A 214-foot single-span covered wooden bridge, built above the cribs of stone in the AuSable River that served to break log jams and ice floes, collapsed during the winter of 1875 under the weight of a three-foot snowfall and high winds. The "Upper Bridge" (pictured) was built in its place.
Masonry

YearAdded:
Image Credit: Public Domain (Released by Creator)Image Caption: The Keeseville Suspension Bridge built 1888, Keeseville, one of the three "Bridges of Keeseville" that span the AuSable RiverEra_date_from: 1878
1987

Ithamar A. Beard, an engineer of some prominence in New England, surveyed the mill brook and selected the best site for a storage dam. Contractor Simeon Cobb, knowledgeable of contemporary civil engineering practices, made major changes to the dam's original design, converting the linear dam into a gentle arch.
YearAdded:
Image Credit: Courtesy Wikipedia/Ymblanter (CC BY-SA 3.0)Image Caption: The Ascutney Mill Arch-Gravity DamEra_date_from: 1834
1970