 It is a complex of four buildings and a concrete dam, built between 1834 and 1906.The main building, originally the Rockville Warp Building, is a large stone structure, 3-1/2 stories in height, which was built in 1834, and is a well-preserved Greek Revival structure.Building 2, the Minterburn Mill, is a four-story structure built in 1906 that is one of the earliest uses of reinforced concrete in an industrial setting.