It is possible that Elizabeth had a son Robert J DOB ca 1823 as well as dau Margaret E DOB ca 1833.
In 1850 Nelson Co., Robert J is 27, Elizabeth appears to be 45 but could be 65 and Margaret E is 17
By 1860, Elizabeth is 74 and Margaret G is 27 with Elizabeth Harness 13 and William Harness 10.
In 1870, Elizabeth 87 and Margaret 38 are living with William Miles 29, his wife Lizzie L 23 and their 3 children: Maggie 4, Lizzie 3, William 2. I think Lizzie Miles is Elizabeth Morgan’s granddaughter.

Elizabeth is listed as born in Augusta Co.

Wm T Miles married Elizabeth L. Harnest 16 Jun 1865 in Nelson Co., VA (https://familysearch.org/pal:/MM9.1.1/XRZT-LJ6 : accessed 30 Oct 2013)

Could Elizabeth L Harnest’s parent’s be William M Harnest and Adelaide Harnest? w/ siblings Philander W 3 and Wilber H 0 ? see 1850 August Co., VA census. Adelaide V Morgan married William M Harnest 23 Jan 1844 in Nelson Co., VA

Robert J Morgan married Mary J Bridgewater 30 Oct 1854 in Lovingston, Nelson, VA

listed as parents on Albert's marriage lic.
From Bureau of V.S. #20 Nelson Co. Deaths : died of old age at 96, consort of William Morgan. info from daughter Margaret Morgan
(Seems too old)
1870 Nelson County lists an Elizabeth Morgan as 87, which puts birth at ca 1783