Over North Branch of the Raritan River
Township of Mendham, New Jersey
Union Schoolhouse Road Bridge, c. 1909
Historically, Union Schoolhouse Road was carried over the river by a king-post truss bridge. A common style in the 18th and 19th centuries, the bridge was constructed of local hardwood timber with a wrought iron king post.
Just upstream, the Pleasant Valley Mill, a fulling mill for finishing woolen cloth, can be seen among the bridge timbers, (see left). Loose wool fabric was washed in a bath of fuller’s earth, a clay-like mineral, or alkali soap to consolidate the fibers using large hammer-like beaters that matted it into a thicker, felted cloth for warmth and water resistance. The structure was converted to a gristmill, with a sawmill addition. In July 1910, after a week of heavy rain, a cloudburst washed out the dam and bridge, damaging the mill beyond repair.
There have been few changes in the immediate landscape except replacement of the bridge by a Pratt pony truss in 1910. That bridge was replaced by a temporary structure in 1983, until total replacement by a steel pony truss in 2015. The handrail represents an historic style used throughout Morris County. The bridge is located within the Ralston Historic District, listed in the New Jersey and National Registers of Historic Places.
Pleasant Valley Mill as a grist and saw mill.