Per Census records, tombstones and obituaries, I have been able to track back as follows:

Washington Merrick married Rebecca
Children: John H. Merrick b: 12-25-1838 d: 12-17-1916
Frank Merrick b: 1850
Daniel Merrick
George Merrick
William Merrick

John H. Merrick married Louisa T. LeCompte
Children: Edward L. Merrick b: 1-09-1881 d: 6-06-1961
Walter Merrick Sr. b: Jan. 1878
Grace Merrick b: Nov. 1884
Virginia Merrick b: 1867
Lula Merrick b: 1869
Philip S. Merrick b: 1871 d: 1942
Herman Merrick b: 1874
William LeCompte Merrick b: 1877

Edward L. Merrick married Lillie Berridge
Children: John Cookman Merrick, Sr. b: 11-11-1902
d: 8-18-1983
Jennie Merrick
Carrie Merrick
Ruth Merrick
Cyril Merrick
Willie B. Merrick
George E. Merrick

John Cookman Merrick, Sr. married Virginia Ann Harding
Children: John Cookman Merrick, Jr. b: 9-04-1929
Betty Ann Merrick
Norma Merrick
Barbara E. Merrick
Robert H. Merrick

John Cookman Merrick, Jr. married Joan Lorraine Goettsche
These are my mother and father in laws.

The Merrick's lived in and around Cambridge, East New Market, Secretary and Woolford, Maryland.

Any additions or connections?