Upper Mississippi River Rafting SteamboatsAs a Wisconsin historical marker explains:After 1837 the vast timber resources of northern Wisconsin were eagerly sought by settlers moving into the mid Mississippi valley. By 1847 there were more than thirty saw mills on the Wisconsin, Chippewa, and St. Croix river systems, cutting largely Wisconsin white pine. During long winter months, logging crews felled and stacked logs on the frozen rivers. Spring thaws flushed the logs down the streams toward