Map showing the mill sites and water power belonging to the St. Anthony Falls Water Power Co.
Understanding this Map
This map is notable in that it shows the ill-fated engineering plan that resulted in the infamous Eastman Tunnel Collapse. It is dated January 1869 and shows engineer Franklin Cook's plan for a tunnel under the Saint Anthony Falls that could bring water power to Nicollet Island. This project was halted in October 1869 when the half-dug tunnel collapsed, sending part of Nicollet Island into the river and threatening the existing water power infrastructure at the falls.
At the bottom of the map is a profile view of the riverbed. The plan shows that the proposed tunnel would begin under the limestone ("limerock") layer, and cut through the sandstone ("sandrock") layer. It would run nearly 3000 feet from the base of the falls to the St. Paul and Pacific Railroad Bridge at the northern end of Nicollet Island. The map also shows the locations of Spirit and Cataract Islands downriver from the Saint Anthony Falls. These islands have since been dredged and are no longer visible.