The information I have on Francis Marion Gratreaks is that he was born 11 Jan 1837, in Delaware County, Ohio. He died 01 Apr 1909, and is buried in the Hartington City Cemetery, Cedar County Nebraska in a gravesite that was purchased 02 Apr 1909 for $10.00. His parents are Oliver Greatreaks of New York, and Jemima Rosecrans of Pennsylvania.
Oliver died 30 Mar 1860, and Jemima died 11 May 1871. Both are buried in the Trenton Cemetery in Delaware County, OH. Oliver's will was written 06 March 1860, and was probated 08 Jun 1860. A "Land Patent" certificate was issued to Oliver 10 Sep 1834 for approx. 82 acres of land in OH.
Francis Marion Gratreaks was married twice. He and his first wife, Emily Sprague, were married 11 Jan 1859 and had two children:
Son: Marion Francis b. 09 Jul 1859, d. 1863 Dau: Harriet Ann b. 25 Jun 1862, d. 03 Oct 1942
Emily filed for divorce on 31 Mar 1865 in Utah.
Francis married Nancy Matilde Clark on 13 Aug 1868.
Hope this helps. I don't have any information on the names of Oliver's and Jemima's parents yet.