The town of Magnolia was organized/set off from Center; a conflicting 1879 reading places the setting-off of Spring Valley and Magnolia in the legislative session of 1846–47.

The evidence

• “It included the present town of Center, and portions of Plymouth, Spring Valley, Magnolia and Janesville, west of Rock River. By an act approved February 2, 1846, the town of Magnolia was set off from it. Subsequently, other changes were made by the formation of new towns, and its present limits are included in the territory known as Township 3 north, of Range 11 east.”

  1879-history-of-rock-county/13-rock-county-ch07-town-histories.md, PDF p. 500 / book p. 504

  Butterfield, C. W., et al. The History of Rock County, Wisconsin: its early settlement, growth, development, resources, etc. Chicago: Western Historical Company, 1879. Cornell University Library via the Internet Archive, archive.org/details/cu31924028871585.

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

  

• “Magnolia, February 2, 1846.”

  1908-brown-rock-county/05-historic-evolution.md, Vol. 1, PDF p. 140 / book p. 125

  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