Facts and Events
There are 3 vital records available on MyHeritage for Joseph Gray, including birth records, marriage records, and death records. Vital records are historical records that are typically recorded around the actual time of the event, which means they are likely accurate. Vital records include information like the event date and place, and the person's occupation and residence. Vital records also often include information about the person's relatives. For example, birth and marriage records include names of parents and divorce records list the names of children.
Information on Joseph Gray
Some sources claim that it was Joseph's brother, John Gray that married Agnes Nancy Denton, but familysearch has several trees with the marriage date listing it as Joseph.
Also the following:
From "1881 History of Marion and Clinton Counties, Illinois", pg. 46:
From "Brinkerhoff's History of Marion County, Illinois", pg. 716: