I, too, am seeking information on Lucy Greer who was the mother of William Jasper Duncan. William was my 3x great-grandfather.

I believe Lucy married a second time to a John C. Richardson. Here's why: some years ago, I received information regarding William that stated William had a half-brother named John Richardson. I find a John C. Richardson on the 1925 Iowa state census living in Davis County, Iowa. His mother's name is listed as Lucy Graier who was born in Virginia. His father is listed as John C. Richardson and was born in Tennessee. In 1850, I find a John C. Richardson with a wife named Lucy in Davis County, Iowa. The couple had two children living with them with a last name that could be Duncan - one of them named William. William is the right age and was born in the right place to be William Jasper. In 1856, I find the couple again and William definitely has the surname Duncan. I can find John and Lucy in 1860 and 1870 but after that I lose track of them.