Robert J SANDERS and Lula (Lucy) M BLACKWELL SANDERS

I posted this about a year ago.  I do most of my research work during the summer.  I have been able to find a bit more on this family.

Robert John SANDERS, b. Oct. 10, 1847, Ballard County, Kentucky;  d. Dec. 20, 1912, Oklahoma

Lula (Lucy) M BLACKWELL, b. about 1855, Virginia (maybe West Virginia); d. ???

I've located them in the 1880 census in Clay, Lafayette, Missouri.

Lula has been the most elusive of the 2.  She died before 1900, as Robert is listed as widowed. But I haven't been able to find her, as Lula,  anywhere before 1880.

I did find in the 1860 census, a Lucy Blackwell in District 2, Mason, Virginia.  I haven't been able to verify if it's her.

Another connection I found was through Robert and Lula's daughter Sallie.  She was listed in the 1900 census in Hooper, Costilla, Colorado with Robert.  There was a Bellie BLACKWELL (Bellie HACKETT)  living with them.  She is listed as Robert's sister-in-law.  So Lula had a brother. (I'm assuming HACKETT) is her maiden name. Again, an assumption, not verified fact.)

Lewis Sanders, listed on the same page of the 1880 census is Robert's father.

On the 1900 census, Lewis T., who is living with Robert and children, is listed as Robert's nephew.

Surnames:  SANDERS, BLACKWELL, HACKETT