Close-up of filling flue during lock construction

Photograph showing a close-up view of the top of a form, which will be used to extend the concrete walls that create the filling passageway beneath the lock floor.
Abstract/Description: Photograph showing a close-up view of the top of a form, which will be used to extend the concrete walls that create the filling passageway beneath the lock floor.
Subject(s): Boats and boating
Soo Locks (Mich.)
Date Created: 1912 (approximate)