Source: 18th Battalion Nominal Roll, April 1915 during research into how many Americans joined the Battalion.
Family Search: When Private Walter Gordon Ross was born on 31 May 1887, in Homestead, Allegheny, Pennsylvania, United States, his father, Hugh Gordon Ross, was 28 and his mother, Martha Anne McCracken, was 34. He married Ada Walker on 28 June 1915, in Saltwood, Kent, England. He lived in Nevada, California, United States in 1935 and Judicial Township 13, Placer, California, United States in 1940. He registered for military service in 1915. In 1915, at the age of 28, his occupation is listed as clerk. He died on 4 November 1945, in Los Angeles, California, United States, at the age of 58, and was buried in Los Angeles, California, United States.
American Citizen.
Born U.S.A. He appears to be associated with Private Hugh Donald Ross, reg. no. 54354 also joined and served in the 18th Battalion.
Note buried at Los Angeles National Cemetery under another iteration of his name.
History of the 18th Battalion CEF, "The Fighting Eighteenth" 