The lower dam was partially swept away and rebuilt.

The evidence

• “The Excelsior Mills, located where the Blodgett Mills now are, were also built during this year by Hamilton Richardson. The lower dam was completed by Ira Miltimore about October, 1848, and stood until 1852, when it was partially swept away and rebuilt. Mr.”

  1908-brown-rock-county/26-history-of-janesville.md, Vol. 2, PDF p. 28 / book p. 542

  Brown, William Fiske, editor. Rock County, Wisconsin: A New History of Its Cities, Villages, Towns, Citizens and Varied Interests, from the Earliest Times, Up to Date. Chicago: C. F. Cooper & Co., 1908. 2 vols. archive.org/details/rockcountywiscon01brow, archive.org/details/rockcountywiscon02brow.

  Grade A: Found on a page of one of our sources