John S. Conley family, Queen Anne's County, MD, ca.1880

Trying to find any information on the family of John S. Conley, living in Centerville Township of Queen Anne's County, Maryland in 1880.John and wife Mary (shown as "May" in the 1880 census) had six sons: Nehemiah, Daniel, George, John S. (Jr.), Wallace, and Harry.I've traced father John S. to 1920 and son Daniel to 1930, but can find no trace of the whereabouts of the other 5 sons, and Mary does not show up at all in 1900 (the family's name was spelled "Connolley" in that census), even though she and John S. had been married for 40 years.Any help would be appreciated.Thank you!Rick at [email protected]