Thank you for your reply. From the source you noted (ancestry.com's Bowling Green newspapers), I looked at the source and found these entries all related to that obit or story:
Pike County, Missouri Deaths, 1878-1917 Name:Mrs. Samuel Oaks Age or Birth Date:6 Nov 1811 Death Date:26 Dec 1891 Issue Date:31 Dec 1891 - AND - Name:Mrs. Rachel Oaks Age or Birth Date:6 Nov 1811 Death Date:26 Dec 1891 Issue Date:31 Dec 1891 - AND - Name:Samuel Oaks Death Date:ca 1877 Issue Date:31 Dec 1891 - AND - Name:Marshall D. Sparks Death Date:ca 1839 Issue Date:31 Dec 1891
We show Marshal Duncan Sparks death date as August 1839 and he is at Second Prairie Creek Cem, Vigo Co., IN.
Marshal Duncan Sparks' name is also written out fully in Benjamin F. Sparks' pension file, I am told. I do not have a copy but typed abstracts from another descendant of Harrison and Mary Ann (Oaks) Moore. Also, Rachel (Martin) Sparks Oaks' grandson, the family history keeper, wrote the same.
I don't know anything further about John D. (Duncan?) Sparks after the 1910 census.
You might want to check out Spencer Co., KY, marriage records further. A William Martin also gave permission for his dau Rachel to marry Sparks in 1811.
I will send more to you via email so as to not take up a lot of space on this board. Thanks again for Rachel's death place. I got a cemetery lookup today for confirmation. That is finally solved!