Robinson

Looking for information on John or Jack Robinson, born about 1871. Married to Maud May or May Maude Stark. Children: Bert, Floyd V., Pearl B. Robinson.
Found John and his family in 1920 US Census, living in Detroit, Michigan. From that point, have been unable to find anything on John or Jack Robinson.
Family states he is buried in unmarked grave in Rock Falls Cemetery, Harbor Beach, Huron County, Michigan.
Please contact me at smokybleu@yahoo.com if you have any information.
Thanks.