Eliza Jane Robison is listed as 22 years old in the 1850 census with Henry and Ann Robison in Whitley County, Indiana. She married William McMannen on September 2, 1855. She gave birth to a son on April 2, 1856. The son, apparently not given a name, died on the day of his birth. Six weeks later, on May 25th, Eliza passed away at the age of 28 years 1 month 12 days. She is buried in South Whitley Cemetery next to her infant son. Their graves are in the "Mannen" plot, which is only six rows away from that of James Robison (possible/potential son of Henry and Ann).
On June 19, 1860 her widowed husband, William McMannen married Ann Maria Sterner. In December 2003, as editor of the quarterly publication of my local genealogy society, I received some correspondence from a descendant of William and Ann which included transcriptions of McMannen family bible records. Those records confirmed the birth date of Eliza and her marriage to William McMannen. The tombstone for their infant son is not legible, even with the use of a foil rubbing. The bible records state that he was born and died on April 2, 1856.
William and Ann Maria McMannen had three children: William Henry (b. 1861), James Monroe (b. 1862) and Eliza Alice (b. 1864). The children dropped the "Mc" from their surname and changed it to Mannen. Interesting, perhaps, that he named his daughter after his first wife?
Just as a side note, Lydia Robison (my ancestor) named her first child Anna Eliza. Anna after her mother and Eliza after her sister? Or merely coincidence? None of her other children have any names even resembling those of Henry and Ann's family.