OHHHH ... the C. In Cadwallader C. Washburn is for Colden! But it may be the New York mayor's *grandfather* that the Wisconsin governor was named after. Cadwallader Colden (1688–1776) served as the Governor of the province of New York several times in the 1750s and 1770s.

So apparently in the 19th century you could name your son after a governor of New York and have a reasonable expectation he would carry that name into the governor's office of a state that didn't exist yet.