http://pec.lib.wvu.edu/record/P160181876Survey of the Monongahela River, and examination of the Louisa Fork of Sandy River : letter from the Secretary of War, transmitting, in compliance with the river and habor [i.e. harbor] act of March 3, 1875, a report of Maj. W. E. Merrill, Corps of Engineers, on the survey of the Monongahela River, &c.Photocopy of government document. "44th Congress, 1st Session, House of Representatives, Ex. Doc. No. 91."United States. Army. Corps of Engineers.Merrill, Wm. E. (William E.)United States. War Department.Monongahela River (W. Va. and Pa.)--Navigation.Monongahela River (W. Va. and Pa.)--Surveys.14256