You have a sharp eye for detail, John. The murals in the Wisconsin Union's Paul Bunyan room illustrate stories from the beloved Wisconsin folk legend (which, each year, the University of Minnesota tries to claim as its own — hence, the Badger football team's fight with the Golden Gophers for Paul Bunyan's Ax). The corner panel depicting lumberjacks sliding across a hot griddle on “skates” of bacon was a replacement, but it was not the work of a second artist.
According to the Wisconsin Union's Director of Cultural Arts, the Wisconsin Union's Paul Bunyan murals were commissioned in 1933 as part of the Public Works of Art Project, the first federal program supporting the visual arts. The artist was a graduate student named James Watrous '31, MA'33, PhD '39, who later became an art history professor at UW-Madison. Although the program ended just six months after its inception, Watrous worked to complete the murals during his free time until 1936.
During the early 1990s, the Union's Student Art Committee asked Watrous to paint a replacement for one of the panels containing phrases and images that, while acceptable during the 1930s, were not appropriate for today's campus environment. Watrous agreed to paint a new section for the Paul Bunyan mural, which stands out because it was nearly impossible to recreate the paint formula — an emulsion of egg yolk and water combined with powdered pigments. Although no longer on display, the original panel is in the Union's art storage for safekeeping.