Comparison of the material. 



IV. Systematic catalog of species. 



I. Introduction. 



The 1903 Field Day of the Chicago Academy of Sciences 

 is one that will long be remembered by those who took 

 advantage of this opportunity to visit one of nature's choicest 

 retreats, at Kilbourn, in the Dells of the Wisconsin Kiver. 

 It was the good fortune of the writer to spend a week in 

 this delightful region, from July 6 to 13, which made possible 

 a very complete natural history survey of the Dells. Ac- 

 knowledgments are due to Mr. Nat Wetzel and Mr. Frank 

 R. Wheeler, the president and the treasurer of the Wisconsin 

 Dells Co., to the Chicago, Milwaukee and St. Paul Railroad 

 for many courtesies, and to Messrs. F. M. Woodruff and 

 T. J. Staley, Jr., for assistance in collecting. 



II. Topography of the region. 



The region of the Dells of the Wisconsin is situated in 

 Juneau, Adams, Sauk and Columbia counties, Wisconsin, 194 

 miles from Chicago. The overlying rock in this part of the 

 State is Potsdam sandstone of varying hardness. The Wis- 



* Presented by title to The Academy of Science of St. Louis, January 18, 



1904. 



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